纳米片Nb/TiNi记忆合金复合材料的力学性能与微观变形行为  

Mechanical Property and Micro Deformation Behavior of Nano-Laminar Nb/TiNi Shape Memory Alloy Composite

作　　者：姜大强[1] 宋健[1] 蒋小华[1] 崔立山[1] Jiang Daqiang;Song Jian;Jiang Xiaohua;Cui Lishan(College of New Energy and Materials,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)新能源与材料学院,北京昌平102249

出　　处：《稀有金属》2021年第4期502-506,共5页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51571212,51731010,51831006,51971243)资助。

摘　　要：已证实利用"应变匹配"概念可以在TiNi相变基体中实现Nb纳米线的高强度,并获得高性能复合材料。然而该纳米线Nb/TiNi复合材料采用的原位共晶反应方法限制纳米线Nb的体积分数最大约25%,因而不利于高性能复合材料的设计与开发。为了获得更高Nb体积分数的相变基纳米复合材料,采用包覆叠轧及拔丝方法制备Nb体积分数达33%的纳米片Nb/TiNi复合材料。利用扫描电镜(SEM)、透射电镜(TEM)、拉伸机、同步辐射对复合材料的微观组织、力学性能及微观变形行为进行了研究。结果表明:复合材料丝由bcc-Nb和B2-TiNi两相组成,且沿丝材轴向具有明显的Nb<110>丝织构,Nb纳米片厚度约为30 nm,与TiNi界面结合良好,没有冶金缺陷。在拉伸循环过程中,复合材料丝材中Nb纳米片的点阵应变最大可达3.2%,复合材料丝材屈服强度约为1150 MPa,经过8%拉伸卸载后再加载过程的近线弹性应变约为4%。Bulk materials generally exhibited only about 10%of their possible theoretical capabilities for strength.At the meantime,nano-dimensioned materials had been found to show high strengths and elastic lattice strains approaching these theoretical limits.Therefore,using nano-dimensioned materials as reinforcements to create super strong bulk composites had become a goal of many scientists.However,practice had proven challenging to harness the extraordinary properties of nanomaterials in bulk composites and these nanomaterial-reinforced bulk composites had all failed to deliver the expected promises.This had been overcome only recently by the concept of lattice strain matching as demonstrated in a Nb/TiNi nanocomposite,in which the high strength of Nb nanowires and high-performance composites were achieved in TiNi matrix.However,the volume fraction of Nb in nanowire Nb/TiNi composite was limited by in-situ eutectic reaction to about 25%,which was not conducive for developing high-performance composites.The ex-situ fabrication method could provide the option for controlling the constituent volume fractions of the composite,and the accumulative roll bonding(ARB)was the most effective one for producing bulk nanocomposites.Traditional cold ARB had been used to fabricate Mg,Al and their alloys thanks to their low work hardening rate.However,it was not suitable for fabricating TiNi shape memory alloy(SMA)composite by cold ARB,because of the strong work hardening effect of TiNi SMA.In order to obtain a composite with higher volume fraction of Nb,the hot packaged ARB(PARB)and subsequent wire drawing were used to prepare nano-laminar Nb/TiNi composite wire with 33%Nb.The commercial TiNi sheets and Nb sheets were used in this study.Small sheets of 50 mm×100 mm in size were first cleaned to remove any surface contamination and then alternately stacked and packed in a steel sheath.The package was then evacuated and sealed before hot rolling at~800°C to bond the laminates.For each rolling pass the thickness reduction was~90%.Aft

关 键 词：TINI 形状记忆合金 马氏体相变 应变匹配 

分 类 号：TG139.6[一般工业技术—材料科学与工程]