Combined effect of process parameters during aluminothermic reaction process on the microstructure and mechanical properties of in situ Al/TiB2 composite

Al/TiB2 particle reinforced composites were processed through aluminothermic reaction process using potassium hexafluorotitanate (K2TiF6) and potassium tetrafluoroborate (KBF4) salts as precursors and Al (A380) alloy as a matrix material, with different processing conditions such as addition time (AT) of precursors (10 min, 20 min, 30 min), holding time of melt (HT) (20 min, 30 min, 40 min) and melt temperature (700 °C, 750 °C, 800 °C, 850 °C). The combined effect of the process parameters of aluminothemic reaction on the formation of TiB2, size and distribution of TiB2 particles in the microstructure and the mechanical properties of Al/TiB2 composite were studied. The formation of TiB2 particles were confirmed from XRD pattern. The microstructures showed uniform distribution of TiB2 particle in Al matrix in the processing condition: addition time (20 min), holding time (30 min) and melt temperature (800 °C). The hardness and ultimate tensile strength of composite have improved 57%, 59% respectively in this condition. The resultant properties were correlated to the microstructure and process parameters. Coarser particles were formed at a lower addition time (10 min) and holding time (20 min) of precursors with all the processing temperatures.