Simulation of the compaction dynamics of Cu + Al2O3 powder mixture under impulse hot pressing

Abstract

The compaction dynamics of Cu + Al 2 O 3 powder mixture under impulse hot pressing is simulated using a third-order dynamic system. The computer simulation has established the time dependence of the force induced by mechanical interaction between the impact machine and a heated porous blank, time variation in density, and root-mean-square strain rates and stresses in the matrix that forms the porous body. The phase trajectory of dynamic system from the beginning of compaction to the elastic recoil of the hammer block characterizes impact dynamics. The mechanical-thermal effect induced by bulk viscous flow and manifested itself as an increase in temperature of the porous body is determined. It is established that the shear viscosity of the porous body matrix shows a stronger dependence upon the initial impact velocity in comparison with the heating temperature. The activation energy of the matrix viscous flow is equal to 0.266 eV.