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A Cu-1.79Ti-0.39Cr-0.1Mg (wt.%) alloy was prepared by a vacuum induction melting furnace in a high-purity argon atmosphere. The effects of room temperature rolling and cryogenic rolling on the microstructure, textures, and mechanical properties of the alloy were investigated by means of electron backscatter diffraction, transmission electron microscopy, and X-ray diffraction. The results show that the hardness of the cryogenically rolled alloy is 18–30 HV higher than that of the room temperature rolled alloy at any tested rolling reduction. The yield strength and tensile strength of the alloy cryogenically rolled by 90% reduction are 723 MPa and 796 MPa, respectively. With the increase of rolling reduction, the orientation density of the Cube texture decreases, while the Brass texture increases. The Brass texture is preferred especially during the cryogenic rolling, suggesting that the cross-slip is inhibited at the cryogenic temperature. The dislocation densities of Cu-Ti-Cr-Mg alloy increase significantly during the deformation, finally reaching 23.03 × 10−14 m−2 and 29.98 × 10−14 m−2 after a 90% reduction for the room temperature rolled and cryogenically rolled alloys, respectively. This difference could be attributed to the impediment effect of cryogenic temperature on dynamic recovery and dynamic recrystallization. The cryogenic temperature promotes the formation of the dislocation and the nano-twins, leading to the improvement of the mechanical properties of the alloy. [ABSTRACT FROM AUTHOR]

A Cu-1.79Ti-0.39Cr-0.1Mg (wt.%) alloy was prepared by a vacuum induction melting furnace in a high-purity argon atmosphere. The effects of room temperature rolling and cryogenic rolling on the microstructure, textures, and mechanical properties of the alloy were investigated by means of electron backscatter diffraction, transmission electron microscopy, and X-ray diffraction. The results show that the hardness of the cryogenically rolled alloy is 18–30 HV higher than that of the room temperature rolled alloy at any tested rolling reduction. The yield strength and tensile strength of the alloy cryogenically rolled by 90% reduction are 723 MPa and 796 MPa, respectively. With the increase of rolling reduction, the orientation density of the Cube texture decreases, while the Brass texture increases. The Brass texture is preferred especially during the cryogenic rolling, suggesting that the cross-slip is inhibited at the cryogenic temperature. The dislocation densities of Cu-Ti-Cr-Mg alloy increase significantly during the deformation, finally reaching 23.03 × 10−14 m−2 and 29.98 × 10−14 m−2 after a 90% reduction for the room temperature rolled and cryogenically rolled alloys, respectively. This difference could be attributed to the impediment effect of cryogenic temperature on dynamic recovery and dynamic recrystallization. The cryogenic temperature promotes the formation of the dislocation and the nano-twins, leading to the improvement of the mechanical properties of the alloy.

A Cu-2.5Ti-0.4Cr-0.1Mg (wt%) alloy was prepared in a vacuum medium frequency induction furnace. The evolution of the microstructure and mechanical properties of the samples deformed by equal channel angular pressing (ECAP) at different temperatures was investigated by hardness tests, tensile tests, optical metallography observation, X-ray diffraction and electron back-scattered diffraction. The cryogenic-temperature-deformed (CDed) samples have a little higher hardness than room-temperature-deformed (RDed) samples at any given ECAP pass. After 8 ECAP passes, the yield strength of CDed and RDed samples is close to each other, with the value of 812 ± 17 MPa and 793 ± 25 MPa, respectively. ECAP deformation significantly refines the grain size of the alloy due to the dislocation subdivision and twin fragmentation, and the average grain sizes of RDed and CDed samples after 8 passes are about 0.32 µm and 0.37 µm, respectively. Calculation results show that dislocation strengthening plays a key role in increasing the strength of ECAPed samples. • ECAP deformation improves comprehensive properties of the designed Cu-Ti-Cr-Mg alloy significantly. • Twin fragmentation is a dominate grain refinement mechanism in the alloy, which leads to ultra-fine grains. • Microstructure evolution during ECAP deformation was systematically analyzed. [ABSTRACT FROM AUTHOR]