An Enhanced Johnson–Cook Model for Hot Compressed A356 Aluminum Alloy,Advanced Engineering Materials

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An Enhanced Johnson–Cook Model for Hot Compressed A356 Aluminum Alloy
Advanced Engineering Materials ( IF 3.4 ) Pub Date : 2020-08-20 , DOI: 10.1002/adem.202000704
Xiao-Min Chen _{1,

2} , Y. C. Lin ₃ , Hong-Wei Hu _{1,

2} , Shun-Cun Luo ₄ , Xiao-Jie Zhou _{1,

2} , Yi Huang _{1,

2}

Affiliation

The isothermal compression experiments with the strain rates of 0.01–10 s⁻¹ and deformation temperature range of 300–420 °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%.

中文翻译：

用于热压A356铝合金的增强型Johnson-Cook模型

等温压缩实验，应变率为0.01–10 s ^-1并在300-420°C的变形温度范围内研究了A356铝合金的热变形行为。此外，分析了复杂的变形机理。发现随着应变逐渐增加，流动应力首先上升，然后出现稳定应力而没有明显的峰值。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。根据测量的数据，为测试的铝合金建立了原始的Johnson-Cook（O-JC）模型和改进的Johnson-Cook模型（M-JC）。但是，O–JC模型和M–JC模型在实验应力和预测真实应力之间存在不同的偏差。考虑到明显的DRV功能，通过引入应力-位错关系，提出了一种增强的Johnson-Cook（EH-JC）模型。EH–JC模型的准确性得到了验证，因为实验结果与预测结果之间的相关系数高达0.997，而平均绝对相对误差仅为2.84％。

更新日期：2020-08-20

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