淬火温度对冷拉态Fe-18Mn-5Si-8Cr-4Ni合金形状记忆效应的影响

Effect of the Quenching Temperature on the Shape Memory Effect of Fe-18Mn-5Si-8Cr-4Ni Alloy as Cold-Drawing

研究了淬火温度对Ｆｅ － １８ Ｍｎ － ５Ｓｉ － ８Ｃｒ － ４Ｎｉ 记忆合金形状记忆效应和显微组织的影响。结果表明：合金的形状回复率和可回复变形量都随淬火温度的升高而增加，冷加工过程中产生的应力诱发ε马氏体的量随淬火温度的升高而减少，在６５０ ℃时形状回复率和可回复变形量达到最大值，在７５０ ℃时应力诱发ε马氏体完全消失，随后形状回复率和可回复变形量随淬火温度的进一步升高而快速下降；但淬火温度高于７５０ ℃以后，淬火温度的进一步升高对合金形状回复率和可回复变形量几乎没有影响，并且随着淬火温度的进一步升高，将产生热诱发ε马氏体，热诱发ε马氏体的量和尺寸也随淬火温度的升高而增加。预变形前基体中存在适量的ε马氏体可提高合金的形状记忆效应。

The effects of quenching temperature on shape memory effect and microstructure of Fe-18Mn-5Si-8Cr-4Ni shape memory alloy have been studied.The results showed that both the shape recovery ratio and the recovery strain increased as quenching temperature increased,the amount of stress-induced ε martensite in the process of cold-work decreased with the increase of quenching temperature,the shape recovery ratio and the recovery strain reached maximum at 650℃,and then decreased rapidly with the further increase in quenching temperature, the stress-induced ε martensite wholly disappeared at 750℃.But when the quenching temperature was higher than 750℃,the further increase in quenching temperature had little effect on shape recovery ratio,the amount and size of thermal-induced ε martensite would increase with the further increase in quenching temperature.The shape memory effct can be improved by the moderate amount of pre-exist ε martensite in the matrix before deforming.