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采用TEM方法对Ti-51 at％Ni合金的高温相、预马氏体转变、马氏体转变以及弥散析出第二相进行了研究。结果表明:TiNi合金高温母相具有CsCl(B_2)有序点阵,经700～900℃淬火到室温后已发生了预马氏体转变,表现出复杂的衍射效应;用母相点阵的机械失稳引起的位移波来解释预马氏体转变似乎是合理的。对温度诱发马氏体和应变诱发马氏体的观察表明它们都具有孪晶亚结构,但可以有不同的组态。采用SAD方法鉴别了弥散析出的X相,它具有f. c. c结构,点阵常数a=15.8(?)与母相具有位向关系: <111>_x∥<111>_β, {110}_x∥{321}_β。
The TEM method was used to study the high temperature phase, the pre-martensitic transformation, the martensitic transformation and the second precipitated phase of Ti-51 at% Ni alloy. The results show that the high temperature parent phase of TiNi alloy has a ordered lattice of CsCl (B 2), and the pre-martensite transformation has occurred after being quenched to room temperature from 700 to 900 ℃, showing a complex diffraction effect. It seems reasonable to explain the pre-martensitic transformation by the displacement wave caused by instability. Observations of temperature-induced martensite and strain-induced martensite show that they both have twinned substructures but can have different configurations. The dispersed phase X was identified by the SAD method and it has the structure of fc c. The lattice constant a = 15.8 (?) Has an orientation relationship with the parent phase of <111> _x // <111> _β, {110} _x // { 321} _β.