On the formation of V-phase in mechanically alloyed AlSiMg–SiCp metal matrix composites with trace scandium additions

Present investigation concerns development of AlSiMg–SiC composite microstructure with trace addition of scandium in the form of master alloy powder utilizing mechanical alloying technique. Influence of Sc on the phase formation in the present alloy has been demonstrated by carrying out differential scanning calorimetry (DSC) of the ball milled and solution treated samples. Variation of Vickers hardness of the samples as a function of ageing time shows that presence of SiC and Sc may reasonably improve the mechanical properties of the age hardened alloy. Scanning electron micrographs (SEM) and transmission electron micrograph (TEM) of the bulk samples demonstrate the influence of ball milling on the morphology and distribution of the SiC particulates and the precipitate. The formation of V-phase as a stable precipitate during ageing has been identified and characterized by carrying out the selected area diffraction pattern (SADP) analysis.