Material response to two-dimensional scratching by wedges

Flats of lead, aluminium, copper and titanium were scratched by normally loaded wedges of attack angles varying from 15° to 45° under dry and lubricated conditions and sliding speeds of $1.66×10^{-5} m s^{-1}$ to $1.66×10^{-3} m s^{-1}$. Scratching of lead showed a cutting mode at attack angles of more than 15°. As the scratched material was changed from lead to aluminium, copper and titanium, in that order, the propensity of cutting at these attack angles and the coefficient of friction decreased while the surface damage increased. On the basis of uniaxial compression data obtained at the strain rates which are of the same order as those experienced in scratching, it is inferred that the observed trends in scratching can be related qualitatively to the microstructural stability of these materials at these strains and strain rate