Influence of parameters used for melt processing by nanosecond electromagnetic pulses on the structure formation of cast aluminum matrix composites

   The paper focuses on establishing the effect of nanosecond electromagnetic pulses (NEPs) with different amplitudes on the formation of the structure of cast aluminum matrix composites of the Al–Mg2Si pseudobinary system with hypoeutectic (5 wt. % Mg2Si) and hypereutectic (15 wt. % Mg2Si) compositions. As the NEP generator amplitude in composites containing 5 and 15 wt. % Mg2Si increases, the matrix alloy structural components (α-solid solution and eutectic) are refined, while no significant differences in the sizes and morphology of Mg2Si primary crystals were observed in the hypereutectic range of compositions. Presumably, the observed nature of the NEP effect on the structure of composites in the hypereutectic region of compositions is associated with the features of their crystallization behavior. The temperature range of the L + Mg2Si two-phase region presence is much lower than NEP irradiation temperatures. Apparently, this is the reason why NEPs have no effect on the thermodynamic state of Mg2Si primary crystal/melt interfaces. It was shown that a promising option for the simultaneous modifying effect on all structural components of Al–Mg2Si aluminum matrix composites (solid solution, eutectic, Mg2Si primary particles) is a combination of thermal-rate treatment and irradiation of melts by NEPs, as well as additional melt processing by NEPs during crystallization.