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

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. [Display omitted] •The as-cast microstructure of equimolar Nb-Mo-Cr-Ti-Al can be homogenized @ 1300 °C.•After homogenization, bcc solid solution with minor secondary phases are observed.•Compression tests reveal a maximum strength of ≈1 GPa @ room temperature.•Increasing ductility up to 24% @ 1200 °C is observed.•Compression leads to mixed 〈001〉 and 〈111〉 fiber texture which indicates pencil glide.