TENSILE DEFORMATION AND FRACTURE BEHAVIOR OF Cu-0.54Al2O3 DISPERSION STRENGTHENED COPPER ALLOY
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Abstract
The tensile deformation and fracture behavior of Cu-0.54%Al2O3 dispersion strengthened copper alloy were examined. The results show that σ</em>0.2, σ</em>b, δ and σ0.2/σb of Cu-0.54%Al2O3 composite reach 250 MPa, 340 MPa, 24% and 74% respectively after hot-extruded in the extrusion ratio of 30∶1. The strength decreases gradually with the increase of annealing temperature, while σ0.2/σb remains high value. Its strain hardening exponent n is 0.256, which is obviously lower than that of pure copper.The Al2O3 nanoparticles with the average size of 18 nm and mean interparticle spacing of 100 nm distribute uniformly in the copper matrix,and improve the strength of the copper matrix and prevent the matrix from recrystallizing during annealing at elevated temperature and lower the strain hardening exponent n. The fracture of the as-extruded composite on a macroscopic scale is cup and cone morphology and features with the toughness failure on the microscopic scale.
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