Microstructure evolution of AS41 magnesium alloy fabricated by ultrasonic vibration

Abstract

The effects of ultrasonic vibration on the grain size and morphology of Mg₂Si in Mg-4 wt% Al-1 wt%Si(AS41) alloys designed were evaluated. The results show that the major constituents of the alloy include β-Mg₁₇Al₁₂ and Mg₂Si phase, and no difference in the type of constituents between without ultrasonic vibration and with ultrasonic vibration. Without any ultrasonic vibration, the grain size and Mg₂Si phase in AS41 alloy are coare structure. However, the microstructure with fine uniform grains and Mg₂Si particles are achieved with ultrasonic vibration. The crystal grains and Mg₂Si particles refine with increase in the ultrasonic vibration intensity. When the ultrasonic vibration intensity was too low or too high, coarse structures could be obtained. The analysis of refinement mechanism indicates that the acoustic cavitation and flows induced by ultrasonic vibration lead to the fine uniform microstructure.

Keywords

magnesium alloy / ultrasonic vibration / microstructure

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