Microstructural and Mechanical Evaluation of NbMoTiVSix(<i>x </i>= 0, 0.25) Refractory High‐Entropy Alloys at High Temperature
Wei Zhang, Wei Jiang, Shuaishuai Wu, Shutian Tao, Baohong Zhu, Shengli Guo
Abstract
The novel refractory NbMoTiVSix( x = 0,0.25) refractory high‐entropy alloys (RHEAs) with both high strength and good ductility simultaneously by vacuum arc melting are developed. The microstructure evolution, compressive mechanical properties, and strengthening mechanism of the RHEAs with the addition of silicon at 1000 °C are analyzed and discussed. Microstructure observation shows that the NbMoTiV RHEA comprises of a single body‐centered cubic (BCC) phase, whereas the NbMoTiVSi 0.25 RHEA consists of a BCC phase and simple multi‐component M 5 Si 3 (M = Nb, Mo, Ti, V) phases. Compressive tests show that the yield and ultimate strength of the NbMoTiVSix( x = 0,0.25) RHEAs at 1000 °C increases from 590 to 931 MPa and from 682 to 1090 MPa with increasing silicon content. The improvement of strength is caused by the dipolar dislocation walls, the pinning effect of the diphasic interface, and a large amount of nano‐silicides phase particles in BCC phase, all of them are the result of silicide formation.