Phase driven strengthening mechanisms in NbMoTiV based refractory high entropy alloys with Cr inclusions

To enhance the mechanical properties of refractory high-entropy alloys (RHEAs), Laves intentionally introduced with body cantered cubic (BCC) structure, and NbMoTiVCr_x (x = 0, 0.25, 0.50, and 0.75, molar ratio) alloys were synthesized via vacuum arc melting. The results show that the formation of Laves phase significantly influences hardness, compressive properties, and corrosion behaviour. The hardness increases systematically with Cr addition due to Laves phase strengthening and microstructural refinement, reaching its maximum at x = 0.75, consistent with the increase in Laves phase volume fraction from 0 to 15%. Compression testing shows that the yield strength and ultimate compressive strength increase markedly from 880 MPa to 1720 MPa and from 1660 MPa to 2380 MPa, respectively, with increasing Cr content. Finally, electrochemical measurements demonstrate that Cr addition does not compromise corrosion resistance; instead, the formation of stable passive films contributes to improved corrosion performance in chloride media. The simultaneous enhancement in hardness, compressive strength, and corrosion resistance confirms that controlled Laves phase formation is an effective strategy for designing NbMoTiV based RHEAs with improved overall performance.