First principles study of interface bonding strength, stability, and tensile properties of Ti2AlC(0001)/Ti3Al(0001) interface

The interface bonding strength, stability, and tensile properties of Ti2AlC(0001)/Ti3Al(0001) interface were revealed on an atomic scale using the first principles. The results show that C-hcp-hollow-BA is an ideal Ti2AlC/ Ti3Al interface because of its maximum work of adhesion (10.91 J/m2), minimum interface energy (-1.24 J/m2), maximum interface fracture toughness (2.60-3.53 MPa m1/2), and best tensile properties (critical strain of 16 % and ideal tensile strength of 29.18 GPa). In first-principles tensile simulation, C-hcp-hollow-BA fractures within the Ti3Al bulk, while the remaining three interface models fracture at the interface. Among them, strong interactions exist at the interface of C-hcp-hollow-BA, and two Ti atoms at the interface of Ti(Al)-bridge-AB repel each other, so their fracture locations don't coincide with the ones suggested by Griffith theory and work of interface separation, respectively. The fracture process of four interface model can be summarized as the successive formation of electron holes, microcracks, and charge depletion regions leading to fracture failure. In addition, Ti(C)-hcp-hollow-AB and Ti(Al)-bridge-AB share similar interface properties due to the same Ti2AlC (0001) surface termination and Ti3Al(0001) surface stacking sequence. This study provides a theoretical and computational basis for the development of Ti2AlC/TiAl composites, thus accelerating the research on the new generation of aero-engines.