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 degrees 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 degrees C. The deformation of the WReTaMo RHEA compressed at 1600 degrees 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 degrees 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 degrees 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 degrees C.