Deformation behavior, microstructure characterization, and dynamic recrystallization mechanism of Au-7.5Ni-1.5Cu alloy

• The thermal deformation behaviors under different temperatures and strain rates of Au-7.5Ni-1.5Cu alloy were revealed. • The constitutive equation with Zener-Hollomon parameter and the DRX model were established. • The optimum processing parameter ranges were observed by establishing the hot processing map. • The microstructure evolution and dynamic recrystallization mechanism of the Au-7.5Ni-1.5Cu alloy were systemically studied. The application of Au-based alloys in precision instruments components has achieved good results as electric contact materials. In order to investigate the hot processing of Au-based alloys, the hot deformation behavior and dynamic recrystallization (DRX) mechanism of Au-7.5Ni-1.5Cu alloy were investigated by the hot compression experiments. The testing machine was Gleeble-3500 and the hot compression temperature range was 750–840 ℃ under different strain rates (0.01–1 /s). The peak stress model was obtained through the Arrhenius relationship and the hot processing map was established with the dynamic material model. The peak stresses during hot processing were accurately predicted through the constitutive relationship and the optimum processing parameter ranges were observed to be 800–840 ℃, 0.01–0.04 s −1 by the hot processing map. The samples after hot compression deformation had been characterized by electron backscattered diffraction (EBSD) technique and optical microscope (OM), the microstructure evolution mechanism was discussed systematically. As the deformation temperature rose form 750 ℃ to 840 ℃, the DRX process weakened and more dynamic recovery (DRV) substructures were found. Different mechanisms of DRX were discussed systematically, and the DRX model was established and the accuracy of the model had been verified to be reliable.