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

Abstract

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 μm 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.