This study was conducted in order to determine the effect of flux (K2TiF6) used to improve Al matrix composites including different ratios of B4C, on microstructural properties. The properties of Al+B4C and Al+B4C+K2TiF6 composites were compared. For this purpose, Al was mixed by adding 5-10-15 and 20% of B4C and 2% of K2TiF6 particles. DTA-TG analyses of mixed powders were carried out and the reaction temperatures were determined. Sintering process was carried out at different sintering temperatures based on the reaction temperature previously determined. Finally, the effect of the flux on density and hardness values were measured and interface properties were examined.