The mixing rates of the Ni‐Pt and Rene´ N4‐Pt systems under high‐energy ion bombardment were measured using Rutherford backscattering spectroscopy. The mixing was induced by various fluences of 1‐MeV Pt+ions. The extent of mixing in Rene´ N4‐Pt was the same as in Ni‐Pt, suggesting the absence of any effects of high voume fraction of ordered second phase (gamma prime) on the mixing phenomenon in the former system. The amounts of mixing predicted by the model based on thermochemical effects were very close to those measured, while cascade collision theory could account for only 2%–3% of the mixing.