A MESOSCALE COMPUTER-SIMULATION OF MULTIAXIAL YIELD IN GASAR POROUS COPPER

The mesoscale biaxial plastic flow of a porous copper material produce d by the 'gasar' gas-eutectic solidification process is examined in th is study. The pore morphology is characterized by elongated, oriented and partially ordered pores. Tensile and compressive testing suggested a very anisotropic yield response, weak coupling between stresses gen erated by deformations applied in the directions parallel to and trans verse to the longitudinal pore axes, and bulk density decreases associ ated with compression in the longitudinal direction. A two dimensional explicit finite element model, based on an image of the microstructur e, was subjected to combinations of tensile, zero and compressive disp lacement loads applied to the model boundaries. The simulations provid ed insight into the evolution of local micro yielding, plastic connect ivity across the microstructures and buckling of the pores to explain the experimental observations. (C) 1998 Elsevier Science S.A. All righ ts reserved.