Microstructure and mechanical properties at elevated temperatures of a new Al-containing refractory high-entropy alloy Nb-Mo-Cr-Ti-Al

Abstract In the present investigation, we provide results on the casting, homogenization, and deformation behavior of a new Al-containing refractory high-entropy alloy, namely the equiatomic Nb-Mo-Cr-Ti-Al. The alloy shows a dendritic microstructure after arc melting. The dendrites completely dissolve due to a heat treatment at 1300 °C for 20 h. Besides a major phase in the form of a solid solution of W prototype structure, identified by X-ray diffraction (XRD) measurements as well as electron backscatter diffraction (EBSD), additional phases of small volume fraction within the grains and at the grain boundaries were observed. Quasistatic compression tests, performed between room temperature and 1200 °C, reveal sustaining and high yield strength up to 800 °C and an increasing ductility with increasing test temperature. The dominant deformation mechanism for quasistatic compression loading between 800 °C and 1200 °C is the 〈 111 〉 pencil glide of dislocations within the solid solution which was proven by the according fiber texture components, evolving during deformation.