取向Ni-Mn-In基合金的马氏体相变行为及磁致应变研究

形状记忆合金的最大可回复应变量与晶体学取向密切相关，因此，从工程实际应用出发，具有择优取向且机械加工性能良好的多晶材料是获得大可回复应变量的关键。本项目提出采用等离子放电烧结(SPS)有序堆叠的具有择优取向合金带材的方法制备致密度高、力学性能优异、且具有一定择优取向的多晶Ni-Mn-In基磁性形状记忆合金的新思路。解决由于多晶材料各向同性和晶粒间相互协调导致的可回复应变量小及金属间化合物易沿晶开裂的本征脆性。考查SPS烧结制备取向Ni-Mn-In基磁性形状记忆合金的织构类型、马氏体相变行为、磁性能、磁场驱动马氏体逆相变特征及此过程可回复应变量的大小，查明合金织构类型与可回复应变量的关系及织构对可回复应变量的影响规律，阐明织构影响Ni-Mn-In基合金马氏体相变行为和磁致形状记忆效应的内在机制，为磁性形状记忆合金的工程实际应用提供理论指导。

The maximum recoverable strain is related to the crystallographic orientation of the shape memory alloy. Thus, it is crucial to .obtain polycrystals with prefered orientation and favorable mechanical property from the viewpoint of pratical application. This .project proposes a new idea to produce Ni-Mn-In based magnetic shape memory alloy with high density, good mechanical property .and preferred orientatation by means of spark plasma sintering the ordered piled melt-spun ribbons, in order to improve the small.recoverable strain due to the isotropy of the polycrystals, self-collaboration between grains and the intergranular fracture due to .the intrinsic brittleness of intermetallics. The texture type, martensitic transformation behavior, magnetic property, charactoristics .of magnetic field induced reverse martensitic transformation as well as the recoverable strain caused by this process will be investigated. .The relationship between the texture and recoverable strain, and the influence mechanism of texture on the mangetic field induced shape memory effect will also be clarified.The aim of this project is to provide theory guidelines for the application of magnetic shape memory alloy.