Enhanced high-temperature strength of HfNbTaTiZrV refractory high-entropy alloy via Al 2 O 3 reinforcement

Novel composites of HfNbTaTiZrV refractory high-entropy alloy (RHEA) reinforced with 0-4 vol.% Al2O3 particles have been synthesized by vacuum arc melting. The microstructure evolution, compressive me-chanical properties at room and elevated temperatures, as well as strengthening mechanism of the com-posites were analyzed. The HfNbTaTiZrV RHEA reinforced with 4 vol.% Al2O3 displayed excellent phase stability at elevated temperatures. A superior compressive yield strength of 2700 MPa at room tempera -ture, 1392 MPa at 800 degrees C, and 693 MPa at 10 0 0 degrees C was obtained for this composite. The improved yield strength resulted from multiple strengthening mechanisms caused by Al2O3 addition, including solution strengthening, interstitial strengthening, grain boundary strengthening, and dispersion strengthening. Be -sides, the effects of interstitial strengthening increased with temperature and was the main strengthen-ing mechanism at elevated temperatures. These findings not only promote the development of oxide-reinforced RHEAs for challenging engineering applications but also provide guidelines for the design of light refractory materials with multiple strengthening mechanisms.

Automated summary

Novel composites of HfNbTaTiZrV refractory high-entropy alloy (RHEA) reinforced with 0-4 vol.% Al2O3 particles have been synthesized, and their microstructure evolution, compressive mechanical properties at room and elevated temperatures, as well as strengthening mechanisms have been analyzed. The addition of Al2O3 not only enhances the phase stability at elevated temperatures but also improves the compressive yield strength through multiple strengthening mechanisms.