Effect of Mechanical Mould Vibration on Solidification Behaviour and Microstructure of A360-SiCp Metal-Matrix Composites

Abstract

In this work the microstructural evolution of an A360 alloy reinforced with 10vol.% SiC particulate is described. During the material solidification, mechanical vibration, in the range of 0-41 times the gravity acceleration, g, has been applied to a steel die. It has been observed that vibrations can promote a quite homogeneous SiC dispersion on macroscopic scale. On the other hand, by using too high vibrations’ intensity, segregation phenomena have been pointed out in the castings. Furthermore, it has been evidenced that the reinforcement distribution is influenced by mechanical entrapment of the particles at grain boundaries and in the interdendritic channel. The metallographic analysis has emphasized a finer microstructure with increasing vibrations’ intensity. By comparing simulated and experimental temperature curves of the mould in the different cases, different HTC made the best fit. By increasing the vibrations’ intensity, the HTC increases in the temperature range of solidification of the composite.