Small-Scale Mechanical Testing of Cemented Carbides from the Micro- to the Nano-Level: A Review

In this overview, we summarize the results published to date concerning the small-scale mechanical testing of WC-Co cemented carbides and similar hardmetals, describing the clear trend in the research towards ever-smaller scales (currently at the nano-level). The load-size effect during micro/nanohardness testing of hardmetals and their constituents and the influence of the WC grain orientation on their deformation, hardness, indentation modulus, fracture toughness, and fatigue characteristics are discussed. The effect of the WC grain size/orientation, cobalt content, and testing environment on damage accumulation, wear mechanisms, and wear parameters are summarized. The deformation and fracture characteristics and mechanical properties, such as the yield and compression strength, of WC-Co composites and their individual WC grains at different orientations during micropillar compression tests are described. The mechanical and fracture properties of micro-cantilevers milled from WC-Co hardmetals, single WC grains, and cantilevers containing WC/WC boundaries with differently-oriented WC grains are discussed. The physical background of the deformation and damage mechanisms in cemented carbides at the micro/nano-levels is descri and potential directions for future research in this field are outlined.