Influence of annealing treatment on properties and microstructures of alumina dispersion strengthened copper alloy
(College of Materials Engineering, Zhengzhou University, Zhengzhou 450002, China)
Abstract: Alumina dispersion strengthened copper (ADSC) alloy was produced by internal oxidation. The hardness, ultimate tensile strength and electrical conductivity measurements and microstructure observation on the produced 0.12%ADSC (0.24% Al2O3, mass fraction) and 0.25%ADSC (0.50% Al2O3) subjected to different annealing treatments were conducted. The results show that the microstructure of the produced ADSC is characterized by an uniform distribution of nano-Al2O3 particles in Cu-matrix; the particles range in size from 20 to 50nm with an interparticle spacing of 30-100nm. The produced 0.12%ADSC can maintain more than 87% hardness retention after 900℃, 1h annealing treatment; the recrystallization can be largely retarded and is not fully completed even after annealing at 1000℃ for 1h, followed by cold deformation of 84%; local grain growth can be observed after 1050℃, 1h annealing treatment. The results also show that increasing either the alumina content or cold deformation degree increases the hardness of the produced ADSC.
Key words: alumina dispersion strengthened copper; deformation; hardness; recrystallization; annealing treatment