关键词: 高温合金, 热等静压, 显微组织, 高温拉伸

Abstract: Effect of hot isostatic pressing (HIP) treatment on microstructure and high-temperature tensile properties of second-generation nickel-based single-crystal superalloy CMSX-4 was investigated by using optical microscope(OM), scanning electron microscope(SEM), energy-dispersive X-ray spectroscopy(EDS) for microstructure characterization, and high-temperature tensile properties testing. The results show that HIP treatment significantly reduces the number of microporosities in the alloy casting, with a porosity reduction of 64.3%. Additionally, the elemental segregation in the dendritic structure of the superalloy is reduced. For the high-temperature tensile properties at 950 ℃ and 1100 ℃, compared to the as-heat-treated specimens, the HIP-treated and subsequently heat-treated specimens exhibit an improvement in total extension of 12.1% and 8.3%, respectively, while maintaining the yield strength of the superalloy. The fracture surfaces of the CMSX-4 superalloy after high-temperature tensile testing show cleavage fracture characteristics. HIP treatment effectively seals the microporosities, altering the fracture mode from nucleation and cracking at microporosities to cracking at residual small eutectic regions. This significantly enhances the high-temperature tensile properties of the superalloy.

Key words: superalloy, hot isostatic pressing, microstructure, high-temperature tensile