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Herein, the microstructure control and performance evolution of hypereutectic Al–20Mg2Si alloy with the addition of novel Al–3.3Ca–10Sb master alloy are investigated. It is found that AlCa11Sb9 and CaSb2 compounds are successfully synthesized through in situ melt reaction of masteralloy. With 0.45 wt% Al–3.3Ca–10Sb master alloy addition, primary Mg2Si particles in hypereutectic Al–20Mg2Si alloy are significantly refined from more than 150 μm to 10.7 μm, which are accompanied with the 3D morphologies changing from dendrites to octahedrons. After heat treatment, Brinell hardnesses of Al–20Mg2Si alloys are remarkably improved to 112 HB. Furthermore, it is also found that the cooling rate of Al–3.3Ca–10Sb master alloys has certain influence on the refinement effect of Al–Mg2Si alloys. The excellent complex modification of this master alloy on Al–20Mg2Si alloy can be attributed to the existence of CaSb2 particles as the heterogeneous nucleation sites of Mg2Si particles and the inhibiting growth effect of residual Ca atoms adsorbed on the surface of Mg2Si phase.

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In this article, the effects of Co addition on microstructure evolution and catalytic efficiency variation of an Fe−P@Cu immiscible alloy were systematically studied. According to the first-principles molecular dynamics simulations, it was found that P in the Fe−P@Cu alloy with Co addition would be preferentially bonded with Fe and/or Co in the first coordination shell, and Cu and (Fe+Co) atoms tended to appear on the opposite side of P atom in the three-dimensional cluster configuration, which would have a significant guiding effect on the subsequent solidification process. Through the microstructure analysis, it was observed that the addition of Co element had an inhibitory action on the liquid phase separation behavior due to the changes of interfacial tension, resulting in the formation of a fine second phase structure. Through the electrochemistry characteristics, it was found that the overpotentials of Fe−P@Cu metallic catalysts containing 8% Co and 16% Co with a current density of 10 mA/cm 2 have been improved to be 160 and 155 mV in 0.5 M H 2 SO 4 respectively. This excellent catalytic performance might be mainly attributed to the rapid transport of ions and the remarkable amount increase of electron transfer, resulting in the obvious promotion of the hydrogen evolution reaction of (Fe x Co 1−x ) n P@Cu alloys.