Microstructures and high-temperature oxidation behavior of directionally solidified Nb–Si-based alloys with Re additions

• Published in: Rare metals Vol. 42; no. 1; pp. 273 - 280
• Main Authors: Zhang, Jie-Chao, Jia, Li-Na, Weng, Jun-Fei, Su, Lin-Fen, Kong, Bin, Zhang, Hu
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.01.2023; Springer Nature B.V
• Subjects: Alloys; Biomaterials; Chemistry and Materials Science; Directional solidification; Energy; High temperature; Materials Engineering; Materials Science; Metallic Materials; Microstructure; Nanoscale Science and Technology; Oxidation; Oxidation resistance; Physical Chemistry; Silicon base alloys; Temperature; Rhenium addition; Oxidation behavior; Nb–Si alloys; Directional solidification; Microstructure
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-016-0788-2

High-temperature oxidation behavior of directionally solidified (DS) Nb–Si-based alloys with Re additions was investigated at 1200 and 1250 °C, respectively. Microstructures and high-temperature oxidation behavior of the alloys were characterized. Results show that the microstructures in vertical section of Nb–24Ti–15Si–4Cr–2Al–2Hf– x Re ( x  = 0, 1, 3; at%) alloys grow parallel to the withdrawal direction and the cross section exhibits bud-like structures. The bud-like structures become finer with more Re additions. The weight gain of the Nb–24Ti–15Si–4Cr–2Al–2Hf–3Re alloy after oxidation at 1200 °C for 100 h is 198.1 mg·cm −2 , and it is a bit higher at 1250 °C. The other two alloys perform somewhat worse. The influence of Re addition on the oxidation resistance at 1250 °C is more significant than that at 1200 °C. Although Re addition does not benefit obviously the high-temperature oxidation resistance of the DS samples, it does not compromise the oxidation resistance with a certain amount of Re additions in contrast with the alloy without Re addition.