The Effect of Variable-Frequency Ultrasonic Melting Treatment Technology on Microstructure and Properties of AZ80 Magnesium Alloy

Abstract:

The traditional fixed-frequency ultrasonic technology (FUT) and the variable-frequency ultrasonic technology (VUT) were used in direct-chill (DC) casting of an AZ80 magnesium alloy with the diameter of ∅255mm. The microstructure evolution, mechanical properties and macro-segment of Al element were investigated. The results show that both FUT and VUT can refine the α-Mg grain while the VUT has better efficiency which can reduce the grain size from 679-1454 μm (DC) to 150-241 μm. The homogeneity of grain size was also improved. These two technologies can also change the morphology and distribution of Mg₁₇Al₁₂ phase and tiny and refined morphology of Mg₁₇Al₁₂ phase and a homogeneous distribution can be obtained after VUT treatment. The YS and UTS were increased following the microstructure evolution, displaying the YS of 88.9-95.1 MPa and UTS of 164.3-173.1 MPa after VUT treatment. The segregation rate of Al element were improved with VUT treatment. Keywords: magnesium alloy; variable frequency ultrasonic technology; microstructure; mechanical properties;

• Periodical: Key Engineering Materials (Volume 821)
• Pages: 209-214
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.821.209
• Online since: September 2019
• Authors: Qi Chi Le, Xing Rui Chen*, Shao Chen Ning
• Keywords: Magnesium Alloy, Mechanical Properties, Microstructure, Variable Frequency Ultrasonic Technology

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