Effects of mechanical vibration on Al-Si eutectic microstructure and mechanical properties for vacuum counter-pressure casting ZL114A alloy

In order to improve the performance of complex thin wall ZL114A aluminum alloy casting， the mechanical vibration was applied to vacuum counter-pressure casting， and the effect of amplitude and frequency on Al-Si eutectic microstructure and mechanical properties of casting were systematically studied. The results indicate that the mechanical vibration can enhance the local convection of the melt. The initial solidified dendrites are broken and the Si phase is broken to form granular and short rod tissue. Meanwhile，the mechanical vibration can promote the uniform distribution of solute in solidification front and inhibit the excessive growth of the Si phase. Therefore， the Al-Si eutectic around the primary phase is induced to transform the network. The effect of amplitude and frequency on strength and plasticity are opposite. At high frequency and low amplitude， the highest tensile strength of the sample near the source of vibration is 335.6 MPa， but the elongation decreases to 1.54%. However， the tensile strength and elongation of the sample staying away from the source of vibration only reach 327.06 MPa and 1.67% because of energy wastage during vibration energy diffused at molten alloy. In addition， the performance attenuation fitting analysis shows that increasing frequency is conducive to inhibiting the wastage of vibration energy and improving the treatment effect of molten alloy which stays away from the source of vibration.