基于速度场的SiCw/6061正挤压变形晶须转动有限元分析

Finite element analysis of whisker rotation of SiCw/6061 composite under extrusion deformation with velocity field

以有限元模拟为研究手段,通过分析正挤压变形后的坯料流动速度场及流线网格变化特征,探讨了挤压变形及挤压比对SiCw/6061复合材料晶须转动的影响规律,并将分析结果与挤压试件的SiC晶须形貌扫描电镜照片进行了对比。研究表明,根据速度场的分布特征,可将正挤压实心件坯料分为速度均匀区、速度剧变区和死区;不同区域材料变形的不均匀性导致塑性流动存在显著的纵向速度梯度,此速度梯度引起晶须转动;随着挤压比的增大,材料流动速度梯度随之增加,晶须转动加剧。

By means of the finite element simulation of forward extrusion, the velocity vector field and flow line of the metal are presented and the effect of extrusion deformation and extrusion ratio on whisker rotation of SiCw/6061 composite was discussed and compared with the SEM photos of SiC whisker morphology. It is shown that according to the characteristic of velocity field, the extrusion billet can be divided into uniform velocity zone, severe velocity variation zone and dead zone. For the non-uniformity of the velocity field, there is an obvious longitudinal velocity gradient and this velocity gradient is the main reason of the whisker rotation, with the increasing of the extrusion ratio, the velocity gradient of metal flow increases and whisker rotation increases simultaneously.