Coarsening Kinetics of Semi-solid A356�5wt%TiB2 in situ Composite

Abstract

An attempt has been made to investigate the coarsening behaviour of semisolid A356�5wt%TiB2 in situ composite produced by Cooling slope casting. It was found that the average grain size of ?-Al in the gravity-cast alloy got reduced from 98 to 48��m in the semi-solid A356�5TiB2 composite. The primary ?-Al in the composite were found to undergo substantial spheroidisation after 5�min at a reheating temperature of 585��C (fs�=�0.5). Further, increase in holding time from 5 to 15�min resulted in grain growth of ?-Al in both the alloy and the composites. The coarsening rate constant, K, for A356�5wt%TiB2 composite was found to be 339.73�?m3/s which is 32�% lower than that of semi-solid A356 alloy, thus proving the effectiveness of TiB2 particles towards grain coarsening. � 2015, The Indian Institute of Metals - IIM.