Phase stability, brittle-ductile transition, and electronic structures of the TiAl alloying with Fe, Ru, Ge, and Sn: a f
- PDF / 1,263,896 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 14 Downloads / 149 Views
ORIGINAL PAPER
Phase stability, brittle-ductile transition, and electronic structures of the TiAl alloying with Fe, Ru, Ge, and Sn: a first-principle investigation Z. K. Yin 1,2 & J. S. Chen 1,2,3
&
P. L. Zhang 1,2 & Z. S. Yu 1,2 & Y. Z. Zhang 4 & Y. Chun 3 & H. Lu 3
Received: 7 July 2020 / Accepted: 18 October 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Phase stability, brittle-ductile transition, and electronic structures of M (M = Fe, Ru, Ge, and Sn) and content change of L10-TiAl (γ-TiAl) and B2-TiAl (β-TiAl) have been investigated using first-principle methods. It is found that M metal atoms preferentially occupy the Al (2e) sites in L10-TiAl and B2-TiAl. According to Pugh’s ratio and Poisson’s ratio, the brittle-ductile transition is predicted for L10-TiAl and B2-TiAl with Fe, Ru, Ge, and Sn. It is found that the brittle-ductile transition from brittle regions to ductile regions with the transition metal elements Fe and Ru in L10-TiAl and B2-TiAl at the low concentration is approximately from 0 to 6.25 at.%. However, the brittle-ductile transition of Ge and Sn at the high concentration approximates from 6.25 to 12.5 at.% in L10-TiAl, comparing with B2-TiAl which approximates from 12.5 to 18.75 at.%. Electronic structure analysis shows that the improvement of brittleness can be attributed to two factors, including different hybridizations of Al-2p (Ti-3d) orbits with Fe-3d (Ge-4p) and Ru-4d (Sn-5p) orbits and different bandwidths of pseudo-gap. Furthermore, the L10-TiAl and B2TiAl at low concentration of Fe and Ru can increase the value of ELF, where Ge and Sn atoms become bigger at a high concentration in L10-TiAl and B2-TiAl. At last, elastic constant (Cij), bulk modulus (B), shear modulus (G), and Young’s modulus (E) of L10 and B2-TiAl with content change are systematically given. Keywords TiAl . Phase stability . Brittle/ductile transition . Electronic structures . First principles
Introduction Wide attention has been attracted to the application prospects of TiAl alloy in the automotive and aerospace fields. Owing to its high melting temperature, low density, high specific modulus, and strength, TiAl alloy is expected to become a
* J. S. Chen [email protected] * Y. Z. Zhang [email protected] 1
School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People’s Republic of China
2
Shanghai Collaborative Innovation Center of Laser Advanced Manufacturing Technology, Shanghai, People’s Republic of China
3
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
4
AECC Commercial Aircraft Engine Manufacturing CO., LTD, Shanghai 200241, People’s Republic of China
replacement for nickel-based super-alloy as a new generation of aviation materials [1–4]. However, due to the low room temperature ductility of TiAl, its development and application are still severely limited [5–7]. Traditional research methods have been carried out to improve its brittle, such as heat treatment, grain refin
Data Loading...
