Enhanced oxidation resistance of (Mo95W5)85Ta10(TiZr)5 refractory multi-principal element alloy up to 1300°C. (15th August 2021)

• Record Type: Journal Article
• Authors: Su, Ranran; Zhang, Hongliang; Ouyang, Gaoyuan; Liu, Longfei; Nachlas, Will; Cui, Jun; Johnson, Duane D.; Perepezko, John H.
• Is Part Of: Acta materialia. Volume 215(2021)
• Publication Date: 2021-08-15
• Subjects: RMPEA -- Refractory metal alloy -- Mo-Si-B coating -- Ultra-high temperature -- Oxidation; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.117114
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Refractory-metal-based alloys are a potential replacement of current nickel-based superalloys due to their excellent mechanical strength at extremely high temperatures. However, severe oxidation in a high-temperature working environment limits their application. To address this challenge, a two-step coating process (including a Mo precoat and a Si-B pack cementation) was applied to an innovative refractory multi-principal element alloy (RMPEA) (Mo95 W5 )85 Ta10 (TiZr)5 . The coating is composed of an aluminoborosilica glass layer on top of a RMPEA-Si-B multilayered structure. The coating effectively protects the RMPEA from oxidation in high-temperature environments, as demonstrated by phase-stable operation at 10–20% higher temperatures over state-of-the-art systems without any forced-cooling system. Following an isothermal exposure at 1300 °C, the weight change of the coated sample follows a paralinear kinetics with a minor weight loss of 4.2 mg/cm 2 after 50 h. Thermal cycling tests between 1300 °C and room temperature in air resulted in the total weight gain of only 2.6 mg/cm 2 after 450 cycles. The coating shows an excellent adherence to the substrate with a boride layer acting as a barrier that maintains the coating integrity. This two-step Mo-Si-B coating method can be adapted to provide environmental resistance to a wide range of RMPEA. Graphical abstract: Image, graphical abstract