Preparation Of In-situ Al₂O₃Particle Reinforced Copper-based Composites

Al2O3/Cu matrix composite is a promising material, with both high strength andhigh electrical conductivity properties of functional materials and structural materials.In this paper, the Al2O3particle dispersion strengthened Cu matrix compositesprepared by in-situ composite method and almost melting casting. By observing thesample microstructure, test the conductivity、hardness and wear resistance mechaniceof the sample, to investigate the influence of process parameters and Al2O3particlecontent to the composite microstructure and properties; Analyze the relationshipbetween the composite microstructure and properties, ultimately determine theoptimal parameters and optimum particle content that preparation high strength andhigh conductivity Al2O3/Cu matrix composites.Experimental reaction system is Al-CuO, choose pure copper as substrate, inorder to avoid the reaction too violenta and reduce the introduction of impurities,choose Cu powder as diluent. The experiments focus on process parameters including:the ratio of reactants, precast block pressure, preheating temperature, pouringtemperature and the content of Al2O3particles. Using optical microscopy、scanningelectron microscopy and transmission electron microscopy observe samplemicrostructure morphology, and test its electrical conductivity, hardness, friction andwear performance.The results showed that：1、Optimum parameters of the preparation process is as follows：Ratio of reactioncomponents and thinner according to Al: CuO: Cu=1:4.4:8.2mass ratio forpreparation, preheating temperature of the reaction is set at1130℃, precast blockpressure is10MPa, at this time, the reaction can be carried out smoothly, and performcomplete. Pouring temperature choose1100℃, close to melting point of compositematerial, at this temperature, the sample of the casting molding organization is veryuniform, and the grain size is less than a micron, between Al2O3particles and coppersubstrates have the half coherent relationship.The addition of in situ Al2O3particleson the material organization has some refinement effect, with the increase of particleconcentration, refining effect more and more obvious. But Al2O3content is not themore the better, when the mass fraction of more than2%, the distribution of particles in the matrix reunion occur easily, deteriorating matrix organization and affect themechanical properties of composite materials.2、 In the case of process parameters for the best, through the test on theproperties of Al2O3/Cu matrix composites can learned that: The hardness and wearresistance properties of composite materials was not always increase with the increaseof content of Al2O3particles. When Al2O3particle mass fraction is1.0%, the hardnessof composite is the largest, up to190HV, when Al2O3particle mass fraction is1.6%,minimum sample of wear, only0.0088g, wear resistance is best; while theconductivity of the composite material has been reduced with the increase of Al2O3,among them, when Al2O3particle mass fraction is1.0%, material conductivity canstill be reached80%IACS.