Continuum damage mechanics for sintered powder metals

Abstract

Sintered metals are characterized by the high porosity ( 8%) and voids/micro-cracks in microns. Inelastic behavior of the materials is coupled with micro-crack propagation and coalescence of open voids. In the present work the damage evolution of the sintered iron under multi-axial monotonic loading conditions was investigated experimentally and computationally. The tests indicated that damage of the sintered iron initiated already at a stress level much lower than the macroscopic yield stress. The damage process can be divided into the stress-dominated elastic damage and the plastic damage described by the plastic strain. Based on the uniaxial tensile tests an elastic-plastic continuum damage model was developed which predicts both elastic damage and plastic damage in the sintered iron under general multi-axial monotonic loading conditions. Computational predictions agree with experiments with different multi-axial loading paths. A phenomenological continuum damage model for the sintered metal is developed based on the experimental observations to predict the inelastic behavior and damage process to failure under multi-axial loading conditions. The proposed damage model is experimentally verified under different loading conditions. sintered metal, porous material, damage evolution, multi-axial damage, continuum damage model PACS number(s): 46.35.+q, 46.50.+a, 81.20.Ev, 81.40.Lm Citation:Yuan H, Ma S Y, Zhang L. Continuum damage mechanics for sintered powder metals.

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