摘要
从应力为应变和应变速率函数的状态方程出发,导出了超塑性拉伸变形的微分本构方程,从而解释了方程中应变硬化指数的力学涵义．导出了应变硬化指数的约束方程,定义了典型变形路径的应变硬化指数,导出了它们之间的相互关系．导出了典型变形路径应变硬化指数的测量公式和数值模拟的精确测量方法,以此为依据对应变硬化指数进行了实验测量,对测量方法和测量结果进行了精细分析．研究结果判明:应变硬化指数不仅不是常数,而且与应变的变化规律及变形路径有密切的联系;在一定变形路径下还与所用的测量公式有密切关系．因此,在引用应变硬化指数时,应该标明所对应的变形路径;在测量应变硬化指数时,应采用所对应变形路径的测量公式．
Based on the state equation that stress is a function of strain and strain-rate, the differential constitutive equation during superplastic tensile deformation is deduced, and then the mechanical meaning of the strain hardening index in the equation is interpreted. The constraint equation of strain hardening index is deduced, the strain hardening indexes in typical deformation paths are defined, and their interrelations are obtained. The formulae for measuring, indexes in typical deformation paths and precise measuring methods combined with numerical simulation are deduced. According to them, strain hardening indexes are experimentally measured, and measuring methods ＆ results are elaborately analyzed. The results proved that the strain hardening index is non-constant, and has close relations to the changing rule of strain and deformation path; strain hardening index has also close relations to the also with adopted measuring formula in the given deformation path. Therefore, as strain hardening index is quoted, the corresponding deformation path should be shown clearly; when measuring strain hardening index, the adopted formula should correspond to deformation path.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2006年第7期673-680,共8页
Acta Metallurgica Sinica
基金
国家自然科学基金项目50375064
吉林大学"985工程"项目资助~~
关键词
超塑性
应变硬化指数
力学解析
实验测量
superplasticity, strain hardening index, mechanical analysis, experimental measure
