材料期刊网

Effect of Compressive Deformation on Lenticular and Thin Plate Martensitic Transformations

ZHA NG Xiumu QI Yan ZHONG Jiaxiang GUO Yunyi ** Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China.Beijing University of Science and Technology , Beijing , 100081 , China. To whom correspondence should be addressed.

材料科学技术（英文）

The effect of compressive deformation tested above the M_s temperature on the martensite morphology in Fe-Ni-C alloys has been studied.In the Fe-30Ni-0.12C alloy,the M_s temperature is -50℃ The cylindrical specimens were compressively deformed at -40℃.The strain rates were 10,20,30 and 40%.X-ray analysis and metallographic examination showed that no strain-induced martensite was found.After quench- ing to -53℃,some thin plates and unusual morphologies of lenticular martensites with bent and/or broken mid-ribs were observed.In the Fe-30Ni-0.34C alloy,the M_s temperature is -120℃.Compressive deformation with different strain rates were carried out at room temperature. After quenching to the liquid nitrogen temperature, some bent thin plate matensites(unbroken)occur- red.The transformed twins in bent plate were also bent and nearly parallel to the γ-α'interfaces. Orientation relationship between austenite and bent martensite has been examined by means of trans- mission electron microscope.It was proved that these unusual morphologies are inherent in the compressive pre-deformed austenite.

关键词: martensitic transformation , null , null , null

挤压态AZ31镁合金单向压缩过程中的退孪生行为

张愔 , 刘天模 , 徐舜 , 何杰军 , 卢立伟

材料热处理学报

用金相法、XRD等技术研究了挤压态AZ31镁合金单向压缩过程中的退孪生行为,并探讨退孪生机理.结果表明,在应变量较低时,拉伸孪晶数量随变形量的增大而增多,而当应变量＞4％时,随着变形量的增大,拉伸孪晶数量反而减少,即产生了退孪生现象.这种特殊的退孪生现象可以通过晶体转动理论解释,即随变形量的增大,基体逐渐转到硬取向,孪晶伴随转动,变形量较大时产生的{1012}拉伸孪晶的受力状态随转动发生改变,在已孪生部分又发生一次{10 12 }拉伸孪生,使原来已孪生部分取向再次与基体相同,即产生了退孪生.

关键词: 镁合金 , 孪生 , 退孪生 , 压缩变形

添加Al-TiB中间合金对铝合金组织、磨损和压缩变形行为的影响

中国有色金属学报 doi:10.1016/S1003-6326(11)61276-4

在7178铝合金中添加不同比例的Al-10％TiB中间合金,考察TiB对铝合金的晶粒细化、磨损和压缩变形行为的影响.组织观察表明,TiB颗粒起着晶粒细化剂的作用,导致生成球状枝晶.当Al-TiB中间合金的添加量超过20％时,合金的耐磨性和强度随着中间合金添加量的增加而降低,即使其枝晶组织变得更细而接近于球状组织.

关键词: 铝合金 , 晶粒细化 , Al-TiB中间合金 , 压缩变形 , 滑动磨损

Mo-Si-B三元系中T2相的脆-韧转变行为

潘昆明 , 张来启 , 王礞 , 林均品

金属学报 doi:10.3724/SP.J.1037.2013.00410

采用压缩和单边缺口三点弯曲实验,研究了MosSiB2 (T2相)合金试样在真空条件和不同温度下的压缩行为和断裂行为,利用XRD,SEM-EDS和TEM等对试样变形后的微观组织、位错组态和断口形貌进行了分析和观察.结果表明,T2相的脆-韧转变温度为1000---1200℃.在外加切应力的作用下,[010](001)和〈110〉{110}等多个滑移系开始开动,导致试样发生明显的塑性变形.由于刃型位错比螺型位错或混合型位错活跃,表现为[010]刃型位错深入到滑移面{110},与〈110〉位错发生交互作用,形成大量位错节点,导致加工硬化.随温度升高,试样断裂模式从单一解理断裂向穿晶解理-沿晶混合断裂转变,在1000℃时,试样断口处能清晰地观察到滑移带.

关键词: Mo5SiB2(T2相) , 压缩变形 , 断裂 , 位错组态 , 脆-韧转变