The Study Of Aluminum-based Composites Reinforced By Nano-particles

Nano-particles reinforced aluminum matrix composites have been applied in aerospace,automobile,shipping and sport equipment due to high specific strength,specific modulus,corrosion resistance property.However,agglomeration and inhomogeneous distribution of nano-particles bring great difficulty to their manufacturing.To manufacture high-property aluminum matrix composites,this study has investigated the ball milling and sintering parameters systematically.At last,we has manufactured four high-properties nano-particles reinforced aluminum matrix composites and have studied the relation between process parameters and microstructure,mechanical and damping properties?The result reveal that the microstructure and properties of nano-particles reinforced aluminum matrix composites has been affected by ball milling and sintering parameters.The gained results show that the reinforced aluminum matrix composites with 2.0vol.%nano-particles has optimum properties.Compared with pure Al material?98MPa?,the ultimate tensile strength of the CNTs/Al?220MPa??Al₂O₃/Al?152MPa??SiC/Al?143MPa??BN/Al?163MPa?composite material have improved by 124%?55%?46%?66%respectively.The reason is that the nano-particles in composites can react with dislocation and inhabit its movement,which result in the improvement of the performance.but when the volume fraction exceed 2%,the nano-particles occur to agglomerate and distribute inhomogeneous,which lead to poor performance.In addition,the research also manifest that with increasing sintering temperature,microstructures of composite material become denser,and the performance has been enhanced.At room temperature,the composite damping values are around 0.01,showing high damping characteristics,because the interface reaction between BN with Al,BN/Al have strong interface binding force,so BN/Al have the highest damping among the four composite,followed by CNTs/Al,Al₂O₃/Al and SiC/Al have the lowest damping.The research findings show the damping property of the composites increase with increasing temperature and stress.At low temperature,the damping mechanism of nano-particles reinforced aluminum matrix composites is dislocation mechanism.With increasing temperature and stress,interface mechanism is stimulated and the main damping mechanism transform to interface mechanism?include the interface slip mechanism and interface relaxation mechanism?,which result in improvement of properties.