Preparation And Properties Of Ti₂AlN-La₂O₃/Cu Composites

Copper matrix composites because of its excellent comprehensive properties, hasbeen widely used in electronic, aerospace and other high-tech fields.Due to its specialcrystal structure, layered ternary Ti₂AlN posses both good electrical conductivity of metaland high strength, hardness of ceramics. Rare earth oxide La₂O₃can refine microstructureof composites, improve dispersibility of particles, resistant ablation. Both are perfectreinforcements of copper.In this paper, High purity of Ti₂AlN material were fabricated by spark plasmasintering（SPS）. Through mechanical grinding and screening,15-20μm Ti₂AlN powderparticles were obtained. Ti₂AlN particles with a about1.5μm-thickness copper coating byelectroness method was effective for interfacial bonding. Ti₂AlN particles with coppercoating mixed with copper powder, La₂O₃/Cu composites powder, Ti₂AlN-La₂O₃/Cucomposites were fabricated using hot pressing sintering. According to the compositematerial physical and mechanical properties, optimized the hot press process of thecomposite, concluded the best content ratio of the two add phase. Combined XRD withSEM, TEM, analyzed the Ti₂AlN/Cu interfacial reaction and the its relationship with themechanical and physical properties of composites.The results indicate that the optimization hot press process of Ti₂AlN-La₂O₃/Cucomposite was: argon atmosphere, sintering temperature900oC, holding time300s,sintering pressure40-45MPa. The addition of reinforcing phase enhanced the bearingcapacity of Cu matrix. With the increasing amounts of Ti₂AlN and La₂O₃, the mechanicalproperties increased. When the reinforcing phase content, Ti₂AlN5wt%, La₂O₃0.7wt%,the tensile strength were325MPa,1.6-fold the properties of pure copper material at thesame conditions, and the conductivity still remained in60%IACS.The analyse of TEM combined with XRD showed that: In the range of sinteringtemperature from880C to940C, a reaction happened between Ti₂AlN and plated copperlayer. Formed a20-50nm-width transition region and New substances, Cu（Al） and TiNx,which was beneficial to tensile strength. In addition, La₂O₃nanoparticles were dispersed which also strengthened the composite in the Cu matrix.