The article reports on the Xe ion beam irradiation studies of Ni3N/Al bilayers at 80 K. The ion-induced modifications were monitored by Rutherford backscattering (RBS), resonant nuclear reaction analysis (RNRA), X-ray diffraction (XRD) and atomic force microscopy (AFM). We found preferential loss of nitrogen from the surface region of the Ni3N top layers. The surface roughness ΔσS and the interface broadening variance Δσint2 increase linearly with the Xe ion fluence Φ. The experimental mixing rate of Δσ2/Φ = 1.8 nm4 is explained by considering an enhancement of ballistic mixing due to chemical reactions at the interface. © 2001 Elsevier Science B.V.