The Effect of Carbon Content on the Microstructure and Mechanical Properties of Cemented Carbides with a CoNiFeCr High Entropy Alloy Binder

Abstract

CoNiFeCr high entropy alloy (HEA) was used as a binder in cemented carbides for developing a new high-performance binder. The microstructure of WC-HEA cemented carbides with different binder components and carbon contents was subsequently studied. It was observed that the (Cr,W)C phase precipitated at the WC/HEA interface, and a coherent interface with a low degree of misfit was formed between WC and (Cr,W)C, thereby resulting in a significant reduction in the interfacial energy and stress concentration. The (Cr,W)C phase exerted a pinning force (Zener-drag) on the moving grain boundaries, which effectively inhibited the growth of WC grains. As a result, compared with WC-Co, WC-CoNiFeCr had smaller WC grain size, smoother grain shape and larger mean free path (MFP) of the binder, which resulted in slightly lower hardness and higher transverse rupture strength (TRS) and fracture toughness. The lower limit of carbon content in WC-CoNiFeCr was higher than that of WC-Co. With the addition of Ni, the width of the two-phase region became wider, whereas the width of the two-phase region became narrower with the addition of Fe and Cr.

Faceting/Roughening of WC/Binder Interfaces in Cemented Carbides: A Review

“…Minor shape changes among WC grains were also observed due to the substitution of cobalt binder in WC-based cemented carbides using various HEAs, such as CoNiFeCr [ 124 , 125 ], CoCuFeNi [ 126 ] and FeCoCrNiAl [ 127 ].…”

“…In particular, it outlines such a nontrivial property as the shape of individual WC grains. In the classical WC-based cemented Minor shape changes among WC grains were also observed due to the substitution of cobalt binder in WC-based cemented carbides using various HEAs, such as CoNiFeCr [124,125], CoCuFeNi [126] and FeCoCrNiAl [127].…”

Effect of Binder on Oxidation Properties of Tungsten Carbides: A Review by a Conceptual Classification Approach

“…Figure9. A summary of publications in the field of cobalt binder substitution using high-entropy alloys (HEAs)[3,[105][106][107][108][109][110][111][112][113][114][115].…”