Effect of annealing temperature and time on the microstructure, mechanical properties and conductivity of cold-rolled explosive Cu/ Al composite sheets

Abstract

The 1.5 mm thick Cu/Al composite sheet was obtained after explosive-welding and 6 passes cold rolling. The effects of annealing temperature and time on the microstructure, mechanical properties, and conductivity of cold-rolled Cu/Al composite sheets were investigated. The results show that the thickness of the interface diffusion layer with compounds of Al2Cu, AlCu, and Al4Cu9 increases with the increase in annealing temperature and holding time, and the total activation energy is 108 kJ mol-1. The tensile strength of composite sheets decreases and the fracture elongation increases with the increase of annealing temperature. Especially when the annealing temperature increased from 300 ℃ to 350 ℃, the tensile yield strength decreased from 225 MPa to 77 MPa, and the elongation increased from 16% to 37.5%. The tensile-shear strength of composite sheets reaches to 117 MPa after annealing at 400 ℃ for 2 h. The conductivity of composite sheet is greatly affected by the annealing time. At the annealing temperature of 350 ℃ and time of 4 h, the composite sheets show a better conductivity of 96.4% IACS.