真空热处理对Ni-Mn-Ga形状记忆合金马氏体相变的影响研究

Effect of Vacuum Heat Treatment on Martensitic Phase Transformation of Ni-Mn-Ga Shape Memory Alloy

采用甩带的方法制备出Ni-Mn-Ga合金薄带,研究了真空热处理对合金薄带马氏体相变的影响规律.研究结果表明:随着真空热处理800℃下保温时间的延长,合金的结晶化程度,结晶组织有序化、均匀化不断改善,相变驱动力增大,马氏体相变及逆相变过程明显.室温XRD的结果也表明热处理后的Ni-Mn-Ga甩带样品的为7层四方调制结构和母相共存的组织,与DSC的测试结果相吻合,随着热处理时间的延长,XRD的衍射图谱主要衍射峰随之增强.

Ni-Mn-Ga ribbons are made by melt-spinning technology, The effect of vacuum heat treatment on martensitic phase transformation of Ni-Mn-Ga shape memory alloy is investigated. With the holding time at 800℃ prolonging during heat treatment, crystallization, microstructure ordering and homogeniza- tion of Ni-Mn-Ga ribbons are improved. Phase transformation driving force is also increased. Martensitic transformation and inverse transformation occur at room temperature. Ni-Mn-Ga ribbon sample after heated treatment are martensitic layer 7 square modulated structure and parent phase, which coexists with the DSC test results. The XRD diffraction peaks increase with the holding time at 800℃.