Copper particles with median diameter 15.2 micrometres were cold sprayed onto a polished aluminium 1139 substrate. Under the spray conditions used, deep embedment of the copper particles occurred. The as-sprayed copper particles were dissected using a focussed ion beam (FIB), and their microstructure investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). At the crater wall an intense shear zone developed due to sliding of copper past aluminium. Evidence of melting is presented.