The Effect of SiC Particles Volume Fraction on Hot Deformation Behavior of AA 2024 Composites Reinforced with SiC Particles

초록

Hot torsion tests were conducted to investigate the hot deformation behavior of AA 2024 composites reinforced with different volume fractions (5, 10, 15, 20, and 30 vol. %) of SiCp reinforcements. Hot restoration, dynamic recrystallization (DRX) and dynamic recovery (DRV) of the composites were studied from the flow curves and deformed microstructures. The matrix grain size and dislocation density of the composites were investigated by transmission electron microscopy. The effect of SiCp volume fraction on the critical strain for onset of DRX was analyzed from the relationship between the work hardening rate and effective strain. DRX was occurred in all the composites during hot deformation at 370 - 430 ℃ under a strain rate of 1.0/sec. Also, the flow stress and the dislocation density of the composites increased with increasing volume fraction of SiCp and also the difference in flow stresses of the composites reinforced with 15, 20, and 30 vol. % of SiCp deformed at 370 ℃ was small.