Enhanced electrical,mechanical and tribological properties of Cu-Cr-Zr alloys by continuous extrusion forming and subsequent aging treatment

摘要

As a promising material for the new generation of high-speed railway contact wires,the comprehensive optimization of the electrical conductivity,strength,hardness and wear resistance of the Cu-Cr-Zr alloy has received extensive attention.In this paper,a high-performance Cu-1Cr-0.1Zr alloy with an ultimate tensile strength of 599.1 MPa,a uniform elongation of 8.6%,a microhardness of 195.7 HV_(0.2) and an electrical conductivity of 80.07%IACS was achieved by the continuous extrusion forming(CEF)and subsequent peak-aging treatment.The grain refinement strengthening,dislocation strengthening and precipitation strengthening are identified to be responsible for the excellent electrical and mechanical properties of Cu-Cr-Zr alloy.The wear behavior of Cu-Cr-Zr alloy was investigated by examining the evolution of worn surface morphology and subsurface microstructure.The microhardness(H)and reduced elastic modulus(E_(r))of the subsurface below the worn surface measured by nanoindentation were calculated to gage the tribological performance of Cu-Cr-Zr alloy.Results show that the continuously extruded and subsequently peak-aged specimen has the best wear resistance,which indicates that the tribological properties of CuCr-Zr alloy strongly depend on its strength and hardness.It can be concluded that the CEF and subsequent aging treatment process provides a new and high-efficiency procedure for the continuous preparation of Cu-Cr-Zr alloys.