纯铜等通道转角挤压工艺有限元分析与实验

Finite element simulation and experimental research on equal channel angular pressing of pure Cu

利用数值模拟和实验研究方法分析圆形纯铜挤压件多道次等通道转角挤压(ECAP)工艺,发现多道次挤压获得的挤压件形变充分,形变分布较为均匀。通过分析挤压件截面的等效应变值与分布,发现模具的内角对挤压后材料等效应变值的影响较大,当内角为90°时,材料单次挤压的等效应变值达1.40,是内角为135°时的2.3倍,但材料的均匀性相对较差;挤压路径和通道形状对挤压后材料的形变均匀性至关重要,Bc路径和圆形通道效果最佳,不易形成应力集中等现象;挤压次数增加,材料的累积应变值和均匀性显著提高。实验中,挤压后棒材的横截面与表面的显微硬度值分别由原始的99HV上升至145HV和148HV,变化趋势与有限元模拟结果吻合。

Multi-pass equal channel angular pressing （ECAP） for round copper is investigated by using numerical simulations and experimental studies. The deformation of copper in multi-pass ECAP is much sufficient and uniform. It is found that, the innerangle plays a very important role in the effective strain. The maximum effective strain equals 1.40 when the inner angle is 90°, which is 2.3 times of that when the inner angle is 135° The route and the shape of the channel are important to the deformationuniformity. The deformation uniformity of the sample in route Bc with round channel is best without stress concentration. The effective strain increases and the deformation uniformity becomes better when the copper is pressed by eight passes. The micro-hardness of the cross-section and surface increases from 99 HV to 145 HV and 148 HV, respectively. The experimental results are in agreement with the finite element analysis results.