本团队张茂副教授、硕士生杨智芯等在Materials Characterization发表研究论文。

摘要：Oxidation behaviors and mechanisms of the CoCrFeNiCu high-entropy alloy prepared via spark plasma sintering (SPS-HEA) are markedly under-explored, which deteriorates its reliability at high-temperature applications and impedes the development of anti-oxidation strategies. This study investigated the high-temperature oxidation behavior of CoCrFeNiCu high-entropy alloys prepared via spark plasma sintering (SPS-HEA) and compared it with their as-cast counterparts (Cast-HEA). Results indicated that while both alloys exhibited an approximate diffusion-controlled parabolic oxide-scale growth trend based on semi-quantitative cross-sectional measurements at 700 °C and 800 °C, their oxide layer structures and internal oxidation behaviors differed significantly, with the SPS-HEA demonstrating superior oxidation resistance over Cast-HEA. The novelty of this work lies in demonstrating that SPS processing enhances oxidation resistance not simply by densification, but by refining and discontinuously distributing Cu-rich phases to suppress continuous CuO-rich scale growth and promote protective Cr-containing oxides. Cast-HEA developed multiple surface oxides influenced by Cu-rich phase barriers, with internal oxidation proceeding along the phase boundaries. In terms of SPS-HEA, internal pores promoted pronounced internal oxidation, and a continuous Cr-rich oxide layer formed under thermodynamic control. The mechanisms that accounted for the oxide spallation at 900 °C differed between the Cast-HEA and SPS-HEA, which were internal oxidation-induced interface weakening and Cu segregation-driven outer layer detachment, respectively.