Determination of a constitutive relationship for AZ31B magnesium alloy and validation through comparison between simulated and real extrusion
Determination of a constitutive relationship for AZ31B magnesium alloy and validation through comparison between simulated and real extrusion
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DOI：
10.1016/j.jmatprotec.2005.09.021
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发表时间：
2006-03-10
影响因子：
6.3
通讯作者：
Duszczyk, J
中科院分区：
文献类型：
--
作者：
Li, L;Zhou, J;Duszczyk, J
通过圆柱形热压缩试验，研究了变形镁合金AZ 31 B的流变应力随温度、应变和应变速率的变化规律。测试涵盖了广泛的温度范围（300-500摄氏度）和应变速率（0.03-90秒（-1）），因为可能会遇到真实的金属成型工艺。结果表明，在低应变速率下，流变曲线在流变应力峰值后的大应变处达到稳定状态。然而，在高应变速率下，流动曲线在峰值之后表现出连续的流动软化。此外，人们注意到，随着应变速率的增加，变形加热变得更加明显。因此，在高应变速率下的变形加热的流动应力的校正是必要的。双曲正弦形式的本构方程中的常数确定与测量的流变应力变形加热校正。验证测试，然后进行通过3D计算机模拟热挤压的基础上校正和未校正的流动应力数据，然后在相同的条件下的真实的挤压实验。在挤出温度和挤出压力的预测值和测量值之间取得了良好的协议。(c)2005 Elsevier B. V.保留所有权利。
In the present study, cylindrical hot compression tests were performed to determine the dependence of the flow stress of a wrought magnesium alloy, AZ31B, on temperature, strain and strain rate. The tests covered wide ranges of temperature (300-500 degrees C) and strain rate (0.03-90 s(-1)), as possibly encountered in real-fife metal-forming processes. It was found that at a low strain rate, the flow curve reached a steady state at a large strain after the flow stress peak. At a high strain rate, however, the flow curve exhibited continuous flow softening after the peak. In addition, it was noticed that with increasing strain rate, deformation heating became more pronounced. Thus, a correction of flow stress for deformation heating at a high strain rate was a necessity. The constants in the constitutive equation of the hyperbolic sine form were determined with the measured flow stresses corrected for deformation heating. Validation tests were then performed through 3D computer simulation of hot extrusion based on the corrected and uncorrected flow stress data, followed by real extrusion experiments under the identical conditions. Good agreements between the predicted and measured values in extrudate temperature and extrusion pressure were achieved. (c) 2005 Elsevier B.V. All rights reserved.