Interfacial stability and mechanical property of TiC/Mg composites produced by in situ combustion synthesis

Interfacial stability of TiC/Mg metal matrix composites (MMCs) produced by in situ combustion synthesis of Al-Ti-C reaction system in molten Mg has been studied in terms of its microstructure, composite density and mechanical properties. Mg and cubic TiC phases were detected through X-ray diffraction and energy dispersive spectroscopy (EDS) analysis, which indicate that the Al-Ti- C reaction system has converted to the TiC phase through a combustion reaction. Microstructural analysis showed the uniform distribution of 1 mm sized spherical TiC within the Mg matrix. In situ produced TiC/Mg MMCs had the formation of an Al layer on the TiC surface. The oxygen contents at the matrix, interface and reinforcement were detected at <1.5 at-% by TEM-EDS analysis. However, the oxygen content of ex situ composites at the interface was 6.5 at-%. An average relative density of the in situ produced composites was 96%, while the ex situ composites, by comparison, were <94%. The ultimate compressive strength and the failure strain value of the in situ composites with 10 vol.-% TiC (392.1 MPa, 5.6%) were higher than those of the ex situ composites (385.4 MPa, 3.7%) respectively.