预变形和热循环对Ni_(50)Ti_(45)Ta_5形状记忆合金相变行为的影响

Effect of thermal cycling and pre-deformation on transformation behavior in Ni_(50)Ti_(45)Ta_5 shape memory alloy

利用示差扫描量热仪研究了预变形和热循环对Ni50Ti45Ta5形状记忆合金相变行为的影响。研究结果表明:预变形后合金的马氏体发生了稳定化现象。形变后第一次热循环,逆相变温度增加,正相变温度降低;而第二次相变循环,马氏体的稳定化现象消失。热循环使相变温度降低,减少了相变热。

The effect of thermal cycling and pre-deformation on transformation behavior in Ni_(50)Ti_(45)Ta_5 shape memory alloy was investigated using differential scanning calorimetry (DSC). The results showed than the critical temperature of the reverse transformation temperature increased and the forward transformation temperature decreased in the first cycle after deformation. A two-way memory effect was developed as a result of the deformation. Thermal cycling stability of Ni_(50)Ti_(45)Ta_5 alloy is good. Thermal cycling decreased the critical transformation temperatures. It was because thermal cycling can cause dislocations developed, thus decrease the thermoelstic energy and transformation enthalpy.