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Lim JM, So YS, Kim JG. Microstructure and Corrosion Behavior of Laser-Welded Al-Mn-Zr Alloy for Heat Exchanger. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6009. [PMID: 37687702 PMCID: PMC10488891 DOI: 10.3390/ma16176009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/26/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023]
Abstract
In this study, an Al-Mn-Zr alloy was designed and its microstructure and corrosion behavior compared after laser welding to that of AA3003. As the results of immersion and electrochemical tests showed, both alloys had a faster corrosion rate in the fusion zone than in the base metal. Laser welding caused interdendritic segregation, and spread the intermetallic compounds (IMCs) evenly throughout in the fusion zone. This increased the micro-galvanic corrosion sites and destabilized the passive film, thus increasing the corrosion rate of the fusion zone. However, Zr in the Al-Mn alloy reduced the size and number of IMCs, and minimized the micro-galvanic corrosion effect. Consequently, Al-Mn-Zr alloy has higher corrosion resistance than AA3003 even after laser welding.
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Affiliation(s)
| | | | - Jung-Gu Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-Gu, Suwon-si 16419, Gyeonggi-do, Republic of Korea (Y.-S.S.)
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Zengin H, Ari S, Turan ME, Hassel AW. Evolution of Microstructure, Mechanical Properties, and Corrosion Resistance of Mg-2.2Gd-2.2Zn-0.2Ca (wt%) Alloy by Extrusion at Various Temperatures. MATERIALS (BASEL, SWITZERLAND) 2023; 16:3075. [PMID: 37109911 PMCID: PMC10141226 DOI: 10.3390/ma16083075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
The current investigation involved casting the Mg-2.2Gd-2.2Zn-0.2Ca (wt%) alloy (GZX220) through permanent mold casting, followed by homogenization at 400 °C for 24 h and extrusion at 250 °C, 300 °C, 350 °C, and 400 °C. Microstructure investigations revealed that α-Mg, Mg-Gd, and Mg-Gd-Zn intermetallic phases were present in the as-cast alloy. Following the homogenization treatment, a majority of these intermetallic particles underwent partial dissolution into the matrix phase. α-Mg grains exhibited a considerable refinement by extrusion due to dynamic recrystallization (DRX). At low extrusion temperatures, higher basal texture intensities were observed. The mechanical properties were remarkably enhanced after the extrusion process. However, a consistent decline in strength was observed with the rise in extrusion temperature. The corrosion performance of the as-cast GZX220 alloy was reduced by homogenization because of the lack of corrosion barrier effect of secondary phases. A significant enhancement of corrosion resistance was achieved by the extrusion process.
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Affiliation(s)
- Hüseyin Zengin
- Institute of Chemical Technology of Inorganic Materials (TIM), Johannes Kepler University Linz, 4040 Linz, Austria
| | - Soner Ari
- Valfsel Armatür Sanayi A.S., 45030 Manisa, Türkiye
| | | | - Achim Walter Hassel
- Institute of Chemical Technology of Inorganic Materials (TIM), Johannes Kepler University Linz, 4040 Linz, Austria
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Vaghefinazari B, Wierzbicka E, Visser P, Posner R, Arrabal R, Matykina E, Mohedano M, Blawert C, Zheludkevich M, Lamaka S. Chromate-Free Corrosion Protection Strategies for Magnesium Alloys-A Review: PART I-Pre-Treatment and Conversion Coating. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8676. [PMID: 36500170 PMCID: PMC9736347 DOI: 10.3390/ma15238676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/10/2022] [Accepted: 11/24/2022] [Indexed: 05/02/2023]
Abstract
Corrosion protection systems based on hexavalent chromium are traditionally perceived to be a panacea for many engineering metals including magnesium alloys. However, bans and strict application regulations attributed to environmental concerns and the carcinogenic nature of hexavalent chromium have driven a considerable amount of effort into developing safer and more environmentally friendly alternative techniques that provide the desired corrosion protection performance for magnesium and its alloys. Part I of this review series considers the various pre-treatment methods as the earliest step involved in the preparation of Mg surfaces for the purpose of further anti-corrosion treatments. The decisive effect of pre-treatment on the corrosion properties of both bare and coated magnesium is discussed. The second section of this review covers the fundamentals and performance of conventional and state-of-the-art conversion coating formulations including phosphate-based, rare-earth-based, vanadate, fluoride-based, and LDH. In addition, the advantages and challenges of each conversion coating formulation are discussed to accommodate the perspectives on their application and future development. Several auspicious corrosion protection performances have been reported as the outcome of extensive ongoing research dedicated to the development of conversion coatings, which can potentially replace hazardous chromium(VI)-based technologies in industries.
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Affiliation(s)
- Bahram Vaghefinazari
- Institute of Surface Science, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Ewa Wierzbicka
- Departamento de Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Department of Functional Materials and Hydrogen Technology, Faculty of Advanced Technologies and Chemistry, Military University of Technology, 2 Kaliskiego Street, 00-908 Warsaw, Poland
| | | | - Ralf Posner
- Henkel AG & Co., KGaA, 40589 Düsseldorf, Germany
| | - Raúl Arrabal
- Departamento de Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Endzhe Matykina
- Departamento de Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Marta Mohedano
- Departamento de Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Carsten Blawert
- Institute of Surface Science, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Mikhail Zheludkevich
- Institute of Surface Science, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Sviatlana Lamaka
- Institute of Surface Science, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
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