Effect of rhenium addition on microstructure and mechanical properties of Ti-48Al-2Cr-2Nb alloys
(1. College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
3. Advanced Materials Additive Manufacturing Innovation Research Center, Hangzhou City University, Hangzhou 310015, China;
4. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China)
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
3. Advanced Materials Additive Manufacturing Innovation Research Center, Hangzhou City University, Hangzhou 310015, China;
4. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: The refractory metal rhenium (Re), with content of 0-2 at.%, was introduced into a typical γ-TiAl alloy of Ti-48Al-2Cr-2Nb (at.%) through vacuum arc melting. The effect of Re content on the microstructure and mechanical properties of the γ-TiAl alloy was investigated. The results show that the γ-TiAl-xRe alloy is composed of γ, α2, and β phases. As the Re content increases, the proportion of β phase increases, while the content and size of α2+γ lamellar structure decrease gradually. Furthermore, the compressive strength increases with increasing Re content. A maximum compressive strength of 2282 MPa is achieved for the γ-TiAl-2Re alloy. The γ-TiAl-2Re alloy exhibits a fracture strain of 36.7%, considerably higher than that of the γ-TiAl alloy (31.0%). Moreover, compared with the γ-TiAl alloy, the hardness and compressive strength of the γ-TiAl-2Re alloy considerably increase by 17.5% and 34.2%, respectively.
Key words: γ-TiAl alloy; rhenium; vacuum arc melting; lamellar cluster; mechanical properties; strengthening mechanism