A new strategy to toughen NbCr₂ Laves phase

Abstract

A new strategy to toughen NbCr2 Laves phase was proposed, in which ductile Cr and Nb solid solutions were incorporated by accelerating solute segregation within NbCr2 matrix using external applied pulsed electric current. A dense bulk consisting of ultrafine NbCr2 grains with abundant Cr and Nb solid solutions along the grain boundaries was produced by spark plasma sintering using monolithic NbCr2 starting powders. The formation of Cr and Nb solid solutions was attributed to the enhanced atomic transport, which facilitated the mobility of dislocations and the selective Joule heating. The fracture toughness of the sample achieved 11.3 MPa·m1/2, which was 9.4 times the as-cast NbCr2 (1.2 MPa·m1/2) and thus can be regarded as a new toughening mechanism.