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利用TEM技术研究了经1000℃,1h(氩气保护)高温处理的50.5at.％Ni-Ti形状记忆合金在水淬和炉冷条件下的低温转变特性。结果表明,在室温下,炉冷试样已发生了有公度预马氏体转交和马氏体转变,同时具有机械记忆性能,而淬火试样仍处于无公度预马氏体转变阶段,并丧失记忆能力;但淬火试样经室温时效后可形成典型的孪晶马氏体组织,并重新呈现记忆行为。对时效现象的本质进行了讨论,认为这与过剩Ni原子形成的置换型结构缺陷有关。
The low temperature transformation properties of 50.5at.% Ni-Ti shape memory alloy treated by high temperature (1000 ℃, 1h) under water quenching and furnace cooling were investigated by TEM. The results show that at room temperature, the furnace cooled samples have taken place before the transfer of martensite and martensitic transformation, while having mechanical memory properties, while the quenched specimen is still in the transition phase of uncoordinated degree, And loss of memory; but after quenching the sample at room temperature can form a typical twin martensite, and re-present the memory behavior. The nature of the aging phenomenon is discussed, and it is believed that this is related to the substitutional structural defects formed by excess Ni atoms.