Characteristic features of impact welding were investigated in a simple model system of colliding copper single crystals. Large grained sheets were used to approximate single crystal to single crystal impact. Optical microscopy and electron backscatter diffraction (EBSD) analyses showed multiple features of the weld interface, which include deformation twinning, adiabatic shear banding, localized melting, and dynamic recrystallization. To support the microstructural findings, numerical simulation based on smoothed particle hydrodynamics method was conducted to predict the local temperature, pressure, and strain distributions. The insights gathered here will aid in the design of materials combinations and systems for impact welding.