Si-induced twinning of TiC and formation of Ti3SiC2 platelets

Abstract Effects of silicon in titanium carbide (TiC) have been investigated using high-resolution electron microscopy combined with high-spatial-resolution analytical electron microscopy. The results demonstrate that Si can reduce the twin boundary energy of TiC, leading to the formation of a lot of two-dimensional (2D) defects in TiC grains containing Si. These defects were identified as microtwins of four (111) spacings thick and structural-related Ti 3 SiC 2 platelets of only one unit cell thick. The twin-stabilizing effect of Si is discussed in terms of coordination environments of Si. Very thin Ti 3 SiC 2 platelets are formed, accompanied by the segregation of Si atoms and carbon vacancies to the twin boundaries. Microtwins and Ti 3 SiC 2 platelets were found to grow in 2D with Si totally confined in the defects.