The Research Of Different Structural Carbon Reinforced Aluminum Matrix Composites In Preparation And Structure Property

Pure Al and Al-Cu alloy matrix composites reinforced with carbonnanotubes and carbon fibres were prepared by powder metallurgy technique. Byusing SEM, XRD, EDS, bending test and hardness test techniques, the effects ofpreparation process, reinforcement content and type on microstructure, density,hardness, resistivity, bending strength of composites were studied in this paper. Themain results were as follows:1. The overall properties of composites were improved after repressing andresintering. Relative density, hardness, bending strength and resistivity of pure Almatrix composite can be up to97.67%,42.7HV,109.19MPa and0.551μ·mrespectively; Relative density, hardness, bending strength and resistivity of Al-Cumatrix composite can be up to97.88%,72.4HV and,123.17MPa and0.305μ·m.2. During preparation process of composites, density, hardness, bendingstrength and resistivity were related to sintering temperature. The best sinteringprocess can be determined by analysis and comparison. For pure Al and Al-Cumatrix composite, the best sintering temperatures were610℃and580℃respectively.3. The enhancement effects of carbon nanotubes and carbon fibers onAl-based composites exhibit similar trend. The density of Al-based compositesdecreased, resistivity increased, whereas hardness and bending strength increasedfirstly and then drop with increase of reinforcement content in the composites.When content of carbon reinforcement was0.3wt%, hardness and bending strengthreached maximum. For carbon nanotubes and carbon fibers reinforced Al-basedcomposites, the former has higher hardness and bending strength than the latterunder condition of the same weight fraction.4. Matrix alloying of Al-based composite were studied. Copper was addedinto aluminum to improve properties of the composites. The results show thatrelative density, hardness, bending strength increased and resistivity decreased withincrease of Cu content in the composites. 5. Carbon nanotubes reinforced Al-Cu matrix composites were heated to550℃for5h then quenched. The microstructure was more compact and theproperties of composites were improved after heat treatment. Relative density,hardness, bending strength increased from95.03%,70.2HV,116.32Mpa to96.37%,75.7HV,133.77Mpa respectively, whereas resistivity reduce from0.604μ·m to0.587μ·m.