Ultrahigh strength and improved electrical conductivity in an aging strengthened copper alloy processed by combination of equal channel angular pressing and thermomechanical treatment

Abstract

In this paper, equal channel angular pressing and thermomechanical treatment was employed to improve the strength and electrical conductivity of an aging strengthened Cu-Ti-Cr-Mg alloy, and the microstructure and properties of the alloy were investigated in detail. The results showed that the samples deformed by the combination of cryogenic equal channel angular pressing (ECAP) and rolling had good comprehensive properties after aging at 400 °C. The tensile strength of the peak-aged and over-aged samples was 1120 MPa and 940 MPa, with their corresponding electrical conductivity of 14.7%IACS and 22.1%IACS, respectively. ECAP and cryogenic rolling introduced high density dislocations, leading to the inhibition of the softening effects and refinement of the grains. After a long time aging at 400 °C, the alloy exhibited ultra-high strength with obvious increasing electrical conductivity. The high strength was attributed to the synergistic effect of work hardening, grain refinement strengthening and precipitation strengthening. The precipitation of a large amount of Ti atoms from the matrix led to the high electrical conductivity of the over-aged sample.

Keywords

Cu-Ti alloy / equal channel angular pressing / rolling / aging treatment / high strength

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