高温退火和时效处理对Ni_(47)Ti_(44)Nb_9合金显微组织和马氏体相变的影响

Effects of Annealing at High Temperature and Aging on Microstructure and Martensitic Transformation of Ni_(47)Ti_(44)Nb_9 Alloy

本文用金相显微镜、电子探针和电阻率-温度曲线测试仪研究了高温退火和时效对Ni_(47)Ti_(44)Nb_9合金显微组织和马氏体相变的影响。结果表明,加热温度高于1050℃时,β-Nb相粒子聚集长大,但对马氏体相变并不产生明显影响。与富Ni的近等原子比Ti-Ni合金不同,Ni_(47)Ti_(44)Nb_9合金在时效过程中没有时效析出和时效硬化现象。Nb加入Ti-Ni合金中抑制了时效析出和R相变,从而降低了马氏体相变温度受热处理制度影响的敏感性,使马氏体相变开始温度比较稳定。

Effects of annealing at high temperature and aging on microstructure and martensitic transformation ofNi_(47)Ti_(44)Nb_9 alloy have been investigated by means of optical microscopy,electron probe x-ray micro-analyz-er and measurement of electrical resistivity vs temperature.It showed that β-Nb phase particles tend to gath-er and grow when the alloy specimens are annealed at temperatures higher than 1050℃,however,whichhas no effect on the martensitic transformation.During aging there are no precipitates and age hardening,which is different from that in Ni-rich Ti-Ni binary alloys.Nb addition of Ti-Ni alloy restricts the precipi-tation and R phase transition.Therefore,the sensitivity of martensitic transformation temperatures to heattreatment is reduced and starting temperature of martensitic transformation is stabilized.