Effect of pre-aging on microstructure and properties of 2000 series aluminum alloy for automoti

T6I6二次时效对A356铸造铝合金力学性能的影响朱满;坚增运;杨根仓;周尧和【摘要】为了解决热处理后材料的强度和塑性变化规律相反的问题,在T6热处理制度的基础上开发了一种新型的T6I6二次时效制度.研究结果表明:采用T6I6热处理制度可以同时提高A356铝合金的强度、塑性、弹性模量和硬度.在相同的自然时效条件下,材料的强度、弹性模量和硬度随着第一次人工时效时间t1的增加呈现先增加后减小的趋势,延伸率既随着第一次人工时效时间的增加而增加,又随着中间自然时效时间的延长而增大.屈服强度和抗拉强度分别在t1为10 min和20 min 时达到最大值237.38MPa和320.15MPa,增幅达到27.53％和15.24％;当t1=120 min且t2=8周时,延伸率达到最大值13.63％.这主要是因为T616中的自然时效阶段形成大量的GP区,在随后的人工时效过程中析出大量细小高密度的β相.【期刊名称】《西安工业大学学报》【年(卷),期】2012(032)008【总页数】5页(P646-650)【关键词】A356铸造铝合金;T6I6二次时效;力学性能【作者】朱满;坚增运;杨根仓;周尧和【作者单位】西安工业大学材料与化工学院,西安710032;西安工业大学材料与化工学院,西安710032;西北工业大学凝固技术国家重点实验室,西安710072;西北工业大学凝固技术国家重点实验室,西安710072【正文语种】中文【中图分类】TG156.9A356（Al-7%Si-0.3%Mg）铸造铝合金是工业上应用范围较广的一种合金，它广泛应用于汽车工业，诸如汽车发动机部件、轮毂以及汽车车身等［1］.该系合金为高硅合金，热处理后析出Mg2Si强化相，具有良好的强化效果，特别是人工时效后机械性能得以明显提高，同时兼具良好的塑性.随着现代汽车工业的高速发展，汽车设计正向轻型化和节能化方向发展，因而，对A356铝合金提出更高的性能要求.为了进一步提高铝合金的强度和塑性，科研人员开发了多种时效工艺制度，譬如二次时效工艺［2-3］、压缩载荷时效过程［4］、峰值时效［5］、两步时效［6］、多次人工时效［7］等.在所有时效工艺中，二次时效工艺是惟一一种在提高合金强度和硬度的同时，又可以起到提高其塑性的时效制度，因而具有广阔的发展潜力. 文中以A356系铝合金为研究对象，分析二次时效制度中各参数对合金性能的影响规律，获得最佳的二次时效工艺，以推广这种新型热处理制度.1 实验过程1.1 实验原材料及制备过程实验用的原材料为A356铸造铝合金，其成分为6.92Si-0.29Mg-0.18Ti-0.099Fe-0.0071Cu-bal Al（w%）.实验过程为将A356铝合金于电阻炉中熔化，待升温至730℃时，采用C2Cl6精炼和Ar除气处理；静置10min中后于金属模中浇注成型.成型后试样的尺寸为∅18mm×130mm.1.2 T6I6二次时效处理制度T6热处理制度为：固溶处理（535℃×8h）＋室温水淬＋人工时效（155℃×6h）.T6I6二次时效（T6I6）的基本思路就是将原有的T6热处理制度中的人工时效过程分成两部分进行，对材料先进行人工时效处理，然后取出材料进行自然时效处理，之后再次进行人工时效处理.T6I6二次时效制度如图1所示.图1 T6I6二次时效制度示意图Fig.1 Diagram of T6I6treatment process图1 中的虚线部分为完整的T6热处理过程；T6I6二次时效中第一次人工时效时间为t1，自然时效时间为t2，剩余人工时效的时间为t3，其中t1＋t3=6h.t1 分别选择10min，20min，40min和120min，自然时效时间t2分别选择1周，2周，4周和8周，采用正交实验设计16组实验，着重分析t1和t2两个参数对合金力学性能的影响规律.1.3 分析及检测对常规铸造成型后的试样分别进行T6和T6I6处理，并分析其力学性能.经加工后获得标准拉伸试棒，直径为∅5mm，标距为25mm，于Instron 8851型万能电子拉伸机上进行室温力学性能测试，抗拉强度（σb）、屈服强度（σ0.2）、延伸率（δ）和弹性模量（E），力学性能数据取四根拉伸试棒的平均值.布氏硬度实验在HB-3000型布氏硬度计进行，载荷为250kg，保压时间为30s.每个试样上打六个点，取六个点平均值作为布氏硬度值.将拉伸断裂后的断口清洗后保留，利用Tescan VegaⅡ型扫描电镜观察试样的拉伸断口形貌.2 实验结果与讨论2.1 力学性能经T6I6热处理后合金的力学性能数据如图2所示，为了对比方便，图中还给出了T6热处理后合金的力学性能数据.由图2可知，与T6热处理后合金的性能相比，采用T6I6热处理后合金的抗拉强度、屈服强度、延伸率、弹性模量和布氏硬度均得到提高，说明此种热处理制度具有很高的开发价值.图2 经T6I6处理后A356铝合金的力学性能Fig.2 Mechanical properties of the A356alloys subjected to T6I6treatment如图2（a）所示，t1和t2对合金屈服强度和抗拉强度的影响规律.当自然时效时间保持一定时，合金的屈服强度和抗拉强度的随t1的变化规律是一致的，他们均随着t1的增加呈先增加而后减小的趋势.在10～40min范围内，屈服强度和抗拉强度的变化最为明显，而在40～120min内，t1的增加对合金强度的影响很不明显.当t1时间相同时，t2为1周时的强度值最大.当t1在10～40min范围内，合金的屈服强度和抗拉强度分别达到最大值237.38MPa和320.15MPa，与T6态合金相比，其最大增幅分别达到27.53%和15.24%.随着自然时效时间延长，峰值强度随着自然时效时间延长而减小.主要是在第一次人工时效和自然时效的双重作用下，半共格和共格析出相增加的缘故［8］. 如图2（b）所示，t1和t2对合金延伸率的影响.由图2（b）可知，t1对合金延伸率的影响规律相同，延伸率随着t1的增加而不断增加；当t1为120min时，合金的延伸率达到最大.当t1相同时，自然时效时间t2对延伸率的影响最为明显，合金的延伸率随着t2时间的增加而增加；当t2为8周时，合金的延伸率最大.如图2（c）所示，t1和t2也影响着合金的弹性模量和硬度.随着t1的增加，弹性模量呈先增加后减小的趋势.布氏硬度的变化规律与强度的变化规律相一致，硬度值最大达到91.在同样的t1条件下，硬度值随着自然时效时间的增加而减小.布氏硬度值随着第一次人工时效时间的增加呈先增加而后缓慢减小的趋势，第一次人工时效时间越短，其峰值点越大，如图2（d）所示.2.2 T6I6时效机理探寻铝合金经高温固溶后然后在进行水淬处理，在基体中形成了大量的过饱和固溶体和较高的空位浓度［9-10］.A356铝合金的强化相为Mg2Si相，其时效析出过程［11-12］为其中SSSS为过饱和固溶体，GP区为含Si原子和Mg原子的溶质偏聚区（GP区呈球状），β″、β′分别为与基体具有共格和半共格关系的析出相，β为稳定相Mg2Si.文献［7］中认为，GP区的形成有利于合金强度和硬度的提高，在时效温度低（130～150℃）或时效时间短时，易形成GP（I）区；而当时效温度高或时效时间延长时，则会形成GP（II）区，它比GP（I）区晶格畸变更大，因而时效强化作用也愈大.铝合金的时效过程是过饱和固溶体的分解过程，在基体中获得均匀分布的细小析出相.自然时效时，由于受到溶质扩散速率小的限制，GP区溶质原子偏聚区与基体呈共格关系，较小的界面能有利于形成共格析出相.GP区和周围的应力场阻碍位错运动，使得强度增加.而在人工时效条件下，析出相的尺寸增加.GP区形成后，在基体中形成具有半共格β″相或共格β′相，直至形成具有非共格关系的稳定相β.在T6I6二次时效中，经过第一次人工时效后，在组织中已经形成一定数量的稳定相β相，从而增加合金的强度和硬度.然而随着时效时间的延长，稳定相β质点不断聚集长大，合金的强度和硬度进一步下降.这也就解释了图2（a）和（d）的峰值点现象的存在.由于将原有的人工时效过程打断而插入了一段自然时效过程，这时候产生了明显的二次时效现象，它增加了GP区的数量；其GP区数量随着自然时效的增加而增加.在接下来的人工时效过程中再次形成了稳定相β，t1时间越短则说明剩余的人工时效时间t3越长，从而越有利于β相的生长，同时又会降低合金的强度.2.3 断口形貌分析对于T6处理的A356合金断裂后，断口形貌如图3所示，宏观上来讲，沿拉伸试棒表面可以观测到塑性变形区；经T6I6处理后，断面上可以看到更多更大的塑性变形区，缩颈现象更加明显.图3（a）为T6处理的A356合金的断口形貌，除了韧窝之外，还有大量的二次解理断裂的存在，其断裂模式以韧性断裂和脆性断裂相结合.然而，经过T6I6热处理后，合金的断口中为均匀细小的等轴韧窝（见图3（b）），未发现解理断裂的存在.表明经T6I6处理后，合金的断裂方式发生显著改变，为韧性断裂.因为经T6I6处理后材料微观组织得到改善，共晶硅变得更加细小圆整，且与基体之间的结合力增加，使得材料的强度和塑性进一步提高.图3 A356铝合金断口形貌分析Fig.3 Fracture photograph of A356alloy treated by T6process（a）and T6I6process（b）3 结论在T6热处理制度的基础上开发出一种新型的T6I6二次时效热处理制度，并以A356铝合金为研究对象，考察T6I6二次时效热处理制度对铝合金的强度、塑性和断裂形态的影响规律.传统的热处理工艺在提高强度的同时，必然降低材料的塑性，而采用T6I6二次时效处理则可以有效克服这一缺点，可同时提高材料的屈服强度、抗拉强度、延伸率和布氏硬度.合金的强度和硬度均随着第一次人工时效时间t1的增加呈现先增加而后减小的趋势，在t1=10和20min处存在明显的峰值点.第一次人工时效t1和中间自然时效t2的增加均有利于合金延伸率的大幅度提高.【相关文献】［1］ JOHN E H.Aluminum：Properties and Physical Metallurgy［M］.Ohio：American Society for Metals，1984.［2］ BUHA J，LUMLEY R N，CROSKY A G，et al.Secondary Precipitation in an Al-Mg-Si-Cu Alloy［J］.Acta Materialia，2007，55（9）：3015.［3］ BUHA J，LUMLEY R N，CROSKY A G.Secondary Ageing in an Aluminium Alloy 7050［J］.Materials Science and Engineering 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第41卷第8期2022年8月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.41㊀No.8August,2022预氧化处理对反应烧结碳化硅微观结构和弯曲强度的影响郝鸿渐1,李海燕1,2,万德田1,2,3,包亦望1,2,3,李月明3(1.中国建筑材料科学研究总院有限公司,绿色建筑材料国家重点实验室,北京㊀100024;2.中国国检测试控股集团股份有限公司,北京㊀100024;3.景德镇陶瓷大学材料科学与工程学院,景德镇㊀333403)摘要:本文提出了一种简单有效的预氧化处理方法,用来强化反应烧结碳化硅(RBSC),研究了800~1300ħ预氧化处理对其微观结构和力学性能的影响,探究了含不同尺寸压痕裂纹的材料在氧化前后残余弯曲强度的变化规律㊂结果表明,随着氧化温度的升高,RBSC 的室温强度和Weibull 模数均存在先下降后上升,然后再下降的趋势,主要原因是不同温度氧化后的RBSC 表面形貌不同㊂在1200ħ下预氧化2h,RBSC 的弯曲强度和Weibull 模数都明显变大,强度提升了19.9%,Weibull 模数由7.3提升到11.8㊂然而,800ħ低温氧化不完全和1300ħ高温氧化反应过于强烈均会导致弯曲强度和Weibull 模数下降㊂在最优氧化条件(1200ħ氧化2h)下,含压痕裂纹(载荷20N)的RBSC 试样的残余弯曲强度在氧化后由201.1MPa 提高到324.2MPa,强化机理是高温氧化生成的SiO 2能够消除材料表面缺陷和微裂纹㊂关键词:反应烧结碳化硅;预氧化;裂纹自愈合;弯曲强度;Weibull 模数;维氏压痕中图分类号:TQ174㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2022)08-2889-07收稿日期:2022-03-29;修订日期:2022-05-10基金项目:国家自然科学基金重点基金(52032011);新型陶瓷与精细工艺国家重点实验室(KF202007)作者简介:郝鸿渐(1996 ),男,硕士研究生㊂主要从事陶瓷性能测试的研究㊂E-mail:haohongjian1996@通信作者:万德田,博士,教授㊂E-mail:dtwan@包亦望,博士,教授㊂E-mail:ywbao@Effect of Pre-Oxidation on Microstructure and Flexural Strength of Reaction Boned Silicon CarbideHAO Hongjian 1,LI Haiyan 1,2,WAN Detian 1,2,3,BAO Yiwang 1,2,3,LI Yueming 3(1.State Key Laboratory for Green Building Materials,China Building Materials Academy,Beijing 100024,China;2.China Testing &Certification International Group Co.,Ltd.,Beijing 100024,China;3.School of Materials Science and Engineering,Jingdezhen Ceramic Institute,Jingdezhen 333403,China)Abstract :In this paper,a simple and effective pre-oxidation treatment method is proposed to strengthen reaction boned silicon carbide (RBSC).The effects of different temperature oxidation treatments from 800ħto 1300ħon its microstructure and mechanical properties were investigated.Changes of residual flexural strength of materials with different sizes of pre-cracks before and after oxidation were also investigated.The results show that with the increment of the oxidation temperature,the strength and Weibull modulus of RBSC have a tend to first decrease,then increase,and then decrease again,mainly due to the different surface morphologies after oxidized at different temperatures.The flexural strength and Weibull modulus of RBSC increase significantly after pre-oxidized at 1200ħfor 2h,the strength increase by 19.9%,and the Weibull modulus increase from 7.3to 11.8.However,both the incomplete oxidation at low temperature of 800ħand the excessively strong oxidation reaction at high temperature of 1300ħlead to the decrease of flexural strength and Weibull modulus.Under the optimal pre-oxidation condition at 1200ħfor 2h,the residual flexural strength of RBSC specimen with indentation cracks (load of 20N)increase from 201.1MPa to 324.2MPa after oxidation.Thestrengthening mechanism is that the SiO 2generated by high temperature oxidation eliminates the microcracks and defects of the material on the surface.2890㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第41卷Key words :reaction boned silicon carbide;pre-oxidation;crack self-healing;flexural strength;Weibull modulus;Vickers indentation0㊀引㊀言碳化硅不仅具备优异的高温力学性能和化学稳定性,还兼具高硬度㊁高强度和高导热系数等特点,在高温窑具㊁燃烧喷嘴㊁热交换器㊁空间反射镜㊁半导体装备用精密陶瓷部件及核燃料包壳材料等具有广阔的应用前景[1-4]㊂然而,碳化硅是一种Si C 键很强的共价键化合物,难以加工和烧结致密化㊂目前常用的烧结技术有反应烧结㊁常压烧结㊁重结晶烧结㊁热压烧结和热等静压烧结等[5]㊂其中反应烧结碳化硅(reaction boned silicon carbide,RBSC)具有烧结温度低㊁近净尺寸烧结和烧结致密度高等优势,是一种有望实现工业化应用的碳化硅陶瓷烧结技术[6]㊂碳化硅陶瓷是一种典型的脆性材料,对表面微裂纹等缺陷比较敏感[7]㊂对于RBSC 来说,其涉及坯体成型㊁干燥和反应烧结等工艺,容易在烧结体中引入孔洞㊁裂纹和分层等缺陷㊂在后期的机械加工中也容易在材料表面产生微裂纹等缺陷㊂氧化或退火处理是一种有效的消除非氧化物陶瓷表面缺陷和裂纹的方法[8-10]㊂氧化处理在非氧化物陶瓷表面产生一层氧化层,氧化层修复表面缺陷或裂纹,甚至产生残余应力,进而提高材料的弯曲强度[11-13]㊂Cheong 等[14]对掺有Y 2O 3和Al 2O 3的碳化硅陶瓷等温退火处后,发现其断裂韧性变大㊂Zhang 等[15]研究了ZrB 2-20%SiC(体积分数)陶瓷的预氧化性能,通过在表面形成硼硅酸盐玻璃从而提高了陶瓷的抗弯强度㊂RBSC 氧化行为对温度㊁时间和气氛等[12]条件非常敏感,氧化速率大多随温度的增加而增加[16]㊂本试验通过控制氧化时间和气氛探究温度对RBSC 陶瓷弯曲强度的影响㊂采用维氏压痕法在RBSC 材料表面三点弯曲受拉面中心点位置预制不同长度的裂纹,以模拟材料在制造和服役过程中受力损伤状况,考察含不同裂纹尺寸材料的三点弯曲强度以及在预氧化之后的残余弯曲强度,分析RBSC 的表面裂纹愈合或尖端钝化机理,探究高温预氧化对其微观结构和弯曲强度的影响㊂1㊀实㊀验1.1㊀材料制备RBSC 购于中国建筑材料科学研究总院陶瓷院,主要成分及物理性能见表1㊂表1㊀反应烧结碳化硅材料的主要成分及物理性能Table 1㊀Main component and physical properties of RBSCDensity /(g㊃cm -3)Porosity /%Content of silicon (mass fraction)/%Content of Fe 2O 3(mass fraction)/%Flexural strength /MPa 3.020.1220.500.05278.501.2㊀预氧化试验将样品切割成3mm ˑ4mm ˑ36mm 的试样,并抛光至1200#SiC 砂纸以上,棱边轻微倒角㊂采用箱式电阻炉,在空气环境中进行预氧化处理,氧化温度分别设定为800ħ㊁900ħ㊁1000ħ㊁1100ħ㊁1200ħ和1300ħ,以10ħ/min 升温至设定的温度并保温2h 后随炉冷却㊂1.3㊀表面形貌表征及强度测试采用X 射线衍射仪(D8Advance Diffractometer,德国布鲁克公司)分析氧化前后的试样表面物相成分㊂通过光学显微镜(KEYENCE VHX-970F,日本基恩士)和冷场发射扫描电子显微镜(S-4800,日本日立)观察氧化后的试样表面及断口形貌㊂室温下,采用微机控制电子万能试验机(Model C45,MTS)测试试样在氧化前后的三点弯曲强度,跨距为30mm,加载速率为0.5mm /min㊂采用线性最小二乘法计算Weibull 模数(样品数为16个),常用的两参数Weibull 方程为[17]:P =1-exp -σσ0()m [](1)第8期郝鸿渐等:预氧化处理对反应烧结碳化硅微观结构和弯曲强度的影响2891㊀式中:σ为应力;P 为在应力σ作用下的断裂概率;m 为Weibull 模数;σ0为本征强度㊂采用数字式显微硬度仪(HXD-2000TM /LCD,上海泰明)在试样拉伸表面的中间位置预制不同尺寸的维氏压痕裂纹,利用三点弯曲法测量含预制裂纹样品在1200ħ预氧化后的残余弯曲强度(样品数为5个)㊂2㊀结果与讨论2.1㊀物相及表面形貌分析图1(a)为不同温度氧化2h 样品表面X 射线衍射全谱结果,图1(b)为RBSC 表面在不同温度氧化后在22ʎ左右的特征衍射峰㊂由图可知原始RBSC 主要由碳化硅和游离硅组成,图中在1000ħ开始出现二氧化硅的方石英相,并且随着温度升高逐渐锐化㊂晶体硅在常温下较为稳定,但在高温下能与氧气等多种元素反应㊂并且硅的熔点在1400ħ左右,因此当服役温度ȡ1400ħ时,RBSC 中残余硅相的熔融软化,会降低RBSC 的高温力学性能㊂碳化硅在高温富氧条件下会发生缓慢氧化,表面会生成SiO 2,称为惰性氧化;而在足够高的温度下或较低的氧分压条件下,碳化硅快速氧化的同时产生挥发性气体,即产生活性氧化㊂游离硅及碳化硅的惰性氧化反应式[18-19]为:Si +O 2 SiO 2(s)(2)2SiC +3O 2 2SiO 2(s)+2CO(g)(3)SiC +2O 2 SiO 2(s)+CO 2(g)(4)图1㊀不同温度氧化2h 后样品表面的X 射线衍射谱Fig.1㊀XRD patterns of the sample surface after 2h of oxidation at differenttemperatures 图2㊀不同温度氧化2h 后样品的质量变化Fig.2㊀Mass change of samples after oxidized at different temperatures for 2h 从反应方程式中可以看出,空气富氧条件下硅与碳化硅氧化明显特征是氧化增重,对RBSC 材料氧化前后质量进行测试得到图2,随着温度升高其每克材料氧化增重逐渐增大,在1300ħ增重最大,说明反应最为剧烈㊂图3为RBSC 表面在不同温度氧化2h 后的光学显微照片㊂结果表明,800ħ时,材料表面便开始氧化,并且900ħ氧化后表面只有碳化硅颗粒之间填充的游离硅完全变成蓝色,而碳化硅还未有氧化痕迹㊂硅的氧化激活能远低于碳化硅,其氧化反应温度也低于碳化硅[20-22]㊂结合XRD 结果发现,800ħ氧化后RBSC 表面游离硅开始氧化生成非晶二氧化硅,1000ħ后硅氧化成的非晶二氧化硅开始结晶㊂RBSC 存在一定量的铁杂质(见表1),铁杂质的存在不仅降低了二氧化硅晶化的温度[22],而且高温氧化生成的Fe 3O 4导致非晶二氧化硅呈蓝色㊂2892㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第41卷1100ħ氧化后碳化硅颗粒也开始氧化生成蓝色,1200ħ还发现粗碳化硅颗粒氧化后非晶态出现由外向内析晶现象㊂这是由于高温相SiO 2的析晶速度非常缓慢,必须在析晶温度保持相当长的时间才能实现这种转变㊂综上,RBSC 随温度升高其氧化过程分为两步:(1)游离硅氧化,再析晶;(2)碳化硅氧化,再析晶㊂图3㊀反应烧结碳化硅在不同温度氧化处理2h 后的表面光学显微照片Fig.3㊀Optical micrographs of RBSC after oxidized at different temperatures for 2h 2.2㊀预氧化对RBSC 弯曲强度和Weibull 模数的影响陶瓷材料的可靠性通常采用Weibull 统计分析,其Weibull 模数的大小反映了材料的可靠性[17]㊂图4为RBSC 材料在不同温度下氧化2h 的弯曲强度和Weibull 模数统计结果㊂原始RBSC 的弯曲强度为(278.5ʃ25.9)MPa,在800ħ氧化后的强度出现下降㊂随着氧化温度升高其弯曲强度逐渐增大,在1000ħ氧化后的强度达到最大值,随后强度值基本不变㊂而其强度的Weibull 模数也在800ħ氧化后先下降,然后随温度逐渐增大,在1200ħ达到最大值㊂Rodríguez 等[23]发现,当氧化温度较低时,碳化硅陶瓷基复合材料的氧化主要由O 2通过表面微裂纹和缺陷的扩散控制㊂因此当氧化温度为800ħ时,氧化主要发生在裂纹孔隙以及晶界位置㊂表面氧化生成的非晶相SiO 2结构疏松,强度比晶相低,从而导致RBSC 的室温强度降低9.6%,Weibull 模数由初始值7.3下降至4.0,表面非晶相会显著增加强度离散性㊂1200ħ氧化后,O 2能够与表面的硅和碳化硅都发生反应并析晶生成晶态的方石英(见图3),这对于消除表面微裂纹和缺陷,提高材料表面致密性均具有重要作用㊂并且表面硅和碳化硅氧化后结晶生成方石英会伴随有一定的体积膨胀[24],在RBSC 表面形成一定的残余压应力,也会对微裂纹扩展起到了一定的抑制作用㊂在两者共同作用下,使得室温强度在氧化后提升了19.9%,Weibull 模数也由初始值7.3上升至11.8,其强度的Weibull 分布函数散点图如图5所示,表明随着RBSC 氧化析晶程度越高,材料的强度可靠性也越高㊂图4㊀RBSC 在不同温度下氧化2h 的弯曲强度和Weibull 模数Fig.4㊀Flexural strength and Weibull modulus of RBSC after oxidized at different temperatures for 2h 图5㊀RBSC 的弯曲强度Weibull 分布函数散点图Fig.5㊀Scatter plot of Weibull distribution function of flexural strength of RBSC第8期郝鸿渐等:预氧化处理对反应烧结碳化硅微观结构和弯曲强度的影响2893㊀㊀㊀当在1300ħ氧化处理后,由于已经接近硅的熔点,O 2与材料表面的硅㊁碳化硅均剧烈反应㊂产生的CO 和CO 2气体快速逸出造成RBSC 表面出现孔洞,及过大的热应力造成表面内部晶界之间的大量缺陷(见图6),其弯曲强度和Weibull 模数均迅速下降㊂图6㊀RBSC 在1300ħ氧化2h 后的SEM 照片Fig.6㊀SEM images of RBSC after oxidized at 1300ħfor 2h 2.3㊀压痕裂纹尺寸对RBSC试样弯曲强度的影响图7㊀不同维氏压痕载荷下裂纹尺寸与相应的残余弯曲强度Fig.7㊀Crack size and corresponding residual flexural strength under different Vickers indentation loads 图7为不同维氏压痕载荷下裂纹尺寸与相应的残余弯曲强度㊂可以看出,在0.5~20N 荷载下,随着维氏压痕荷载的增大,其压痕裂纹尺寸2c 也逐渐增大㊂裂纹尺寸及材料的弯曲强度符合σɖ(2c )-1/2的Griffith 断裂理论,即随着表面裂纹尺寸增大,材料强度逐渐下降㊂当预制裂纹平均长度达到110.2μm 时,RBSC 材料的三点弯曲强度由初始的278.5MPa 下降至201.1MPa㊂图8为材料在预制裂纹断裂后的光学照片,说明表面预制的裂纹会主导断裂的发生㊂图9为表面含预制裂纹的RBSC 经1200ħ氧化2h 后的残余弯曲强度㊂对比图7结果表明,与含预制裂纹的RBSC 未氧化相比,材料的残余弯曲强度均有部分提高㊂其中含20N 预制裂纹的试样其残余弯曲强度在氧化后强度提升了61.2%,由氧化前201.1MPa 提高到324.2MPa,维氏压痕法预制裂纹导致材料强度衰减的现象在氧化后消失㊂图8㊀表面预制裂纹的断裂位置光学显微图Fig.8㊀Optical micrograph of fracture location with pre-crack 通过观察表面裂纹1200ħ氧化后微观形貌变化(见图10),发现氧化后其断裂位置不再穿过预制裂纹的压痕区,并且预制的裂纹被氧化物所覆盖愈合㊂RBSC 表面施加压痕后,压痕及裂纹部位表面积增大,压2894㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第41卷痕及裂纹表面自由能也增大㊂1200ħ氧化2h 处理后,压痕裂纹处易发生氧化反应从而愈合㊂这就意味着预制的裂纹经高温氧化后发生不仅不会产生强度衰减,反而加强,断裂起始源变为预制裂纹区域以外的位置㊂图9㊀含预制裂纹的反应烧结碳化硅经1200ħ氧化2h 后的残余弯曲强度Fig.9㊀Residual flexural strength of RBSC with pre-crack after oxidized at 1200ħfor 2h 图10㊀表面预制裂纹氧化前后光学显微照片Fig.10㊀Optical micrographs of surface pre-crack before and after oxidation 3㊀结㊀论合适的高温预氧化处理是一种有效地消除RBSC 陶瓷表面孔隙和微裂纹并且提升强度和可靠性的方法,但不同的表面微观形貌会对室温弯曲强度造成不一样影响㊂(1)材料在1200ħ高温氧化2h 后,强度提升了19.9%,Weibull 模数由初始值的7.3提高至11.8,表面氧化析晶度越高,其强度可靠性更好㊂(2)材料经800ħ氧化处理后,表面会生成少量的斑点状非晶二氧化硅,导致强度下降9.6%,Weibull模数由初始值7.3下降至4.0,表面非晶相会显著增加强度离散性㊂(3)在最优氧化条件(1200ħ氧化2h)下,含压痕裂纹(载荷20N)的RBSC 试样的残余弯曲强度在氧化后提高了61.2%,强化机理是表面高温氧化生成的SiO 2能够愈合表面微裂纹㊂通过简单合理的高温氧化提高了RBSC 构件的强度和可靠性,有望能降低机加工及抛光成本并且延长陶瓷构件的使用寿命㊂参考文献[1]㊀PARSHIN V,SEROV E,DENISOV G,et al.Silicon carbide for high-power applications at MM and THz ranges[J].Diamond and RelatedMaterials,2017,80:1-4.[2]㊀XU M,GIRISH Y R,RAKESH K P,et al.Recent advances and challenges in silicon carbide (SiC)ceramic 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Industry Press, 2017(in Chinese).[18]㊀EL SHAFEI K,AL NASIRI N.Oxidation of reaction-bonded silicon carbide-boron carbide in air[J].Ceramics International,2021,47(12):17463-17470.[19]㊀魏明坤,张丽鹏,武七德.渗硅碳化硅材料的高温氧化[J].硅酸盐通报,2001,20(4):52-55.WEI M K,ZHANG L P,WU Q D.High temperature oxidation behavior of melt-infiltrated silicon carbide[J].Bulletin of Thechinese Ceramic Society,2001,20(4):52-55(in Chinese).[20]㊀CHEN S Y,ZENG Y,XIONG X,et al.Static and dynamic oxidation behaviour of silicon carbide at high temperature[J].Journal of theEuropean Ceramic Society,2021,41(11):5445-5456.[21]㊀LEE S K,ISHIDA W,LEE S Y,et al.Crack-healing behavior and resultant strength properties of silicon carbide ceramic[J].Journal of theEuropean Ceramic Society,2005,25(5):569-576.[22]㊀OGBUJI L U.Development of oxide scale microstructure on single-crystal SiC[J].Journal of Materials Science,1981,16(10):2753-2759.[23]㊀RODRÍGUEZ-ROJAS F,ORTIZ A L,GUIBERTEAU F,et al.Oxidation behaviour of pressureless 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林玉金，等：Zr与时效处理工艺对Al-Zn-Mg-Cu合金组织与性能的影响工艺技术/信息报道The effect of Zr and aging process on the microstructure ofAl-Zn-Mg-Cu alloy impact of performanceLin Yujin1,Xia Peng2,Zhou Nan2,Hu Quan1(1.Foshan Sanshui Fenglv Aluminum Co.,Ltd.,Foshan528133;2.Institute of Advanced Materials,Guangdong Academy of Sciences,Guangzhou510650,China)Abstract:The effects of adding trace Zr and different heat treatment processes such as T6(aging),RRA(regression re-aging)and FSA(four-stage aging)on microstructure,mechanical properties and stress corrosion properties of Al-Zn-Mg-Cu alloy were investi⁃gated by TEM,electrochemical workstation and slow strain rate tensioning machine.The results show that the mechanical properties and stress-corrosion resistance of Al-Zn-Mg-Cu alloy are obviously improved after Zr microalloying,and the optimal mechanical properties can be obtained by T6treatment.The stress-corrosion resistance of Al-Zn-Mg-Cu alloy is further improved by RRA and FSA treatment.Key words:Al-Zn-Mg-Cu alloy;Zr microalloying;microstructure;stress corrosion resistance电池铝箔产量快速增长，新型复合铝箔材料备受追捧传统铝箔重量重、成本高、安全性较差，面临很大的问题。

未溶相和再结晶对Al-Zn-Mg-Cu合金应力腐蚀抗力的影响黄俊;彭国胜;宋广生;陈康华;陈送义【摘要】采用慢应力拉伸技术,结合金相、扫描和透射电镜观察,研究了未溶相和再结晶对Al-Zn-Mg-Cu合金应力腐蚀抗力的影响。

结果表明：未溶相引起的点蚀导致应力腐蚀裂纹萌生;再结晶加速了L-T和T-L方向应力腐蚀裂纹扩展,降低了应力腐蚀抗力。

应力腐蚀抗力主要由再结晶因素控制。

再结晶降低应力腐蚀抗力主要是由再结晶晶界析出相较差耐蚀引发的。

【期刊名称】《齐鲁工业大学学报：自然科学版》【年(卷),期】2018(032)002【总页数】5页(P45-49)【关键词】铝合金;再结晶;未溶相;晶界析出相;应力腐蚀抗力【作者】黄俊;彭国胜;宋广生;陈康华;陈送义【作者单位】[1]安徽工业大学材料科学与工程学院,马鞍山243002;;[1]安徽工业大学材料科学与工程学院,马鞍山243002;;[1]安徽工业大学材料科学与工程学院,马鞍山243002;;[2]中南大学高性能复杂制造国家重点实验室,长沙410083;;[2]中南大学高性能复杂制造国家重点实验室,长沙410083;【正文语种】中文【中图分类】TQ174.4航空铝合金,特别是7000系铝合金,容易发生应力腐蚀,引发飞机灾难性事故。

现有研究表明,合金的应力腐蚀抗力直接受未溶相和材料再结晶的影响。

工业上通常通过优化合金成分和热处理制度改变材料的未溶相和再结晶组织,达到提高合金应力腐蚀抗力的目的。

综述已发表文献,一般认为7000系合金组织通常包含不同类型的未溶相,例如Al2 CuMg和Al7 Cu2 Fe等[1-3]。

未溶相由于与铝基体存在电位差,容易引发点蚀[4]。

7000系合金应力腐蚀一般都是沿晶腐蚀,所以该系列合金应力腐蚀抗力直接与晶界析出相有关。

晶界析出相一般可通过时效处理工艺加以调整。

大量文献报道表明,粗大而不连续的晶界析出相有利于提高合金的应力腐蚀抗力[5-12]。

第50卷第3期2021年6月有色金属加工NONFERROUS METALS PROCESSINGVol.50No.3June2021D0I：10.3969/j.issn.1671-6795.2021.03.012预时效对汽车用6008合金吸能元件压溃性能的影响祝艳娇，刘欢,金智澎，张岩，王特（辽宁忠旺集团有限公司，辽宁辽阳111003）摘要：对预时效处理T4P状态与未处理T4状态的6008合金吸能元件做对比试验。

结果表明，T4P状态经后期人工时效处理后屈服强度提前达到270MPa，且抗拉强度较大，因此屈强比较小,成性性能较好;进而压溃试验峰值载荷相同条件下，下压量为60%时,T4P+T6状态压溃试样褶皱较均匀，肉眼可见的裂纹细微,相对应的载荷曲线周期性强，波动幅度最大，吸收的能量最高。

关键词：6008合金;屈强比;压溃;吸能性中图分类号:TG146.21文献标识码:A文章编号：1671-6795（2021）03-0052-04有研究表明，用于汽车吸能铝合金中，在不发生破裂情况下,6008合金具有较佳的吸能效果［1］。

汽车保险杠系统中的吸能盒作为汽车重要吸能元件，将车辆发生碰撞而产生的撞击力全部吸收且自身变形,从而减免白车身结构的伤害，保护车辆，降低成本。

吸能盒简单的理解就是可以吸收能量的盒子，在低速碰撞时,要求其在受力后完全被压瘪，相反吸能盒发生较小变形,而与其连接的防撞梁大幅度变形的设计是不合格的［2,3］。

汽车碰撞过程是一个非常复杂的动力学过程，多数吸能盒是薄壁构件，而且在碰撞初始阶段的碰撞力是最大的,吸能盒碰撞压缩变形稳定、褶皱均匀，才不致使由于碰撞力过大而降低吸能盒的作用［4］o汽车零部件的转运和存储一般需要两周左右的时间，在此期间不同合金都会存在不同程度的由不稳定状态向稳定状态转变,从而影响后期人工时效的性能，因此需要在转运和存储之前进行一定的预处理,以满足后期人工时效所需的性能［5,6］。

精 密 成 形 工 程第16卷 第3期 76JOURNAL OF NETSHAPE FORMING ENGINEERING 2024年3月收稿日期：2024-01-04 Received ：2024-01-04基金项目：国家自然科学基金（52205427）；山西省基础研究计划-青年科学研究项目（20210302124322）；山东省重点研发计划（2023JMRH0302）；山东省博士后创新项目（SDCX-ZG-202203072）Fund ：The National Natural Science Foundation of China (52205427); the Basic Research Program of Shanxi Province (20210302124322); Key Research and Development Plan in Shandong Province (2023JMRH0302); Shandong Postdoctoral In-novation Project (SDCX-ZG-202203072)引文格式：任贤魏, 崔旭, 赵熹, 等. 应力时效影响Al-10Zn-3Mg-3Cu 合金带外纵筋筒形件组织性能研究[J]. 精密成形工程, 2024, 16(3): 76-85.REN Xianwei, CUI Xu, ZHAO Xi, et al. Effect of Stress-aging on Microstructure and Mechanical Properties of Al-10Zn-3Mg- 3Cu Alloy Cylindrical Parts with External Longitudinal Ribs[J]. Journal of Netshape Forming Engineering, 2024, 16(3): 76-85. *通信作者（Corresponding author ） 应力时效影响Al-10Zn-3Mg-3Cu 合金带外纵筋筒形件组织性能研究任贤魏1,2*，崔旭3，赵熹2，薛勇1,2（1.中北大学 材料科学与工程学院，太原 030051；2.国防科技工业复杂构件挤压创新中心，太原 030051；3.陆装驻包头地区第一代表室，内蒙古 包头 014032） 摘要：目的 研究应力时效条件下Al-10Zn-3Mg-3Cu 合金带外纵筋筒形件筋部试样的应力松弛行为，探明基体应力松弛机制以及强韧性协同提升机理。

收稿日期:2006 10 16; 修订日期:2006 10 18基金项目:内蒙古工业大学校基金资助项目,项目编号(004 20064879)作者简介:李 峰(1974 ),山西灵丘人,讲师,工学硕士.研究方向:稀土钢与铝合金材料.Email:yangxiaohuilieng@铸造技术F OU N DRY T ECH NO LO GY Vo l.27No.12Dec.2006重熔与时效工艺对ZL101铝合金组织与抗拉强度的影响李 峰,张 娟,史志铭(内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051)摘要:ZL101铝合金重熔后,浇注时间和浇注位置对其组织与性能影响很大。

从ZL 101铝合金不同浇注时间、不同浇注的位置取样,对铸态和时效后的试样进行抗拉强度性能测试,用光学显微镜观察其微观组织,研究重熔与时效工艺对ZL 101铝合金组织与性能的影响规律。

结果表明,在浇注过程中,试样的晶粒先发生粗化,随着浇注时间的延长,晶粒又发生细化。

其抗拉强度也是先降低而后又升高。

随着浇注位置的变化,由下向上晶粒逐渐粗化,共晶硅的分布逐渐变得不均匀,且抗拉强度逐渐降低。

合金的时效与铸态的组织、性能的变化规律一致。

关键词:重熔;时效;浇注时间;浇注位置中图分类号:TG146.2+1 文献标识码:A 文章编号:1000 8365(2006)12 1326 03Effect of Remelting and Aging Process on Microstructureand Tensile Strength of ZL 101Al AlloyLI Feng,ZHANG Juan,SHI Zhi ming(School of Material Science and Engineering,Inner Mongolia University of Technology,Huhhot 010051,China)Abstract:Pou ring time and pourin g locations have obviou s effects on microstru ctu res and properties after ZL101Al alloy is remelted.Samples were cu t from ZL101Al alloy with different pou ring locations an d different pouring time.The tensile stren gth of sam ples at as cast and aged state was tested and th eir microstructu res were observed with optical m icroscope.Effectof remelting and agin g process on the microstru ctures an d properties of ZL101Al alloy were investigated .The resu lts show that grain s are coarsened at the early stage of casting,th en refin ed with increase of the casting time.The ten sile stren gth decreases firstly,reach es the min imu m,an d then increases.The grain s become coarser gradu ally from the bottom to th e top with chan ge of pourin g location and the distribu tion of eutectic crystal Si becomes n on u niform,and the ten sile strength decreases gradu ally.The variation of microstru cture an d properties at the aged state has the sam e ten den cy as th at at the as cast state.Key words:R emelting;Aging;Pourin g time;Pou ring positionZL101合金目前被广泛应用于汽车、摩托车轮毂铸造和其它领域中,是一种很有发展前途的铝合金[1~5]。

Investigating the Effect of Aging onMaterialsIntroductionMaterials are essential for the development of modern society, they provide us with the necessary tools to build our buildings, create our vehicles and develop new technologies. But materials are not invincible, they can degrade over time due to several factors, including exposure to the environment, stress, and aging. Therefore, it is important to investigate the effect of aging on materials to better understand how they will perform over time and ensure their longevity.What is aging?Aging is a natural process that affects all materials, including metals, polymers, ceramics, and composites. It can be defined as the gradual deterioration of material properties due to various mechanisms such as chemical reactions, physical processes like diffusion, and structural changes on the atomic and molecular levels.The aging process is influenced by several factors, including temperature, humidity, exposure to UV radiation, and other environmental factors. Additionally, mechanical and physical stresses can also cause materials to age more quickly.The Effects of Aging on MaterialsAging can affect materials in several ways. One of the most significant effects is the degradation of mechanical properties, including strength, ductility, and toughness. Aging can cause microstructural changes that affect the material's ability to withstand stress and deformation.For example, metals can age due to corrosion, which can cause cracks and other defects that weaken the material's strength. Polymers can also undergo aging through oxidation, which can result in cracking, embrittlement, and loss of strength.Aging can also affect a material's thermal and electrical properties. For example, thermal conductivity may decrease due to the accumulation of impurities or changes in the microstructure. Additionally, aging can cause materials to become less electrically conductive.Methods of Investigating AgingThere are several methods for investigating the effect of aging on materials, including field experiments, laboratory testing, and simulation.Field experiments involve monitoring the performance of materials in real-world environments over a long period of time. This method is useful for investigating the effects of aging on materials in actual service conditions.Laboratory testing involves exposing materials to specific environmental conditions, such as temperature, humidity, and UV radiation, and monitoring their properties over time. This method is useful for simulating the effects of aging on materials in controlled conditions.Simulation involves predicting the aging behavior of materials using computer models. This method is useful for investigating the effect of aging on materials that are difficult or expensive to test in the laboratory or field.ConclusionThe effect of aging on materials is an important area of research that has implications for many industries. Understanding how materials age can help to develop more durable and reliable materials, which can enhance the safety and performance of critical infrastructure and other applications where materials are used. Methods of investigating the effect of aging on materials are diverse, and a combination of laboratory testing, field experiments, and simulation is often used to gain a comprehensive understanding of the aging process.。

人工时效处理对2D70铝合金组织和性能的影响摘要：2D70铝合金属于Al-Cu-Mg-Fe-Ni系铝合金，是可热处理强化的耐热铝合金，具有塑性高、耐热性好以及良好的铸造性能等特点。

在冷和热状态下均具有高的塑性，其半成品齐全，主要有预拉伸厚板、板材、型材、管材、自由锻件和模锻件等，该合金能制造各种形状、尺寸不同的飞机零件。

2D70铝合金的强化机制是固溶及沉淀强化，合金元素Cu和Mg有强化作用。

2D70铝合金在150℃可长时间工作，在175℃以下时，合金的性能和组织变化都不明显。

其热加工工艺复杂，在不同的工艺条件下，2D70铝合金可获得不同的组织和性能。

本综合试验将2D70铝合金在510℃下进行固溶处理后，在经过不同温度（100~200℃）和不同保温时间（10~25t）的人工时效处理后，通过对2D70铝合金不同硬度和金相组织的分析，研究时效对2D70铝合金组织和性能的影响。

关键词：2D70 时效组织性能Artificial aging treatment on Microstructure and properties of 2D70 aluminum alloy effectAbstract: Aluminum alloy 2D70 belongs to Al-Cu-Mg-Fe-Ni series aluminum alloy, is strengthened by heat treatment heat resistant aluminum alloy, with high plasticity, good heat resistance and good casting properties. In the cold and hot state have high plasticity, the semi-finished product range, mainly the prestretching plates, plates, profiles, pipe, forgings and forging pieces, the alloy can manufacture various shapes, sizes and aircraft parts. The strengthening mechanism of 2D70 aluminum alloy solid solution and precipitation strengthening, the alloying element Cu and Mg have aggrandizement effect. 2D70 aluminum alloy at a temperature of 150 DEG C can work for a long time, in 175 DEG C, alloy performance and organizational change is not obvious. The heat treatment technology is sophisticated, under different conditions, 2D70 aluminum alloy can be obtained with different microstructures and properties. The comprehensive test of 2D70 aluminum alloy in 510 DEG C. after solid solution treatment, after different temperature ( 100 ~ 200 ) and different holding time ( 10 ~ 25t ) artificial aging treatment, through to the 2D70 aluminum alloy with different hardness and metallographic structure analysis, to study the effect of aging on microstructure and properties of 2D70 aluminum alloy .Keywords：2D70prescription microstructure。

通过形变时效工艺同时提高Al-Mg-Si-Cu合金强度和电导率陈敬;陈江华;刘春辉;赖玉香;顾媛【摘要】铝是一种优良的导电材料,但由于强度低,其应用受到很大限制.随着铝在电力工业中应用逐渐增加,近年来,越来越多的工作致力于提高铝的导电率与强度的综合性能.通过改变传统T6时效工艺顺序发明一种同时显著提高Al-Mg-Si-Cu合金导电率和强度的形变时效工艺.本文采用显微硬度测量,导电率测试以及透射电镜(TEM)微观结构表征研究了形变时效工艺与传统T6时效工艺制备的材料在综合性能和微观组织上的差异.轧制变形引入的位错在后续时效过程调控析出,析出相形貌的改变是导电率相对T6工艺提高的原因,而残留位错可提高材料强度.【期刊名称】《功能材料》【年(卷),期】2016(047)002【总页数】5页(P2139-2142,2147)【关键词】铝合金;导电率;强度;位错;析出相【作者】陈敬;陈江华;刘春辉;赖玉香;顾媛【作者单位】湖南大学材料科学与工程学院,长沙410082;湖南大学材料科学与工程学院,长沙410082;湖南大学材料科学与工程学院,长沙410082;湖南大学材料科学与工程学院,长沙410082;湖南大学材料科学与工程学院,长沙410082【正文语种】中文【中图分类】TG113;TM241铝在电器制造工业、电线电缆工业和无线电工业中有广泛的用途。

在铝材料中商业纯铝拥有最高的导电率，大约为62%IACS(国际退火铜标准)，然而它的抗拉强度仅仅只有160 MPa左右，这使得它的应用受到很大限制[1-2]。

为了提高铝材料在电力相关行业中的应用，我们必须在保证它优良的导电性能的情况下，尽可能地提高强度。

早期的工作者通过合金化来提高强度，比如添加Mg和Si元素形成的Al-Mg-Si系合金[2]。

虽然合金强度获得了一定的提升，但是金属的导电性能对于其微观结构很敏感。

溶质原子、晶格自振动和缺陷都会成为电子运动的散射源，阻碍电子的运动，从而使铝合金的导电性能下降。

毕业设计论文外文翻译沈阳航空航天大学外文翻译原文及译文学院机电工程学院专业机械电子工程34060403班级2013040604110学号姓名曾闯指导教师钦兰云负责教师钦兰云沈阳航空航天大学2011年6月热处理对7085铝合金应力腐蚀开裂、断裂韧性和强度的影响陈送义1，2，陈康华2，董朋轩2，叶升平2，黄兰萍21.轻合金研究所,中南大学,中国长沙410083;2.粉末冶金国家重点实验室,中南大学,中国长沙410083。

摘要采用慢应变速率拉伸应力腐蚀测试、Kahn撕裂实验和室温拉伸实验结合透射电子显微镜和扫描电子显微镜,研究热处理对7085铝合金应力腐蚀开裂、断裂韧性和强度的影响。

结果表明:与T6时效相比,经T74时效处理的合金的断裂韧性提高22.9%,但屈服强度降低13.6%;经回归再时效(RRA)处理的合金屈服强度与T6的相当,断裂韧性提高14.2%。

经两次回归再时效(DRRA)处理的合金断裂韧性与T74处理的相当,但屈服强度提高14.6%。

合金的应力腐蚀开裂抗力依次为:T6<RRA<DRRA≈T74。

热处理对合金应力腐蚀开裂和断裂韧性的影响主要与基体析出相和晶界析出相有关。

关键词：7085铝合金；热处理；应力腐蚀开裂；断裂韧性；1介绍Al-Zn-Mg-Cu系合金已广泛用作航天结构材料，由于其较低的密度，优异的抗应力腐蚀和断裂韧性[1]。

高强度、应力腐蚀开裂（SCC）性能和断裂韧性是相互矛盾的组合，它明显是由成分和热处理的影响[2-8]。

例如，Cu含量高增加了抗腐蚀开裂（SCC）性而使降低断裂韧性[2]，Zn和Mg会使强度增加而降低耐腐蚀开裂（SCC）性，经过T7x时效回火处理增加了应力腐蚀开裂（SCC）性能而降低强度。

提出了提高抗应力腐蚀性能和断裂韧性的热处理方法。

时效(RRA)处理增加抗应力腐蚀性、断裂韧性而不降低强度[6,9]。

重复的实效RRA处理提高SCC性能及提高强度与RRA处理的近似[10]。

急性胰腺炎患者肠道菌群变化及益生菌的应用吕彦青，李嘉杰，刘坤禹，郭汝华，季慧范吉林大学白求恩第一医院肝胆胰内科，长春 130021通信作者：季慧范，************.cn（ORCID： 0000-0001-8816-1906）摘要：肠道菌群是人体中最复杂和最重要的微生态系统，肠道菌群失调与急性胰腺炎的发生、发展密切相关，近年来靶向调控肠道微生态辅助治疗急性胰腺炎逐步被人们重视。

本文详细叙述了急性胰腺炎患者肠道菌群变化情况及机制，总结了益生菌应用的研究现状，指出益生菌辅助治疗方案的研究方向，并提出了预测急性胰腺炎患者优势菌群的新方法，以期为急性胰腺炎的治疗带来新思路。

关键词：胰腺炎，急性坏死性；胃肠道微生物组；鼠李糖乳杆菌基金项目：吉林市人口与健康发展研究（371170143428）Changes in intestinal microbiota and application of probiotics in patients with acute pancreatitisLYU Yanqing， LI Jiajie， LIU Kunyu， GUO Ruhua， JI Huifan.（Department of Hepatobiliary and Pancreatic Medicine， The First Hospital of Jilin University， Changchun 130021， China）Corresponding author： JI Huifan，************.cn（ORCID： 0000-0001-8816-1906）Abstract：Intestinal microbiota is the most complex and important microecosystem in the human body， and gut microbiota dysbiosis is closely associated with the development and progression of acute pancreatitis. Targeted regulation of intestinal microecology in assisting the treatment of acute pancreatitis has attracted more attention in recent years. This article describes the changes in intestinal microbiota and related mechanisms in patients with acute pancreatitis，summarizes the current research status of the use of probiotics， points out the research direction of probiotics as the adjuvant treatment regime， and proposes a new method for predicting the dominant flora in patients with acute pancreatitis， in order to bring new ideas for the treatment of acute pancreatitis.Key words：Pancreatitis， Acute Necrotizing； Gastrointestinal Microbiome； Lactobacillus RhamnosusResearch funding：Research on Population and Health Development of Jilin City （371170143428）急性胰腺炎（acute pancreatitis，AP）是多种病因导致胰腺组织自身消化所致的胰腺水肿、出血及坏死等炎症性损伤，组织学上以腺泡细胞破坏为特征。

摘要6016铝合金板材主要制造汽车覆盖件，特别是乘用车内外罩、后行李箱和门框等汽车外板，是汽车轻量化的关键材料。

而目前国内的铝合金板材仍存在着成形性、抗凹性及零件成形后质量差等问题，无法满足使用要求。

因此开展6016铝合金板材关键的预时效工艺和冲压成形工艺研究，对提高板材的成形质量十分重要。

本文将545 o C固溶30 min的6016铝合金（Al-0.55%Mg-1.0%Si-0.18%Cu）板材水淬后，经60 o C~160 o C×5 min~30 min预时效，室温停放25天后，进行185 o C×20 min的模拟烤漆处理。

采用硬度、拉伸试验，结合示差扫描量热法（DSC）、扫描电子显微镜（SEM）等分析技术，研究预时效工艺对合金的力学性能及微观组织的影响规律。

通过数值模拟仿真实际的冲压过程，并预估零件成形后可能出现的质量缺陷，优化关键成形工艺参数。

结果表明：①固溶淬火后立即进行预时效可以抑制自然时效过程，T4P态合金的成形性和烘烤硬化性能都得到改善。

烤漆前后的硬度随着预时效温度升高，出现先缓慢增加后迅速增加的趋势。

预时效温度为100 o C，预时效时间为20 min合金烘烤前屈服强度低于120 MPa，延伸率在25%左右；烘烤后屈服强度高于180 MPa（预变形2%合金烘烤硬化值达到104 MPa），烘烤后的延伸率在22%左右，综合比较优于其他预时效工艺。

②结合DSC曲线对β”析出温度和激活能进行计算，研究发现，随预时效温度升高，β”析出峰左移，激活能也降低。

说明预时效可以抑制合金自然时效过程，提高合金T4P态成形性能，而且促进烘烤过程中β”的析出，增强烘烤硬化效果。

③以铝制汽车发动机罩内板为对象，建立冲压CAE模型，对板料冲压过程仿真，研究了不同成形工艺对成形后最大减薄率、最大增厚率及最大回弹量的影响规律。

④对多因素的优化问题，首先通过灰色关联分析法，获得较优的工艺参数为：压边力500 KN，摩擦系数0.1，凹凸模间隙1.1t（1.32 mm）、凸模速度3 m/s，仿真试验后出现了少量拉裂缺陷。

Microstructure evolution and mechanical properties of1 000 MPa cold rolled dual-phase steelZHAO Zheng-zhi(赵征志), JIN Guang-can(金光灿), NIU Feng(牛枫), TANG Di(唐荻), ZHAO Ai-min(赵爱民) Engineering Research Institute, University of Science and Technology Beijing, Beijing 100083, ChinaReceived 10 August 2009; accepted 15 September 2009Abstract: The microstructure evolution of 1 000 MPa cold rolled dual-phase (DP) steel at the initial heating stages of the continuous annealing process was analyzed. The effects of different overaging temperatures on the microstructures and mechanical properties of 1 000 MPa cold rolled DP steel were investigated using a Gleeble−3500 thermal/mechanical simulator. The experimental results show that ferrite recovery and recrystallization, pearlite dissolution and austenite nucleation and growth take place in the annealing process of ultra-high strength cold rolled DP steel. When being annealed at 800 ℃ for 80 s, the tensile strength and total elongation of DP steel can reach 1 150 MPa and 13%, respectively. The microstructure of DP steel mainly consists of a mixture of ferrite and martensite. The steel exhibits low yield strength and continuous yielding which is commonly attributed to mobile dislocations introduced during cooling process from the intercritical annealing temperature.Key words: cold rolled dual-phase steel; microstructure evolution; recrystallization; mechanical property; overaging temperature1 IntroductionAdvanced high-strength steels (AHSS) have been used in the automotive industry as a solution for the weight reduction, safety performance improvement and cost saving. Among them, the dual-phase (DP) steels, whose microstructure mainly consists of ferrite and martensite, are an excellent choice for applications where low yield strength, high tensile strength, continuous yielding, and good uniform elongation are required [1−4].The continuous annealing process to produce cold rolled DP steels typically has the following stages: heating to the intercritical temperature region, soaking in order to allow the nucleation and growth of austenite, slow cooling to the quench temperature, rapid cooling to transform the austenite into martensite, overaging, and air cooling. The amount and morphology of the constituents formed depend on such annealing parameters. The effects of the retained austenite, ferrite, and martensite morphologies on the mechanical behavior of DP steels have been intensively investigated[5−9]. As we all known, overaging treatment is an important process during the production of dual-phase steel. It can reduce the hardness of martensite and improve the comprehensive mechanical properties of DP steel [10−14].The purpose of the present research was to study the microstructure evolution of cold rolled DP steel at the initial heating stages of the continuous annealing process using a Gleeble simulator. At the same time, the effects of overaging temperature on the mechanical properties of DP steel were also studied. The microstructures of specimens simulated on a Gleeble simulator, were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).2 ExperimentalThe chemical compositions of the experimental steel (mass fraction, %) were: 0.14−0.17C, 0.40−0.60Si, 1.70−1.90Mn, 0.02−0.04Nb, 0.40−0.60Cr, ≤0.010P, ≤0.010S, 0.02−0.06Al and balance Fe. Firstly, experimental steels were smelted in a 50 kg vacuum induction furnace. After smelting, experimental steels were forged into 35 mm×100 mm×100 mm cubic samples. The forged slabs were reheated to 1 200 ℃and soaked for 1 h. The hot rolled thickness was 3.5 mm after 6 passes rolling. The finish rolling temperature was about 880 ℃. The coiling temperature was 620 ℃. After being pickled in hydrochloric acid, the hot rolledFoundation item: Project(2006BAE03A06) supported by the National Key Technology R&D Program during the 11th Five-Year Plan Period Corresponding author: ZHAO Zheng-zhi; Tel: +86-10-62332617; E-mail: zhaozhzhi@ZHAO Zheng-zhi, et al/Trans. Nonferrous Met. Soc. China 19(2009) s563−s568 s564bands were cold rolled to the final thickness of 1.0 mm, and the reduction was about 70%. Finally, the cold rolled sheets were cut into the samples for the simulation of continuous annealing experiment.The microstructure evolution at the initial steps of the continuous annealing process was studied using a Gleeble 1500 simulator. The steel was heated at 10 ℃/sto the different heating temperatures (550, 630, 670, 710, 730, 750 and 780 ℃) and held for 20 s followed by water-quenching. The effects of different overaging temperatures on the microstructures and mechanical properties of DP steel were investigated using a Gleeble 3500 simulator. The processing schedules and parameters used are shown in Fig.1. The soaking temperature of intercritical region was set at 800 ℃, soaking time is 80 s; after a slow cooling, the samples were rapidly cooled to 240, 280, 320 and 360 ℃, respectively and soaked for 300 s; at last, the samples were air cooled to the room temperature.Fig.1 Continuous annealing process of DP steelAfter heat treatment, the steel sheet would be cut into standard tensile specimens (length 200 mm, gauge length 50 mm). The tensile test was performed with CMT4105-type tensile test machine to test mechanical properties. The longitudinal cold rolling plane sections of samples after annealing were prepared and etched with 4% natal. The microstructure was analyzed by scanning electron microscopy (SEM). Some samples were analyzed using transmission electron microscopy (TEM).3 Results and discussion3.1 Mechanical properties and microstructures ofsamples after hot-rolling and continuousannealingTable 1 shows the tensile test data for the two samples after hot-rolling and continuous annealing in terms of yield strength, ultimate tensile strength and total elongation. When the annealing temperature is 800 ℃and soaking time is 60 s, the tensile strength reaches 1 110 MPa and the total elongation reaches 12%. Compared with the hot-rolled samples, the yield strength and total elongation of sample after annealing are similar, but the tensile strength increases by about 450 MPa. The yield ratio decreases obviously. The engineering uniaxial tensile stress—strain curve of the sample after continuous annealing is characterized by very uniform plastic flow until necking. There is no physical yield point and yield point extension, that is, the steel exhibits continuous yielding which is commonly attributed to mobile dislocations introduced during cooling from the intercritical annealing temperature. Many dislocation sources come into action at low strain and plastic flow begins simultaneously through the specimen, thereby suppressing discontinuous yielding[15].Table 1 Mechanical properties of samples after hot rolling and annealingConditionYieldstrength/MPaTensilestrength/MPaYieldratio*Totalelongation/% Hot rolling555 665 0.83 16 Annealing540 1110 0.49 12* Yield ratio is defined as the ratio of yield strength to tensile strength.The microstructures of the hot-rolled and cold-rolled samples are shown in Fig.2. It can be observed that hot rolled steel features a band microstructure, i.e. pearlite band in a ferrite grain matrix. The ferrite grain size is measured to be 5.0−9.0 µm. After cold rolling, the microstructure consists of elongated grains of ferrite and deformed colonies of pearlite (Fig.2(b)). After cold-rolling, there is an increase in the stored energy of the steel due to the high dislocation density and this provides the driving pressure for the ferrite recrystallization during annealing process. The total ferrite grain boundary area increases and the cementite laminar structure in pearlite is broken down. The latter has been shown to promote spheroidization of cementite during subsequent annealing process.The SEM micrograph of the sample after annealing is given in Fig.3(a). The microstructure of DP steel consists of a mixture of ferrite, martensite, martensite/austenite constituent. There is also some bainite in the microstructure. The martensite islands are homogeneously distributed in ferrite matrix. The DP steel has finer grain size and the size of ferrite grain and martensite island are about 1.0−2.0 µm. Some martensite islands have a bright white circle around the edge, and the center of martensite is of irregular black structure.ZHAO Zheng-zhi, et al/Trans. Nonferrous Met. Soc. China 19(2009) s563−s568 s565Fig.2 Microstructures of steel after hot rolling (a) and cold rolling (b)Fig.3 SEM images (a) and TEM micrograph (b) of steel after continuous annealingThe main reason is the manganese partitioning will occur during the continuous annealing process. During the heating process, a high-Mn side lap forms around austenite, which makes the hardenability of austenite island edge higher than that of the center. So, it makes high-Mn side lap form around martensite in the cooling process. The volume fraction of martensite is about 40%, which is the main reason for DP steel with a higher strength. After the continuous annealing process, band structure is significantly improved, which plays an important role in improving the performance of DP steel.The fine structures of martensite and ferrite are shown in Fig.3(b) by the TEM observation. The lath martensite is fine, and is relatively clean; at the same time, a very high density of dislocations can be observed in the ferrite grain adjacent to martensite. These dislocations are generated in order to accommodate transformation induced strain built between martensite transformed by quenching and retained ferrite. In addition, they are known to be mobile and play an important role on rapid, extensive strain hardening of DP steel from the onset of its plastic deformation.3.2 Microstructure evolution at initial steps ofcontinuous annealing processThe microstructure evolution at the initial stages of the continuous annealing process is very important for producing the ultra-high strength DP steel. During the annealing process of high strength DP steel, ferrite recovery and recrystallization, pearlite dissolution and austenite nucleation and growth will occur. When the sample is heated to 550 , the℃microstructure has no visible change as compared with the cold rolled sample. The ferrite grain is stretched along the rolling direction significantly; lamellar pearlite is stretched along the rolling direction too. At the same time, there are some carbide particles in the ferrite matrix, as shown in Fig.4(a). At this temperature, the recrystallization nucleus was not found in the structure. So, at this stage the sample is still at the recovery stage. When the heating temperature is 630 , the℃recrystallization nucleus begins to appear in the microstructure. The nucleus of crystal appears mainly nearby the large deformation ferrite (Fig.4(b)). The recrystallization nucleus is fine and equiaxed. Large deformation storage power is present in the large deformation region. So, recrystallization nucleus forms in this region firstly. With the heating temperature increasing, the recrystallization nucleus begins to grow. Therefore, the size of recrystallization is uneven at this stage, as shown in Fig.4(c). When the heating temperature is 670 ℃, the deformation structure still exists in the microstructure. With the temperature increasing, the deformed ferrite grains are replaced by recrystallization ferrite grains. When the heating temperature is 710 , the d℃eformation structure has already vanished, which is replaced by theZHAO Zheng-zhi, et al/Trans. Nonferrous Met. Soc. China 19(2009) s563−s568 s566equiaxed recrystallization grain. So, the process of recrystallization completes basically. In the ferrite recrystallization process, the pearlite transforms to granular from lamellar gradually.When the heating temperature is 730 ,℃it begins to enter the two-phase region; and the ferrite and spheroidised carbides begin to transform to austenite. A small amount of austenite nucleates in the original pearlite region, as shown in Fig.4(e). Austenite nucleates mainly in the ferrite and pearlite grain boundary; and a part of austenite also nucleates in the carbide particles of ferrite. After austenite nucleation, it begins to grow rapidly. At this stage, the pearlite dissolves rapidly. When the temperature reaches 750 , the austenite℃transformation occurs obviously. The bright white particle which distributes in the ferrite matrix is the martensite island. The martensite transforms from austenite during the rapid cooling process. At the same time, a small amount of martensite particles can also be observed in ferrite; and there are still some non-dissolved carbide particles in the ferrite matrix. The initial austenite growing-up is mainly controlled by the carbon Fig.4Microstructure evolutions duringcontinuous heating process: (a) 550 ℃; (b)630 ℃; (c) 670 ℃; (d) 710 ℃; (e) 730 ℃; (f)750 ℃; (g) 780 ℃ZHAO Zheng-zhi, et al/Trans. Nonferrous Met. Soc. China 19(2009) s563−s568 s567diffusion in the austenite, and the diffusion path is along the pearlite/austenite interface. When the annealing temperature is 780 , the austenite volume increase℃s, and the number of carbide particles is reduced gradually. There is only a very small amount of carbide particles distributing in ferrite matrix.3.3 Effect of overaging temperature onmicrostructure and mechanical properties ofDP steelThe overaging is a temper treatment to harden martensite in the dual-phase steel, reduce the hardness of martensite and improve the comprehensive mechanical properties[16]. Fig.5 shows the effect of overaging temperature on the mechanical properties of dual-phase steel. All the samples are intercritically annealed at 800℃ with different overaging temperatures. As can be seen from Fig.5, the highest tensile strength is achieved in the sample overaged at 280 ℃. The yield strength is 560 MPa, the tensile strength is 1 150 MPa, and the total elongation reaches 13%. The good combination of high strength and toughness properties is obtained. And then, with the increase of overaging temperature, the yield strength and tensile strength of samples decrease, while the total elongation increases. When the overaging temperature reaches 360 ℃, the tensile strength decreases, the yield strength does not change significantly. The mechanical properties of sample cannot meet the necessary requirements of CR980DP. At the same time, the stress—strain curve of the steel shows discontinuous yielding behaviour and develops yield plateaus.Fig.6 shows the SEM microstructures with different overaging temperatures. It can be seen that the microstructure mainly consists of dark grey ferrite grains and white martensite. When the overaging temperature is 360 ℃, the martensite boundary is fuzzier than that of sample overaged at 320 ℃, and there are more carbides, which is due to the effects of tempering on the martensite, such as the volume contraction of martensite during the tempering, the changes of the martensite strength and additional carbon clustering or precipitation near the ferrite and martensite interfaces.Fig.5 Effects of different overaging temperatures on mechanical propertiesFig.6 SEM images of microstructures of DP steel overaged at different temperatures: (a) 240 ℃; (b) 280 ℃; (c) 320 ℃; (d) 360 ℃ZHAO Zheng-zhi, et al/Trans. Nonferrous Met. Soc. China 19(2009) s563−s568 s5684 Conclusions1) When the DP steel is annealed at 800 ℃ for 80 s and overaged at 280 ℃, the tensile strength and total elongation of ultra-high strength dual-phase steel can reach 1 150 MPa and 13%, respectively.2) The microstructure of DP steel consists of a mixture of ferrite, martensite, martensite/austenite constituent. There are also some bainites in the microstructure. The martensite islands are homogeneously distributed in ferrite matrix. The ferrite and martensite island grain size are about 1.0−2.0 µm. When the overaging temperature reaches 360 ℃, the tensile strength decreases, the yield strength does not change significantly. The mechanical properties of sample cannot meet the necessary requirements of CR980DP. At the same time, the steel shows discontinuous yielding behaviour and develops yield plateaus.References[1]KANG Yong-lin. Quality control and formability of the mordernMotor plate [M]. 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热处理工艺对2A97铝锂合金拉伸性能和腐蚀性能的影响林毅;郑子樵;韩烨;张海锋【摘要】研究不同热处理工艺对2A97铝锂合金拉伸性能和腐蚀性能的影响.结果表明：合金经热处理工艺C(5%预变形+100℃,1.5 h+5%中间变形+160℃, t)处理后,获得较好的强度与塑性的配比,在峰时效状态下,合金抗拉强度和伸长率分别为597 MPa和7.4%.同时,合金耐晶间腐蚀性能优异,平均晶间腐蚀深度为22μm.在分步变形和双级时效的综合作用下,合金在峰时效晶内获得大量弥散细小的T1相和少量的S′相,晶界处析出相稀少,无沉淀析出带不明显,使2A97合金获得高强度的同时,改善塑性和耐晶间腐蚀性能.【期刊名称】《中国有色金属学报》【年(卷),期】2012(000)008【总页数】6页(P2181-2186)【关键词】2A97铝锂合金;微观组织;晶间腐蚀;双级时效【作者】林毅;郑子樵;韩烨;张海锋【作者单位】中南大学材料科学与工程学院,长沙 410083;中南大学材料科学与工程学院,长沙 410083;中南大学材料科学与工程学院,长沙 410083;中南大学材料科学与工程学院,长沙 410083【正文语种】中文【中图分类】TG116.3Abstract:The effects of various heat treatment processes on tensile and corrosion properties of 2A97 Al-Li alloy were investigated. The results show that, undertaken with heat treatment process C (pre-deformation 5%+100 ℃, 1.5 h+mid-deformation 5%+160 ℃, t), the alloy obtains preferable combination of strength and ductility. At the peak-aged condition of heat treatment process C, the tensile strength and elongation of 2A97 Al-Li alloy are 597 MPa and 7.4%,respectively. Meanwhile, the intergrannular corrosion resistant is excellent, and the average intergranular corrosion depth is 22 μm. Under the comprehensive function of multi-step deformation and two-step aging, the large quantities ofT1precipitate dispersedly in grain with some S′ phase, few second phases precipitate in grain boundary, and the precipitation free zone is not obviously near grain boundary, which respond to the favorable tensile properties and corrosion properties of 2A97 Al-Li alloy at peak-aged.Key words:2A97 Al-Li alloy; microstructure; intergrannular corrosion; two-step agingAl-Cu-Li系合金为时效强化型变形铝合金。

Value Engineering———————————————————————基金项目:国家市场监督管理总局科技计划项目（2022MK165）“大容量电站锅炉奥氏体耐热钢高温蠕变-低周疲劳损伤模型及寿命预测研究”；陕西省市场监督管理局科技计划项目（2021KY12）“二氧化硅-氟硅烷阵列超疏水耐蚀涂层在热力管道的应用研究”。

作者简介:陈梦诗（1992-），女，河北任丘人，本科，工程师，从事承压类特种设备检验检测及安全与节能技术研究。

0引言节能减排是我国未来经济和社会可持续发展的重要战略方向之一，效率低下、污染严重的传统火电机组逐步面临被低能耗、低污染的超超临界发电机组所取代。

性能优良的耐热钢是研发超超临界发电机组的关键技术之一。

奥氏体耐热钢Super304H 是日本钢铁研发机构在奥氏体耐热钢TP304的基础上，添加0.45%Nb 、3%Cu 以及少量N 元素，制备的新型奥氏体耐热钢。

超超临界发电机组运行过程中，显微组织析出的ε-富Cu 、Cr 23C 6、Nb （C ，N ）和NbCrN 相产生强化作用，显著提高奥氏体耐热钢Super304H 高温服役性能[1,2]。

目前针对奥氏体耐热钢的研究大多集中在高温时效及服役过程中碳化物析出相变化及显微组织对力学性能的影响。

本论文对奥氏体耐热钢Super304H 进行不同时间的高温时效处理，对时效处理后的试样进行金相组织观察和物相分析，研究碳化物析出相的分布、形态和颗粒大小随时效过程的变化规律，并通过进行拉伸强度试验、冲击性能试验，研究时效过程对力学性能的影响。

本论文的研究为苛刻服役条件下长周期运行的大容量电站锅炉的寿命预测和安全风险评价提供理论基础和数据支持，可以有效对大容量电站锅炉运行状态和安全状况给予科学判断，延长大容量电站锅炉安全运行时间和减少因奥氏体耐热钢高温蠕变-低周疲劳失效造成的机组停运损失，保障人民生命财产安全，具有显著的经济和社会效益。

高强度铝合金淬火敏感性表征方法建立与应用1. 引言- 研究背景和意义- 相关研究概述- 本文研究内容和目标2. 高强度铝合金淬火敏感性表征方法建立- 材料和试验方法介绍- 宏观性能测试- 组织观察与分析- 微观性能测试- 基于结果的表征方法建立3. 表征方法的应用与优化- 对比分析不同淬火工艺的表征结果- 优化淬火工艺以改善淬火敏感性- 尝试应用表征方法到其他高强度铝合金材料中4. 结果与讨论- 对淬火敏感性进行定量表征- 淬火工艺对宏观与微观性能的影响- 表征方法的优缺点分析- 结果讨论和解释5. 结论和展望- 本文工作的意义和局限性- 总结本文研究成果- 提出未来研究的方向和展望6. 参考文献1. 引言随着工业发展和现代科技的不断进步，高强度铝合金被广泛应用于航空、汽车、船舶等领域。

其中，7系列铝合金具有优异的强度、刚度和耐腐蚀性能，因此被广泛使用。

然而，高强度铝合金在淬火过程中，由于形变和残余应力的存在，容易引起淬火敏感性，导致材料性能的降低和组织缺陷。

因此，对高强度铝合金的淬火敏感性进行研究是至关重要的。

此外，近年来，关于高强度铝合金淬火敏感性的研究已经非常广泛。

许多研究表明，淬火过程的参数，如淬火速率、淬火温度和保温时间等因素，对材料性能的影响非常重要。

然而，淬火敏感性的评价仍然存在很多挑战和困难，因为淬火过程中发生的复杂的相变和组织演变难以被直接观察和了解。

因此，建立一种合适的表征方法来评估高强度铝合金的淬火敏感性显得非常必要。

本文旨在通过分析不同淬火工艺下高强度铝合金的性能，建立一种高强度铝合金淬火敏感性表征方法，并优化淬火工艺以改善淬火敏感性。

该研究将有助于为高强度铝合金的淬火工艺优化提供参考，同时也可以为其他类似铝合金的材料提供有用的表征方法。

本文的一般结构如下：第一章介绍本文的研究背景和意义、相关研究概述以及本文研究内容和目标。

第二章描述建立高强度铝合金淬火敏感性表征方法的材料和试验方法。

表面技术第53卷第4期杂质镓对纯铝表面锆钛转化膜的组织及耐腐蚀性能的影响辛延琛，王友彬*，陈志文，冯济强，高峰，汤宏群（广西大学 a.资源环境与材料学院 b.省部共建特色金属材料与组合结构全寿命安全国家重点实验室，南宁 530004）摘要：目的探究杂质镓对纯铝锆钛转化膜的生长规律和防护性能的影响。

方法采用扫描电化学显微镜（SECM）技术表征了含镓纯铝表面锆钛转化膜在3.5%（质量分数）NaCl溶液中局部腐蚀的演变过程，结合X射线衍射仪（XRD）、X射线光电子能谱（XPS）、扫描电镜（SEM）等技术分析了镓对纯铝锆钛转化膜的组织及成分的影响规律，采用开路电位法（OCP）、电化学阻抗技术（EIS）以及极化曲线（Tafel）等探究了杂质镓对纯铝表面转化膜的生长和耐腐蚀性能的影响规律。

结果锆钛转化膜主要由冰晶石Na3AlF6、氧化物（如TiO2、ZrO2、Al2O3）和有机金属络合物组成；杂质镓的添加会抑制铝表面转化膜的生长，破坏膜层的完整性。

随镓含量（质量分数）从0%增大到0.5%，锆钛转化膜阻抗值从4.75×104Ω·cm2不断减小到2.49×103Ω·cm2，自腐蚀电流密度由0.45 μA增加到13.4 μA，腐蚀电位从−0.485 V降低到−0.890 V，耐腐蚀性能逐渐降低。

在锆钛转换膜的SECM微区腐蚀演变过程中，膜层自修复行为会降低膜层的被腐蚀倾向，但富集在表面的镓会抑制自修复膜层的形成，导致基体被严重腐蚀。

结论铝中的杂质镓能够直接影响锆钛膜的完整性，降低对铝基体的保护，导致了铝基体局部腐蚀溶解的发生。

关键词：杂质镓；锆钛转化膜；局部腐蚀；扫描电化学显微镜；微区电化学中图分类号：TG178文献标志码：A 文章编号：1001-3660(2024)04-0046-12DOI：10.16490/ki.issn.1001-3660.2024.04.004Effect of Impurity Ga on the Microstructure and Corrosion Resistance of Zirconium Titanium Conversion Coating on Pure AlXIN Yanchen, WANG Youbin*, CHEN Zhiwen, FENG Jiqiang, GAO Feng, TANG Hongqun(a. School of Resources, Environment and Materials, b. State Key Laboratory of Featured Metal Materials andLife-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China)ABSTRACT: Al alloys are widely used in many applications such as aerospace, rail transit, automobile, and power electronics industry due to the advantage of low density, high strength, and good formability. However, Al alloys are easily corroded in the solution containing Cl− ions, which causes local corrosion, such as pitting corrosion and intergranular corrosion, resulting in the decrease of service life. To improve the corrosion resistance of Al alloys, zirconium titanium (Zr/Ti) conversion coating is收稿日期：2022-12-24；修订日期：2023-05-18Received：2022-12-24；Revised：2023-05-18基金项目：广西自然科学基金面上项目（2021GXNSFAA196046）；国家自然科学基金（11975082）Fund：Guangxi Natural Science Foundation (2021GXNSFAA196046); National Natural Science Foundation of China (11975082)引文格式：辛延琛, 王友彬, 陈志文, 等. 杂质镓对纯铝表面锆钛转化膜的组织及耐腐蚀性能的影响[J]. 表面技术, 2024, 53(4): 46-57. XIN Yanchen, WANG Youbin, CHEN Zhiwen, et al. Effect of Impurity Ga on the Microstructure and Corrosion Resistance of Zirconium Titanium Conversion Coating on Pure Al[J]. Surface Technology, 2024, 53(4): 46-57.*通信作者（Corresponding author）第53卷第4期辛延琛，等：杂质镓对纯铝表面锆钛转化膜的组织及耐腐蚀性能的影响·47·usually prepared to protect the Al substrate. Ga is the one of the main impurity elements in Al alloy, and can enhance the electrochemical activity of Al alloy in the corrosive medium, which makes it challenging to generate natural dense oxide film on the surface of Al alloys and significantly reduces the corrosion resistance of the Al alloy. During the preparation process of Zr/Ti conversion coating, Ga dissolved from the Al substrate can be enriched on the surface, which is a hidden danger to the protective performance of the Zr/Ti conversion coating. At present, there is little research on the adverse effect of Ga on the Zr/Ti conversion coating, which needs further exploration. The work aims to explore the effect of impurity Ga on the growth and protective properties of the Zr/Ti conversion coating. The evolution of local corrosion of Zi/Ti conversion coating on pure Al containing gallium in 3.5wt.% NaCl solution was characterized by scanning electrochemical microscope (SECM). The effect of impurity Ga on composition of coating was investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and scanning electron microscopy (EDS). The growth of the Zr/Ti conversion coating on Pure Al was studied by open circuit potential (OCP), and the electrochemical impedance spectroscopy (EIS) and polarization curve (Tafel) were used to investigate the variation of corrosion resistance of conversion coating on pure Al with Ga content.The Zi/Ti conversion coating was mainly composed of Na3AlF6 and organic metal complexes, in addition to oxides such as TiO2, ZrO2, and Al2O3. The impurity Ga could inhibit the growth of the Zr/Ti coating, and reduce the integrity of the Zr/Ti coating. The corrosion resistance of the Zr/Ti conversion coating significantly decreased with the increase of Ga content from 0% to 0.5%, the electrochemical impedance of the Zr/Ti conversion coating decreased from 4.75×104 kΩ to 2.49×103 kΩ, the corrosion current density of coating increased from 0.45 μA to 13.4 μA, and the corrosion potential decreased from −0.485 V to −0.890 V. During the evolution of SECM micro-zone corrosion of the Zr/Ti conversion coatings, the self-healing behavior of the coatings could reduce the corrosion tendency. However, Ga enriched on the resurface could inhibit the formation of self-repairing film, leading to severe corrosion of the Al substrate. Therefore, the impurity Ga in Al can directly affect the integrity of the Zr/Ti coating, and reduce the protection of the Al substrate, leading to the occurrence of localized corrosion and dissolution of the Al substrate.KEY WORDS: impurity Ga; zirconium titanium conversion coating; localized corrosion; scanning electrochemical microscope (SECM); localized electrochemistry铝合金因其比强度高、耐蚀性及成形性好等优势，被广泛应用于交通运输、船舶、航空航天等领域。

DZ408合金低周疲劳行为张仕朝【摘要】研究了 DZ408合金在950℃，1000℃和1050℃，应变比为0．05条件下的低周疲劳性能。

结果表明：平均应变为正时，非对称循环应变控制会产生平均应力松弛现象，且随着温度与应变幅的增大，平均应力松弛速率增大；在950℃，1000℃和1050℃时，材料具有 Massing 特性，采用修正的 SWT 模型能很好地预测不同温度下应变比为0．05的低周疲劳寿命，且给出了修正 SWT 模型参数随温度变化的关系式Δεt 2σmax ＝（－38．9＋0．101 T）N（0．96－0．0014T）。

%The total strain-controlled low cyclefatigue(LCF)behaviors of directionally solidified(DS)superalloy DZ408 at 950 ℃, 1000 ℃ and 1050 ℃ for R =0.05 were investigated.The results of LCF tests indicate that the mean stress relaxation is occurred under asymmetric straining .The rate of mean stress relaxation is increased with the increase of temperature and strain amplitude.The alloy has Massing characteristic at 950 ℃,1000 ℃ and 1050 ℃ for R =0.05.All the LCF data obtained under various temperatures are well correlated by the modified SWT approach for lifetime prediction,and also the relationship between temperature and parameter of modi-fied SWT model are obtained.【期刊名称】《航空材料学报》【年(卷),期】2016(000)001【总页数】5页(P93-97)【关键词】DZ408;低周疲劳;应变比;平均应力松弛【作者】张仕朝【作者单位】北京航空材料研究院，北京 100095; 航空材料检测与评价北京市重点实验室，北京 100095; 先进高温结构材料科技重点实验室，北京 100095【正文语种】中文【中图分类】TG132.33定向凝固高温合金由于很好的综合力学性能，被广泛应用航空工业中。