Liquid phase sintering of SiC/γ-TiAl composite using microwave heating

Liquid phase sintering of SIC grains with gamma-TiAl binder is attempted in this investigation. Since silicon carbide is a good microwave susceptor, it is possible to heat the silicon carbide grains to the melting temperature of gamma-TiAl using microwave energy and melt the titanium aluminide forming a liquid phase. Molten gamma-TiAl then binds the SiC grains together forming a dense composite. The composite processed at 900 W microwave power exhibited 92% theoretical density. The intercept grain sizes of silicon carbide grains were determined on a polished sample surface using optical metallography and their statistical distribution was studied. The density of composite increased with the microwave power, and this is attributed to enhanced spreading of molten gamma-TiAl at higher microwave power, and rearrangement, dissolution and reprecipitation followed by grain growth of SiC.