退火温度对Ti-50.8Ni-0.1Zr合金的相变、组织和拉伸性能的影响  

Effects of annealing temperatures on transformation,microstructure and tensile properties of Ti-50.8Ni-0.1Zr alloy

作　　者：樊勇军[1] 周晓龙[1] 贺志荣[2] 曹建春[1] 曹宇[1] 陈敬超[1] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]陕西理工学院,陕西汉中723003

出　　处：《材料热处理学报》2013年第S1期30-34,共5页Transactions of Materials and Heat Treatment

基　　金：金川预研基金(金川201102)

摘　　要：用示差扫描热分析仪、光学显微镜和拉伸试验研究了不同退火温度(Ta)对Ti-50.8Ni-0.1Zr合金相变行为、显微组织和拉伸行为的影响。结果表明:Ta=400℃时,合金冷却/加热时的相变类型为A→R→M/M→R→A两阶段可逆相变,而Ta=500℃时,冷却/加热合金正逆转变为A→R→M/M→A,在M逆转变过程中没有出现R相。在Ta为600℃和700℃时,合金冷却/加热时发生A→M/M→A一阶段可逆转变。退火时,合金发生回复、再结晶和晶粒长大3个过程。Ta=350～450℃时,为回复阶段,合金组织为纤维状。Ta=500～600℃时,为再结晶阶段,合金组织由纤维状变为无畸变的等轴晶。Ta=650～700℃时,为晶粒长大过程,显微组织为不均匀的粗大等轴晶。随着Ta的升高,合金抗拉强度在减小,马氏体相变临界应力先增大后减小,Ta较高时伸长率显著增大,600℃以后随着晶粒尺寸增大,伸长率有所下降。Effects of annealing temperatures(Ta) on microstructure,transformation behavior and tensile behavior of Ti-50.8Ni-0.1Zr shape memory alloy were investigated by DSC,optical microscopy and tensile tests.The results show that when Ta=400 ℃,the transformation types during cooling or heating is A→R→M/M→R→A(reversible transformation with two stages),when Ta=500 ℃,the reversible transformation types is A→R→M/M→A,the R phase doesn't occur at the reverse transformation of R phase.When Ta=600-700 ℃,the reversible transformation types are A→M/M→A(one stage).The recovery,recrystallization and grain growth occur in the alloy during annealing.When Ta=350-450 ℃,the alloy is at the recovery stage,and the microstructure is fibriform.When Ta=500-600 ℃,the alloy is at the recrystallization stage,the microstructure turns to the unstrained equiaxed grains.When Ta=600-800 ℃,the alloy is at the grain growth stage,the microstructure shows larger and asymmetrical grains.With the increasing annealing temperature(Ta),the tensile strength of the alloy decreases,the critical stress of the stress-induced martensitic transformation declines at first and then rises,but the elongation of alloy increases at high annealing temperature,and then decreases due to the grain growth when Ta>600 ℃.

关 键 词：Ti-50.8Ni-0.1Zr合金 形状记忆合金 退火温度 相变行为 显微组织 拉伸性能 

分 类 号：TG156.2[金属学及工艺—热处理]