Effect of magnesium content on the semi solid cast microstructure of hypereutectic aluminium-silicon alloys

Litterature review -- Principles of semi solid metal (SSM) processing -- Solidification characterization and thermodynamic evaluation of hypereutectic A1-Si alloys -- Mechanical properties of A1-Si alloys -- Methodology and experimental procedures -- Alloys under study -- Thermodynamic evaluation of the alloy system -- Preparing the high Mg content alloys -- Measurement of density by Archimedes's principle -- Microstructural characterization -- Rheological characterization -- Results and scientific findings -- Thermodynamic evaluation of hypereutectic A1-Si (A390) alloy with addition of Mg content -- Effects of Mg content on the evolution of eutectic microstructure for conventionnally cast and rheocast hypereutectic A1-Si alloy -- Effect of isothermal ageing on the semi solid microstructure of rheoprocessed and partially remelted of A390 alloy with 10% Mg addition -- Rheological characterization of hyper-eutectic A1Si sllloy with 10% Mg -- General discussion -- Contributions and recommendation

Rheological characteristics of hypereutectic Al-Si (A390) in the semi-solid state

Conventional (non stirred) solidification -- Non-dendritic solidification -- Rheology of suspensions -- Characteristics of A390 alloy -- Microstructure of undercooled hypereutetic A1-Si alloys -- Advantages and disadvantages of A390 alloy -- The fragmentation mechanism of the primary silicon under shear force -- Si coarsening of hypereutetic alloy in the semi-solid state -- The Factsage software -- Measurement of the reological characteristics -- Mettalography of A390 -- Thermodynamic evaluation -- As cast microstructure of A390 -- The rheological behaviour of A390

The sequence of intermetallic formation and solidification pathway of an Al-13Mg-7Si-2Cu in-situ composite

The phase transformation sequence and solidification behaviour of an Al-13Mg-7Si-2Cu in-situ composite was examined using a combination of computer-aided cooling curve thermal analysis and interrupted quenching techniques. Five different phases were identified by analysing the derivative cooling curves, the X-ray diffraction profile, optical and scanning electron microscopy images and the corresponding energy dispersive spectroscopy. It has been found that the solidification of this alloy begins with primary Mg2Si precipitation and continues with the formation of eutectic Al-Mg2Si, followed by Al5FeSi and simultaneous precipitation of Al5Cu2Mg8Si6 and Al2Cu complex intermetallic phases. The formation of the last three intermetallic compounds changes the solidification behaviour of these composites remarkably due to their complex eutectic formation reactions. The solidification of the alloy, calculated using the Factsage thermochemical analysis software, has demonstrated a good agreement with the experiments in terms of compound prediction, their weight fractions and reaction temperatures