Hot compressive deformation of W-modified FeCr2V-based medium entropy alloys: Microstructure and strengthening mechanism studies

The microstructure and mechanical properties of FeCr2VWx (x = 0, 0.1, 0.3, 0.5) medium-entropy alloys (MEAs) manufactured using arc melting under an argon atmosphere were investigated. The investigated FeCr2VWx (x = 0, 0.1, 0.3) MEAs exhibited a dual-phase microstructure consisting of body-centred-cubic (BCC) phases. With the further addition of W, additional W-rich phase formed in the microstructure of the FeCr2VW0.5 sample. Compression tests at the ambient and elevated temperatures revealed that the compressive performance of the MEAs improved with the introduction of W. Among them, FeCr2VW0.3 demonstrated an exceptional combination of enhanced strength and ductility, showing the yield strength of 1452 MPa at ambient temperature and 627 MPa at 1223 K as well as compression reduction over 30% at both temperatures. These compressive properties are comparable to those of existing low activation refractory high-entropy alloys. The excellent high-temperature performance was attributed to the enhanced strengthening effects of precipitation and solid-solution resulting from W addition. Moreover, it was found that during the hot deformation process FeCr2VWx MEAs with higher W contents (above 0.3) resulted in more work hardening than that of the lower W contents, and required more dynamic recrystallization to achieve the dynamic equilibrium. These results provide valuable insights for the future development and microstructural engineering of new MEAs.