Abstract:Cu-1Cr-0.2Zr-0.2Hf alloy was systematically prepared using a two-step cryogenic rolling and aging process (CⅡ). The microstructure evolution of the as-rolled and aged samples of the alloy were thoroughly investigated through the electron backscattering diffraction (EBSD), scanning electron microscopy (SEM) and so on. The corresponding ultimate tensile strength and electrical conductivity were determined at the same time. The effects of cryogenic treatment and final aging on the evolution of orientation and properties of Cu-1Cr-0.2Zr-0.2Hf alloy were emphasized. The results showed that cryogenic rolling promoted the transformation of the alloy texture from a Copper-type texture to a Brass-type texture, and the formation of the Brass-type texture originates from the twinning of grains with Copper orientation and the subsequent slip. The final aging treatment did not change the texture type of the as-rolled sample, only the strength of the texture. The fracture of the two-step cryogenic rolling and aging process (CⅡ) samples had a large number of dimples and the fracture mode was typical of ductile fracture. The two-step cryogenic rolling and aging process prepared a high-strength and high-conductivity Cu-1Cr-0.2Zr-0.2Hf alloy with an ultimate tensile strength of 642±2 MPa and an electrical conductivity of 79.00±0.15 %IACS (IACS: International Annealed Copper Standard), which provided a new strategy for the preparation of high-strength and high-conductivity copper alloys.