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应用TEM分析技术对一种富Ni钛镍形状记忆合金时效后的组织进行了研究 ,结果表明 ,在不同温度下时效析出物的相结构和形态是不同的 .在 6 73～ 773K温度时 ,析出物都是Ti1 1 Ni1 4 相 ,随时效温度的提高 ,析出物的形态由细点状变为透镜状截面的椭圆板 ,这种相与B2母相是共格的 ,它的应变场使R相变与马氏体相变分离 ,Ti1 1 Ni1 4 相的析出会改善钛镍形状记忆合金的性质 .此外 ,在更高温度下时效合金将析出稳定的TiNi3相 ,该相与基体没有共格关系 ,同时导致基体镍含量下降 ,提高了马氏体转变温度 .
TEM analysis of a nickel-rich Ni-Ti shape memory alloy after aging organization, the results show that the aging precipitates at different temperatures phase structure and morphology are different at 673 ~ 773K temperature, the precipitation Ti1 1 Ni1 4 phase. With the increase of aging temperature, the morphology of precipitates changed from fine point to elliptical plate with lenticular section. This phase is in common with the B2 matrix, and its strain field makes R phase And the martensitic transformation, the precipitation of Ti1 1 Ni1 4 phase will improve the properties of TiN shape memory alloy.In addition, the stabilized TiNi3 phase will be precipitated at higher temperature, which has no coherent relationship with the matrix , At the same time lead to the matrix nickel content decreased, increased martensite transformation temperature.