Investigation on the Microstructure, Microhardness and Tensile Strength of Stir-Casted A713-TiB2 Composites

A parametric experimental investigation has been conducted to investigate effects of stir casting process parameters on recently developed A713-TiB2 composites. The manufacturing process involved varying the stirring time (5, 10, and 15 minutes) and speed of stirring (500, 600 & 700 rpm). The microstructure and mechanical properties of the manufactured composites were evaluated by analyzing the effects of the varying stirring speeds and times. The analysis techniques used include optical microscopy (OM), scanning electron microscopy (SEM), micro-hardness and tensile testing. Grain size analysis of the as-cast MMCs revealed that coarser grain structure was observed at lower stirring time and lower speed. Finer grain structure was achieved by increasing stirring time and speed. Microhardness and tensile strength was observed to be affected by both stirring speed and stirring time, as demonstrated by the test results. The uniform dispersion was attained when stirring was done at 600 rpm for 10 minutes. Further increase in stirring speed and stirring time leads to the reduction in microhardness and tensile strength. In the present study, the relationship between the microstructure and mechanical properties of the A713-TiB2 composite and the processing parameters such as stirring speed and stirring time have been investigated.