CONSTITUTIVE MODELING FOR PLASTICITY OF METAL POWDERS DURING COMPACTION

In works dealing with the plastic behavior of metal powders, the material density or relative density has been a major isotropic hardening parameter. In this work, in a more realistic modeling, the equivalent plastic strain of the porous material, in addition to the relative density, is considered as an isotropic hardening parameter. Using an associated flow rule, the plastic deformation rate is derived and then, by fitting some experimental data obtained from hydrostatic compaction and simple compression tests on aluminum powder, the model parameters are identified for this powder. The identified model is finally verified by some other experimental results obtained from closed-die compaction tests. This last step also confirms that the model could take into account the powder characteristics via loose relative density.