Melting Point Of Aluminum Research Articles

Morphology engineering of low-temperature-synthesized aluminum nitride

We have developed an aluminum nitride (AlN) manufacturing method that operates below the melting point of aluminum. To examine the nucleation and growth mechanisms of AlN during the synthesis process, we used a variety of characterization techniques, including high-resolution transmission electron microscopy and rapid Fourier transform, which highlighted the development of its single-crystal and polycrystalline forms. The microstructural investigation showed that nitridation began with forming AlN shells on the surface of aluminum particles. Subsequently, volume nitridation occurred by transforming a single aluminum particle into either polycrystalline AlN with a columnar structure or single-crystal AlN. In addition, various interesting morphologies were observed during the microstructural investigation of low-temperature synthesized AlN, including truncated dodecahedrons, nanowires, particles, pillars, plates, and other polyhedral shapes. The study's microstructural findings provide crucial data on the AlN particle formation process, offering valuable insights expected to deepen understanding and expand the applications of AlN. Therefore, the consequence of this study is expected to make a meaningful contribution to understanding the formation mechanism of the particle type of AlN.

Study on Thermal Runaway Behavior and Jet Characteristics of a 156 Ah Prismatic Ternary Lithium Battery

Ternary lithium batteries have been widely used in transportation and energy storage due to their high energy density and long cycle life. However, safety issues arising from thermal runaway (TR) need urgent resolution. Current research on thermal runaway in large-capacity ternary lithium batteries is limited, making the study of hazard indicators during the thermal runaway ejection process crucial. This study places a commercial 156 Ah prismatic battery (positive electrode material: Li(Ni0.8Mn0.1Co0.1)O2, negative electrode material: graphite) in a nitrogen-filled sealed container, triggering thermal runaway through lateral heating. The experimental results show that the battery’s maximum surface temperature can reach 851.8–943.7 °C, exceeding the melting point of aluminum. Temperature surge inflection points at the battery’s bottom and near the small side of the negative electrode coincide with the inflection point on the heated surface. The highest jet temperatures at three monitoring points 50 mm, 150 mm, and 250 mm above the safety valve are 356.9 °C, 302.7 °C, and 216.5 °C, respectively. Acoustic signals reveal two ejection events. The average gas production of the battery is 0.089 mol/Ah, and the jet undergoes three stages: ultra-fast ejection (2 s), rapid ejection (32 s), and slow ejection (47 s). Post-thermal runaway remnants indicate that grooves from internal jet impacts are mainly located at ±45° positions. This study provides valuable insights for the safety design of batteries and the suppression of thermal runaway propagation.

Optimizing Aluminum Melting with Sustainable Biomass Fuels: A Case Study of Ulin (<i>Eusideroxylon zwageri</i>) Wood and Galam (<i>Melaleuca cajuputi</i>) Wood

Wood waste biomass has emerged as an abundant source of alternative energy. This alternative energy source holds significant potential in the industrial sector, particularly in the field of metal casting. The development of aluminum melting equipment aims to provide invaluable support to aluminum craftsmen by harnessing wood waste as an easily accessible fuel source. The approach employed in this research involves the design of a wood waste combustion chamber capable of reaching the aluminum melting point. Two types of wood, Ulin (Eusideroxylon zwageri) and Gelam (Melaleuca cajuputi), were utilized in the study. The research achieved a temperature of 863°C in 28 minutes with Ulin wood, whereas with Gelam, a temperature of 821°C was reached in 29 minutes. This study makes a significant contribution to the efficient utilization of wood waste biomass in the aluminum casting industry, offering remarkable environmental and economic benefits.

Certification of welder for tungsten inert gas welding in unmanned aerial vehicle systems

Aluminum and its alloys is one of the extensively used non-ferrous metal in aerospace engineering applications due to its excellent properties like higher strength to weight ratio, non-magnetic property, high thermal conductivity, good machinability, recyclability, and excellent formability. However, welding of aluminum and its alloys has always been a challenge due to drastic reduction in strength near heat affected zone (HAZ). Due to softness, ductility, lower melting point of aluminum and its alloys impose additional challenges to weld aluminum alloy components. Due to this, the quality and quantum of skill set needed to weld aluminum alloy joints for flight critical components is much more than that of welding of ferrous materials. The qualification and certification of welder is one of the prime requirements in welding applications especially in aerospace industry. This paper mainly discusses the various aspects involved in qualifying and certifying a welder for tungsten inert gas (TIG) welding process of aluminum alloys, which is treated as one of the special processes. The welder certification is a written verification that weld joints produced by welder meets the prescribed standard of welder performance. It is to verify the ability of an individual to execute a qualified welding procedure specification to produce a sound weld. Aluminum alloy 6xxx series is considered for base metal for sample preparation and weld joint assessment studies, as it is one of the prevalently used aluminum alloy material in unmanned aerial vehicle (UAV) applications. Weld samples are prepared as per internationally practiced standards and welding procedure specification (WPS) is recorded. Various mechanical tests carried out on weld samples during certification process are discussed in the paper. Weld joints are subjected to tensile testing, bending test and macro test. The certifying agencies are involved at every stage to ensure consistency of welder performance.

Effect of the Reinforcing Particle Introduction Method on the Tribomechanical Properties of Sintered Al-Sn-Fe Alloys

The present paper reports the results of the comparative study of mechanical properties of sintered disperse-strengthened Al–40Sn alloy depending on the method of reinforcing particle introduction. The study is performed on two mixtures of aluminum and tin powders: one is admixed with 5.5–14.6 wt% of pure iron powder and the other contains the same amount of iron, but as a component of aluminide Al3Fe powders. The volume fraction of tin remains unchanged in all mixtures, being equal to 20%, and the concentration of hard particles increases due to a decrease in the volume fraction of the aluminum phase. Green compacts are sintered in the vacuum furnace at a temperature above the melting point of aluminum. The sintered material is a composite containing three phases: α-Al, β-Sn, and Al3Fe, in which the tin volume fraction is constant. Testing of the sintered composites for compression shows that the addition of finished Al3Fe particles has a more beneficial effect on their mechanical properties as compared to the addition of pure iron powders. In the latter case, aluminides are formed during sintering. The ultimate strength of composites reaches 180 MPa. Mechanisms of sintering of composites and the related structure and mechanical properties are discussed.

Experimental Investigation on Morphological Characteristics and Propulsion Performance of Typical Metals Ablated with Multipulse Nanosecond Laser

For laser ablation micropropulsion technology with metal as the target to increase the total impulse, the effective utilization and supply of a working medium is a crucial aspect. In this research, the ablation characteristics and propulsion performance of the typical metal targets, copper and aluminum, ablated via nanosecond laser ablation are analyzed. Due to the low melting point of aluminum, the protrusion characteristics in the remelted area are more prominent. Its surface morphology has characteristics for height extremum and roughness that are higher than those of copper. Affected by the anisotropy of the rough surface, the absorbed energy decreases with increasing roughness. The impulse coupling coefficient of the metal decreases and stabilizes at about 6 μN·W−1. The specific pulse of aluminum obtains a minimum value of 603.6 s at 6000 pulses and improves with increasing pulses. The propulsion parameters of copper alters slightly under various working conditions, with a maximum specific impulse of 685 s.

Multi-Component Evaporation and Uneven Aluminum Distribution during High-Power Vacuum Laser Welding of Ti-6Al-4V Titanium Alloy

Titanium alloy is an important material for the manufacture of key components of deep-sea submersibles. High-power vacuum laser welding is an important method for welding TC4 thick plate (40–120 mm) structures. However, due to the low melting point of aluminum, its uneven distribution in the weld caused by evaporation during welding affects the quality of joints. This paper conducted experimental and simulation studies to investigate the effect of process parameters on multi-component evaporation and uneven aluminum distribution. Based on a three-dimensional model of vacuum laser welding, the mechanism of the uneven distribution of aluminum in the weld is explained. The results show that the uneven distribution of aluminum in the weld is mainly related to the metal vapor behavior and keyhole morphology. As the welding speed rises from 1 m/min to 3 m/min, the proportion of aluminum in the metal vapor and the degree of compositional unevenness increase. When the laser power increases from 6 kW to 18 kW, the proportion of aluminum in the metal vapor and degree of unevenness increase, peak at 12 kW, and then decrease. This work facilitates the selection of suitable process parameters to reduce aluminum evaporation during the high-power vacuum welding of Ti-6Al-4V alloys. Joints with a more stable performance can be obtained by avoiding the uneven distribution of aluminum.

A STUDY OF THE PHENOMENON BUE CREATION IN TROCHOIDAL MILLING

Aluminum alloy 6061-T6 is a commonly used material in various industries, including automotive parts manufacturing. However, its machining process can be challenging due to the occurrence of build-up edge (BUE) at the cutting edges. To address this issue, this research employed trochoidal milling to machine aluminum alloy 6061-T6 specimens, utilizing a small step over and a suitable depth of cut. The engagement of the tool during the machining process generates fluctuating forces, which consequently leads to fluctuations in temperature. This phenomenon is not only observed in trochoidal milling but also in conventional machining methods. The results indicate that the calculated maximum temperature (350°C) is lower than the aluminum's melting point (652°C). Moreover, the experimental results show minimal BUE formation on the cutting edge and an improved milling process.

Semi-Analytical Solution for Modelling Moving Heat Sources in a Semi-Infinite Medium with Radiative and Convective Boundary Conditions

The weld quality is highly related to the thermal history of the weld and there have been many trials to monitor the quality using an infrared (IR) sensor. To obtain the real temperature of a surface based on the brightness temperature values measured by an IR camera, the emissivity value must be derived. For an accurate assessment of the emissivity, one must be aware of the melting point isotherm. The temperature profiles only depend on three factors during laser processing, specified as constants the characteristics of the material: laser beam speed (v), laser beam diameter (d), and power (P). Predicting the width of the melted zone reached during the welding process as the parameters vary is a tool for helping a quality laser processing and for determination of true temperature in laser welding using IR camera. This study describes the semi-analytical (SA) solution of the heat conduction equation for a localized moving Gaussian heat source with constant parameters on a semi-infinite medium. The solution, simple and quick to obtain, provides information on the width of the melted zone with an average error < 5 %. The outcome is assessed numerically and contrasted with FEM solutions for a Gaussian source, the latter having undergone experimental validation. With two distinct defocus values, def0 and def-6, and by varying the speed and power settings, two separate types of experiments were run. Thus, the SA solution was obtained and compared after the FEM solution had been obtained with a good approximation (max err 4.3 %, average err 2.7 %). Only in regard to the 1AL test is an error more than 5 % detected; in the other case, the average error is 3.75 %. Two more tests at the defocus values of def-4 and def-8 were conducted to confirm the model's validity as the parameters varied. Overall, the average error between the semi-analytical and the FEM solution is 4.1%. The SA solution may be used to effectively estimate the isotherms related to the melting point of aluminum (770 K). This allows to obtain a tool which helps restoring the real temperature based on the brightness values measured by the IR camera during laser welding. At the same time, this effective tool allows to investigate the importance of different processing parameters in laser manufacturing.

How positioning of a hard ceramic TiB2 layer in Al/CuO multilayers can regulate the overall energy release behavior

This study reports on a new ternary thermite comprising of Al-TiB2/CuO multilayers, designed to take the advantage of high ignitability of titanium (Ti), high volumetric density of boron (B), and low melting point of aluminum (Al). Results demonstrate synergetic effects leading to an energetic layer outperforming its single fuel counterparts, Al/CuO or TiB2/CuO, while being safe to handle. The additive TiB2 not only lowers the ignition energy by 100%, but also enhances the burn rate by more than a factor of two compared to the single fuel samples (Al/CuO and TiB2/CuO). The thermite reaction sequences and synergy of Ti, B and Al oxidation, examined by thermo-analytical analyses coupled with X-ray spectroscopy and high-resolution electron energy loss spectroscopy, demonstrate the strong affinity of TiB2 to oxygen that catalyzes CuO decomposition at temperatures as low as 380 °C; followed by a dual-step TiB2 oxidation: first to TiO, and then to TiO2 led by a reaction limiting step of oxidizer availability. Finally, Al undergoes oxidation via liquid boron oxide as well as gaseous oxygen. This study also underlines the crucial effect of the nanolayer morphology in the thin-film technology: when Al is sputter-deposited onto the TiB2 layer, Al ions penetrate into the grain boundaries penalizing TiB2 reactivity. The results demonstrate the advantages of using TiB2 fuel to improve the ignitability and the combustion performance of Al based thermite and offer some means to finely tune the energetic properties.

Molecular Dynamics Investigation of the Effect of the Interface Orientation on the Intensity of Titanium Dissolution in Crystalline and Amorphous Aluminum

The influence of the interface orientation on the intensity of dissolution of titanium in crystalline and amorphous aluminum is studied by molecular dynamics simulation. The following four orientations of the Ti–Al interface with respect to the Ti (hcp) and Al (fcc) lattices are considered: (1) (0001):(111), (2) (0001):(001), (3) (101¯0101¯0):(111), and (4) (101¯1101¯1):(001). The interface orientation is found to influence the intensity of dissolution of titanium in aluminum, which increases for the accepted designations in the order 1–2–3–4. An important phenomenon in this case turns out to be the formation of a thin (2–3 atomic planes thick) crystalline layer in aluminum, which repeats the crystal lattice of titanium, at the initial stage of dissolution. At a temperature below the melting point of aluminum, a grain boundary parallel to the interface forms behind this layer. At temperatures above the melting point of aluminum, this crystalline layer is preserved, but its thickness decreases gradually as the temperature increases. For aluminum in an amorphous state at temperatures below its melting point, the dissolution of titanium occurs at almost the same intensity as in the crystalline state of aluminum, which is explained by the formation of a similar crystalline layer in aluminum at the interface in all cases.

Investigation of mechanical properties of Al3Zr intermetallics at room and elevated temperatures using nanoindentation

This work deals with the measurement of mechanical properties of single and polycrystalline Al3Zr specimens from ambient to elevated temperatures using nano-indentation experiments. In this study, we employed three kinds of intermetallic specimens produced from Al3Zr crystals chemically extracted from an Al-3 wt% Zr alloy. The properties such as elastic modulus and hardness were determined under quasistatic loading conditions. Constant multicycle indentation testing (MCT) was further performed using a Vickers indenter to understand the fatigue response of intermetallics at high load low cycle conditions. The results showed that hardness and elastic modulus of Al3Zr intermetallics depended on the crystal structure/orientation, with polycrystalline samples showing higher elastic modulus than single crystal specimens at room temperature conditions. MCT experiments revealed that contact pressure of more than 7 GPa was needed to fracture a crack-free crystal under dynamic loading conditions. Consequently the properties of intermetallics at temperatures up to 700 °C were determined for the first time, using high-temperature nano-indentation technique. Elevated temperature measurements indicated that intermetallics had high creep resistance at low and intermediate temperatures, but exhibited significant plastic deformation and creep close to the melting point of pure aluminium.

P – T – х диаграмма состояния системы Al – Ba

Intermetallic compounds formed in Al – Ba system are stable at temperatures above the melting point of both barium and aluminum, which allows to consider barium as a promising element for aluminum alloys operating at high temperatures and characterized by relatively high vapor pressure of barium. On the other hand, aluminum-barium ligature is widely used in various fields of metallurgy for the preparation of alloys and complex modification of steels and cast irons: aluminum improves the quality of steels, acting as a reducing agent for iron in its oxide compounds, and barium contributes to the graphitization of cast irons, which leads to an improvement in the pearlite and ferritic structures. The study of the aluminum-barium system (Al – Ba) demands taking into account the high vapor pressure of Ba, which requires analysis of the system in the pressure-temperature-concentration coordinates (p – T – x diagrams), which is the aim of the present paper. The results obtained in this work can be successfully used in the development of ternary and more alloys containing aluminium and barium.

Emissivity Prediction for an IR Camera During Laser Welding of Aluminum

Laser processing is becoming increasingly important in industrial applications. The success of the process relies on two fundamental parameters: the surface temperature of the medium and the thickness of the hardened layer. One of the most important factors during a laser process is certainly the temperature, which presents high temperature gradients. The speed at which a material undergoes a phase transition, the chemical reactions that take place during processing and the properties of the material are all dependent on temperature changes. Consequently, the measure of temperature is a demanding undertaking. This study proposes to measure temperature for the duration of laser welding with the infrared camera (IR) Optris PI. To restore the real temperature based on the brightness temperature values measured by the IR camera is needed to evaluate the emissivity to be attributed to the IR camera. For this purpose, firstly, the isotherms consistent with the melting point of aluminum (785 K) were assessed and then compared with the temperature distribution gauged in the zone of irradiation of the laser. Such data were then compared with the thickness of the melted zone. The use of the melting point isotherm allowed the calculation of the value of emissivity and the restoration of the temperature. Thermography software data acquisition wrongly presupposes the emissivity value does not change. This generates incorrect thermographic data. The surface emissivity normally hinges on temperature. Therefore, the values on which the literature relies may not work for materials of interest in the conditions of the process. This is particularly the case, where welding is carried out in keyhole mode (Tmax = Tvap). However, the physical phenomena involved, including evaporation and plasma plume formation, high spatial and temporal temperature gradients, and non-equilibrium phase transformations, influence the optical conditions of the brightness of the emission of light from the molten pool, making, De Facto, the emissivity value not constant. Thus, what we propose here is a methodological procedure that allows the measurement of the effective emissivity of the surface, at the same time taking into consideration the consequence of physical phenomena and the conditions of the surface. Two procedures (Standard and Simplified) capable of providing the correct emissivity value in relation to the working parameters have been proposed. The results showed that the procedures are correct, fast, and easy to use.

Analytical Investigation of Lightning Strike-Induced Damage of OPGWs Based on a Coupled Arc-Electrical-Thermal Simulation

This study investigated lightning-induced damage of optical fiber overhead ground wires (OPGWs) through damage measurements, numerical simulations and influencing factor analysis. A high-precision damage measurement method was proposed to calculate the lightning damage volume based on laser profile scanning and a developed data processing program. The time-and-space-varying current and heat flows obtained from an arc magnetohydrodynamic model were loaded on OPGWs by stepwise segmental injection to establish a coupled arc-thermal-electric model and simulate the heating and damage behavior of OPGWs. The comparisons indicated that the simulated metal phase transition region agreed well with the actual damage distribution, and the area surrounded by the aluminum melting point isotherm provided a good prediction of the arc sweep damage. The hysteresis of the temperature rise suggested that lightning damage was dominated by heat flow conduction rather than the Joule heating effect. Furthermore, the continuing current was the main cause of severe damage. The damage volume increased linearly with increasing charge transfer. As the discharge gap increases, the arc loading intensity decreases, but the damage volume undergoes a non-monotonic change, which is due to the complex variations in the arc attachment area regulated by the discharge gap and current intensity.

Electrodeposited from Ion-Organic Melt Ti-B Protective Coatings on Al-Foil

The great demand for advanced batteries in applications such as mobile devices, the transportation sector, and stationary storage has spurred intensive research and development on rechargeable lithium batteries. The corrosion behavior of Al-foil, as material for theirs current collectors, has long been a concern due to uniform or localized pitting corrosion occurs in contact with an organic electrolyte. Pitting corrosion is attributed to inhomogeneous current flow through the aluminum / electrode interface and results in local breakdown of the passive film on Al-foil. Particular attention among different protective coatings of Al-foil excites Ti-B coatings as conductive and electrochemically inactive protective layers.The main objectives of the present work are investigation of regimes for electrodeposition of Ti-B protective coatings onto Al-foil and examination of the corrosion behavior of Al-foil with such electrodeposited Ti-B protective coatings in contact with an organic electrolyte under various electrodes charging conditions.Low melting point of aluminium (tm = 6600C) made impossible electrodeposition of Ti-B coatings from chloride-fluoride melts (tel = 7000C). But it is possible from ion-organic melts at 70−2000C. In this work was investigated electrodeposition of Ti-B coatings from carbamide melt contains titanium and boron oxides. Cyclic voltammetry has shown the limit current density and potential of electrochemical synthesis. Ultra fine Ti-B coatings were electrodeposited onto Al-foil at 1300C. Figure shows the surface morphologies of an obtained Ti-B coating. Such cost-effective method of obtaining Ti-B protective coatings on Al-foils gives excellent results under theirs using as current collectors in rechargeable lithium batteries. Figure 1

Plasma Foil Aluminizing of Steel at a Temperature Below Aluminum Melting Point

Plasma Foil Aluminizing of Steel at a Temperature Below Aluminum Melting Point

Joining of aluminum and ceramic substrates by interposing molten aluminum–silicon alloy

AbstractThe effects of interposing a molten aluminum alloy layer between pure aluminum and silicon nitride on the strength of joining and properties of the joined sample were investigated. An aluminum‐based alloy containing 12 wt% silicon with a melting point lower than the 660°C melting point of pure aluminum was joined to pure aluminum and a silicon nitride substrate by using polymethylphenylsiloxane. A specimen with the same joining area (1600 mm2) and no alloy layer was prepared for comparison. In thermal cycling tests of Δ190 K, cooled at –40°C and heated at 150°C, the specimen without the alloy layer failed after 200 cycles, whereas the specimen with the alloy layer failed after 500 cycles. The bending strength of the sample with the alloy was approximately 1.5 times that of the sample without the alloy. These results indicate that the alloy layer facilitated the strong joining of the aluminum and substrate.

Preparation of Al/AlN composites by in-situ reaction in the nitridation-induced self-forming process

Recently, we developed and reported an easy and cost-effective process called nitridation-induced self-forming Al composites (NISFAC) for manufacturing aluminum matrix composites from Al powder. In this process, AlN is formed by an in situ reaction between Al powder and nitrogen gas, and Al/AlN composites are self-sintered at temperatures below the melting point of aluminum because of the thermal energy released by the nitridation reaction of the Al powder. Because AlN is formed by an in situ reaction in the Al matrix, it is not only chemically stable, but also beneficial in terms of its wettability with the matrix. In this study, we prepared Al/AlN composites using the NISFAC process by increasing the amount of ex-situ added AlN reinforcement. The coefficient of thermal expansion (CTE) was effectively reduced by increasing the volume fraction of AlN, which was significantly lower than the theoretically expected value; a CTE of ∼10.8 × 10−6/°C could be achieved by adding only 20 vol.% of AlN. This demonstrates that the in situ formation of AlN during the NISFAC process may help reduce the CTE of Al/AlN composites.

Enhanced combustion performance of core-shell aluminum with poly(vinylidene fluoride) interfacial layer: Constructing the combination bridge of aluminum powder and poly(vinylidene fluoride)

Uniform coating of organofluorides on aluminum powder surfaces has always been a challenging problem. Herein, the polyvinylidene fluoride (PVDF) is uniformly bonded to the surface of the aluminum powder via the bridge formed by the self-assembly reaction of tannic acid (TA) and iron ions, and successfully prepared an dual-core shell structure aluminum composite (Al@TA-Fe@PVDF) coated with PVDF uniformly. Molecular dynamics simulation calculations reveals that the binding energy of PVDF and TA is much higher than that of Al2O3 on the surface of aluminum powder. In addition, the results reveals that PVDF layer of Al@TA-Fe@PVDF is uniformly coated on the surface of aluminum particles. The hydrophobicity brought by the F and C elements in the double interfacial layer TA-Fe@PVDF can improve the water corrosion resistance of aluminum powder. More importantly, the combustion and ignition performance of Al@TA-Fe@PVDF are greatly improved compared with pure aluminum powder. The TA-Fe@PVDF interfacial layer can promote the aluminum powder to be ignited at a temperature lower than the melting point of aluminum in oxygen, changing the typical reaction process of aluminum.