The influence of microstructure on the strength and electrical conductivity of directionally-solidified Cu-Ag microcomposites.

摘要

An analysis of the interrelationships between microstructure and both mechanical and electrical properties in deformation-processed Cu-Ag alloys is presented. The effects of microstructure on the strength, electrical conductivity and strength-conductivity combinations were evaluated to provide guidelines for property optimization. Different microstructures were prepared by varying (a) the growth conditions during directional solidification, (b) alloy composition, (c) deformation level, (d) lamellar orientation and (e) thermomechanical processing schedule. The increased interfacial area of the eutectic structure is shown to result in a more rapid decrease in conductivity during deformation when compared with those alloys with considerable volume fractions of the primary phase. As the initial interlamellar spacing becomes smaller, the hardening rate is not changed while the conductivity of the eutectic alloy decreases more rapidly with deformation. Both lamellar and rod-like eutectics were investigated and the resulting structures and properties after deformation were considerably different. The dominant factors determining the value of the strength-conductivity factor (SCF), where the SCF is the ratio of the ultimate strength to the conductivity are the volume fraction, interlamellar spacing, morphology and orientation of the Cu-Ag eutectic.