Publication

Abstract : Aluminium and its alloys have been garnering significant attention for a long time. These alloys find application in the automobile, marine, and in aviation industries. Al–Si–Mg alloys in particular provide a superb mix of ductility and strength. Multiple experimental investigations have demonstrated that the presence of precipitate phases significantly affects the mechanical strength of the alloys. Accordingly, to identify the cause, molecular dynamic simulations of U2-Al4Mg4Si4 and AlMg4Si3 precipitate phases were performed to investigate the uniaxial compressive behaviour of the Al–Si–Mg ternary phases. The total radial distribution function (RDF) was used to interpret the results obtained from the mechanical tests performed from a microstructural perspective. Further, size analysis of the phases was undertaken to glean into the evolution of the nature of the strength of the precipitate at nanoscale. The Young's modulus of the U2-Al4Mg4Si4 and AlMg4Si3 phases were found to depend on the chemical composition and steadily increased as the size increased. The RDF results reveal a closer atomic packing in the U2-Al4Mg4Si4 phase compared to the AlMg4Si3 phase, indicating that the former phase can withstand better plastic deformation. It was found that increasing the presence of the U2-Al4Mg4Si4 phase softens Al–Si–Mg alloys and improves ductility.