AZ31镁合金板材轧制边裂深度预判模型

Prediction Model of Edge Crack Depth of Rolled AZ31 Magnesium Alloy Sheets

在400℃下,分别以压下量10%,15%,20%,25%,30%,35%,40%和45%对初始厚度为7 mm的AZ31镁合金板材进行了轧制过程数值模拟以及实验验证研究,并观察轧制后的显微组织。结果表明,在本实验轧制条件下,当单道次压下量达到20%时,板材边部将有裂纹萌生,并且边部裂纹深度随着压下量的增大而不断增大,由20%时的5.24 mm增加到压下量45%时的14.056 mm;根据数值模拟结果,得到了沿板宽方向的损伤值分布情况,建立了边部裂纹深度预判模型;对于裂纹深度,轧制实验实测值和所建立的裂纹深度预判模型的计算值之间的平均误差为9.23%;SEM观察结果表明,边部裂纹附近的显微组织中含有大量孪晶。

The numerical simulation and experimental verification of the rolling process of as-cast AZ31 magnesium alloy sheet with an initial thickness of 7 mm were carried out at 400 ℃. The reductions were 10%, 15%, 20%, 25%, 30%, 35%, 40% and 45%. The microstructure and edge cracks were analyzed after rolling. The results show that edge cracks occur when the single pass reduction reaches 20%. The edge crack depth increases from 5.24 mm at 20% reduction to 14.056 mm at 45% reduction in the rolling condition. According to the numerical simulation results, the damage distribution along the width of the plate was obtained, and the prediction model of the edge crack depth was established. For the edge crack depth, the average error between the actual measured data and the calculated value by the prediction model is 9.23%. SEM observations show that the microstructure near the edge crack contains a large number of twins.