Hot deformation behaviour of bamboo leaf ash-silicon carbide hybrid reinforced aluminium based composite

摘要

Isothermal compression testing of BLA-SIC hybrid reinforced Aluminium composites was performed on Gleeble 3500 thermomechanical simulator under different deformation temperatures (300-400) and strain rates (0.01-1 s-1). The flow behaviour and the softening mechanisms were established using the trend of the stress-strain curves, activation energy and microstructural examination. The results showed that flow stress increased with decreasing temperature; but was not entirely strain rate sensitive - a characteristic identified in some Al 6XXX based metallic systems. Also, uncharacteristic flow stress oscillations were observed at strain rates of 0.01 and 0.1 s~(-1) while steady state flow stress was observed at 1 s~(-1). The hot working activation energy was 290.5 kJ/mol which was intermediate to the range of 111-509 kJ/mol reported in literature for various Al based composites. It was proposed that at strain rates of 0.01 and 0.1 s~(-1), dynamic recrystallization and/or dislocations-reinforcements interactions were the dominant deformation mechanism(s), while at 1 s~(-1), dynamic recovery was predominant.