Effect of geometric work-hardening and matrix work-hardening on new constitutive relationship for aluminium-alumina P/M composite during cold upsetting

摘要

The densification and strain hardening behaviour during cold deformation of sintered alumi-num-3.5% alumina powder metallurgy preforms were investigated by constitutive model and experimental data obtained with no and with subsequent annealing. The mechanisms most likely involved in the constitutive model, namely, densification and strain hardening were studied. The effect of geometric and matrix work hardening on the various constants involved in the constitutive model, namely, instantaneous density coefficient, instantaneous strain hardening index, instantaneous strain rate sensitivity and instantaneous strength coefficient were discussed in detail.