EVOLUTION OF MICROSTRUCTURE DURING THE PREPARATION OF TIB2 REINFORCED IN-SITU ALUMINIUM MATRIX COMPOSITES

Abstract: AA6082 aluminium alloy was reinforced with 5wt% of TiB2 particles using the Flux Assisted Technique (FAS) using inorganic K2TiF6 and KBF4 salts at 800ºC. The evolution of the microstructure and the grain size effect was investigated by varying the reaction time of the salt with aluminium alloy melt. The reaction time was varied from 0-90min in steps of 30min. At lower reaction time the presence of more number of Al3Ti, AlB2 particles were predominantly observed. As the reaction time increased the formation of more number of TiB2 particles in the matrix alloy was evident. At lower reaction time of 30min the grain size of the composite decreased compared to the matrix alloy due to the presence of more number of effective Al3Ti nucleant particles, whereas at higher reaction time increase in grain size was observed due to the absence of Al3Ti particles, which dissociates to form TiB2 particles.

Keywords: AA6082-TiB2 composite, in-situ processing, microstructure evolution.