摘要
采用光学显微镜、X射线衍射仪(XRD)和万能试验机等仪器对铸态以及退火条件下Ti_(49)Ni_(51)形状记忆合金的微观组织和力学性能进行了研究。结果表明,合金随着退火温度的升高,晶粒逐渐由纤维状向等轴状过渡,晶粒变得粗大。XRD分析发现,对于铸态合金,在非晶态弥散衍射峰基础上呈现出Ti Ni晶体相衍射峰;样品在723 K和773 K退火,非晶态弥散衍射峰消失,XRD谱图上显示出现Ti Ni晶体相的衍射峰。Ti_(49)Ni_(51)合金在723 K和773 K温度下热处理30 min后进行压缩试验的结果表明,723 K热处理试样在加载过程中母相奥氏体朝马氏体起始转变应力σAs大于773 K热处理试样的母相奥氏体朝马氏体起始转变应力;然而,前者母相奥氏体朝马氏体完成转变应力σAf小于后者母相奥氏体朝马氏体完成转变应力;另外,在卸载试验中,前者的残余应变小于后者的残余应变。
In this paper, the microstructure and mechanical properties of as-cast and annealed Ti49Ni51 shape memory alloy were investigated by means of optical microscope, X-ray diffraction （XRD） and universal testing machine. The results show that the grain sizes of the alloy increases with the increase of the annealing temperature. In addition, the grain size is gradually changed from the like-fiber crystal to equal axis crystal. The diffraction peaks of TiNi crystal phase for the cast alloy were found on the basis of the non crystalline diffuse diffraction peak of XRD patterns. When the samples were annealed at 723 K and 773 K, the non crystalline diffuse diffraction peaks disappeared and a TiNi crystal phase exhibited in the XRD patterns. The Ti49Ni51 alloys with heat treatment of 723 K and 773 K at 30 min were compressed. The results show that the beginning stress （erAs） of the austenite phase transforming the specimen at heat treatment of 723 K is larger than that of the specimen at heat treatment of 773 K. However, the finishing stress of austenite phase transformation for the former was smaller than for the latter. In addition, the residual strain of the former was less than that of the latter in unloading experiments.
出处
《有色金属工程》
CAS
CSCD
北大核心
2016年第6期20-23,共4页
Nonferrous Metals Engineering
基金
陕西省教育厅专项基金(16JK1152)
陕西理工大学博士科研启动项目(SLGKYQD2-22)
