TiNi形状记忆合金变形特性实验研究

EXPERIMENTAL STUDY OF MECHANICAL BEHAVIOUR OF TiTi SHAPE MEMORYALLOY

给出了一种ＴｉＮｉ形状记忆合金（多晶）的单轴拉压、循环拉伸加卸载、形状记忆效果、恢复力、相变塑性变形及拉压。扭转比例、非比例加卸载的实验结果，实验结果显示，其变形特性非常不同于普通的弹塑性材料：如Ｂａｕｓｃｈｉｎｇｅｒ效果提前，甚至于会出现于卸载阶段；低温下的残余变形会在加热后消失；恒载下冷却时产生相当大的塑性变形（相变塑性变形）且在加热时消失等等。多轴加载实验结果表明，比例加载时该材料的加载屈服面及卸载屈服面都基本满足Ｍｉｓｅｓ准则，但非比例加载时则不然。

This paper presents experimental results of uniaxial tension-compression de-formation,cyclic tensile loading-unloading deformation, shape memory effect, recovery force,transformation plastic deformation and proportional and nonproportional tension/compressio-torsion deformation for a TiNi polycrystalline shape memory alloy。 The results shows thatthe mechanical behaviour of the shape memory alloy is very different from the ordinaryelastic-plastic materials in many aspects. For example, the“Bauschinger”effect appearsvery early even during the unloading process,the residual plastic deformation caused bythe deformation at low temperature recovers during the heating process,the large plasticdeformation(transformation plasticity)occurring and recovering under constant load duringthe cooiing and heating process,etc,The multipleaxial loading experimental results showthat either forward and reverse yield condition seem can be expressed by von Mises rulefor proportional loading,however,for non-proportional loading, the yield conditions don’tfollow the von Mises rule。