WReTaMo Refractory High‐Entropy Alloy with High Strength at 1600 °C

Structural materials with higher melting temperatures and better mechanical properties than superalloys are in high demand in refractory applications. A promising WReTaMo refractory high‐entropy alloy (RHEA) with high strength at 1600 °C is fabricated by vacuum arc melting. The WReTaMo RHEA has a body‐centered cubic (BCC) structure with a maximal compressive strength of 1140 MPa and Vickers microhardness of 654 HV at room temperature. The alloy displays a strong resistance to high‐temperature softening, showing the high maximal compressive strength of 244 MPa at 1600 °C. The deformation of the WReTaMo RHEA compressed at 1600 °C maybe resulted from the grain boundary sliding, which leads to the propagation of the cracks along grain boundaries. Face‐centered cubic (FCC) phase forms at the surface region of samples annealed above 1800 °C due to the diffusion of carbon atoms by gas carburizing in the graphite crucible at such high temperatures. The increase in hardness at temperatures above 1600 °C results from the solid solution strengthening of dissolved carbon. The forming ability of the WReTaMo RHEA is also discussed. This work presents a promising high‐temperature structural material and fills the vacancy of the mechanical properties of Re‐containing RHEAs at 1600 °C.