时效对富镍Ti-50.7at%Ni形状记忆合金马氏体多步相变行为的影响  

Effect of Aging on Behavior of Multi-step Martensitic Phase Transformation in Ni-rich Ti-50.7at% Ni Shape Memory Alloy

作　　者：于学勇 邹昱 YU Xueyong ZOU Yu(Automotive Engineering Department, Changshu Institute of Technology, Changshu 215500, China)

机构地区：[1]常熟理工学院汽车工程学院,江苏常熟215500

出　　处：《热加工工艺》2017年第20期236-238,242,共4页Hot Working Technology

摘　　要：采用DSC(差示扫描量热法)热循环研究了Ti-50.7at%Ni形状记忆合金经时效处理后马氏体多步相变演化行为和相变机制。结果表明:合金在250、400、550℃时效1 h水冷后,相变为B2→R,R→M1(沉淀相附近)和R→M2(母相附近)三阶段相变;700℃时效后,相变为B2→M一阶段相变。400℃时效时合金析出的沉淀相Ti3Ni4最多,使Ms(B2→M的起始温度)升至32℃,Af(M→B2的终了温度)升至50℃,马氏体相变温度是由沉淀相Ti3Ni4的析出速率和组织的回复进程共同决定的。The evolution behavior and mechanism of multi-step martensite phase transformation in Ti-50.7at%Ni shape memory alloy after aging treatment were studied by using differential scanning calorimetry （DSC） thermal cycling. The results show that after aging at 250,400 and 550℃ for 1 h and then water cooling, the phase transition of the alloy is the three stages： B2→R, R→M1 （Near the precipitated phase） and R→M2 （Near the parent phase）; after aging at 700℃, the phase transition is one stage： B2→M. During the aging at 400 ℃, the precipitation phase Ti3Ni4 of the alloy is the most, M, （starting temperature of B2→M） reaches 32 ℃and Af （finishing temperature of M→B2） reaches 50℃. The martensitic phase transformation temperature is determined by the precipitation rate of precipitated phase Ti3Ni4 and the recovery process of the microstructure.

关 键 词：富镍NiTi记忆合金 马氏体多步相变 差示扫描量热法 

分 类 号：TG156.92[金属学及工艺—热处理] TG111.5[金属学及工艺—金属学]