[en] Pulsed ion beams have been used to irradiate Pt/Si, Co/Si, and Au/Si samples. The thicknesses and compositions of the reacted layers were determined using Rutherford backscattering spectrometry. The phases in the reacted layers were identified using x-ray diffraction and transmission electron microscopy. Low-energy-density irradiation produced interfacial layers having near-eutectic compositions. High-energy-density irradiation produced interfacial layers having graded compositions (ranging between two solidus phases). The experimentally determined compositions, compositional gradients, and phases are consistent with interfacial melting at temperatures at or above the eutectic