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Enhanced corrosion behavior and mechanical properties of AZ91 magnesium alloy developed by ultrasonic‐assisted friction stir processing
Author(s) -
Baradarani Faraz,
Mostafapour Amir,
Shalvandi Maghsoud
Publication year - 2020
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201911084
Subject(s) - materials science , friction stir processing , microstructure , corrosion , alloy , magnesium alloy , metallurgy , magnesium , ultimate tensile strength , scanning electron microscope , polarization (electrochemistry) , composite material , chemistry
In this study, ultrasonic‐assisted friction stir processing (UaFSP) and friction stir processing (FSP) were conducted on AZ91 magnesium alloy sheets, and their microstructure, corrosion behavior, and mechanical properties were comparatively investigated. Scanning electron microscopy, open‐circuit potential, and potentiodynamic polarization were used to study the corrosion behavior of the material. Electrochemical measurements reveal that employing UaFSP, the corrosion rate of the AZ91 magnesium alloy was significantly reduced where lower corrosion current density for UaFSP specimens was obtained (2.09 µA/cm 2 ) compared with 3.42 µA/cm 2 for the FSP and 6.82 µA/cm 2 for the base metal. This is mainly attributed to the alteration of morphology and better distribution of the β‐Mg 17 Al 12 phase during UaFSP. By using ultrasonic vibration in FSP, a finer grain structure was obtained, which improved the tensile strength and hardness of the AZ91 Mg alloy.