A comprehensive DFT study on the thermodynamic and mechanical properties of L12-Al3Ti/Al interface. (January 2021)

• Record Type: Journal Article
• Authors: Zhang, Xieyi; Huang, Yuanchun; Liu, Yu; Ren, Xianwei
• Is Part Of: Vacuum. Volume 183(2021)
• Publication Date: 2021-01
• Subjects: L12-Al3Ti/al -- Interface -- Surface energy -- Structure stability -- Interfacial strength -- Plasticity; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2020.109858
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: In this present work, we systematically studied the properties of metastable Al3 Ti/Al (L12 -Al3 Ti/Al) low-index coherent interface, including structure stability, fracture behavior, plasticity, stacking fault energy, electron structure, and density of states by first-principles calculation. The results of the rigid scheme indicated that the strongest interfaces of L12 -Al3 Ti(001)/Al(001), L12 -Al3 Ti(110)/Al(110), and L12 -Al3 Ti(111)/Al(111) were stacked similarly to bulk L12 -Al3 Ti or Al, and the work of adhesion ( W ad ) of 2.78, 2.81, and 1.83 J/m 2, respectively. In the rigid scheme, the theoretical tensile strength for L12 -Al3 Ti(001)/Al(001), L12 -Al3 Ti(110)/Al(110), and L12 -Al3 Ti(111)/Al(111) interfaces were 15.30, 14.23 and 12.39Gpa, respectively. We simulated the fracture behavior by the full-relaxed scheme, and tensile stresses are 10.65, 10.10, and 8.27 GPa for L12 -Al3 Ti(001)/Al(001), L12 -Al3 Ti(110)/Al(110), and L12 -Al3 Ti(111)/Al(111) interfaces, respectively. Furthermore, our findings revealed that the interfaces were prone to break on the Al side in the full-relaxed stretching scheme, which was closer to reality. Moreover, the partial density of states (PDOS) indicated that s-p-d hybridization orbitals formed among the Al and Ti atoms. Finally, unstable stacking fault energy and Rice ratio indicated that the L12 -Al3 Ti(001)/Al(001), L12 -Al3 Ti(110)/Al(110) interfaces had good plasticity to some extent. However, it can start slipping in <11-2> direction with D = 3.02 and turn into another direction after μ/b = 0.11 . Highlights: The results of the rigid scheme of L12 -Al3 Ti/Al interfaces show that the bulk-like structure of the interface is the most stable, with the largest adhesion work ( Wad ) and interface strength. Simulation of the full relaxation model indicates that the L12 -Al3 Ti/Al interface is easier to break on the aluminum side, and L12 -Al3 Ti(001)/Al(001) has the highest strength. Electronic structure and density of states indicate that the atomic orbitals of the interfacial atoms are hybridized to form s-p or s-p-d hybrid orbitals. The electron density on the fracture surface will change drastically, and electron holes and the rigon with excessively accumulated electron appear. Stacking fault energy and Rice ratio indicate that the L12 -Al3 Ti(001)/Al(001) and L12 -Al3 Ti(110)/Al(110) interfaces have better plasticity.