The influence of interface alloying on the phase and strength of the short-range oscillations of the interlayer exchange coupling (IEC) in the Fe/Cr multilayers is analyzed on the basis of stochastic modeling of interdiffusion with subsequent self-consistent calculations of magnetic structure. We explain the experimentally observed behavior of the IEC in the Fe/Cr/Fe trilayers grown on Fe whisker. Experiments with artificially alloyed FeCr layer deposited at the top of the Cr spacer allow the determination of intermixing parameters for the Fe/Cr and for the Cr/Fe interfaces.