Microstructural evolution of A380 aluminum alloy produced by gas-induced semi-solid technique (GISS)

Abstract

Gas-induced semi-solid (GISS) technique is a new rheo-casting process that utilises the principle of rapid heat extraction and vigorous local convection using the injection of fine gas bubbles through a graphite diffuser in molten metal. This study presents microstructural evolution of A380 aluminium alloy produced by GISS process. Samples of semi-solid A380 aluminium alloy were taken at different gas injection times in an optimum temperature above liquidus. Microstructural studies revealed that after conducting GISS process, the morphology of primary α-Al changes from coarse dendritic to rosette-like and finally to fine globular. The sphericity of 0.88, particle size of 54.23 μm and number of 177 α-Al particles per mm2 for α-Al phase were achieved using GISS technique under optimum condition. The results showed the well distribution of α-Al phases in the microstructure of the alloy produced by GISS process. Also the impact strength of A380 alloy was increased with employing GISS process, and more ductility of A380 alloy was achieved.