真空感应重熔NiTi形状记忆合金室温拉伸力学性能

On the Mechanical Properties of Remelting NiTi Shape Memory Alloy by Vacuum Induction Melting

采用真空感应熔炼炉制备NiTi合金,并对重熔后的合金进行不同制度热处理。研究NiTi形状记忆合金边角料重熔合金不同温度时效后的室温拉伸力学性能。结果表明,NiTi形状记忆合金边角料重熔后,其室温屈服强度和抗拉强度均有不同程度的提高,断后延伸率略有增加,应力诱发马氏体相变对应的形状回复率降低;合金塑性变形能力随时效温度的升高而变差;合金中R相重新取向所提供的延伸率从总体上看比由单质原材料一次熔炼而成的合金要高。

The leftover materials of NiTi shape memory alloy were remelted via vacuum induction melting in a graphite crucible. After rolling,the remelted alloy plates were aged at different temperatures and their room temperature mechanical properties were investigated. Results show that after remelting of the leftover materials of NiTi shape memory alloys,their yield strength and tensile strength are increased to different extents,while the elongation is only increased a little. The shape recovery rate by stress-induced martensite transformation is decreased. At the same time,the ability of plastic deformation becomes poorer with the aging temperature increasing. On the whole,the elongation provided by reorientaion of R phase is longer than that of another NiTi shape memory alloy melted from electrolytic nickel and sponge titanium.