Titanium alloying enhancement of mechanical properties of NbTaMoW refractory high-Entropy alloy: First-principles and experiments perspective

Abstract

Poor ductility of Refractory high entropy alloys (RHEAs) at room temperature (RT) is the main problem restricting their practical applications. Alloying is an effective method to improve the mechanical properties of RHEAs. Here, Ti was employed to enhance the RT ductility of NbTaMoW RHEAs by means of alloying. The influence of Ti addition on the mechanical properties of the equiatomic NbTaMoW RHEA was investigated from the perspective of first-principles calculation combining experiments. The phase structure, lattice parameters, densities, elastic properties and electronic structure were calculated, respectively. The results show that NbMoTaW and NbMoTaWTi alloy were single-phase BCC structure. Both alloys were electrically conductive and shown metallic characteristic. Ti alloying effectively enhanced the atomic interaction, strength and ductility of NbMoTaW alloy due to the increasing Ti–Ti metallic bonds and decreasing covalent bonds. The calculated data were well agreed with the experimental results, demonstrating that first-principles calculation was an effective method to predict the alloying performance enhancement of RHEAs.