CAJ | 학술논문

对镍钛形状记忆合金在-20~120℃的温度区间内进行了应变控制下的循环加/卸载实验研究。实验结果表明,在温度低于80℃时,相变应力和耗散能均随循环周次的增加而迅速降低,残余应变随循环周次的增加而增加,它们均在一定的循环周次后均趋于稳定值；一旦温度超过80℃,逆相变开始应力随循环周次的增加反而增加,向前相变开始应力和逆相变结束应力与温度的线性关系不再保持。温度低于奥氏体完成温度之前,初始为马氏体相或马氏体-奥氏体混合相,残余应变随温度增加而减小,耗散能随着温度的增加而增加；温度高于奥氏体完成温度时,初始为奥氏体相,残余应变随温度的增加而增加,耗散能随温度的增加而下降,二者分别在40和20℃达到最小值和最大值。
대얼태형상기억합금재-20~120℃적온도구간내진행료응변공제하적순배가/사재실험연구。실험결과표명,재온도저우80℃시,상변응력화모산능균수순배주차적증가이신속강저,잔여응변수순배주차적증가이증가,타문균재일정적순배주차후균추우은정치；일단온도초과80℃,역상변개시응력수순배주차적증가반이증가,향전상변개시응력화역상변결속응력여온도적선성관계불재보지。온도저우오씨체완성온도지전,초시위마씨체상혹마씨체-오씨체혼합상,잔여응변수온도증가이감소,모산능수착온도적증가이증가；온도고우오씨체완성온도시,초시위오씨체상,잔여응변수온도적증가이증가,모산능수온도적증가이하강,이자분별재40화20℃체도최소치화최대치。
Within the temperature range of -20-120 ℃,the cyclic transformation characteristics of NiTi SMA were investigated in this work under the strain-controlled cyclic loading conditions.Experimental results show that,when the test temperature was lower than 80 ℃,the transformation stresses and dissipation energy de-cease rapidly with the increasing number of cycles and reach to their stable values after certain cycles.However, when the test temperature was higher than 80 ℃,the start stress of reverse transformation (i.e.,from induced martensite to austenite phase)increases during the cyclic loading,and then the start stress of forward transfor-mation (i.e.,from induced martensite to austenite phase)and finish stress of reverse transformation do not in-crease linearly with the temperature any more.When the test temperature was lower than the austenite finish temperature,the initial phase of the alloy consists of the martensite or the mixed martensite and austenite,the residual strain and dissipation energy decrease and increase with an increasing temperature,respectively;how-ever,once the test temperature was higher than the austenite finish temperature,the initial phase of the alloy was pure austenite,the residual strain and dissipation energy increase and decrease with an increasing tempera-ture,respectively.The minimum and maximum values of them were observed at 40 and 20 ℃,respectively.