Ni-Mn-Ga合金具有高的热稳定性，通过调节成分，Ms温度可达400℃以上，是一种极具发展潜力的高温记忆合金。但该合金脆性大，已成为制约其发展和应用亟待解决的瓶颈。本项目拟采用Gd掺杂和非晶薄膜快速加热退火细化晶粒，制备高塑性Ni-Mn-Ga-Gd高温记忆合金薄膜。研究Gd掺杂对非晶薄膜晶化行为和晶化动力学的影响规律和机制，精确调控晶粒尺寸；研究晶粒尺寸对马氏体相变、拉伸变形行为及其机制、形状记忆效应及其热稳定性的影响规律和物理本质，确定发生马氏体相变临界晶粒尺寸；阐明马氏体亚结构、变体特征及其自协作形态随晶粒尺寸减小的演化规律，揭示马氏体相变尺寸效应的微观机制；建立晶粒尺寸-塑性-相变温度-可逆应变定量关系，研制出高塑性、高热稳定性高温记忆合金薄膜。这些研究对于发展微纳米尺度下马氏体相变和形状记忆效应理论及新型高温记忆材料具有重要意义。

Ni-Mn-Ga alloy is a kind of promising high temperature shape memory alloy (SMA) due to its excellent thermo-stability and high transformation temperature. It should be noted that the Ms is up to 400 C by adjusting the composition. However, its instinctive brittleness seriously prohibits its further development and applications. In the present project, a high-plasticity Ni-Mn-Ga-Gd SMA thin film with fine grain is obtained by Gd doping and rapid annealing of amorphous films. The influence and mechanism of Gd doping on the crystallization behavior and crystallizaiton kinetics of Ni-Mn-Ga-Gd SMA thin films is studied to accurately adjust and control the grain size. The influence of grain size on martensitic transformation, tensile deformation, shape memory effect and its thermo-stability is investigated to reveal the corresponding mechanisms. The critical grain size for martensitic transformation is determined by both experiments and calculation. The evolution of martensite substructure, variants characteristics and self-accommodation morphology with the decrease of grain size is investigated to disclose the mechanism of size effects of martensitic transfomation. The relationship among grain size, plasticity, martensitic transformation and reversible strain is bulit up. The high-temperature SMA thin film with high plasticity and high thermo-stability is developed. This enriches the theory of martensitic and shape memory effect and provides the guidance to develop new type high temperature SMAs.