AZ91D镁合金等径道角挤压制备半固态坯数值模拟

基于半固态坯采用等径道角挤压（ECAE）制备的应用背景，采用PRO／E建立了等径道角挤压的几何模型，通过压缩实验获取了AZ91D镁合金的高温应力应变曲线，采用有限元软件DEFORM-3D对ECAE挤压变形过程进行了模拟，分析了内外转角部位的应力（平均应力、最大主应力和等效应力）变化、应变分布情况等，以揭示等径道角挤压变形跟模具内转角半径的关系。结果表明，模具内转角半径不为零时，坯料挤压过程中，将有正虚力存在，并且内外转角应力变化不尽相同；应变分布不均匀，具有一定梯度；内转角部位，除了承受剪切，还受到压缩作用，外转角反之。

Numerical Simulation of ECAE Process for Preparing AZ91D Semi-solid Billet

Based on the background of preparing semi-solid billet by equal channel angular extrusion(ECAE),the model of ECAE was built up by PRO/E,the stress-stain curve of AZ91D magnesium alloy at elevated temperature was gained through compression experiments,and the extrusion processes were simulated using finite element method analysis software DEFORM-3D.The variation of stress(mean stress,max principle stress,equivalent stress) and the distribution of strain in the inner and outer corner were obtained to discover the relation between the radius of inner corner and the extrusion deformation.The results show that there exist normal stresses in the extrusion when the radius of inner corner is not zero,and their changes are not identical,especially in inner and outer corner;the strain is non-homogeneous and a graded distribution appear;in the inner corner,besides the simple shear,there are also compression,and the outer corner inverses.