Investigation of Micromechanical Deformation Mechanisms in Sinter Powder Metals

摘要

Sintered powder metals have found wide applications in industry. However, the constitutive description under complex loading conditions is an open issue. In the present work, the inelastic deformation mechanisms of sintered iron are investigated using nano-indentation technique. With help of the finite element method, the material behaviour of powder particles can be identified from extensive nano-indentations. Furthermore, the micro-hardness of pre-strained specimens has been investigated as a function of the macro strains up to 14%. Nano-indentation measurements provide a linear correlation between the micro strains in power particles and macro deformation. Ca. 55% of total inelastic deformations are contributed from powder particles and the rest is caused by the void growth as well as micro crack propagation. In sintered metals the micro porosity plays an important role in inelastic deformations.