Hot deformation behaviors and processing map of Mg2B2O5w/Al matrix composites prepared via powder metallurgy

Abstract

The hot deformation behaviors of a 20 vol% Mg2B2O5w/6061Al matrix composite were studied from 573–723 K and a strain rate range of 0.0005–0.5 s−1 using a Gleeble-3500 thermo-mechanical simulator. The results indicated that the flow stress depended strongly on strain rate, deformation temperature, and reinforcement. The constitutive model was established and the average activation energy was 110.56 kJ mol−1. Microstructure observations exhibit the typical characteristic of dynamic recover (DRV) and a onset of dynamic recrystallization (DRX) of the materials. The unstable domains of processing map were attributed to whisker debonding, void formation, and matrix cracks. The high temperature and lower strain rate resulted in good effects during hot deformation of the composites. The optimum processing parameters were 400 ∼ 450 °C/5 × 10−4 ∼ 2 × 10−3 s−1.