摘要
对Hollomon关系式σ=k.εn所定义的应变硬化指数n值的力学本质进行了不同拉伸控制模式下的解析,通过单向拉伸实验分析了不同拉伸速率对n值的影响。研究表明:应变硬化指数n值不是常数,而是与控制模式有关的变量;由于多晶体金属材料塑性变形过程的时间性特点,提高拉伸速率会降低n值;拉伸在均匀塑性变形阶段推荐使用应变速率控制模式。由于是静载荷拉伸试验,采用较低的拉伸速率使得拉伸各项特征值更接近真实值。
The mechanical nature of strain hardening exponent（n-value）,which is defined by Hollomon formula,was analyzed under different kinds of tensile control modes.The effort on n-value of different tensile rates through one — way tensile test was analyzed as well.The study shows that,instead of a constant,the strain hardening exponent is a variable relevant to control mode.Because of polycrystalline metallic materials plastic deformation process time character,increasing tensile rate will decrease n-value.It is recommended to use strain rate control mode for tensile at the stage of uniform plastic transformation.Because of static load tensile test,utilizing lower tensile rate made each tensile character more close to the true value.
出处
《物理测试》
CAS
2010年第6期13-16,共4页
Physics Examination and Testing
关键词
应变硬化指数
控制模式
拉伸速率
strain hardening exponent
control mode
tensile rate
