Effect of Semisolid Casting and Rapid Solidification Processes on Microstructure and Damping Behavior of A356 Aluminum Alloy

Abstract

This research seeks to enhance the vibration‐damping and noise‐suppression performance of automobiles, while also increasing the damping capacity of A356 aluminum alloys employed in vehicle components. Accordingly, A356 aluminum alloys were prepared via semisolid casting combined with a rapid solidification process, and the effects of semisolid processing parameters on their damping performance were systematically studied. A notably more uniform microstructure is obtained through the synergistic application of semisolid casting and rapid solidification, which simultaneously refines the primary α‐Al grains and eutectic Si while fragmenting and refining the coarse Fe‐rich intermetallic compounds. The semisolid, rapidly solidified alloy exhibits 57% and 52% higher internal friction (IF) at room and elevated temperatures, respectively, than conventionally cast A356 alloys, resulting in an 83% overall improvement in damping performance. This enhancement stems largely from the pronounced microstructural refinement and homogenization brought about by the combined process of semisolid casting and rapid solidification. As the semisolid stirring speed and stirring time are raised, the IF value of the A356 alloy exhibits an initial ascent and a later descent. At a stirring speed of 240 r/min and a stirring time of 10 min, the A356 aluminum alloy exhibits optimal damping performance at both room and elevated temperatures.