Converting hcp Mg–Al–Zn alloy into bcc Mg–Li–Al–Zn alloy by electrolytic deposition and diffusion of reduced lithium atoms in a molten salt electrolyte LiCl–KCl

doi:10.1016/j.scriptamat.2006.12.017

Scripta Materialia

Volume 56, Issue 7, April 2007, Pages 597-600

https://doi.org/10.1016/j.scriptamat.2006.12.017 Get rights and content

A body-centered cubic (bcc) Mg–12Li–9Al–1Zn (wt.%) alloy was fabricated in air by electrolysis from LiCl–KCl molten salt at 500 °C. Electrolytic deposition of Li atoms on cathode (Mg–Al–Zn alloy) and diffusion of the Li atoms formed the bcc Mg–Li–Al–Zn alloy with 12 wt.% Li and only 0.264 wt.% K. Low K concentration in the bcc Mg alloy strip after the electrolysis process resulted from 47% atomic size misfit between K and Mg atoms and low solubility of K in Mg matrix.

References (20)

B.L. Mordike et al.
Mater. Sci. Eng. A
(2001)
D.H. Kim et al.
Scripta Metall. Mater.
(1994)
G.S. Song et al.
Mater. Sci. Eng. A
(2004)
R. VanFleteren
Adv. Mater. Process.
(1996)
H. Haferkamp et al.
Mater. Trans.
(2001)
R. Ninomiya et al.
J. Jpn. Inst. Light Met.
(2001)
J.H. Jackson et al.
Trans. AIMME
(1949)
M. Shimizu et al.
Int. J. Cast. Met. Res.
(1997)
T. Aida, H. Hatta, C.S. Ramesh, S. Kamado, Y. Kojima, in: G.W. Lorimer (Ed.), Proceedings of the third International...
M. Sahoo et al.
J. Mater. Sci.
(1982)

There are more references available in the full text version of this article.

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This phenomenon is achieved by creating a dual-phase structure (BCC-HCP) in the weight percent range of 5.7 to 11 percent lithium [3–6]. According to previous researches, adding lithium into the magnesium alloys compositions, in addition to density reduction and dramatic ductility improvement, especially at ambient temperature, can cause strength loss and poor corrosion behavior [7]. Generally, there are various methods to improve mechanical properties such as alloying, cold work, and heat treatment.
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Oxidation behaviour of Mg–Li–Al based alloy, namely Mg–9 wt% Li–7 wt% Al–1 wt% Sn (LAT971R) was studied at 50 °C, 150 °C and 300 °C by using Thermo-gravimetric analysis (TGA), scanning electron microscope, and Raman spectroscopy. Cross sectional observations of oxide layer using SEM shows that the thickness value of oxide layer increases with increase in oxidation temperature. The Raman spectra observed with Raman shift of 1092cm^-1, 1459cm^-1 and 1920cm^-1 which were detected as Li₂CO₃, MgCO₃ and Mg-oxide respectively. The oxidation mechanism of LAT971 alloy has also been discussed based on the TGA and Raman Spectroscopy.
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Molten LiCl–KCl salt was electrolyzed in air at 480 ± 25 °C in an electrolytic cell. The arrangement of the electrolytic cell was referred from previous studies by Smolinski [26] and Lin et al. [27,28]. The electrolyte contained a mixture of 45 wt.
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Addition of Sn also forms the high melting point (1043 K) Mg2Sn phase, and because of their relatively lower costs, Sn is a cost effective alternative as well when compared to RE additions. Although the Mg–Li–Al system has been studied in detail [3,9–13], several important issues still remain unanswered, namely (i) lithium distribution in the α and β phases, (ii) microstructural evolution due to thermo-mechanical (TM) processing, and (iii) the change in the lattice parameter of hcp and bcc phase due to the combined effect of alloying in the Mg–Li–Al based alloys. In this investigation, two alloys have been focused upon: (i) Mg–9 wt% Li–7 wt% Al–1 wt% Sn (LAT971) and (ii) Mg–9 wt% Li–5 wt% Al–3 wt% Sn–1 wt% Zn (LATZ9531).
In the present study, the influence of alloying and thermomechanical processing on the microstructure and texture evolution on the two Mg–Li–Al based alloys, namely Mg–9 wt% Li–7 wt% Al–1 wt% Sn (LAT971) and Mg–9 wt% Li–5 wt% Al–3 wt% Sn–1 wt% Zn (LATZ9531) has been elicited. Novel Mg–Li–Al based alloys were cast (induction melting under protective atmosphere) followed by hot rolling at ∼573 K with a cumulative reduction of five. A contrary dual phase dendritic microstructure rich in α-Mg, instead of β-Li phase predicted by equilibrium phase diagram of Mg–Li binary alloy was observed. Preferential presence of Mg–Li–Sn primary precipitates (size 4–10 μm) within α-Mg phase and Mg–Li–Al secondary precipitates (<3 μm) interspersed in β-Li indicated their degree of dissolution during hot-rolling and homogenization in the dual phase matrix. Presence of Al, Sn and Zn alloying elements in the Mg–Li based alloy has resulted an unusual dual-phase microstructure, change in the lattice parameter, and intriguing texture evolution after hot-rolling of cast LAT 971 and LATZ9531 alloy. Strong texture was absent in the as-cast samples whereas texture development after hot-rolling revealed an increased activity of the non-basal $(1 0 \bar{1} 0)$ slip planes. The quantification of the grain average misorientation (less than 2°) using electron backscattered diffraction confirmed the presence of strain free grains in majority of the grains (fraction >0.75) after hot-rolling of Mg–Li–Al based alloys. Role of alloying in rendering distribution of dual-phase structure has strongly influenced dynamic-recrystallization and grain-growth in the hot-rolled Mg–Li–Al based alloys.
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However, due to the limiting factor of hydrogen evolution, mainly alloys [6–19] and semiconducting compounds [20–25] of electropositive metals are produced in this way. Alloys [26–37] and compounds [2,5,38–62] of more electronegative metals are usually produced from molten salts, without a limitation caused by hydrogen evolution. This method is perspective even in producing and refreshing wettable cathodes in aluminium electrolytic cells [63–66].
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Converting hcp Mg–Al–Zn alloy into bcc Mg–Li–Al–Zn alloy by electrolytic deposition and diffusion of reduced lithium atoms in a molten salt electrolyte LiCl–KCl

Mater. Sci. Eng. A

Scripta Metall. Mater.

Mater. Sci. Eng. A

Adv. Mater. Process.

Mater. Trans.

J. Jpn. Inst. Light Met.

Trans. AIMME

Int. J. Cast. Met. Res.

J. Mater. Sci.