Lithium Alloy Research Articles

Impact of Titanium Addition on Microstructure, Corrosion Resistance, and Hardness of As-Cast Al+6%Li Alloy

Aluminum-lithium alloys have the potential for use in aerospace applications, and improving their physical, mechanical, and operational characteristics through alloying is a pressing task. Lithium, with a density of 0.54 g/cm3, enhances the elastic modulus of aluminum while reducing the weight of the resulting alloys, making them increasingly attractive. Adding transition metal additives to aluminum alloys enhances their strength, heat resistance, and corrosion resistance, due to their modifying effect and grain refinement. The study aimed to investigate the impact of titanium content on the microstructure, corrosion resistance, and hardness of Al-Li alloys. Four alloys were prepared with varying amounts of titanium at 0.05 wt%, 0.1 wt%, 0.5 wt%, and 1.0 wt%. The results showed that the microstructure of the alloy was modified after adding Ti, resulting in a decrease in average grain size to about 60% with the best refinement at 0.05 wt% Ti content. SEM and EDS analysis revealed an irregular net-shaped interdendritic microstructure with an observed microsegregation of Al3Li compounds and other trace elements at the grain boundaries. The samples showed casting defects due to the high content of Li in the alloy, which absorbed air during casting, resulting in casting defects such as shrinkage holes. The corrosion resistance test results were low for the samples with casting defects, with the least resistance recorded for a sample containing 0.1 wt% Ti content, with more casting defects. The addition of Ti increased the microhardness of the alloy to an average of 91.8 ± 2.8 HV.

Defects-Abundant Ga2 O3 Nanobricks Enabled Multifunctional Solid Polymer Electrolyte for Superior Lithium-Metal Batteries.

Polyethylene oxide (PEO)-based polymer electrolytes with good flexibility and viscoelasticity, low interfacial resistance, and fabricating cost have caught worldwide attention, but their practical application is still hampered by the instability at high voltages and the low ionic conductivity (10-8 to 10-6 S cm-1 ). Herein, we rationally designed defects-abundant Ga2 O3 nanobricks as multifunctional fillers and constructed a PEO-based organic-inorganic electrolyte for lithium metal batteries. Due to the abundant O-defects feature of Ga2 O3 filler, this PEO-based composite electrolyte not only broadens electrochemical stability window (over 5.3 V versus Li/Li+ ) but also in situ forms a Li-Ga alloy and solid electrolyte interphase (SEI) film during the cycling process causing a rapid diffusion of Li+ ions. The as-prepared electrolyte has good interface compatibility with Li metal (without short-circuiting over 500 h at 0.2 mA cm-2 ) and possesses superior high ionic conductivity. The assembled all-solid-state LiFePO4 //Li cells attained an excellent cycling performance of 146 mAh g-1 over 100 cycles at 0.5 C. The XPS analysis reveals that Ga2 O3 nanobricks can form in situ a Li-Ga alloy layer at the polymer/anode interface. This work shed a light on designing high ionic conductivity lithium alloys in the composite electrolyte, which can improve the electrochemical properties of PEO-based polymer electrolytes.

Laser-Induced Ignition and Combustion of Single Micron-Sized Al-Li Alloy Particles in High Pressure Air/N2

To solve the problems associated with micron-sized aluminum (Al), including sintering, agglomeration, and slag deposition during the combustion of aluminized propellants, aluminum–lithium (Al-Li) alloy, prepared by introducing a small amount of Li (1.0 wt.%) into Al, was used in place of Al. Then, the ignition and combustion characteristics of single micron-sized Al-Li alloy particles were investigated in detail using a self-built experimental apparatus and multiple characterization methods. The ignition probability, ignition delay time, flame propagation rate, burn time, combustion temperature, flame radiation spectra, and microexplosion characteristics were obtained. The TG-DSC results demonstrated that, as compared to the counterpart Al, the Al-Li alloy had a lower ignition temperature. The emission lines of AlO revealed the gas-phase combustion of the Al-Li alloy, and thus the Al-Li alloy exhibited a mixed combustion mode, including surface combustion and gas-phase combustion. Moreover, during combustion, a microexplosion occurred, which increased the combustion rate and reduced the burn lifetime. The ambient pressure had a significant effect on the ignition and combustion characteristics of the Al-Li alloy, and the ignition delay time and burn time exponentially decreased as the ambient pressure enhanced. The combustion temperature of the Al-Li alloy at atmospheric pressure was slightly higher than those at elevated pressures. The Al-Li alloy burned in N2, but no microexplosion was observed. Finally, the ignition and combustion mechanism of the Al-Li alloy in air was demonstrated by combining SEM, EDS, and XRD analyses of the material and residues. The results suggest that the addition of Li promoted the combustion performance of Al by changing the surface structure of the oxide film and the combustion mode.

An ionic liquid-assisted strategy for enhanced anticorrosion of low-energy PEO coatings on magnesium–lithium alloy

A low-energy plasma electrolytic oxidation (LePEO) technique is developed to simultaneously improve energy efficiency and anti-corrosion. Ionic liquids (1‑butyl‑3-methylimidazole tetrafluoroborate (BmimBF4)) as sustainable corrosion inhibitors are chosen to investigate the corrosion inhibition behavior of ionic liquid (ILs) during the LePEO process for LA91 magnesium–lithium (Mg–Li) alloy. Results show that the ionic liquid BmimBF4 participates in the LePEO coating formation process, causing an increment in coating thickness and surface roughness. The low conductivity of the ionic liquid is responsible for the voltage and breakdown voltage increases during the LePEO with IL process (LePEO-IL). After adding BmimBF4, corrosion current density decreases from 1.159 × 10−4 A·cm−2 to 8.143 × 10−6 A·cm−2. The impedance modulus increases to 1.048 × 104 Ω·cm−2 and neutral salt spray remains intact for 24 h. The superior corrosion resistance of the LePEO coating assisted by ionic liquid could be mainly attributed to its compact and thick barrier layer and physical absorption of ionic liquid. The ionic liquid-assisted LePEO technique provides a promising approach to reducing energy consumption and improving film performance.

Effect of Al–Li Alloy on the Combustion Performance of AP/RDX/Al/HTPB Propellant

Aluminium–lithium alloy (Al–Li alloy) powder has excellent ignition and combustion performance. The combustion product of Al–Li alloy powder combined with ammonium perchlorate is gaseous at the working temperature of solid rocket motors, which greatly reduces the loss of two-phase flow. Experimental investigations were thoroughly conducted to determine the effect of the Al–2.5Li (2.5 wt% lithium) content on propellant combustion and agglomeration based on thermogravimetry-differential scanning calorimetry, heat combustion, laser ignition, combustion diagnosis, a simulated 75 mm solid rocket motor and a condensed combustion products (CCPs) collection device. The results show that the exothermic heat and weight gain upon the thermal oxidation of Al–Li alloy is obviously higher than those of Al powder. Compared with the reference propellant’s formulation, Al–2.5Li leads to an increase in the burning rate and a decrease in the size of the condensed combustion products of the propellants. As the Al–2.5Li alloy content gradually increases from 0 wt% to 19 wt%, the burning rate increases from 5.391 ± 0.021 mm/s to 7.244 ± 0.052 mm/s at 7 MPa of pressure; meanwhile, the pressure exponent of the burning rate law is changed from 0.326 ± 0.047 to 0.483 ± 0.045, and the d43 of the combustion residue is reduced from 165.31 ± 36.18 μm to 12.95 ± 4.00 μm. Compared to the reference propellant’s formulation, the combustion efficiency of the HTPB propellant is increased by about 4.4% when the Al–2.5Li alloy content is increased from 0 to 19%. Therefore, Al–2.5Li alloy powder is a promising fuel for solid propellants.

The effect of electron beam oscillation on the porosity of third-generation AW2099 aluminium lithium alloy welded joints

The influence of beam oscillation on the porosity of third-generation aluminium lithium (Al-Li) alloy was evaluated. 4 mm thick AW2099 was used for electron beam welding. Heat inputs of 55 J/mm and 66 J/mm with and without beam oscillation were used for the production of butt-welded joints. Circular oscillation pattern was used for welding. The higher the heat input, the larger the porosity. Furthermore, porosity of welded joints produced with a heat input of 55 J/mm dropped from 0.23 to 0.19 % when beam oscillation was utilized. Similarly, the application of electron beam oscillation for the production of welded joints with a higher heat input of 66 J/mm led to the drop of porosity from 0.33 to 0.2 %.

Effect of Heat Treatment on the Electrochemical Behavior of AA2055 and AA2024 Alloys for Aeronautical Applications

Since their development, third-generation aluminum–lithium alloys have been used in aeronautical and other applications due to their good properties, replacing conventional Al-Cu and Al-Zn alloys and resulting in an increase in payload and fuel efficiency. The aim of this work was to investigate the influence of different heat treatments on the electrochemical corrosion behavior of the alloys AA2055 and AA2024 in the presence of three different electrolytes at room temperature, using an electrochemical noise (EN) technique in accordance with the ASTM-G199 standard. In the time domain, the polynomial method was employed to obtain the noise resistance (Rn), the localization index (IL), skewness, and kurtosis, and in the frequency domain, employing power spectral density analysis (PSD). The microstructure and mechanical properties of the alloys were characterized using scanning electron microscopy (SEM) and the Vickers microhardness test (HV). The results demonstrated better mechanical properties of the AA2055 alloy, which had a Vickers hardness of 77, 174, and 199 in the heat treatments T0, T6, and T8, respectively. An electrochemical noise resistance (Rn) of 2.72 × 105 Ω·cm2 was obtained in the AA2055 T8 alloy evaluated in a NaCl solution, while the lowest Rn resistance of 2.87 × 101 Ω·cm2 occurred in the AA2024 T8 alloy, which was evaluated in a HCl solution. The highest electrochemical noise resistance (Rn) was obtained in the AA2055 alloys, which had received the T6 and T8 heat treatments in the three solutions.

Surface layer strengthening mechanism of 2060 aluminum–lithium alloy after shot-peening

The microstructure evolution and strengthening mechanism of materials after shot peening have always been the focus of research. In this paper, a novel coupled constitutive model was proposed to predict the depth of fine-grain of the 2060-T8 aluminum-lithium (Al–Li) alloy after shot peening. Besides, combining the numerical and experimental methods, the influences of shot size on yield stress, dislocation density, and crystal orientation of Al–Li alloy were systematically studied to reveal the strengthening mechanism. The results show that larger shot sizes can significantly improve the depth of the dislocation density layer and the fine-grain layer of 2060 Al–Li alloy. The depth of the refinement layer increases from 50 μm to 80 μm when the shot size grows from 0.3 mm to 0.6 mm. It is found the depth of the grain refinement layer in the experiment is consistent with the depth where is a sudden change of grain size in the simulation. Additionally, electron backscatter diffraction (EBSD) shows that many sub-grains are produced in the material due to high dislocation density, and the proportion of low-angle grain boundaries (LAGB) increases significantly, from 48.3% to more than 98.4%. The crystal orientation in the grain has changed obviously and Goss texture {100}<001> obtained in the deformation band. In contrast, with the increase in shot size, the proportion of the Schmid factor with a high-level trend increases. However, the hardening effect of the material is much greater than the softening effect which results in higher yield stress and microhardness of the top surface.

Corrosion of Molybdenum-Based and Ni–Mo Alloys in Liquid Bismuth–Lithium Alloy

Bismuth–lithium alloys are considered primary candidates for the reductive extraction step in the on-line reprocessing of molten salt reactor fuel. The corrosion behavior of molybdenum-based alloys and Hastelloy® B-3 alloy (taken for comparison) was examined here in a liquid Bi–Li (5 mol.%) alloy at 650 °C. MoW10, MoW30, and TZM corrosion-resistant alloys were studied as prospective construction materials for holding liquid bismuth–lithium alloy. Rates of corrosion were determined by the gravimetric method as well as by chemical analysis of corrosion products formed in liquid-phase Bi–Li alloy. The microstructure and chemical composition of samples of the materials and Bi–Li alloys containing the corrosion products after the tests were determined using inductively coupled plasma–atomic emission spectroscopy, X-ray fluorescence analysis, scanning electron microscopy, and energy dispersive spectroscopy. TZM molybdenum-based alloy corrodes in the bismuth-lithium alloy due to the formation of a zirconium–bismuth intermetallic compound, which passes into the liquid phase. The corrosion rates of MoW10, MoW30, and TZM alloys at 650 °C were 16, 16, and 23 µm/year, respectively. Hastelloy® B-3 alloy, despite its high molybdenum content, was subjected to severe corrosion in liquid Bi–Li alloys due to dissolution of nickel in liquid bismuth. The corrosion rate of this alloy was 14 mm/year.

Influence of Mg Content on the Corrosion Behavior and Precipitation of Aged Al-Cu-Li-xMg Alloys

Aluminum (Al)–copper (Cu)–lithium (Li) alloys are susceptible to environmental degradation, which limits the in-service lifetime of the components. Because of their complex composition, there are seldom studies focusing on corrosion behavior influenced by one single element, which is essential to clarify the corrosion mechanism. Herein, the sole influence of Mg on the corrosion behavior of Al–Cu–Li–xMg alloys was analyzed. Results revealed that the addition of Mg can affect the nucleation and precipitation process of the T1 precipitate, resulting in a difference of potential between grain interior and grain boundary. The precipitation of the T1 precipitate was promoted in a 0.7Mg alloy while impeded in a 1.1Mg alloy, due to the competition of Cu atoms and nucleation sites between T1 and S′. Two types of corrosion behavior of Al–Cu–Li–xMg alloys appeared due to the potential difference and continuity of grain boundaries. Continuous precipitates in grain boundaries and less precipitates within the grain are likely to cause intergranular corrosion (IGC), while more precipitates within the grain will result in pitting.

Vanadium-Tailored Silicon Composite with Furthered Ion Diffusion Behaviors for Longevity Lithium-Ion Storage.

As one of the promising anode materials, silicon has attracted much attention due to its high theoretical specific capacity (∼3579 mAh g-1) and suitable lithium alloying voltage (0.1-0.4 V). Nevertheless, the enormous volume expansion (∼300%) in the process of lithium alloying has a great negative effect on its cyclic stability, which seriously restricts the large-scale industrial preparation of silicon anodes. Herein, we design a facile synthesis strategy combining vanadium doping and carbon coating to prepare a silicon-based composite (V-Si@C). The prepared V-Si@C composite does not merely show improved conductivity but also improved electrochemical kinetics, attributed to the enlarged lattice spacing by V doping. Additionally, the superiority of this doping strategy accompanied by microstructure change is embodied in the relieved volume changes during the repeated charging/discharging process. Notably, the initial capacity of the advanced V-Si@C electrode is 904 mAh g-1 (1 A g-1) and still holds at 1216 mAh g-1 even after 600 cycles, showing superior electrochemical performance. This study offers an alternative direction for the large-scale preparation of high-performance silicon-based anodes.

High-Throughput Screening Lithium Alloy Phases and Investigation of Ion Transport for Solid Electrolyte Interphase Layer

High-Throughput Screening Lithium Alloy Phases and Investigation of Ion Transport for Solid Electrolyte Interphase Layer

The effect of the amount of lithium in aluminum lithium alloys on the property of fluidity

The effect of the amount of lithium in aluminum lithium alloys on the property of fluidity

Effect of Sc Addition on High-Temperature Oxidation Performance of Al-Li Alloy

Aluminum–lithium alloys were treated by high-temperature oxidation. The oxidation kinetics were analyzed by oxidation weighing. The surface morphology of the oxidized samples was observed by FESEM scanning electron microscopy. A phase analysis of the oxidized alloys was conducted by XRD. The outcomes demonstrate that the aluminum–lithium alloy with a Sc element is oxidized at a high temperature under the same conditions, improving the high-temperature oxidation resistance, the weight increase from oxidation is minimal, and the oxidation kinetic reaction index is decreased. The resulting oxidation product is Li2CO3. The addition of a Sc element can prevent the movement of metal cations, improve the high-temperature oxidation resistance of Al–Li alloy to a certain extent, and the resulting oxide film is more complete and compact.

Destruction of Heterogeneous Laser Welded Joints of Aluminum–Lithium and Titanium Alloys

Destruction of Heterogeneous Laser Welded Joints of Aluminum–Lithium and Titanium Alloys

Effects of friction stir welding process on the microstructure and mechanical properties of AA8090—T87 aluminium alloy

AA8090 aluminium lithium alloy which is employed in the fuselage of airplane and in the cryogenic fuel tank was successfully welded using friction stir welding technique. Nine set of experiments were conducted by employing 700 rpm, 900 rpm, and 1100 rpm rotation speed with varying traverse speeds of 30 mm min−1, 50 mm min−1, 70 mm min−1 to arrive at the best possible combination of inputs and obtain better joint efficiency. The macroscopic, microscopic and mechanical property analysis were performed to determine the effectiveness of the joint. Based on the results of the aforementioned studies, the best combination of input parameters such as rotational speed and traverse speed for the welded specimens were determined as 700 rpm and 30 mm min−1, 700 rpm and 70 mm min−1 respectively. Tensile strength of 700 rpm and 30 mm min−1, 700 rpm and 70 mm min−1 joints were found as 238.1 MPa and 222.56 MPa, micro hardness of the afore-mentioned joints were 107.3 VHN and 123.1 VHN and are subjected to microstructural analysis using scanning electron microscopy and electron back scattered diffraction techniques in stir zone and in heat affected zone. The above studies revealed the reason for the deviation in the grain size, increase in micro hardness, tensile strength owing to precipitate formation in the grains, and grain refinement in the weld zone.

Application of Four Different Models for Predicting the High-Temperature Flow Behavior of 1420 Al–Li Alloy

In this paper, the high-temperature rheological behavior of 1420 aluminum–lithium alloy under experimental conditions (temperatures of 350–475 °C and strain rates of 0.01–10 s−1) was systematically investigated using a Gleeble-3500 thermal simulation tester (temperature 350~475 °C, strain rate of 0.01~10 s−1). Based on the flow stress curves of this alloy, four different types of high-temperature constitutive models of the alloy were constructed: the Arrhenius (AR) model, the Modified Johnson–Cook (MJC) model, the Modified Zerilli–Armstrong (MZA) model, and the VOCE model. The prediction accuracy of the four constitutive models was compared, and the response of the accuracy of the four constitutive models to the deformation parameters (temperature, deformation rate, and strain) was analyzed. The results showed that the VOCE, AR, and MZA models had high overall prediction accuracy with average absolute relative error (AARE) of 1.8933%, 3.9912%, and 7.8422%, respectively. The VOCE model could achieve the prediction of large strain deformation resistance under small strain with small batch experimental conditions for the corresponding conditions. The AR model had optimal prediction accuracy for the high-rate deformation process. The MJC model had the optimal prediction accuracy for the low-temperature low-rate deformation process. The MZA model had better prediction accuracy for the low-rate high-temperature deformation process. The 1420 aluminum–lithium alloy process parameters selection area constitutive model matching diagram was constructed.

Microstructure evolution and mechanical properties of 2060 Al-Li alloy via friction stir additive manufacturing

Aluminum has low evaporation temperature and high reactivity with oxygen, and it could cause a lot of challenges during traditional melt-based additive manufacturing (AM) process. However, as a solid-state technology, friction stir additive manufacturing (FSAM) is expected to avoid the melting-solidification during entire manufacturing and solve these defects eventually. In this study, the microstructure evolution and mechanical properties of 2060 aluminum lithium alloy manufactured via FSAM were carried out at various process parameters. The results indicate that the best combined parameter could be obtained at rotational speed as 1600 r/min, translational speed as 300 mm/min and splice rate as 80%. Due to dynamic recrystallization from plastic deformation and heat input, finer equiaxed grains with size between 2 and 5 µm could be obtained in the nugget zone and a maximum microhardness could reach 135 HV.

Overcoming Anode Instability in Solid‐State Batteries through Control of the Lithium Metal Microstructure

AbstractEnabling the lithium metal anode (LMA) in solid‐state batteries (SSBs) is the key to developing high energy density battery technologies. However, maintaining a stable electrode–electrolyte interface presents a critical challenge to high cycling rate and prolonged cycle life. One such issue is the interfacial pore formation in LMA during stripping. To overcome this, either higher stack pressure or binary lithium alloy anodes are used. Herein, it is shown that fine‐grained (d = 20 µm) polycrystalline LMA can avoid pore formation by exploiting the microstructural dependence of the creep rates. In a symmetric cell set‐up, i.e., LiǀLi6.25Al0.25La3Zr2O12(LLZO)ǀLi, fine‐grained LMA achieves &gt; 11.0 mAh cm−2 compared to ≈ 3.6 mAh cm−2 for coarse‐grained LMA (d = 295 µm) at 0.1 mA cm−2 and at moderate stress of 2.0 MPa. Smaller diffusion lengths (≈ 20 µm) and higher diffusivity pathway along dislocations (Dd ≈ 10−7 cm2 s−1), generated during cell fabrication, result in enhanced viscoplastic deformation in fine‐grained polycrystalline LMA. The electrochemical performances corroborate well with estimated creep rates. Thus, microstructural control of LMA can significantly reduce the required stack pressure during stripping. These results are particularly relevant for “anode‐free” SSBs wherein both the microstructure and the mechanical state of the lithium are critical parameters.

A comparative study and optimization of corrosion resistance of Mg–Al layered double hydroxides films at different hydrothermal temperatures on LA103Z Mg–Li alloy

AbstractIn this study, to improve the corrosion protection system of Mg–Li alloy, Magnesia–alumina Layered double hydroxide (Mg–Al LDH) films were prepared on the LA103Z magnesium–lithium (Mg–Li) alloy by the in situ hydrothermal method. Subsequently, the microstructure of the Mg–Al LDH films was characterized by scanning electron microscope, X‐ray spectrometer, X‐ray diffraction, Fourier‐transform infrared spectroscopy, and the effect of different hydrothermal temperatures on the growth of the film was studied. Electrochemical impedance spectroscopy (EIS) and hydrogen evolution test were used to study the corrosion behavior of the films, revealing the anticorrosion mechanism of the films. The results show that the LDH film is in the form of a sheet‐like structure that crosses vertically on the LA103Z substrate. With the increase of the hydrothermal temperature, the size of the Mg–Al LDH sheet increases, and the distribution is denser. Electrochemical tests showed that the coated samples had significantly improved impedance modulus (|Z|) and charge transfer resistance (Rt) compared to bare samples. The potentiodynamic polarization curves demonstrated that the Mg–Al LDH film can effectively improve the corrosion resistance of the LA103Z magnesium alloy substrate.