Microstructure and mechanical behaviors of 6061 Al matrix hybrid composites reinforced with SiC and stainless steel particles

Abstract

Hybrid aluminum matrix composites are appealing in the aviation, aerospace and automotive industries and have the potential to substitute single reinforced composites due to their enhanced comprehensive properties. In the present work, 6061 Al matrix composite hybrids reinforced with SiC and stainless steel particles were prepared to improve the strength and ductility by the powder metallurgy method. The mechanical properties, fracture behaviors and deformation mechanisms under various aging conditions were investigated by uniaxial tensile tests and microstructural characterizations. The results showed that the composite hybrid reinforced with SiC and stainless steel particles could effectively enhance the ductility without losing strength compared to the composite reinforced with single SiC particles. Under various artificial aging treatments, the mechanical properties of the composites changed, but the stainless steel particles always played a positive role in the composites and did not change the precipitation sequence of the aluminum matrix. The improvement in ductility was mainly attributed to the deformable nature of the reinforcement particles. The load was successfully transferred to the stainless steel particles and resulted in a uniform strain distribution of the hybrid reinforced composites. Conversely, the interfacial fracture caused by high interfacial dislocation pileup during deformation limited the plasticity of aluminum matrix composites reinforced with single SiC particles.