The improved strength and toughness in the quinary Cr₂Nb/Cr in-situ composite

A quinary Cr–12Nb–5Ti–5Mo–5Si (at.%) alloy was prepared by arc melting in this study to improve the strength and toughness of Laves phase Cr₂Nb alloy. The quinary alloy was solidified with full eutectic Cr₂Nb/Cr, in which the Cr₂Nb phase exceeded 55 vol % and existed as matrix. The eutectic was developed with an orientation relationship of {001}Cr₂Nb//{001}Cr, leading to a low lattice mismatch of 15.57% at the eutectic interface. The yield strength and fracture toughness of the quinary alloy reached 1950–1980 MPa and 14.0–14.8 MPa⋅m^1/2, respectively, much higher than most reported Cr₂Nb alloys. The reason for the superior properties is the synergistic effects of solid solution strengthening, alloying toughening, and eutectic strengthening-toughening.