Evolution laws of microstructures and mechanical properties during heat treatments for near-α high-temperature titanium alloys

• Published in: International journal of minerals, metallurgy and materials Vol. 29; no. 8; pp. 1596 - 1607
• Main Authors: Ma, Xiaozhao, Xiang, Zhilei, Li, Tao, Chen, Yilan, Liu, Yingying, Chen, Ziyong, Shu, Qun
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01.08.2022; Springer Nature B.V; Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China%Pinggao Group CO.,LTD,State Grid Corporation of China,Pingdingshan 467000,China%Aviation Industry of China(AVIC)Manufacture technology institute,Beijing 100024,China
• Subjects: Aging; Alloys; Beta phase; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Cooling; Corrosion and Coatings; Evolution; Fracture surfaces; Glass; Heat resistant alloys; Heat treating; Heat treatment; High temperature; Intermetallic compounds; Lamellar structure; Materials Science; Mechanical properties; Metal fatigue; Metallic Materials; Microstructure; Natural Materials; Niobium; Room temperature; Scanning electron microscopy; Silicides; Surfaces and Interfaces; Temperature; Thin Films; Titanium alloys; Titanium base alloys; Tribology; Zirconium; microstructures; silicides; fractographs; solution temperatures; mechanical properties
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-021-2248-8

Evolution laws of microstructures, mechanical properties, and fractographs after different solution temperatures were investigated through various analysis methods. With the increasing solution temperatures, contents of the primary α phase decreased, and contents of transformed β structures increased. Lamellar α grains dominated the characteristics of transformed β structures, and widths of secondary α lamellas increased monotonously. For as-forged alloy, large silicides with equiaxed and rod-like morphologies, and nano-scale silicides were found. Silicides with large sizes might be (Ti, Zr, Nb) 5 Si 3 and (Ti, Zr, Nb) 6 Si 3 . Rod-like silicides with small sizes precipitated in retained β phase, exhibiting near 45° angles with α/β boundaries. Retained β phases in as-heat treated alloys were incontinuous. 980STA exhibited an excellent combination of room temperature (RT) and 650°C mechanical properties. Characteristics of fracture surfaces largely depended on the evolutions of microstructures. Meanwhile, silicides promoted the formation of mico-voids.