The use of physical agents when casting aluminum alloys has proven to be an effective route for grain refinement and avoids the inconvenience of residual impurities left in the material when chemical agents are used. The application of ultrasonic waves to the molten metal before casting generates acoustic cavitation, which promotes extensive heterogeneous nucleation and contributes to degassing of the metal. In addition, the application of mechanical vibration during solidification has been proven to promote dendrite fragmentation, and therefore, grain refinement. The aim of this work is to evaluate microstructural refinement due to cavitation produced by ultrasonic melt treatment (UST) of Al5Si5Zn alloy (Al-5wt pctSi-5wt pctZn) and to compare the resulting microstructure with that achieved with and without simple mechanical vibration (MV) during casting so that the best manufacturing procedure for refining aluminum silicon feedstock for subsequent thixoforming can be identified. After casting, the alloy produced under each condition was partially melted to a 0.45 solid fraction to obtain a primary phase with a spheroidized microstructure. The rheological behavior of each semisolid slurry was also evaluated. Microstructural characterization was performed using optical and scanning electron microscopy. Mechanical performance was evaluated by means of tensile tests and hardness measurements. The use of ultrasonic stirring for 30 seconds resulted in slightly better mechanical performance than the other casting conditions. However, because of the short life expectancy of the sonotrodes, mechanical vibration can be considered a simpler, superior solution for feedstock production.

中文翻译：

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超声波熔体处理与机械振动在触变成型Al5Si5Zn合金原料制造中的应用比较

在铸造铝合金时使用物理试剂已被证明是一种有效的晶粒细化途径，并避免了使用化学试剂时残留杂质留在材料中的不便。在铸造前对熔融金属施加超声波会产生声空化，这会促进广泛的异质成核并有助于金属脱气。此外，已证明在凝固过程中施加机械振动可促进枝晶破碎，从而促进晶粒细化。这项工作的目的是评估由于 Al5Si5Zn 合金 (Al-5wt pctSi-5wt pctZn) 的超声熔体处理 (UST) 产生的空化导致的微观结构细化，并将所得微观结构与使用和不使用简单机械振动 (MV) 获得的微观结构进行比较) 在铸造过程中，可以确定精炼铝硅原料以用于后续触变成型的最佳制造程序。铸造后，在每种条件下生产的合金部分熔化至 0.45 固含量，以获得具有球化显微组织的初生相。还评估了每种半固体浆料的流变行为。使用光学和扫描电子显微镜进行微观结构表征。通过拉伸试验和硬度测量来评估机械性能。使用超声波搅拌 30 秒导致机械性能略好于其他铸造条件。然而，由于超声波发生器的预期寿命较短，机械振动可以被认为是原料生产的一种更简单、更优越的解决方案。