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本文研究了Ni含量变化对NiTi形状记忆合金的相变温度和性能的影响,结果表明,对经过中温热处理试样的A_S,T_R,M_S,M_f转变温度对Ni含量变化很敏感。当Ni含量为51at％Ni时,T_R.M_S,M_f转变温度处于最低值,偏离这一成份,T_R,M_S转变温度急剧升高。当Ni含量处于51～52at％Ni范围,合金的回复率和强度处于最高值,但合金在形状回复时的作功值在Ni含量为51at％Ni时为峰值。低于此Ni含量,作功值急剧下降;高于此Ni含量,作功值下降率较小。 室温X线衍射分析表明,Ni含量在49～52at％Ni范围,相的组成分数与Ni含量也是密切相关的。并且在Ni含量为51at％Ni或以上的合金中,除了B_2相,马氏体相和R相外,还出现了一组未确定相的衍射线条。
In this paper, the effect of Ni content on the phase transformation temperature and properties of NiTi shape memory alloys was studied. The results show that the A_S, T_R, M_S and M_f transformation temperatures of the samples after heat treatment are sensitive to the Ni content changes. When Ni content is 51at% Ni, T_R.M_S, M_f transition temperature is the lowest, deviate from this component, T_R, M_S transition temperature increased sharply. When the Ni content is in the range of 51-52at% Ni, the recovery rate and strength of the alloy are the highest values, but the work values of the alloy in the shape recovery are peak values when the Ni content is 51at% Ni. Below this Ni content, the working value dropped sharply; higher than this Ni content, the working value decreased rate was small. X-ray diffraction at room temperature shows that Ni content is in the range of 49- 52 at% Ni, and the phase composition and Ni content are also closely related. And in the Ni content of 51at% Ni or more alloys, in addition to the B_2 phase, martensite and R phase, but also appeared a group of undetermined phase diffraction lines.