Particulate Aluminum Alloy Research Articles

A review on constituents, applications and processing methods of metal matrix composites

Metal matrix composites (MMCs) exhibit superior mechanical and wear resistant properties, allowing them to be deployed in a variety of manufacturing applications, including structural, automotive, aerospace domains etc. Aluminium as the matrix material has numerous applications due to its high strength-to-weight ratio. The inclusion of hard ceramic particles in aluminium alloys increases overall strength and wear-resistance. It is important to know about different constituents of composite materials. In the present review paper an attempt has been made to highlight important constituents of metal matrix composites and their applications. Also, this review paper covers the various manufacturing techniques of metal composites.

Flow Behavior of Complex-Shaped Particle Mixtures in Rotary Drums: A DEM Study

Metal matrix composites hold great potential as functional materials for energy conservation applications. These composites are manufactured using powder metallurgy, which involves the incorporation of fine particles with diverse shapes. Understanding the flowability of particle mixtures with varying shapes is crucial for optimizing industrial processes. This study focuses on analyzing the flowability and flow behavior of mixtures composed of alumina and aluminum alloy particles using the discrete element method. The particle shapes are modeled to closely resemble actual particles, and their flow behavior in a rotating drum is simulated. The upper and lower dynamic angles of repose, outlines of particle bed surface, particle displacements, and particle velocity distributions were analyzed to understand the flow characteristics of complex-shaped particles. The results reveal the influence of particle shape on the flow behavior of powder mixtures, providing valuable insights for process optimization and design.

Inhibition effect of NH4H2PO4 on explosion flame propagation of aluminum alloy dust cloud

To investigate the inhibitory effect of NH4H2PO4 on the flame propagation of aluminum alloy dust clouds, experiments were conducted in cylindrical vertical ducts. High-speed cameras were employed to capture the explosion flames of aluminum alloy dust clouds under the coupled effect of NH4H2PO4 with different concentrations and particle sizes. The flame propagation behavior of NH4H2PO4/aluminum alloy dust was analyzed, and mathematical models were developed to describe the maximum distance and maximum velocity of NH4H2PO4 inhibition on the flame propagation of aluminum alloy dust clouds. Additionally, the inhibition characteristics of NH4H2PO4 on aluminum alloy dust explosions were studied in a 20 L spherical explosion container, and the thermal decomposition properties of NH4H2PO4 and aluminum alloy particles were investigated using a simultaneous thermal analyzer. Furthermore, the inhibition process of NH4H2PO4 on aluminum alloy dust was explored. The results demonstrate that the concentration of NH4H2PO4 has a greater impact on the inhibition effect on aluminum alloy dust, while the particle size has a smaller influence. Generally, as the concentration of NH4H2PO4 increases, the flame propagation distance and flame development rate decrease, leading to an enhanced inhibitory effect. The addition of NH4H2PO4 slows down the peak pressure of aluminum alloy dust explosions, resulting in a longer duration and smaller peak values of the “double-peak” pressure structure. When the particle size of NH4H2PO4 decreases and the concentration increases, the possibility of the “double-peak” structure decreases, forming a single-peak structure with lower peak values and pressure rise rates. The decomposition temperature of NH4H2PO4 precedes the combustion temperature of aluminum alloy particles. NH4H2PO4 absorbs thermal energy from the reaction system, exerting an inhibitory effect on aluminum alloy dust. The research findings provide valuable references for optimizing explosion suppression parameters and improving powder explosion suppression techniques.

Assessment of Mechanical Behaviour and Microstructure of Micro Boron Carbide Particles Reinforced Al2011 Alloy Metal Matrix Composite for Aerospace Applications

Due to the superior qualities nowadays, composite materials are already replacing conventional materials as constituents. The incorporation of micro particles brings about an innovation in the material world. Micro particles also affect manufacturing and mechanical characteristics. In the current study, three different types of samples are fabricated by stir casting method by reinforcing the 0% wt., 2.5% wt. and 5% wt. of boron carbide (B4C) micro particles in aluminium alloy (Al2011) matrix. Finally, mechanical and microstructural properties are evaluated by conducting tensile, compression and hardness tests on fabricated samples. The study revealed that by the addition of 2.5% wt. and 5% wt. of B4C micro particles to Al2011 alloy then on comparing to the pure Al2011 alloy, the mechanical properties of the matrix with the Al2011 particles are improved. Additionally, the findings of the experiments demonstrate that the addition of B4C micro particles reduces the ductility of the composites. Furthermore, micrography analysis by SEM and FEA analysis has been carried out on the developed composites, SEM analysis shows that uniform a distribution of B4C particles in the Al2011 matrix. Also, FEA analysis revealed that there is closeness amongst FEA results and analytical results.

Sulfur Loading as a Manufacturing Key Factor of Additive-Free Cathodes for Lithium-Sulfur Batteries Prepared by Composite Electroforming

The promised prospects of Li–S technology, especially within the energy situation of the 21st century, have sparked a renewed interest from the scientific community in the 2000s. In this context, we present our new vision for the fabrication of novel cathodes for Li–S batteries that were synthesized using the first combination of composite plating and electroforming (composite electroforming). The latter consists of electroforming the current collector foil directly in a one-step process. Simultaneously, the active material is introduced into the metal matrix by means of composite plating. Reduced technological steps, better performance and resource-saving production, combined with a potentially easier and highly efficient way of recycling electrodes, are achievements of the current method. In the present work, novel cathodes for lithium–sulfur batteries were synthesized by composite electroforming of AlSi10Mg0.4@Ni foil from a nickel sulfamate-based electrolyte with AlSi10Mg0.4 particles used as dispersoids. The composite foil is subsequently etched in order to increase the specific surface area of the aluminum alloy particles. The last manufacturing and key step of the ready-to-use cathodes for Li–S batteries is the sulfur loading, which was conducted using two different ways: by spin coating in melted sulfur at 160 °C or electrochemically from a sodium sulfide aqueous solution (Na2S(aq)). Morphological and electrochemical characterization by SEM and galvanostatic cycling, respectively, exhibited a remarkable difference in terms of the sulfur distribution and the surface morphology as well as a considerable improvement of the rate capability and cyclability for the electrochemically loaded cathode as against the spin-coated one.

Nucleation and growth of L12-Al3RE particles in aluminum alloys: A first-principles study

The internal mechanisms of nucleation and growth of L12-Al3RE (RE = Sc, Y, La–Lu) second phases in Al alloys were investigated by combining first-principles calculations with quasi-harmonic approximation (QHA). The calculated results show that the diffusion rate Ds and chemical potential ΔGV increase with the increase of temperature. With the increase of atomic number, the Ds and the strain energy ΔECS increase firstly from Sc to La, and then decreases, while the calculated interface energy γα/β and ΔGV show opposite tendency. Based on above calculated results, the critical nucleation radius R∗ and coarsening rate KLSW are obtained from the classical nucleation theory (CNT) and LSW model of the Ostwald ripening of particles, respectively. With the increase of atomic number, the R∗ increases firstly, and then decreases for all planes at finite temperatures. Whereas the KLSW shows opposite variation to the R∗. From this point of view, it is reasonably speculated that Y and later RE elements can replace the expensive Sc for heat-resistance Al alloys. The solubility c∞ of particles is usually very small at low temperature, and there is obvious solubility only when the temperature reaches 600 K. The surface energies Esur of Al3RE compounds and Al solid solution are respectively larger and smaller than that of pure Al, respectively, except for the surface (001) and (110) of Al3La. For all planes, with the increase of atomic number of RE, Esur decreases firstly from Sc to La, and then increases linearly to Lu. These results are helpful for designing high performance heat-resistance Al alloys.

Experiment and numerical simulation of aluminum silicon alloy corrosive treatment in the water vapor generation autoclaves

In order to explain the morphology and structure of coating precursor shell on the surface of aluminum silicon alloy, the Al-12 wt%Si powders were treated in two kinds of water vapor generation autoclaves, and the water vapor parameters were numerically simulated. The morphology of reactant products was observed by scanning electronic microscopy and analyzed combined with numerical simulation results. The results show the water vapor, liquid water and air co-exist with different distributions. Under the same temperature and pressure, the higher amount of water vapor leads to the formation of stable flake-like boehmite, while the lower amount of water vapor slows down the reaction rate of Al-Si with water, and stable bayerite with prism-like are formed on the surface of Al-Si particles. Different shapes of bayerite, boehmite and pseudo-boehmite are formed on the Al-Si particle surface because of no-uniform distribution of water vapor. This study provides suggestions on selecting the proper establishment and the water vapor parameters for getting the ideal morphology of reactants on the surface of aluminum alloy particles.

High Strength Al-La, Al-Ce, and Al-Ni Eutectic Aluminum Alloys Obtained by High-Pressure Torsion.

A comparative analysis of the effect of high-pressure torsion (HPT) on the microstructure and tensile properties of the Al–10% La, Al–9% Ce, and Al–7% Ni model binary eutectic aluminum alloys is carried out. An HPT of 20-mm diameter specimens in as-cast state was carried out under constrained conditions, at room temperature, pressure P = 6 GPa, and number of turns N = 5. It is shown that the formation of nano- and submicrocrystalline structures and the refinement of eutectic particles in aluminum alloys simultaneously provide a multiple increase in strength while maintaining a high plasticity margin. This combination of properties has been achieved for the first time for severely deformed binary aluminum eutectics. The relationship between the type of eutectic particles, the structure formation process and the mechanical properties of the aluminum alloys has been established. The thermal stability of severely deformed aluminum alloys at heating up to 200 °C has been studied.

Characterisation of Aluminium Metal Matrix Composites reinforced with SiC (Carborundum) & Al2O3 (Corundum)

Aluminium alloys are widely used in aerospace and automotive industries due to their advantages of physical and mechanical properties. This paper presents a study on the performance of stir cast SiC & Al2O3 reinforced Aluminium metal matrix composite materials. The particulate reinforcement of SiC & Al2O3 is in the ration of 3:2. The mechanical characterization of AMMC indicates that the composite exhibit improved physical and mechanical properties such as low coefficient of thermal expansion, high ultimate tensile strength, high impact strength and hardness. Through scanning electron microscope, the microstructure of AMMC & distribution of SiC & Al2O3 particles in Aluminium alloy (Al 1350) is uniform. By experimental analysis, it is observed that AMMC with 15% of particulate reinforcement of SiC & Al2O3 with a ration of 3:2 (9% of SiC & 6% of Al2O3) is the optimum mixture for AMMC to obtain better mechanical characteristics. This AMMC has good potential for the applications in automotive industry to manufacture engine components.

Influence of processed waste bagasse fibre-stone dust-6063 aluminium alloy particle on the characteristics of hybrid reinforced recycled HDPE composites

ABSTRACT A novel hybrid composite material was developed through the compression moulding technique by adding bagasse fibre, stone-dust and 6063 aluminium alloy (Al-Mg-Si) particles to recycled high-density polyethylene (rHDPE) matrix. The bagasse fibres were treated while the stone-dust and 6063 aluminium alloy (Al-Mg-Si) particles were sieved to particle sizes of ˂75 µm and ˂250 µm, respectively, before blending with the matrix. The work investigates comparatively, the influence of bagasse fibre-stone dust (hybrid-of-2) and bagasse fibre-stone dust-Al-Mg-Si particles (hybrid-of-3) on composite formation systems for reinforced rHDPE composites. The properties of recycled HDPE and rHDPE composites were thoroughly investigated through selected mechanical properties, wear resistance and thermal conductivity tests. The results show that the addition of bagasse fibre-stone dust-Al-Mg-Si alloy particles improves the mechanical, wear and thermal properties of the composites. The ultimate tensile strength was enhanced by 39% having a UTS value of 32 MPa, tensile modulus by 13% with a value of 98 MPa and wear resistance by 53% with a value of 0.8 g. SEM images showed that these reinforcements blended more properly when lower contents were added. This is responsible for the enhancement observed in the mechanical properties of the hybrid-of-3 reinforced composite.

HVAF deposition mechanism of γ-TiAl-based coating containing β phase

The Ti-45Al-7Nb-4V, Ti-45Al-7Nb-4Cr, Ti-45Al-7Nb-2V-2Cr alloy coatings were prepared on the surface of the aluminum alloy by high-velocity-air-fuel (HVAF). The surface and cross-section of three kinds of titanium aluminum alloy coatings and the micromorphology of the bonding interface between the coating and substrate were observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The deformation behavior of titanium aluminum alloy particles and the phase composition of the titanium aluminum alloy coating were analyzed by X-Ray Diffraction (XRD) and energy dispersive x-ray analysis (EDAX). The results show that the coordinated deformation between TiAl particles and Al alloy matrix is a necessary condition for the deposition of the first layer of titanium‑aluminum alloy particles. The bonding mechanism of the TiAl coating and the matrix is mechanical bonding, and there are both mechanical bonding and metallurgical bonding between spraying particles. In the process of coating deposition and formation, the β phase grains undergo coordinated deformation to form typical structures such as striped grains and circular columnar crystals. The deformation mechanism of the titanium aluminum alloy particles is the slip and kink mechanism in the grains, and the sliding and rotation mechanism of the grain boundary and the phase boundary. Adiabatic shear instability and dynamic recrystallization occurred during the formation of titanium aluminum alloy coating.

The behaviour of iron-containing intermetallic particles in aluminium alloys in alkaline solution

The behaviour of Fe-containing particles during alkaline etching and desmutting of AA5052 aluminium alloy is investigated by quasi in situ monitoring of the compositional and morphological evolution of the particles. In alkaline solution, multi-layered oxide/hydroxide films are rapidly formed on the particles, rendering them electrochemically inactive. The particles are inactive in nitric acid due to formation of thin alumina layer. The treatment doesn’t significantly change the total population of Fe-containing particles with the population of Al3Fe being reduced and that of Al(Fe,Mn,Cr)Si remaining almost unchanged. Further, relevance of the observed behaviour to localized corrosion of aluminium alloys is also discussed.

Direct metal laser sintering of AlSi10Mg alloy parts: Modeling of temperature profile

Laser powder bed fusion process is a frontier technology in the additive manufacturing sector for the printing of near net shape structure with design freedom. One of the key problems allied with this process is the temperature instability that occurs because of the moving laser beam. The temperature dissemination in the building layer becomes inhomogeneous and leads to stress generations. As a result, the engineering properties of the printed component worsen. The current study focused on the development of a mathematical model to examine the heat transfer behavior in the build layer during the printing of aluminum alloy parts in the laser powder bed fusion process. ANSYS 17.0 commercial software platform was used for the development of the model by considering aluminum alloy particles i.e., AlSi10Mg as the powder material. The developed model assists to understand the heat transfer mechanism and temperature distribution at different laser energy inputs, scan speed, and initial porosity present in the powder layer. From the numerically simulated model, it is established that laser energy input has a profound effect on the rise of temperature in the build layer and vice-versa with scan speed. The present simulation results will assist the manufacturers for the selection of appropriate experimental conditions for the printing of ideal components for the desired application.

Microstructure and mechanical behaviour of Al/SiC/Al2O3 hybrid metal matrix composite

In the present investigation, aluminium 6061 alloy was taken as matrix material. SiC was taken as primary reinforcement material. Al2O3 was taken as secondary reinforcement material. Microstructure image shows a uniform distribution of reinforcement material in matrix AA6061. Tensile strength and hardness were improved by adding the SiC and Al2O3 ceramic particles in aluminium. However, toughness was reduced by adding the SiC and Al2O3 ceramic particles in aluminium alloy. Results showed that hard ceramic particles SiC and Al2O3 ceramic particles enhanced hardness significantly, but toughness reduced. Results showed that after the heat treatment process, the mechanical properties of composite material significantly improved.

Preparation of millimeter scale second phase particles in aluminum alloys and determination of their mechanical properties

The mechanical parameters such as elastic moduli E and shear moduli G of second phases are critical inputs for modeling and optimizing mechanical properties of aluminum alloys. However, some of these mechanical parameters are lacking because these micron or even nano scale phases are hard to be tested. The aim of this paper is to present an efficient approach to test the mechanical properties of second phases in aluminum alloys accurately. The α-AlFeSi, β-AlFeSi and Mg2Si particles at the millimeter scale were prepared by directional solidification with the aid of calculation of phase diagrams (CALPHAD). Such a large size can effectively reduce the impact of particle penetration into matrix in nanoindentation and Vickers hardness experiments. The elastic moduli of α-AlFeSi, β-AlFeSi and Mg2Si were determined as 183.81 ± 8.64 GPa, 174.13 ± 6.81 GPa and 116.38 ± 4.06 GPa, respectively, and their Vickers hardness values were 883 ± 64, 765 ± 21 and 475 ± 22 HV, respectively. Besides, the continuous uniform plastic deformation (without pop-in phenomenon in load-displacement curve) of Mg2Si was observed and is attributed to the anti fluorite structure of Mg2Si. Further, by Vickers hardness and electron backscatter diffraction (EBSD) it was found that the hexagonal α-AlFeSi had greater hardness anisotropy than the near-tetragonal β-AlFeSi. Overall, the hardness values of α-AlFeSi particles in <u 0u¯w> direction were higher than others, the hardness values of β-AlFeSi particles near <001> were lower than others.

Precipitation and strengthening modeling for disk-shaped particles in aluminum alloys: Size distribution considered

For an ICME (Integrated Computational Material Engineering) modeling framework used for the age-hardening aluminum alloy design and heat treatment parameters optimization, it is critical to take into account the geometric shape of precipitates, as it is tightly related to the precipitation kinetics and particles' hardening effect. The aim of this paper is to present such an ICME modeling approach to describe the precipitation of disk-shaped hardening particles during aging treatment and predict the final yield strength. The classical Kampmann–Wagner Numerical (KWN) model is extended to consider the influence of disk-shaped particle morphology on growth kinetics. The extension consists of two correction factors to the growth rate equation and to the Gibbs-Thomson effect. The extended model, coupled with a metastable thermodynamic database, is applied to simulate precipitation kinetics of Al-Cu and Al-Mg-Zn alloys during aging treatment. The predicted microstructural features are in reasonable agreement with the reported experimental observations. Furthermore, a strengthening model for disk-shaped particles, which considers the size distributions of precipitates, is developed. The predicted yield strengths are compared with reported tensile test results and with predictions from other strength models. Unlike other models, the proposed strength model can reveal the strength contribution from disk-shaped precipitates without an additional tuning parameter for accounting for the impact of the mean particle spacing in the slip plane.

Fabrication and Characterization of Aluminium Boron Nitride Composite for Fins

Fins are being used to dissipate the heat from the object mainly for cooling purpose. Conventionally, In heat sinks Aluminium alloys are the common material used till date as fin material. In this preliminary research work, a new class of heat transfer material is engineered by dispersing ceramic particles in conventionally used heat transfer aluminium alloys. The fabrication of Aluminium Matrix Composites (AMC) reinforced with micro-sized cubic boron nitride (CBN) particles was prepared by bottom tapping stir casting method. In this process, 2% of magnesium was added as wetting agent for uniform dispersion of CBN. Characterizations of prepared composite specimens are carried out in optical microscope, SEM & EDX. A preliminary heat transfer study using pin fin apparatus on the fabricated Al/BN composite is investigated and their temperature distribution properties are compared. The result shows the significant enhance in heat transfer rate due to the addition of CBN particles in Aluminium alloy (AA 6061 T6).

Research on Liquid Management Technology in Water Tank and Reactor for Propulsion System with Hydrogen Production System Utilizing Aluminum and Water Reaction

High pressure hydrogen produced by aluminum and water reaction is considered to be applied to space propulsion system. Water tank and hydrogen production reactor in this propulsion system require gas and liquid separation function under microgravity condition. We consider to install vane type liquid acquisition device (LAD) utilizing surface tension in the water tank, and install gas-liquid separation mechanism by centrifugal force which swirling flow creates in the hydrogen reactor. In water tank, hydrophilic coating was covered on both tank wall and vane surface to improve wettability. Function of LAD in water tank and gas-liquid separation in reaction vessel were evaluated by short duration microgravity experiments using drop tower facility. In the water tank, it was confirmed that liquid was driven and acquired on the outlet due to capillary force created by vanes. In addition of this, it was found that gas-liquid separation worked well by swirling flow in hydrogen production reactor. However, collection of hydrogen gas bubble was sometimes suppressed by aluminum alloy particles, which is open problem to be solved.

Effect on Aluminium Metal Matrix Composite Reinforced with Nano Sized Silica Particles

In recent times, it could be observed that metal matrix composites receive considerable importance on account of improved properties compared to unreinforced alloys which includes high specific strength, specific modulus, damping capacity and good wear resistance. Interest in composites containing low density and low cost reinforcements has been since growing. Among various discontinuous particulate, silica is one of the most inexpensive and low density reinforcement available in large quantities. Hence, composites with aluminium oxide as reinforcement after the in-situ reaction of aluminium and silica are likely to overcome the cost barrier for wide spread applications in automotive and small engine applications. It is therefore expected that the incorporation of aluminium oxide particles in aluminium alloy will improve the mechanical properties of base material that will see increased usage in aircraft application due to reduced weight. In this research an effect on aluminum matrix composite reinforced with nano sized silica particles with different weight percentage was carried out. From the results it was found that the composites with 4 to 6wt% particle volume fraction to be the best with good tensile strength, yield stress and percentage elongation.

Combined effects of reinforcement fraction and porosity on ultrasonic velocity in SiC particulate aluminum alloy matrix composites

Abstract This work aims at applying the broadband laser-ultrasonic spectroscopy for quantitative evaluation of combined influence of the reinforcement fraction and the porosity content on the phase velocity of longitudinal acoustic waves in stir cast SiC particulate aluminum alloy matrix composites. The investigated composites contain 3.8–15.5 wt % of SiC particles with an average size of 14 μm. The growth of SiC fraction is accompanied by the growth of the total porosity content that reaches 4.7% for the maximum fraction of SiC. These combined factors cause the occurrence of dispersion of the phase velocity – it decreases in the frequency band 3–10 MHz and increases in the frequency band 20–40 MHz in comparison with that in the matrix without any reinforcement. It was found that the relative velocity dispersion increases with the growth of the porosity content within the investigated composite area regardless of the SiC fraction. The derived empirical relation between the relative velocity dispersion and the porosity content can be used for rapid quantitative porosity characterization in stir cast SiC particulate aluminum alloy matrix composites to reveal any potential areas with a reduced strength before the fabrication of composite products.