Next Article in Journal
Improved Reliability and Mechanical Performance of Ag Microalloyed Sn58Bi Solder Alloys
Previous Article in Journal
Effects of a Post-Weld Heat Treatment on the Mechanical Properties and Microstructure of a Friction-Stir-Welded Beryllium-Copper Alloy
Article Menu
Issue 4 (April) cover image

Export Article

Open AccessArticle

Effect of Manganese on Microstructure and Corrosion Behavior of the Mg-3Al Alloys

National Key Laboratory of Science and Technology for National Defence on High-strength Structural Materials, Central South University, Changsha 410083, China
School of Materials Science and Engineering, Central South University, Changsha 410083, China
Author to whom correspondence should be addressed.
Metals 2019, 9(4), 460;
Received: 25 March 2019 / Revised: 12 April 2019 / Accepted: 16 April 2019 / Published: 19 April 2019
PDF [5630 KB, uploaded 25 April 2019]


Microstructure and corrosion behavior of the Mg-3Al-xMn (x = 0, 0.12, 0.21, 0.36, 0.45) (hereafter in wt.%) alloys were experimentally investigated by electron probe microanalysis (EPMA), scanning electron microscope equipped with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), electrochemical, and hydrogen evolution tests. A new self-constructed Mg-Al-Mn-Fe thermodynamic database was used to predict the solidification paths of the alloys. The addition of Mn showed no grain refinement in the cast Mg-3Al alloys. According to the microstructure observation, Al-Fe phases were observed in the non-Mn-added alloy, while Al8Mn5(LT) (Al8Mn5 in low temperature) became the main intermetallic phase in the Mn-added alloys, and the amount increased gradually with the Mn addition. The τ–Al0.89Mn1.11 phase with lower Al/(Fe + Mn) ratio was observed in the alloys with 0.36 and 0.45 wt.% Mn content. According to the electrochemical tests, all five alloys showed localized corrosion characteristics in 3.5 wt.% NaCl solution. Compared with the Mg-3Al alloy, the corrosion resistance of Mn-added alloys were significantly improved and increased gradually with the Mn addition, which was due to the variation of Al-containing intermetallic compounds. The present experimental investigations and thermodynamic calculations confirmed the mechanism that the increasing amount of Al8Mn5(LT) with Mn addition could encapsulate the B2-Al(Mn,Fe) phase with higher Fe. Therefore, it could prevent this detrimental phase from contacting magnesium matrix, thus suppressing micro-galvanic corrosion and improving corrosion resistance gradually. View Full-Text
Keywords: Mg-Al-Mn; microstructure; thermodynamic calculations; corrosion Mg-Al-Mn; microstructure; thermodynamic calculations; corrosion

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Yao, S.; Liu, S.; Zeng, G.; Li, X.; Lei, T.; Li, Y.; Du, Y. Effect of Manganese on Microstructure and Corrosion Behavior of the Mg-3Al Alloys. Metals 2019, 9, 460.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Metals EISSN 2075-4701 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top