Abstract:The use of deep undercooling rapid solidification technology resulted in different undercooling degrees of Cu65Ni35 alloy, with a maximum undercooling of 284 K. The microstructure morphology characteristics and evolution laws of Cu65Ni35 alloy were systematically studied by taking metallographic images of rapidly solidified microstructure. The results indicate that Cu65Ni35 alloy exhibits grain refinement phenomenon in both the large undercooling range and the small undercooling range. Electron backscatter diffraction detection was performed on the Cu65Ni35 alloy structure with typical grain refinement characteristics. It was found that the high undercooling structure and the low undercooling structure had completely different grain orientation information. The grain refinement of the structure under low undercooling was caused by dendrite remelting and fracture, while the grain refinement of the structure under high undercooling was achieved by stress induced recrystallization.