A model for the erosion of metals by spherical particles at normal incidence

A theoretical analysis is presented for the erosion of metals by spheres at normal incidence. The model employs a criterion of critical plastic strain to determine when material will be removed, and velocity exponents of 3 for erosion and ?2 for the mass of spherical particles which must hit the surface before material is removed are predicted. The mechanical properties of the metal are described by two quantities: the dynamic hardness of the metal and the ductility of the metal under erosion conditions. Data obtained in experiments with aluminium alloys, as well as previously published data, are compared with the theory.