Improved corrosion resistance of extruded Mg–8Sn–1Zn–1Al alloy by microalloying with Mn

Ha, Heung Yong; Kim, Hyeon Ju; Baek, Soo-Min; Kim, Peter Beomcheol; Sohn, So-Dam; Shin, Hyung‐Joon; Jeong, Hu Young; Park, Sung Hyuk; Yim, Chang Dong; You, Bong Sun; Lee, Jung Gu; Park, Sung Soo

doi:10.1016/j.scriptamat.2015.07.013

Cited by 48 publications

(17 citation statements)

References 22 publications

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“…[1][2][3][4] Currently, some of the best heatresistant Mg alloys, with good mechanical properties at both ambient and elevated temperatures, are those based on the Mg-RE-Zn system. 5 Many previous reports have indicated that the addition of RE elements such as Gd, La, and Y can remarkably improve the heat-resistance and high strength of Mg alloys.…”

Section: Introductionmentioning

confidence: 99%

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

et al. 2017

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A "RE-free" and I-phase-containing Mg-8Sn-based alloy system was developed and successfully fabricated through the equal channel angular pressing (ECAP) process. The influence of the Zn/Al mass ratio on the microstructures and mechanical properties of the as-ECAPed Mg-8Sn-(5,6,7) Zn-2(wt%)Al alloys was investigated using an optical microscope, an X-ray diffractometer, a scanning electron microscope, a transmission electron microscope, and a universal testing machine. Grain size, dynamic recrystallization behavior, and texture were found to be greatly affected by the Zn/Al mass ratio. Furthermore, the ultimate tensile strength (250 MPa) and elongation (14.5%) of the alloy with a Zn/Al mass ratio of 3 were considerably increased compared to those of the as-ECAPed alloys with Zn/Al ratios of 2.5 and 3.5 (ultimate tensile strength and elongation of 215 MPa and 13% and 184 MPa and 10%, respectively). This significant enhancement was attributed to extensive grain boundary strengthening, precipitation strengthening, and higher work hardening capacity as well as texture randomization. The strength and ductility of the as-ECAPed alloys are also discussed in terms of the I-phase and Mg 2 Sn formation.

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Section: Introductionmentioning

confidence: 99%

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

et al. 2017

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“…There were two reasons for the improvement. First, the potential difference of Al-Mn(-Fe) particles was significantly less than Al-Fe particles with respect to the magnesium matrix [11,22,37,89]. Second, as shown in the above thermodynamic calculations, the first precipitated Fe-rich B2-Al(Mn,Fe) could be encapsulated by Al 8 Mn 5 (LT), which prevented the contact of the Fe-rich phase and the (αMg) matrix [74].…”

Section: Electrochemical Tests and Corrosion Analysismentioning

confidence: 88%

“…As shown in Figure 5a, the Al/Fe ratio of the particles determined by EPMA was about 3.25, which was close to the composition of Al13Fe4. According to the Mg-Fe phase diagram and isothermal section of Mg-Al-Fe shown in Figure 1c and Figure 3b, respectively, we can see that the solid solubility of Fe in Mg was very limited, indicating that the Fe atoms would precipitate as Al-Fe phases [22,70,71]. To analyze the effect of Mn addition on the microstructure, it was crucial to identify the type and investigate the composition and morphologies of particles in the alloys.…”

Section: Microstructure Observationmentioning

confidence: 99%

“…Corrosion performance is one of the major concerns for applications of magnesium alloys [6,7]. Influences of alloy elements such as Ce [8,9], Nd [9][10][11][12][13], Zn [14,15], Y [11,16], Ca [11,17], and Mn [9,11,15,[18][19][20][21][22][23] on the corrosion behavior of magnesium alloys have been investigated widely in literature. It is widely admitted that Mn addition could combat impure Fe in Mg-Al alloys and reduce corrosion rates of the Mg-Al alloys [11,18,19].…”

Section: Introductionmentioning

confidence: 99%

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

Shan

Liu

Zeng

et al. 2019

Metals

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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.

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“…However, in practical applications, magnesium alloys are not standing as strong competent to others due to the poor corrosion resistance, which is a main disadvantage. The high chemical reactivity, magnesium alloys exhibits higher corrosion rates even in atmospheric and other mediums of corrosion tests [5][6][7][8][9][10][11][12]. Two types of approaches were employed on Mg alloys to improve corrosion resistance; one is alloying [13] and the second is application of external coatings.…”

Section: Introductionmentioning

confidence: 99%

Corrosion Characteristics of Hydrotalcite and Mg(OH)2 Surfaces of AZ31 Alloy Accomplished via Hydrothermal Surface Modification

Dhanalakshmi¹,

Cyril²

2019

Asian J. Chem.

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In this work, the surface of AZ31-Mg alloy is modified by hydrothermal treatment in high alkali solutions to attain high corrosion resistance. A class of magnesium hydroxide family with a layer structured compound hydrotalcite [Mg6Al2CO3(OH)16•4H2O] rhombohedral phase has been formed along with hexagonal Mg(OH)2 phases on AZ31 alloy surface. The hydrotalcite and hexagonal Mg(OH)2 phases were confirmed by X-ray diffraction analysis. The modified surfaces of AZ31 alloy are examined by field emission scanning electron microscope and location specific elemental compositions are obtained by EDS analysis. The hydrotalcite and Mg(OH)2 corrosion behavior was analyzed in 3.5 % NaCl electrolyte. For comparison purpose, only hexagonal Mg(OH)2 surfaces were also prepared by hydrothermal treatment and compared the corrosion rates with the hydrotalcite surfaces. The linear polarization and electrochemical impedance spectroscopy results revealed that the hydrotalcite surfaces demonstrated more noble or positive shift on open circuit potential, corrosion current density and resistance than those of only hexagonal Mg(OH)2 and bare AZ31 alloy. The formation of layered double hydroxide of magnesium with carbonates on AZ31 alloy led the more protection and this work paves newer directions on hydrothermal surface modification of Mg alloys.

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Improved corrosion resistance of extruded Mg–8Sn–1Zn–1Al alloy by microalloying with Mn

Cited by 48 publications

References 22 publications

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

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

Corrosion Characteristics of Hydrotalcite and Mg(OH)2 Surfaces of AZ31 Alloy Accomplished via Hydrothermal Surface Modification

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