Preparation and properties of medium entropy CoCrNi/boride metal matrix composite

The present work deals with synthesis, microstructural and mechanical properties' evaluation of a metal matrix composite, produced by a combination of mechanical alloying and spark plasma sintering utilizing FCC CoCrNi medium entropy alloy as the matrix phase, with dispersion of Cr5B3 particles. Cr5B3 was formed in-situ, by the reaction of B4C, which was added to the powders prior to mechanical alloying, during sintering with Cr element present in the powders. The composite exhibited excellent tensile strength level with R-m of 1432 MPa, tensile elongation to fracture of 1.83%, and elastic modulus of 226 GPa. Very fine dimple-like fracture morphology has been observed, despite the composite's high strength properties. (C) 2018 Elsevier B.V. All rights reserved.