Tailoring microstructure and improving oxidation resistance of an additively manufactured high Nb containing TiAl alloy via heat treatment

• Published in: Corrosion science 2023-08, Vol.220, p.111287, Article 111287
• Main Authors: Liang, Zhenquan, Xiao, Shulong, Yue, Hangyu, Li, Xinyi, Li, Qingchao, Zheng, Yunfei, Xu, Lijuan, Xue, Xiang, Tian, Jing, Chen, Yuyong
• Format: Article
• Language: English
• Subjects: Heat treatment; Oxidation; Selective electron beam melting; Titanium aluminides
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2023.111287

In this paper, the effects of heat treatment on the microstructure and oxidation behavior of Ti-45Al-8Nb alloy prepared by selective electron beam melting were investigated. The results show that the microstructure of alloy changes from near-γ structure to duplex structure after heat treatment, but both present the heterostructure characteristics. The oxidation tests reveal that heat treatment can effectively improve the oxidation resistance, which mainly results from the optimization of phase constitution, the introduction of more twin boundaries and the formation of continuous AlNb2 barrier layer. These factors will inhibit the inward diffusion of oxygen ions into the substrate. •Heat treatment can modify the microstructure of additively manufactured Ti-45Al-8Nb alloy from near-γ to duplex structure.•The oxidation resistance of alloy can be significantly improved by heat treatment.•The correlation between microstructure characteristics and oxidation resistance was discussed.