First-principles investigation of structural, mechanical and electronic properties for Cu-Ti intermetallics

To design a high-performance Cu-Ti intermetallic coating, first-principles calculation is conducted to systematically investigate the phase stability, mechanical and electronic properties of the Cu-Ti binary intermetallics. The phase stability and mechanical properties are studied by calculating the formation enthalpy and independent elastic constants, respectively. The calculated formation enthalpy indicates that beta-Cu4Ti, CuTi and CuTi2 are stable phases at 0 K, while alpha-Cu4Ti, Cu3Ti, Cu3Ti2, and Cu4Ti3 are meta-stable phases. In addition, the mechanical properties of Cu-Ti intermetallics present a positive correlation with their formation enthalpy. The electronic structures of the Cu-Ti intermetallics are evaluated by analyzing the bonds character to reveal the bonding characteristics, which is crucial to the phase stability and mechanical properties. Among the Cu-Ti intermetallics studied, CuTi phase exhibits the highest stability, hardness and a higher brittleness among all Cu-Ti intermetallics, while other Cu-Ti intermetallics show good toughness. Based on the calculated results, a high strength Cu-Ti intermetallic coating consisting of hard CuTi particles on a ductile Cu4Ti3 matrix is proposed. (C) 2016 Elsevier B.V. All rights reserved.