• Journal of the Korean Society for Heat Treatment
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• v.7 no.2
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• pp.96-102
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• 1994

The present work was aimed to examine the changes of the shape and particle size distribution(PSD) of ${\delta}^{\prime}$ particles on ageing in Al-Li-(Cu, Zr) alloys which had low density, high specific strength and stiffness, Increasing ageing time and temperature resulted in particles whose aspect ratio tended toward 1. The aspect ratio of ${\delta}^{\prime}$ particles was not dependent upon the ageing temperature and time in Al-Li-Cu alloy but was dependent upon them in Al-Li-Zr alloy. The PSD of ${\delta}^{\prime}$ particles in Al-Li-Zr alloy skewed to the right hand compared with that in Al-Li-Cu alloy, because $Al_3Zr$ phase in Al-Li-Zr alloy formed before ageing promoted the precipitation and growth of ${\delta}^{\prime}$ phase. Therefore, the PSD of the ${\delta}^{\prime}$ particles was found to be affected by the presence of $Al_3Zr$ particles. The growth rate of ${\delta}^{\prime}$ phase was not affected by the existence of the third transition phase $T_1$ formed by the addition of Cu in Al-Li alloy but was affected by the existence of $Al_3Zr$ formed by the addition of Zr in Al-Li alloy.

• Resources Recycling
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• v.7 no.5
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• pp.52-57
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• 1998

Effect of Si in the electrochemical corrosion characteristics of Mg-Li-Al light alloy has been investigated by means of potentiodynamic polarization study. The elecrochemical behaviors were evaluated in 003% NaCl solution and the solution buffered with KH$_{2}PO_{5}{\cdot}$NaOH at room temperature. It was found that the addition of very small quantity of Si (0.48 wt%) in Mg-Li-Al light alloy increased corrosion rates and amount of corrosion products and decreated the pitting resistance of the alloy. From the results it was concluded that Si which is added to increase the strength of Mg-Li-Al alloy is harmful to corrosion properties of the alloy.

• Journal of Korea Foundry Society
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• v.15 no.4
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• pp.351-359
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• 1995

The effects of In and Be additions on the aging behaviors and mechanical properties in the Al-Cu-Li alloy were investigated using the transmission electron microscope, the scanning electron microscope, hardness and tensile strength measurement. The aging is promoted and the double hardness peak is appeared by the addition of In and Be in the Al-Cu-Li alloy. The strength is increased, but the elongation and toughness are decreased by the addition of In in the Al-Cu-Li alloy. And the Al-Cu-Li-In-Be alloy has good combination with the strength, the elogation and toughness than Al-Cu-Li-In alloy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.129-130
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• 1999

The superplastic deformation characteristics is powder metallurgy(PM) Al-Li alloy has been studied within the framework of a recently proposed internal variable theory of superplasticity(SSP). The flow curves were obtained by performing a series of load relaxation tests at the temperature range from 45$0^{\circ}C$ to 52$0^{\circ}C$ It has been found that the overall flow curves were separated into the grain boundary sliding(GBS) and the accommodating dislocation glide processes/ The tensile curves were also obtained to clarify the superplastic deformation bahavior of PM Al-Li alloy. The microstructural features of PM AL-Li alloy have been examined through the transmission electron microscopy.

• Journal of Korea Foundry Society
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• v.12 no.2
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• pp.149-154
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• 1992

The wetting behaviour of SiC/Al-Li composite interface has been investigated by using an infiltration method. The critical pressure for melt infiltration into SiC particulate preform has been determined by measuring the melt infiltration distance changes with the variation of applied pressure. The threshold pressure of pure Al, Al-0.2wt%Li, Al-0.5wt%Li for melt infiltration are 3.94, 3.93, $3.7Kg/cm^2$ respectively, which implies a slight improvement in wettability of SiC/Al composite by addition of Li. The threshold pressure for melt infiltration also changes with the variation of other parameters such SiC particulate size, SiC particulate fraction and melt temperature.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.3
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• pp.1-6
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• 1991

In this study, intermediate thermo-mechanical treated Al-2.0 wt%Li, and Al-2.0 wt%Li-1.2 wt%Cu-1.0 wt%Mg-0.12 wt%Zr alloys were tested in tension at $10^{\circ}C$ and elevated temperature(100, 200 and $300^{\circ}C$). The results are follows : The tensile strength of Al-Li-Cu-Mg-Zr alloy is the highest but the elongation of Al-Li alloy is the highest(106%) among the all alloys in tension at $300^{\circ}C$. The Portervin-LeChartlier effect is showed in AI-Li-Cu-Mg-Zr alloy at 10 and $100^{\circ}C$, because of tangled dislocation by Mg and Cu. In the true stress-strain curves of all alloy, the peaks of stress at $300^{\circ}C$ are showed at the strain less than 0.1. In the binary alloy, the dynamic restoration process at 200 and $300^{\circ}C$ is nearly similar to dynamic recovery type. The hot deformation stress is decreased with increase of dynamic recovery degree, but the elongation is increased. When the strain the strain rate are constant, the temperature dependence of hot deformation stress is increased with increase of deformation temperature. The elongation and degree of dynamic recovery are decreased with increase of hot deformation activation energy, but the deformation stresses slightly increased.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.4
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• pp.233-239
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• 1992

A study of the precipitation process of Al-Li binary alloy at low ageing temperature has been carried by electrical resistivity measurement. Two types of G.P.zones were formed during ageing at low temperature. G.P. (1) zone and G.P. (2) zone have been formed primarily at ageing temperature below $60^{\circ}C$ and at ageing temperature range of $80^{\circ}C$ to $100^{\circ}C$, respectively. Therefore the precipitation process of Al-Li binary alloy was as follows; G.P.(1) zone ${\rightarrow}$ G.P.(2) zone ${\rightarrow}{\delta}^{\prime}{\rightarrow}{\delta}$ G.P. (1) zone might be affected by excess vacancies, but G.P. (2) zone might be affected by secondary defects. clusters and Li-vacancy pairs. The activation energy for formation of G.P. (2) zone is 0.87eV. It is lower than that of Al-Cu alloy.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.1
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• pp.37-41
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• 1991

In this study, the effect of solution treatment temperature on the tensile property in intermediate thermo-mechanical treated Al-Li alloys are investigated. After the intermediate thermo-mechanical treated Al-Li, Al-Li-Mg and Al-Li-Mg-Zr alloys were solution treated at various temperatures (500, 520 and $540^{\circ}C$), these were aged at $190^{\circ}C$, $240^{\circ}C$ and tested tensile properties. The results obtained from the experiment are as follows ; 1) The optimum solution heat-treatment temperature is $540^{\circ}C$ for a Al-Li alloy, and the recrystallized grain size is about $70{\mu}m$. 2) The optimum solution heat-treatment temperature is $500^{\circ}C$ for a Al-Li-Mg alloy, and the recrystallized grain size is the most coarse in all alloys. 3) The tensile property is independent of the solution treatment temperature in a Al-Li-Mg-Zr alloy, and the recrystallized grain size is the finest owing to addition of Zr.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.1
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• pp.17-24
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• 1994

The evaluation and analysis of diffusivity of lithium for coarsening and coarsening kinetics of ${\delta}^{\prime}$ precipitate in Al-Li-Cu-Mg-Zr alloy aged at $170^{\circ}C$ have been investigated by transmission electron microscopy. With ageing time, ${\delta}^{\prime}$ precipitate coaesened to followed $\bar{\gamma}{\propto}t^{1/3}$ and coarsening kinetics was found to be obeyed to the Lifshitz-Slyozov-Wagner(LSW) theory and diffusivity of lithium for coarsening of ${\delta}^{\prime}$ precipitate in Al-Li-Cu-Mg-Zr alloy was obtained to be $5.85{\times}10^{-17}{\sim}1.53{\times}10^{-16}$ by experimental coarsening rate constant and various coarsening kinetic theory. Diffusivity of lithium measured by using various model but MLSW and Tsumuraya (VI) et al. model in Al-Li-Cu-Mg-Zr alloy is similar to that calculated by the Costas's diffusivity equation. It was, therefore, suggested that additing to the Cu, Mg and Zr element in Al-Li system have no great effect on diiffusivity of lithium for coarsening of ${\delta}^{\prime}$ This suggest that in matrix.

• Journal of Electrochemical Science and Technology
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• v.10 no.1
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• pp.82-88
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• 2019

Here, we report on nanocrystalline Si-Al-M (M = Fe, Cu, Ni, Zr) alloys for use as an anode for lithium-ion batteries, which were fabricated via a melt-spinning method. Based on the XRD and TEM analyses, it was found that the Si-Al-M alloys consist of nanocrystalline Si grains surrounded by an amorphous matrix phase. Among the Si-Al-M alloys with different metal composition, Ni-incorporated Si-Al-M alloy electrode retained the high discharge capacity of 2492 mAh/g and exhibited improved cyclability. The superior $Li^+$ storage performance of Si-Al-M alloy with Ni component is mainly responsible for the incorporated Ni, which induces the formation of ductile and conductive inactive matrix with crystalline Al phase, in addition to the grain size reduction of active Si phase.