Theoretical prediction of high temperature mechanical, thermodynamic and surface O adsorption properties of W-Cu alloys: Advanced high temperature super strength alloy materials

Abstract

This paper constructs four alloy structural models of W15Cu1, W14Cu2, W13Cu3 and W12Cu4 as research objects. Based on phonon spectra analysis, the structure of W12Cu4 is unstable. Thus, the mechanical and thermodynamic properties for pure W, W15Cu1, W14Cu2 and W13Cu3 are studied using first-principles methods. The results show that the bulk modulus of W-Cu alloys exhibits the characteristics of high-temperature strength alloys. In particular, the bulk modulus of W14Cu2 and W13Cu3 increases rapidly with temperature increasing; Meanwhile, The W-Cu alloys at high temperatures exhibit low expansion behavior. The coefficient of thermal expansion of W14Cu2 at 1290 K starts to be lower than that ofW, and decreases with temperature increasing. At 1370 K, the coefficient of thermal expansion of W13Cu3 begins to be lower than that of W14Cu2, which also decreases with temperature increasing. The W-Cu alloys at high temperatures exhibit excellent phonon thermal conductivity. The phonon thermal conductivity of W14Cu2 at 2230 K transcends pure W and then maintains a thermal conductivity of about 5.55Wm-1K−1. The phonon thermal conductivity of W13Cu3 at 2140 K begins to transcend W14Cu2, and also exceeds pure W at 2180 K, and increases rapidly with temperature increasing. At 0 K, the addition of Cu to W reduces the mechanical strength but increases the ductility.