Indentation-induced deformation mechanisms in laser-processed directionally solidified WC-W2C eutectoids

Indentation-induced surface and subsurface deformation mechanisms in directionally solidified WC-W2C eutectoids are investigated. The microstructures of the WC-W2C composites consist of primary WC regions, W2C-rich regions, and lamellar-type eutectoid regions, which form during the sequential phase transformations during laser processing. Indentation-induced surface crack profiles indicate little propensity for debonding at the WC-W2C eutectoid interfaces, although some interactions with larger-scale microstructural features are observed. In the subsurface indentation regions, dislocation networks predominantly composed of partial dislocation pairs having Burgers vectors are observed in the primary WC regions, whereas shear banding and grain refinement are commonly observed in the micrometer-scale W2C-rich regions. Deformation in the sub-micrometer eutectoid regions is distinct, with the dislocation activity primarily limited to the WC phase, with Burgers vectors of that terminate at the interfaces.