Preparation and Evaluation of Mechanical Properties of 6061Al-B4Cp Composites Produced via Two-Stage Melt Stirring

The present work aims at producing 6061Al metal matrix composites reinforced with 5 and 7wt% of B4C particulates at temperature of 750 degrees C via melt stirring method involving two-step additions. In order to improve wettability and to avoid agglomeration of B4C particulates, K2TiF6 halide salt in the ratio of 0.2 were mixed with B4C particulates and the mixture were being dropped into the melt batch wise (twice). The prepared composites were characterized by scanning electron microscopy (SEM)/energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) studies. SEM microphotographs revealed homogeneous dispersion of B4C particulates without agglomeration in 6061Al matrix. Indexing of the XRD peaks confirmed the presence of alpha-Al, B4C and minor phases like Al3Ti and Al3BC. Presence of Al3Ti phase as confirmed by XRD and EDX studies is clear indication of Ti compound/layer formed around the B4C particles. Further, improvements in mechanical properties like hardness, tensile and compression strengths of the 6061Al matrix were obtained in the composites.