An Enhanced Johnson-Cook Model for Hot Compressed A356 Aluminum Alloy
An Enhanced Johnson-Cook Model for Hot Compressed A356 Aluminum Alloy
复制标题
热压缩 A356 铝合金的增强型 Johnson–Cook 模型
DOI：
10.1002/adem.202000704
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发表时间：
2020-09-13
影响因子：
3.6
通讯作者：
Huang, Yi
中科院分区：
文献类型：
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作者：
Chen, Xiao-Min;Lin, Y. C.;Huang, Yi
为了研究A356铝合金的热变形行为，进行了应变速率0.01~10 s(-1)、变形温度300~420 ℃的等温压缩实验。此外，还分析了复杂的变形机制。研究发现，随着应变逐渐增加，流变应力首先上升，然后出现稳定应力，没有明显的峰值。显微组织表现出大的拉长晶粒，并且在大多数变形条件下仅出现少量小的新晶粒。这是因为动态恢复（DRV）是主要的软化机制。根据测量数据，为测试铝合金建立了原始Johnson-Cook（O-JC）模型和修改后的Johnson-Cook模型（M-JC）。然而，O-JC模型和M-JC模型的实验结果与预测的真实应力存在不同的偏差。考虑到明显的DRV特征，通过引入应力-位错关系，提出了增强的Johnson-Cook（EH-JC）模型。实验结果与预测结果的相关系数高达0.997，而平均绝对相对误差仅为2.84%，验证了EH-JC模型的准确性。
The isothermal compression experiments with the strain rates of 0.01-10 s(-1)and deformation temperature range of 300-420 degrees C are performed to investigate the hot deformation behavior of A356 aluminum alloy. Also, the complex deformation mechanisms are analyzed. It is found that, as the strain is gradually increased, the flow stress first rises, and then the stable stress appears without a tangible peak. The microstructures exhibit large elongated grains, and only a few small new grains appear under most deformation conditions. It is because the dynamic recovery (DRV) is the dominant softening mechanism. Based on the measured data, both the original Johnson-Cook (O-JC) model and modified Johnson-Cook model (M-JC) are built for the tested aluminum alloy. However, there are different deviations between the experimental and the predicted true stresses by O-JC model and M-JC model. Considering the obvious DRV features, an enhanced Johnson-Cook (EH-JC) model is proposed by introducing the stress-dislocation relation. The accuracy of the EH-JC model is validated because the correlation coefficient between the experimental and predicted results is as high as 0.997, whereas the average absolute relative error is merely 2.84%.