Ni_(47)Ti_(44)Nb_9合金的相变滞后和应变马氏体的稳定性

TRANSFORMATION HYSTERESIS AND STABILITYOF STRAIN MARTENSITE IN Ni_(47)Ti_(44)Nb_9 ALLOY

用不同温度下的拉伸试验、电阻法测量和透射电镜分析系统地研究了Ni_(47)Ti_(44)Nb_9合金的相变滞后及其影响因素,探讨了应变马氏体的稳定性。结果表明,存在一个特征形变温度和形变量范围,在这个范围内形变时,可以得到宽的相变滞后和高的应变恢复率。不规则的孪晶马氏体和含有位错亚结构的马氏体,以及与β-Nb质点相交截的马氏体都具有较高的稳定性。

The transformation hysteresis and stability of strain martensite in Ni_(47)Ti_(44)Nb_9 alloy have been studied by means of tensile test under various temper- atures, electrical resistance measurement and TEM observation. It was shown that there is a characteristic deformation temperature and a strain range, in which the critical yield stress for stress-induced transformation acquires optimum matching with the yield strength of the β-Nb particles. In this case, deformation effectively increases the transformation hysteresis, while the strain recovery ratio remains use- fully high. The martensite with irregular fine twin substructure and martensite containing some dislocations as well as martensite intersected by the β-Nb particles possess high stability.