  Tungsten carbide cobalt hardmetals are commonly used as cutting tools subject
to high operation temperature and pressures, where the mechanical performance
of the tungsten carbide phase affects the wear and lifetime of the material. In
this study, the mechanical behaviour of the isolated tungsten carbide (WC)
phase was investigated using single crystal micropillar compression.
Micropillars 1-5 ${\mu}$m in diameter, in two crystal orientations, were
fabricated using focused ion beam (FIB) machining and subsequently compressed
between room temperature and 600 {\deg}C. The activated plastic deformation
mechanisms were strongly anisotropic and weakly temperature dependent. The flow
stresses of basal-oriented pillars were about three times higher than the
prismatic pillars, and pillars of both orientations soften slightly with
increasing temperature. The basal pillars tended to deform by either unstable
cracking or unstable yield, whereas the prismatic pillars deformed by
slip-mediated cracking. However, the active deformation mechanisms were also
sensitive to pillar size and shape. Slip trace analysis of the deformed pillars
showed that {10-10} prismatic planes were the dominant slip plane in WC. Basal
slip was also identified as a secondary slip system, activated at high
temperatures.
