A Continuum Elastic and Plastic Model of Powder Materi

A.F.Fedotov
 

Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2011, #05/06
http://www.materials.kiev.ua/article/1418

Abstract

Based on physical hypotheses of the discrete contact model, a continuum elastic and plastic model is developed for isotropic powder materials, taking into account nonuniform deformation of the solid phase. Localization of elastic and plastic deformation is taken into account in the hypothesis on the solid-phase formation of deformable and nondeformable volumes, and deformation resistance is associated only with the magnitude of the deformable volume. An analytical dependence of the deformable volume on the density of powder material is provided. The proposed model ensures high accuracy in fitting the experimental densification curves at the stages of interparticle slip and plastic deformation of particles. In the initial stage of plastic deformation, the particulate material is regarded as cast one, which is already plastically deformed and hardened to the effective yield strength of the powder phase. The particulate material is further strengthened as work-hardened cast material does. Good agreement is reached between calculated and experimental data on the elastic moduli and plastic densification of powders in isostatic pressing and deposition in a high-pressure chamber.


DEFORMABLE VOLUME, ELASTIC MODULI, PLASTICITY CONDITION, POWDER MATERIALS, RESTRAIN DEFORMATION