铸态和锻态Ni_(47)Ti_(44)Nb_9合金的热诱发马氏体相变  

Thermally Induced Martensitic Transformation of As-cast and As-forged Ni_(47)Ti_(44)Nb_9 Alloy

作　　者：孟玉堂[1] 张永皞[1] 孙明艳[1] 范啟超[1] 黄姝珂[1] 魏齐龙[1] 

机构地区：[1]中国工程物理研究院机械制造工艺研究所,绵阳621999

出　　处：《机械工程材料》2018年第3期24-27,32,共5页Materials For Mechanical Engineering

基　　金：中国工程物理研究院科学技术发展基金资助项目(2015B0302060);四川省科技厅应用基础项目(2017JY0319)

摘　　要：采用差示扫描量热仪(DSC)、X射线衍射仪(XRD)、光学显微镜(OM)和扫描电子显微镜(SEM)等设备,对比研究了铸态和锻态Ni_(47)Ti_(44)Nb_9合金热诱发马氏体相变及其逆转变的特征,分析了显微组织对相变过程的影响机理。结果表明:铸态合金由尺寸较大的初生NiTi相、共晶相(细小NiTi相+β-Nb相)以及分布在共晶区的(Ti,Nb)_2Ni相组成,锻造后合金中的β-Nb相和(Ti,Nb)_2Ni相弥散分布在NiTi基体相中;铸态合金中初生NiTi相和共晶NiTi相间的铌含量不同及化学成分偏析造成了相变峰和逆转变峰呈宽而扁的特征;经锻造后,NiTi相得到细化,合金的成分更加均匀,其相变峰和逆转变峰呈窄而尖的特征。The characteristics of thermally induced martensitic transformation and the reverse transformation of as-cast and as-forged Ni_（47）Ti_（44）Nb_9 alloy were studied and compared by using differential scanning calorimetry（DSC）,X-ray diffraction（XRD）,optical microscopy（OM）and scanning electronic microscopy（SEM）,and the influence mechanism of microstructure on phase transformation was analyzed.The results show that the as-cast alloy was composed of large primary NiTi phase,eutectic phase（fine NiTi phase andβ-Nb phase）and（Ti,Nb）_2Ni phase distributed in the eutectic area.β-Nb phase and（Ti,Nb）_2Ni phase of the alloy after forging diffusely distributed in the matrix of NiTi phase.The phase transformation peaks and reverse transformation peaks of as-cast alloy were wide and flat because of the compositional segregation and the difference of Nb content in primary and eutectic NiTi phases.NiTi phase became fine and the chemical composition became more homogeneous after forging and thus resulted in the narrowness and sharpness of the phase transformation peaks and reverse transformation peaks.

关 键 词：NiTiNb形状记忆合金 热诱发马氏体相变 铸态 锻态 

分 类 号：TP139[自动化与计算机技术—控制理论与控制工程]