Structure and properties of alumina-reinforced copper matrix composites prepared by powder metallurgy at different sintering temperatures

Abstract

In this paper, alumina-reinforced copper-based composite materials were prepared by using the electroless plating method to coat copper powder with a layer of silver and then combining the solution sol method and powder metallurgy method. The results show that recrystallized structures and twins appear in composite materials after high-temperature sintering. As the sintering temperature increases, the ratio of recrystallized structures and twins gradually decreases, and straight coherent [Formula: see text]3 annealing twins appear in the structure, the number of high-angle grain boundaries decreased, the number of small-angle grain boundaries continues to increase, the average grain size increased from 3.89 to 4.83[Formula: see text][Formula: see text]m, the tensile strength increased from 156[Formula: see text]MPa to 167.5[Formula: see text]MPa, the maximum elongation was 9.4%, and the density increased from 6.81[Formula: see text]g/cm3 increased to 7.62[Formula: see text]g/cm3, the porosity dropped from 13.3% to 5.5%, the conductivity increased from 60.3% IACS to 73.2% IACS, the maximum hardness value was 68.71 HV, the best performance of the composite was achieved by sintering at 900°C with the tensile strength and elongation are 163[Formula: see text]MPa and 9%, respectively, the conductivity is 68.9% IACS, and the density is 7.35[Formula: see text]g/cm3. Its fracture surface shows mostly ductile features.