應(yīng)力誘發(fā)相變行為演變的原位研究
(中國(guó)科學(xué)院 金屬研究所 金屬腐蝕與防護(hù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，
沈陽(yáng) 110016)
摘 要: 利用馬氏體相變有相變潛熱釋放的性質(zhì)，通過(guò)精確測(cè)量TiNi形狀記憶合金在不同變形條件下試樣溫度的變化波形， 結(jié)合應(yīng)力應(yīng)變響應(yīng)研究了循環(huán)應(yīng)力作用下TiNi形狀記憶合金相變行為的演變過(guò)程， 對(duì)循環(huán)應(yīng)力造成形狀記憶合金超彈性退化的原因進(jìn)行了探討。 結(jié)果表明： 試樣的溫度變化比普通金屬材料高許多，可以用溫度法來(lái)研究馬氏體相變?cè)谧冃芜^(guò)程中的變化； 在應(yīng)力控制的循環(huán)應(yīng)力作用下， 試樣內(nèi)應(yīng)力誘發(fā)馬氏體相變量隨著循環(huán)周次的增加而不斷減小， 每一周內(nèi)應(yīng)力誘發(fā)馬氏體相變行為也在不斷演化，發(fā)生應(yīng)力誘發(fā)馬氏體相變的臨界應(yīng)力不斷減小， 而由馬氏體彈性變形所攜帶的應(yīng)力增加。
關(guān)鍵字: NiTi形狀記憶合金； 疲勞； 應(yīng)力誘發(fā)相變；超彈性退化
transformation in TiNi shape memory alloy during cyclic deformation
（ State Key Laboratory for Corrosion and Protection of Metals, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China）
Abstract: The stress-induced martensitic transformation (SIMT) behavior and its change in TiNi shape memory alloys (SMAs) were investigated through accurately monitoring the fatigue specimen temperature change, along with the study of the stress-strain response. The effect of cyclic loading on the degradation of super elasticity (SE) was discussed. The results show that the temperature change of TiNi SMAs is much higher than that of common metallic materials due to SIMT. Therefore, it is reasonable to study the SIMT behavior by accurately monitoring the specimen temperature change. With increasing loading cycles, the amount of SIMT decreases under stress control. SIMT can take place at lower stress, and the stress is carried by elastic deformation of SMAs, instead of by SIMT.
Key words: TiNi shape memory alloy; fatigue; stress-induced martensitic transformation; degradation of super elasticity
