Design of Cu–Cr Alloys with High Strength and High Ductility Based on First-Principles Calculations

Abstract

Designing a material to realize the simultaneous improvement in strength and ductility is very meaningful to its industrial application. Here, the first-principles calculations based on density functional theory (DFT) were adopted to investigate the stability, elastic properties and Debye temperature of binary Cu–Cr alloys; and the effect of micro-alloying elements on their mechanical properties, including the bulk modulus B, shear modulus G, Yong’s modulus E and Poisson’s ratio σ, was discussed. The elastic constants show that all the studied binary Cu–Cr alloys are mechanically stable, and the Cu–0.7Cr alloy has a combination of good strength and ductility. Moreover, the addition of Ag, Sn, Nb, Ti and Zr can improve the basic properties of Cu–0.7Cr alloy, and the Cu–0.7Cr–1.1Sn possess a large strength combined with improved ductility and strong covalent bonds due to the large Debye temperature. Additionally, the introduction of Y and In further improves the mechanical properties (strength and ductility) of the excellent Cu–0.7Cr–1.1Sn alloy. Our studied results can provide guidance for the theoretical design and experimental improvement of Cu-based alloys.