The constitutive equations were gained by regression analysis and some material constants were derived from that with the aid of om , x - ray , sem and tem , the deformation structure of the mid - strength weldable 1420aluminum - lithium alloy on different hot deformation conditions was studied and the soften mechanism was discussed . at the same time , the fracture behavior has been studied as an important part . the fracture mechanism of 1420 aluminum - lithium alloy was confirmed 结合金相显微镜、 x -射线衍射、扫描电镜、透射电镜等现代化的试验手段，研究了中强可焊1420铝锂合金热变形不同变形条件下的组织变化及软化机制，分析了不同变形条件对合金材料组织变化的影响，确定了合金材料的软化行为机理；同时，结合合金材料的热变形高温拉伸试验，重点研究了材料的断裂行为，分析了合金材料的断裂现象，探讨了合金材料的断裂机理。
