U-Nb形状记忆合金热弹性马氏体相变的相场模拟

Phase-Field Simulation of Thermoelastic Martensitic Transformation in U-Nb Shape Memory Alloys

U-Nb形状记忆合金具有优异的抗腐蚀性和力学性能,其中亚稳α"相的典型微观组织为多层级孪晶马氏体。利用相场法模拟α"相热弹性马氏体的形成过程。结果表明,在弹性应变能最小化的驱动下,获得了多种自协调马氏体组织,也发现了多种自协调模式。对比本研究模拟结果和文献中的实验结果,认为相变变形梯度矩阵的反对称性和界面兼容性显著影响变体结对和孪晶面。另外,基于变体重排过程,预测了相变态组织在变形初期的织构演化。

Metastable α"-phase U-Nb shape memory alloys exhibit outstanding corrosion resistance and mechanical property, in which multi-level twinning martensite is the typical microstructure. Phase-field method was used to simulate the formation process ofα" thermoelastic martensite. Results show that driven by minimization of elastic strain energy, various self-accommodated martensite clusters are obtained, and several self-accommodation modes are found. Comparing the simulated results with experimental results, it is suggested that the asymmetric deformation gradient tensor and interface compatibility notably influence the variant pair and twinning plane. In addition, the texture development upon deformation was predicted based on the variant rearrangement process.