NiMnGa合金是近年来备受关注的一类新型磁控功能材料，经应力场训练显示出优异的磁感生应变性能。然而，NiMnGa多晶合金中存在大量晶体学取向不同的马氏体变体，应力场训练中除孪生/去孪生还需中间马氏体相变共同协调变体间变形，由此引入的第二相马氏体和单一变体再取向路径极大地限制了应力场训练简化马氏体组态的效率，成为合金组织调控和性能优化的瓶颈问题。基于观察到的应力诱发连续正、逆中间马氏体相变现象，本项目提出揭示该现象的驱动条件和应变协调机制，以此为变体再取向间接路径优化应力场训练方法的设计思路。拟借助现代材料结构与性能分析技术表征变形中马氏体微观组织的演变，确定第二相马氏体的晶体结构和取向特征，揭示应力诱发连续正、逆中间马氏体相变的驱动条件和晶体学机理，阐明不同应力条件下该现象的变形协调机制，并以此过程作为变体再取向间接路径优化应力场训练方法，为NiMn基合金的组织调控和性能优化提供借鉴。

NiMnGa alloys is a new type of magnetic control functional material that have attracted great attention recently, these alloys show excellent magnetic field induced strains after stress field training. However, there are a large number of martensite variants with different crystallographic orientations in NiMnGa polycrystalline alloys. In addition to twinning / detwining, intermartensitic transformations are also required to accommodate the deformation between the variants during stress field training. The introduction of another martensite phase and the single path of variant reorientation greatly limit the efficiency of simplifying the martensite configuration by stress field training, which becomes a bottleneck for controlling the microstructures and optimizing the performances of the alloys. Based on the stress-induced direct and reverse intermartensitic transformation observed, we propose the reveal of driving conditions and strain accommodation mechanisms of this phenomenon, and make it to be the indirect path of variant reorientation to optimize the stress field training methods in this project. Firstly, the crystal structure and the crystallographic characteristics of the second martensite phase will be determined through the evolutions of martensite configuration in deformation process. Then, the driving conditions and the crystallographic mechanisms of continuous stress induced direct and reverse intermartensitic transformations will be figured out. Furthermore, the mechanisms of deformation accommodation of this phenomenon under different stress conditions will be clarified. Based on the above results, we will optimize the stress field training method with this process to be the indirect path of variant reorientation. This project may provide reference for the structure controlling and performance optimization of NiMn based alloys.