Preparation of High‐Performance WC–MgO Composites by Spark Plasma Sintering

Abstract

Herein, tungsten carbide (WC)–4.3 wt% MgO composite powders are synthesized by high‐energy planetary ball milling method and then consolidated by spark plasma sintering (SPS). Submicrometer WC–MgO composite powders are consolidated to obtain a nearly complete density of WC–MgO composites (99.15%). The nanosized MgO distributed along the WC grains in WC–MgO composite plays an important role of dispersion strengthening and achieving high flexural fracture strength of WC–MgO composites (1348 MPa). As the addition of MgO increases the interfacial strength, the fracture mode of WC–MgO composites is mainly a mixture of transgranular fracture and intergranular fracture. High value on Vickers hardness (1660HV) and fracture toughness (9.37 MPa m1/2) of WC–MgO are also observed due to the crack deflection and crack bridging. Binderless WC–MgO composites have similar properties to WC–Co and are expected to replace WC–Co hard metal for saving resources and reducing cost.

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

“…Minor changes in the shape of WC crystallites were also observed through the alloying of conventional WC-Co cemented carbides using Ti 3 SiC 2 [ 48 ], WCoB [ 49 ], Al 2 O 3 , La 2 O 3 , Y 2 O 3 , CeO 2 [ 50 ], NbC [ 44 ], CrC [ 51 ], graphene oxide [ 52 ], MgO [ 53 ], Al 2 O 3 , Y 2 O 3 [ 21 ], Ti(C 0.5 , N 0.5 )-Mo [ 54 ], VC, Cr 3 C 2 [ 55 ], multiwalled carbon nanotubes [ 56 , 57 , 58 ], SiC [ 59 ], graphene [ 60 ], VC [ 61 ], TiC [ 62 , 63 ], VC and (Ta, Nb)C [ 62 ]. It appeared to be challenging to maintain carbon nanotube and graphene during sintering, as carbon easily dissolves in both solid and liquid cobalt at elevated temperatures.…”