  We propose that the machinability of hard ceramics can be improved by
reversible electrochemical doping. On the example of TiO2, we show in a
combined density functional theory-molecular dynamics computational study that
a small amount of intercalated lithium, which preserves the host structure and
can be introduced reversibly, leads to a lowering of the strength of work
materials and the cutting force. This is in spite of the fact that there are no
significant modifications of the elastic constants at room temperature, i.e.
the effect is mostly on plastic properties. This approach is expected to be
applicable to a class of ceramics exhibiting similar mechanisms of host-dopant
interactions and presents a reversible and non-destructive way of modifying
mechanical properties.
