Research On Fabrication Technique And Property Of SiCp Reinforced 6061 Aluminum Matrix Composites By MA And P/M

SiC particle reinforced 6061 aluminum matrix composites were fabricated by themechanical alloying (MA) and the powder metallurgy (P/M) technique with 10vol%and 20vol% SiC particles. The microstructure and property of the powders wereinvestigated at different period of MA processing. The effect of the aging temperatureand aging time on the property of the composites, which were prepared by MA ,sintering and solid-solution treatment, were investigated. The aging-hardeningmechanism of the SiCp/6061Al composites was also discussed. The tribological andwear property of the SiCp/6061Al composites were investigated at differenttemperature, and the wear mechanism of the SiCp/6061Al composites waspreliminarily analysised.The result showed that several steps happened during MA's processing: plastictransformation of matrix alloy, fracture of reinforcement, work-hardening of matrixalloy, cold-welding, formation of lamination structure and uniform distribution of SiCparticles in matrix. A homogeneous distribution of SiC particles achieved by MAtechniques.There was no change of the sequence of precipitation of composites by addition ofSiC particle compared with that of unreinfored alloys during aging. But, an obvioushardening effect can be observed in the SiCp/6061Al composites resulting from theintroduction of numerous dislocation. Duration of peak-aging of the sample aged atroom temperature (Natural Aging, NA) was 48h, longer than that of the sample ofaged at a higher temperature (Artificial Aging, AA). The peak-microhardness of NAsample was lower than that of AA sample's. The TEM morphology of 10MMCexhibited that interface of Al-SiC had a "cleaned" bonding and had no evidence ofchemical reaction product at the interface.The SiCp/6061Al composites have better wear resistance compared with that of 6061alloy. The wear resistance improved with increasing of the volume fraction of SiCparticles. At room temperature, good wear resistance of SiCp/6061Al compositessamples achieved by the addition of SiC particles was induced by the formation of themechanically mixed layer (MML). It was showed that the wear mechanism ofSiCp/6061Al matrix composites was related to the formation of MML rubbed againstthe iron , 6061Al exhibited a slighter wear mass loss than that of SiCp/6061Alcomposites below 150℃. At 200℃, the wear mass loss of Al increased dramaticallythan that of the SiCp/6061Al composites.