背压对非致密纯相粉末等径角挤压致密固结的影响

摘要

以非致密纯钼粉末为例，采用离散元模拟软件PFC-2D对钼粉在有背压和无背压两种情况下的等径角挤压(ECAP)过程进行模拟。获得了两种情况下的颗粒流动规律、载荷变化曲线和相对密度分布。实验获得的一道次等径角挤压试样形状和显微硬度分布与模拟结果具有较好的一致性。实验及模拟结果表明：非致密粉末等径角挤压过程中施加背压可有效控制粉末颗粒流动，提高粉末材料塑性变形能力，增加粉末材料变形量和变形均匀性，提高粉末材料致密固结效果。%Taking non-dense pure molybdenum powder as an example, the molybdenum powders either with or without back pressure were carried out using equal channel angular pressing (ECAP) and simulated with the two-dimensional district element model (DEM). Two cases of granular flowing law, the load curve and the distribution of the relative density were obtained. The shape and microhardness distribution of 1st pass ECAP specimens from the experiment have good consistency with the simulation results. Experimental and simulation results show that:Non-dense powder ECAP process of applying back pressure can effectively control the flow of powder particles, back pressure can effectively increase the plasticizing efficiency and the deformation uniformity, in addition improve the effect of dense consolidation.