Improvement of shape memory effect for high-temperature shape memory alloys

形状记忆效应与形状记忆合金中的马氏体相变有关。在本研究中，阐明了高温形状记忆合金的合金设计，其在高温下施加的应变可以通过加热到相变温度以上来恢复。重点研究了相变温度较高的Ti（Pt, Ir）。研究了Ti（Pt, Ir）的相变和应变恢复。在850℃变形的Ti（Pr, Ir）中，加热到相变温度以上，得到2%的恢复应变。这清楚地表明Ti（Pt, Ir）是一种很有前途的高温形状记忆合金。在相变过程中控制相变应变和添加Ir控制晶体结构可以提高应变恢复。

Shape memory effect is related with martensitic transformation in shape memory alloys. In this study, alloy design of high-temperature shape memory alloys whose applied strain at high temperature is recovered by heating above phase transformation temperature will be clarified. We focused on Ti(Pt, Ir) with high phase transformation temperature. Phase transformation and strain recovery of Ti(Pt, Ir) were investigated. The 2% of recovery strain was obtained in Ti(Pr, Ir) deformed at 850 degree C after heating above phase transformation temperature. It clearly indicates that Ti(Pt, Ir) is very promising as high-temperature shape memory alloys. It is also clear that strain recovery will be improved by controlling of phase transformation strain during phase transformation and crystal structure by addition of Ir.