Microstructure and properties evolution, toughening mechanism of 10 % SiC/6063 composite fabricated by strip casting: Experiment and simulation

Abstract

The 10 % SiC/6063 composite was prepared by strip casting technology for the first time. The microstructure evolution and toughening mechanism before and after cold rolling were investigated by experimental and finite element methods. The hardness and strength of the composite cast strip were higher than that of 6063 aluminium alloy due to grain refinement and dislocation obstruction of SiC particles. After cold rolling, the strength of the composite material increased by 33 MPa, with a substantial 240.2 % increase in elongation from 9.7 ± 3 % to 33 ± 5 %. The significant increase in elongation is mainly attributed to the high proportion of <111>//RD {Cubic} texture (48.5 %) of the densely packed surface providing favourable conditions for dislocation slip, allowing the material to coordinate deformation through dislocation motion. The simulation and KAM results confirm that there is stress concentration around the SiC particles, which can share the stress and hinder the crack propagation. This corresponds to the low angle grain boundary of the composite material after cold rolling up to 97.7 %. Different from 6063 alloy, the recrystallisation volume of composite materials fraction increased to 5.15 % and possessed uniform continuous recrystallisation characteristics to uniformly disperse the stress. This makes the composite material structure more uniform, reduces local stress, and improves comprehensive mechanical properties.