Formation of 3D-Cr2(C1-yOy) at Cr2AlC / AlOx interfaces

• A multilayer AlO x -Cr 2 AlC thin film grown at 580 °C by direct current magnetron sputtering. • A 3D-Cr 2 (C 1-y O y ) phase forms within the AlO x -Cr 2 AlC multilayered film. • DFT calculation support formation of 3D-Cr 2 (C 1-y O y ) phase. • Characterization of C and related defects are performed by iDPC STEM. We report on the microstructural characterization of a multilayer AlO x -Cr 2 AlC thin film grown at 580 °C by direct current magnetron sputtering. Instead of stabilizing a two-dimensional carbide derivative, intentional periodic excess oxygen incorporation during thin film deposition leads to the formation of a 3D-Cr 2 (C 1-y O y ) phase within the AlO x -Cr 2 AlC multilayered film. The microstructure of the film was investigated by combining various imaging techniques in aberration corrected scanning transition electron microscopy. The distribution of C and related defects at atomic scale was revealed by the integrated differential phase contrast method.