Physics-Based Constitutive Model of Porous Materials for Die/Isostatic Compaction of Metallic Powders

Abstract

A physics-based constitutive model of porous materials is proposed to enhance the accuracy of numerical analysis in die/isostatic compaction. The correlation between the yield function and equivalent work equation was derived, and the numerical integration method was modified with the correlation. It is found that the apparent work of porous materials is lower than the product of relative density and equivalent work of solid materials at the beginning of compaction, implying the kinematic motion of powders and the resultant particle rearrangement. For verification of the proposed model, finite element analyses were performed for the die/isostatic compaction of three metal powders: Ti, SUS316L, and Al6061 powders. Compared with two conventional constitutive models, the proposed model improves the accuracy of the densification behaviors in all the stage during die/isostatic compaction. Furthermore, this study is a groundwork to link the densification behavior of porous materials at bulk scale to the particulate behavior of powders at microscale.