Abstract The isothermal oxidation behavior of WC-based cemented carbides with AlxCoCrCuFeNi (x = 0, 0.5, 1.0, 1.5) high-entropy alloy (HEA) binders at 600∼800oC in air was studied by a thermogravimetric method, as well as WC-Co for comparison. The oxidation of the WC-HEA cemented carbides accompanies swelling and follows a linear law that is controlled by reaction at the oxide layer/matrix interface. The WC-HEA cemented carbides show better oxidation resistance than WC-Co, even though WC-Co has a denser microstructure and coarser WC grain size. With increase of Al content in the HEA binder, the oxidation rate of WC-HEA decreases, and the specific mass gains of the samples with HEA binder containing Al are at least 20% smaller than that of WC-Co after isothermal oxidation at 800oC for 2 h. Moreover, as the HEA content increases from 5 to 20 wt.%, the specific mass gain reduces from 61.89 to 24.55 mg/cm2. Selective oxidation of the HEA binder occurs, and the excellent anti-oxidation property of the HEA binder impedes inward diffusion of oxygen to the oxide layer/matrix interface, which suppresses oxidation of the matrix and enhances oxidation resistance of the WC-HEA. The results also indicate that the improved oxidation resistance of the WC-HEA system should not be attributed mainly to the formation of a dense oxide layer with high tungstate content during oxidation.

中文翻译：

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超细WC基硬质合金与Al CoCrCuFeNi高熵合金结合剂的氧化行为

摘要 采用热重法研究了含 AlxCoCrCuFeNi (x = 0, 0.5, 1.0, 1.5) 高熵合金 (HEA) 粘结剂的 WC 基硬质合金在 600~800oC 空气中的等温氧化行为，以及 WC-用于比较。WC-HEA 硬质合金的氧化伴随着膨胀并遵循由氧化层/基体界面处的反应控制的线性规律。WC-HEA 硬质合金显示出比 WC-Co 更好的抗氧化性，尽管 WC-Co 具有更致密的微观结构和更粗的 WC 晶粒尺寸。随着HEA结合剂中Al含量的增加，WC-HEA的氧化速率降低，含Al的HEA结合剂样品在800oC等温氧化后比质量增加至少比WC-Co小20% 2 小时。此外，随着 HEA 含量从 5 重量％增加到 20 重量％，比质量增加从 61.89 减少到 24.55 mg/cm2。HEA粘结剂发生选择性氧化，HEA粘结剂优异的抗氧化性能阻止氧向内扩散到氧化层/基体界面，抑制基体氧化，增强WC-HEA的抗氧化性。结果还表明，WC-HEA 体系提高的抗氧化性不应主要归因于在氧化过程中形成了具有高钨酸盐含量的致密氧化层。