The interface of single‐crystal SiC and Al brazed at 1273 K is investigated by high‐resolution electron microscopy. The orientation relationship of SiC to the Al4C3reaction layer that forms between the SiC and the Al can be expressed as (0001)SiC∥(0001)Al4C3and [11∼00]SiC∥[11∼00]Al4C3. Furthermore, a very thin (two tetrahedral layers thick) transition phase and misfit dislocations are observed between the SiC and Al4C3lattices. The structure of the transition phase is discussed based on the high‐resolution electron microscopy, the stacking of the (Al,Si)C4tetrahedral layers, and the charge balance. The same reaction product, with the same orientation relationship, is observed at the interface of a polycrystalline SiC and Al