Mechanical definition and standardized measurement of the strain hardening exponent in tensile deformation
Mechanical definition and standardized measurement of the strain hardening exponent in tensile deformation
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发表时间：
2001
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通讯作者：
Song Yu-quan
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作者：
Song Yu-quan
由塑性拉伸变形状态方程推导出Hollomon方程，定义了该方程中的材料常数和应变硬化指数。给出了恒应变速率、恒速度和恒载荷三种典型变形条件下的测量公式。文中还给出了传统测量方法、计算机模拟测量方法和各公式对应的精确测量方法，并给出了典型材料Zn5%AI在18℃和340℃三种典型条件下的测量结果。由于这些结果之间存在较大偏差，因此，即使在相同的应力状态下，应变硬化指数也与成形条件密切相关。这就提出了如何解释偏差及其力学本质的新问题。
Hollomon' s equation is deduced from the state equation of plastic tensile deformation and the material constant and the strain hardening exponent in the equation are defined. The measuring formulae are put forward under three typical deformation conditions, i.e. constant strain rate, constant velocity and constant load. This paper also offers the traditional measuring method, the computer simulating measuring method and the exact measuring method corresponding to every formula, and the measuring results on the typical material Zn5%AI at 18℃ and 340℃ are given under three typical conditions. Due to the large deviation among these results, it is argued that the strain hardening exponent is closely related to the forming condition, even in the same stress state. Thereupon, new problems of how to explain the deviation and what is its mechanical essence are raised.