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.

Concentration-dependent atomic mobilities in FCC CoCrFeMnNi high-entropy alloys

“…Furthermore, the single phase observed in HEAs might be a high temperature phase with a kinetically constrained transformation 5 . Focusing on high temperature mechanical properties 7,8 , creep strength [9][10][11][12] , oxidation resistance [13][14][15] and coating applications 16 , numerous HEAs have been investigated following an originally introduced paradigm of four 'core' effects, i.e. a high entropy, severe lattice distortion, 'cocktail' effect and 'sluggish' diffusion 2 .…”

Tracer diffusion in single crystalline CoCrFeNi and CoCrFeMnNi high entropy alloys

“…In recent years, numerous HEAs have been investigated focusing on high temperature mechanical properties [7,8], creep strength [9,10,11,12], oxidation resistance [13,14,15] and coating applications [16], following an originally introduced paradigm of four 'core effect', i.e. a high entropy, severe lattice distortion, 'cocktail' effect and sluggish diffusion [2].…”

Design of Light-Weight High-Entropy Alloys

“…Due to the demand from transportation and defense industries, the development of a new generation of light-weight alloys has also brought widespread interest in HEAs to the materials science and engineering communities, expressly, for the purpose of saving energy and raw materials [7][8][9][10][11][12][13][14][15]. The trial-and-error approach that has been used for traditional alloys design is costly and time-consuming for the discovery of new HEAs because of the vast compositional space that they occupy.…”