Effect of Ce addition on microstructure evolution and precipitation in Cu-Co-Si-Ti alloy during hot deformation

Hot compression tests of the Cu-Co-Si-Ti and Cu-Co-Si-Ti-Ce alloys were carried out on the Gleeble-1500 simulator at 0.001-10 s(-1) strain rates and 500-900 degrees C deformation temperatures. Compared with the Cu-Co-Si-Ti alloy, the flow stress of the Cu-Co-Si-Ti-Ce alloy increased under the same deformation conditions. The micro texture of the Cu-Co-Si-Ti and Cu-Co-Si-Ti-Ce alloys were analyzed by EBSD. In addition, the texture of Cu-Co-Si-Ti alloy deformed at 700 and 800 degrees C is {011} < 100 > Goss texture and {112} < 111 > copper texture, respectively. However, the {001} < 100 > cubic texture and {011} < 100 > Goss texture in Cu-Co-Si-Ti-Ce alloy deformed at 700 and 800 degrees C were obtained, respectively. The constitutive equations of Cu-Co-Si-Ti and Cu-Co-Si-Ti-Ce alloys were obtained. The activation energy of Cu-Co-Si-Ti and Cu-Co-Si-Ti-Ce alloys is 500.79 kJ/mol and 539.94 kJ/mol, respectively. The Co2Si precipitate was found in both the Cu-Co-Si-Ti and Cu-Co-Si-Ti-Ce alloys, while the Co2Si precipitate of Cu-Co-Si-Ti-Ce alloy is smaller than that of the Cu-Co-Si-Ti alloy. Moreover, the dislocation density of Cu-Co-Si-Ti-Ce alloy is higher than Cu-Co-Si-Ti alloy under the same conditions. Finally, Ce addition increased flow stress and activation energy, and inhibited the dynamic recrystallization, which can be attributed to the higher dislocation density and finer Co2Si precipitate. The CDRX and DDRX mechanisms are the two main DRX mechanisms for Cu-Co-Si-Ti and Cu-Co-Si-Ti-Ce alloys during hot deformation. (C) 2020 Elsevier B.V. All rights reserved.