半固态A356铝合金触变锻造成形过程有限元模拟

针对高固相率条件下半固态触变锻造成形,开发了一个热力耦合触变锻造模拟模型.对触变锻造成形过程中温度场分布、最高/最低温度分布规律以及成形过程中模具运动速度对成形力的影响规律等,进行了计算和分析.研究发现,在半固态触变锻造成形过程中常伴有低于半固态温度的热加工现象出现,高成形速度会降低成形力,同时也会导致成形坯料的液固相分离.试验验证中最大成形力与模拟得到的最大成形力相吻合的事实表明,所开发的计算模型能较准确地预测触变锻造成形最大成形力, 但成形过程中两者所得到的成形力仍存在一定差异,这表明计算模型还需要一步优化.

FEM (Finite Element Method) Simulation of Temperature Field and Forming Force Field in Semi-solid A356 Aluminum Alloy During Thixo-forging

A thermal-mechanical model was developed to describe semi-solid thixo-forging process with high solid fraction,including temperature field,maximum/minimum temperature distribution,moving speed of the mould as well as forming force.The simulated results reveal that occurrence of conventional hot-forging can be observed during thixo-forging,meanwhile,high forging speed can decrease forming force,which can result in the liquid-solid phase separation in the billets.The simulated maximum forming force is well in agreement with experimental one,showing the availability of the model,however,there exists the difference in forming force during thixo-forging,which means the model need be further optimized.