Effects of Microstructure and Rare-Earth Constituent on the Oxidation Behavior of Ti–5.6Al–4.8Sn–2Zr–1Mo–0.35Si–0.7Nd Titanium Alloy

• Published in: Oxidation of metals Vol. 81; no. 3-4; pp. 373 - 382
• Main Authors: Zhang, S. Z., Zhou, B., Liu, N., Chen, L. Q.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.04.2014; Springer
• Subjects: Applied sciences; Chemistry and Materials Science; Corrosion; Corrosion and Coatings; Corrosion environments; Exact sciences and technology; Inorganic Chemistry; Materials Science; Metallic Materials; Metals. Metallurgy; Microstructure; Original Paper; Oxidation; Oxidation resistance; Rare earth metals; Scale (corrosion); Titanium base alloys; Titanium dioxide; Tribology; Ultimate tensile strength; Oxidation; Rare-earth constituent; Near-α titanium alloy; Microstructure; Rare-earth metal addition; Lanthanide; Corrosion
• ISSN: 0030-770X; 1573-4889
• DOI: 10.1007/s11085-013-9445-4

The isothermal oxidation behavior in air of high-temperature titanium alloy Ti–5.6Al–4.8Sn–2Zr–1Mo–0.35Si–0.7Nd with bimodal and lamellar microstructures was investigated at 600–800 °C. The results revealed that the alloy with lamellar microstructure has better oxidation resistance than that with bimodal microstructure. The porous oxide scales that form mainly contain TiO 2 . A noticeable observation concerns the preferential attack around rare-earth particles, associated rapid oxygen diffusion along the incoherent rare-earth precipitate/matrix interface and cracks formed during oxidation. The resulting internal attack caused fragmentation of rare-earth particles and further oxidation of substrate to form TiO 2 scale with some fine dispersoids of Al 2 O 3 . Tensile tests showed that the ultimate strength and ductility of the specimens with removed surface were higher than that with a surface scale.