Tribo-corrosion resistance of Ti-Nb-Cr-Mo-Al refractory high-entropy alloys in molten aluminum

Ti40Nb25Cr15Mo10Al10 and Ti40Nb20Cr20Mo10Al10 refractory high-entropy alloys (RHEAs) were designed and fabricated, aiming at investigating their mechanical properties, corrosion and tribo-corrosion behavior in molten aluminum. Compared with H13 steel, these RHEAs exhibit significantly better combinations of high-temperature mechanical properties, corrosion and tribo-corrosion resistance. Low solubility of constituent elements in molten aluminum along with slow diffusion of Al atoms in RHEAs’ matrices, are responsible for the outstanding corrosion resistance of RHEAs. Exceptional tribo-corrosion resistance of RHEAs derives from their outstanding combinations of corrosion resistance and high-temperature mechanical properties. Additionally, higher content of Cr in RHEAs would lead to worse tribo-corrosion resistance.