Effect of Equal Channel Angular Pressing on Microstructure and Mechanical Properties of a Cu-Cr-Ni-Si-Co Alloy

Abstract

The microstructural and property of a Cu-Cr-Ni-Co-Si alloy produced by equal channel angular pressing (ECAP) were systematically investigated. After fourth pass ECAP deformation, the average grain size was refined from 30 μm (solid solution state) to below 3 μm, resulting in a fine and regularly shaped equiaxed crystalline microstructure. The distribution of grain boundaries became more uniform. During ECAP deformation, the volume fraction of Copper texture {001} <100> decreased, while that of the Brass {011} <211> increased, and the Shear (S) {123} <634> remained almost constant. The escalation of ECAP deformation pass facilitated dynamic recrystallization, leading to the increase of the fraction of the recrystallized texture. After thermomechanical treatment (first pass ECAPed +450℃ aging/120minutes+80% cold deformation +450℃ aging/30minutes), the alloy exhibited good mechanical properties, with a tensile strength of 546 MPa, a yield strength of 475 MPa, an elongation of 18.2%, and an electrical conductivity of 52.8 %IACS. The main strengthening mechanisms included precipitation strengthening, dislocation strengthening and grain boundary strengthening, with the precipitation strengthening accounting for 45.6% of the yield strength.

Keywords: Equal channel angular pressing (ECAP), Cu-Cr-Ni-Co-Si alloy, strength and electrical conductivity, Microstructure evolution, properties