Pure Aluminum Alloy Research Articles

Effect of heat treatment before fast multiple rotation rolling on friction surfaced Al–Si–Cu alloy

In this study the effect of combination of heat treatment of consumable rod and solid solution heat treatment before fast multiple rotation rolling (FMRR) processing on microstructure, mechanical property and wear resistance of Al–Si–Cu alloy friction surfaced on commercial pure aluminum alloy were investigated. Results show that after the FMRR process, there is a significant reduction (99% reduction) in the friction surfaced coating surface roughness. The surface roughness after FMRR processing in the coatings created by homogenized and solid solution treated consumable rod is 0.74 ± 0.12, and 0.56 ± 0.08 μm, respectively. In the coating created by homogenized rod the minimum grain size (1.7 ± 0.2 μm) formed in the FMRR processed layer. Using homogenized consumable rod and FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, the maximum hardness (9.8 ± 0.3 GPa) and minimum wear rate (4.6 ± 0.1 μg/m) created at processed layer. FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, result in 27 and 24 % increasing in hardness at friction surfaced coating created by homogenized and solid solution treated consumable rods, respectively.

Effect on Ti/Mg isothermal oxidation of refinement microstructure and tribological behaviour of pure aluminium alloy by plasma spray coating

Effect on Ti/Mg isothermal oxidation of refinement microstructure and tribological behaviour of pure aluminium alloy by plasma spray coating

Research on the Ablation Resistance of TiC Particle-Reinforced Aluminium-Based Composite Coatings on Armature Surface

The work aims to enhance and modify the armature surface in electromagnetic rail launch systems and improve its anti-ablation performance to better resist the impact ablation effects of high-temperature and high-speed arcs during the electromagnetic rail launch process and improve launch reliability. TiC particles are widely selected as metal material reinforcements, with advantages such as high melting points and high hardness. In this paper, the arc impact model of pure aluminum alloy and the arc impact model of TiC particle-reinforced aluminum-matrix composite coating–pure aluminum alloy were constructed based on molecular dynamics simulation. The ablation resistance of the material was evaluated by analyzing the depth of arc impact, the mass loss of the model, the number of gasification atoms, and the surface temperature of the material. The protection mechanism of the modified layer on the substrate was revealed by analyzing the damage degree of the surface and subsurface of the material after arc impact. The results showed that the strengthening mechanism of TiC particle-reinforced aluminum-matrix composites included fine grain strengthening, dispersion strengthening, dislocation strengthening, and so on. Covering TiC particle-reinforced aluminum-matrix composite coating on the surface of aluminum alloy armature is helpful in improving its ablation resistance. The research results can provide a theoretical basis and technical support for the modification design and performance control of electromagnetic rail armature.

The investigation of laser beam interaction with aluminum/titanium overlap joint

In-situ analysis of dissimilar laser welding in overlap configuration, which finds the most frequent application in industry, attracts an increasing attention of the research community. In the present work, emission spectroscopy and high-speed imaging were used to investigate the vapor plume behavior during a Yb:YAG laser pulse on the overlap joint between pure titanium and aluminum alloy A5754. A 15 ms long laser pulse was applied to the overlap joints, where titanium and then A5754 were placed on the top. Correlation of the obtained results with post-mortem observation of the impact zones and with a finite-element model of the keyhole evolution was performed. The combination of these approaches facilitated the development of a comprehensive phenomenological timelines of the processes, along with an evaluation of the efficacy of the employed online methods to discern the involvement of the bottom material with the melted zone. The considered configurations showed very different behavior: with reflective A5754 placed on top, the use of high laser power produced an intense keyhole propagation in bottom titanium plate, inducing rapid mix between the elements, while with titanium on top, the use of lower laser power produced prolongated keyhole stagnation at the interface with reflective A5754. High-speed imaging showed very fluctuating behavior of the plume, where the involvement of the bottom material was traduced either by a drastic drop of thermal and atomic emission after the keyhole tip enters the bottom A5754 plate, or by strong periodic bursts of Ti-rich jet after the keyhole reaches the bottom titanium plate. The results of emission spectroscopy were found in adequation with the involvement of bottom material into the melted zone, however, they are affected by plume fluctuations and by the pollution of the top plate by volatile elements.

RETRACTED: Tribological and microstructure studies of LM26/SiC metal matrix composite materials and structures for high temperature applications

This study aimed to investigate the tribological and microstructural characteristics of LM26 composites reinforced with silicon carbide to evaluate their suitability for high-temperature applications. For the sample fabrication, the modified stir-casting method was optimized using a Taguchi L16 orthogonal array. The wear rate and friction behavior were evaluated using the Taguchi’s S/N ratio analysis. When SiC was incorporated into the composite, the wear resistance increased by up to 15 wt%. The wear resistance of the LM26/SiC composite was improved compared to that of the pure LM26 aluminum alloy. The results of this study provide useful information to improve the wettability of metal matrix composites made from commercial-grade LM26 aluminum alloy by adjusting the SiC weight percentage. This type of composite has the potential as a replacement material for traditional applications such as heat sinks, heat exchanger fins, and electronic packaging.

Prospective cold metal working and analysis of deformation susceptibility of CuMg alloys with high magnesium content

Metal alloys designated for cold metal working exhibit much higher strength properties than pure materials due to solid-solution hardening. However, with the increase of mechanical properties its plasticity and workability decreases. Constant development and demand in this area has led to research on many copper alloys, such as copper alloys with high content of magnesium which were never tested before. The limitations regarding cold metal working of CuMg alloys is the main objective of this paper. Here we show that the tested materials exhibit much higher mechanical properties than currently used as electric conductors and carrying-conducting equipment materials such as pure copper, aluminum, M63 brass or CuNiSi alloy. The results were obtained using Hollomon relation, Considére criterion, Gubkin method and hardness measurements. It lead to assessing the prospective cold metal working of CuMg alloys with 2 wt% of magnesium up to 4 wt% of magnesium. The test range included upsetting with 10–50% of cold deformation. It provided the results on evolution of mechanical properties and deformability of tested alloys. Additional information was provided based on the alloys subjected to 50% of strain. The results have proven that as the amount of magnesium increased so did the assessed values, however, it was also linked with increasing friction coefficient. Measured hardness was 2 times higher and calculated Ultimate Tensile Strength (UTS) was even 2.5 times higher in reference to pure copper in the as-cast state. However, with magnesium content at 3.6 wt% or higher, the elevated amount of α + β phase causes brittleness making it impossible to subject these materials to cold metal working processes. We anticipate our assay to be a starting point for more sophisticated models and experimental research concerning cold metal working processes of CuMg alloys of high-strength, which may lead to developing novel and promising set of alloys.

MgO/KH2PO4 and Curing Moisture Content in MKPC Matrices to Optimize the Immobilization of Pure Al and Al-Mg Alloys.

Magnesium Potassium Phosphate Cements (MKPCs) are considered a good alternative for the immobilization of aluminium radioactive waste. MKPC composition and moisture curing conditions are relevant issues to be evaluated. The corrosion of pure aluminium (A1050) and AlMg alloys (AA5754) with 3.5% of Mg is studied in MKPC systems prepared with different MgO/KH2PO4 (M/P) molar ratios (1, 2, and 3M) and moisture curing conditions (100% Relative Humidity (RH) and isolated in plastic containers (endogenous curing)). The Al corrosion potential (Ecorr) and corrosion kinetic (icorr and Vcorr) are evaluated over 90 days. Additionally, the pore ion evolution, the matrix electrical resistance, the pore structure, and compressive strength are analysed. The corrosion process of Al alloy is affected by the pH and ion content in the pore solution. The pore pH increases from near neutral for the 1M M/P ratio to 9 and 10 for the 2 and 3M M/P ratio, increasing in the same way the corrosion of pure Al (AA1050) and AlMg alloys (AA5754). The effect of Mg content in the alloy (AA5754) becomes more relevant with the increase in the M/P ratio. The presence of phosphate ions in the pore solution inhibits the corrosion process in both Al alloys. The MKPC physicochemical stability improved with the increase in the M/P ratio, higher mechanical strength, and more refined pore structure.

Correlative evaluation of the corrosion resilience and passivation properties of zinc and aluminum alloys in neutral chloride and acid-chloride solutions

Abstract Comparative analysis of the corrosion resilience and passivation characteristics of pure zinc (Zn) and aluminum (Al) alloys in neutral chloride and acid-chloride solutions at 0.5–3% NaCl concentrations was done with potentiodynamic polarization, potentiostatic evaluation, optical characterization, and open circuit potential measurement. Results show Al alloy was more resistant to general corrosion in both solutions with values ranging from 0.031 to 0.082 mm/year, and 0.037 to 0.389 mm/year compared to Zn alloys with values of 0.432–0.691 mm/year and 0.465–5.016 mm/year. Corrosion potential values of Zn alloy were significantly more electronegative than the values for Al alloy. The passivated region of the polarization plots for Al was thermodynamically unstable with visible current transients compared to that of Zn. Passivation of Al occurred at the early onset of anodic polarization in the neutral chloride solution. Zn alloy passivated at specific potentials, coupled with stable passivation behavior. The passivation range values of Al were generally greater than the values for Zn due to delayed stable pitting activity. Optical images for Al showed extensive localized degradation along specific regions and grain boundaries, whereas Zn morphology indicates general surface degradation. Open circuit potential plots indicate significant growth of Al2O3 oxide on Al coupled with active–passive transition behavior of the oxide. This contrasts the observation for Zn where the plot configuration indicates limited oxide formation and growth but significant thermodynamic stability.

Effect of initial heat treatment of A390 alloy on microstructure and tribological behavior of friction surfaced coating

In this study, the effect of the A390 alloy consumable rod's three preprocessing heat treatment conditions (homogenization, solid solution, and artificial aging treatment) on the microstructural evolution, mechanical properties, and wear resistance of the friction surfaced coating applied on a commercially pure aluminum alloy substrate was investigated. The results showed that friction surfacing using artificially aged and solid solution-treated consumable rods results in minimum (3.45 ± 0.35 μm) and maximum (5.63 ± 0.25 μm) coating grain sizes, respectively. Friction surfacing using artificially aged treated consumable rods results in smaller, more uniformly distributed Si particles in the coating microstructure. The [111] and [101] directions of most grains in the consumable rod and coating are parallel to the consumable rod axial axis and surfacing direction, respectively. Recrystallization texture components, including Goss and Cube-Twin, are observed in coatings. Compared to the other consumable rods, the coatings fabricated using artificially aged treated consumable rod result in highest hardness (117.62 ± 9.58 HV0.1), maximum bond strength (13.98 ± 1.02 kN), and lowest wear rate (5.6 ± 0.8 μg/m).

Growth Behavior of Pores and Hydrogen Desorption Behavior in Pure Aluminum and A6061 Aluminum Alloys

Growth Behavior of Pores and Hydrogen Desorption Behavior in Pure Aluminum and A6061 Aluminum Alloys

Effect of preprocessing heat treatment of the Al-16Si-4Cu alloy on microstructure and tribological behavior of friction-surfaced coating

This study investigated the simultaneous effect of the consumable rod's preprocessing heat treatment conditions (homogenization, solid solution, and artificial aging treatment) and severe plastic deformation on the properties of Al-Si-Cu alloy friction surfaced on a commercially pure aluminum alloy substrate. The friction-surfaced coating's microstructural evolution, mechanical properties, and wear resistance were evaluated. The results showed that coatings fabricated using artificially aging (T6)-treated consumable rods resulted in the highest coating width (17.02±0.83 mm) and maximum efficiency (39.78 ± 1.23 %). Friction surfacing using artificially aged and solid solution-treated consumable rods results in minimum (2.78 ± 0.28 µm) and maximum (6.32±0.34 µm) coating grain sizes, respectively. Friction surfacing using T6-treated consumable rods results in smaller, more uniformly distributed Si particles in the coating microstructure. Compared to the other consumable rods, the coatings fabricated using T6-treated consumable rods result in the highest hardness (110.54±10.29 HV0.1), maximum bond strength (14.15±0.75 kN), and lowest wear rate (0.20±0.03 µg/Nm).

Influence of cerium and yttrium addition on strength and electrical conductivity of pure aluminum alloys

To develop pure aluminum alloys with high conductivity and strength, Al-0.2Ce and Al-0.2Ce-0.1Y alloys were prepared by rolling and annealing processes in this study. The effects of trace rare earth elements on the strength and electrical conductivity of the pure aluminum alloys were investigated. It is revealed that the addition of Ce and Y to pure aluminum can effectively enhance the strength and electrical conductivity of the alloys. In Al-0.2Ce, the addition of Ce can effectively refine the grain size of α-Al, with an average grain size of 90.68 μm in the as-cast state. The grain size of the alloy is further reduced to 87.55 μm by the simultaneous addition of Y. The synergistic addition of Ce and Y changes the properties of the alloy. The addition of Ce and Y also produces the Al11Ce3 and Al3Y second phases, which have coherent relationship with α-Al. The two-dimensional mismatch degree was calculated to be only 4.43% and 0.85%, respectively, which can provide a certain amount of nucleation substrate for α-Al in the incubation stage. The interfacial match between the L12 structure of Al3Y and α-Al was calculated using first-principles simulations. The results indicate that Al3Y has a strong bonding effect with α-Al. Nanoscale second phases at grain boundaries can be effective in reducing resistivity due to dislocation motion. Nanoscale second phases with better matching interfaces to the substrate have no positive effect on the scattering motion of electrons.

Influence of TiC Particles on Mechanical and Tribological Characteristics of Advanced Aluminium Matrix Composites Fabricated through Ultrasonic-Assisted Stir Casting

The present investigation highlights the development of high-performance materials in the construction materials industry, with a special focus on the production of aluminium matrix composites (AMCs) containing titanium carbide (TiC) particles. The stir casting method with ultrasonic assistance was employed to enhance the mechanical and tribological properties. ASTM standards were employed to evaluate the influence of TiC particles on density, hardness (VHN), ultimate tensile strength (UTS), and wear resistance at various TiC weight fraction percentages (0.0 wt.%, 2.0 wt.%, 4.0 wt.%, 6.0 wt.%, and 8.0 wt.%). Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis were performed to analyse the microstructural changes and elemental phases present in the synthesised composite. Results revealed that the incorporation of 8 wt.% TiC reinforcement in the metal matrix composites demonstrated significant improvements compared to the base alloy. In particular, a substantial enhancement in hardness by 32%, a notable increase of 68% in UTS, and a significant 80% rise in yield strength were observed when contrasted with the pure aluminium alloy. The tensile fracture analysis of the specimens revealed the presence of dimples, voids, and cracks, suggesting a brittle nature. To assess the wear characteristics of the composites, dry sliding wear experiments were performed using a pin-on-disc wear tester. Incorporation of TiC particles resulted in a lower coefficient of friction than the base alloy, with the lowest friction coefficient being recorded at 0.266 for 6 wt.% TiC, according to the data. FESEM and energy-dispersive X-ray spectroscopy (EDXS) were used to examine the surfaces of the worn pin. Overall, the inclusion of TiC reinforcement particles in the matrix alloy greatly enhanced the wear resistance and friction coefficient of the Al-6TiC composites. Ploughing and adhesion under lower loads and delamination under higher loads were the wear mechanisms observed in the wear test.

The Effect of Tool Rotation Speed on the Formation of Eutectic Structure during Friction Stir Welding of Aluminum to Magnesium

Friction stir welding (FSW) is a solid-state welding process capable of joining a wide range of light metals. However, liquation and solidification may occur during joining of dissimilar metals which leads to eutectic formation. This article aims to discover the influence of tool rotation speed on the formation of eutectic structure during friction stir welding of aluminum to magnesium. To do so, friction stir welding was performed at 600 and 950 rpm to join pure aluminum and ECO-AZ91 magnesium alloy in a lap configuration. In order to investigate the influence of the welding speed, the welding speeds of 23.5 and 37.5 mm/min were also chosen. Scanning electron microscopy (SEM) was used to study the microstructure of the joints. A shear-tensile test was used to evaluate the joints’ strengths. The fracture surfaces were also studied by SEM. The results revealed that changing the rotation speed directly affects the eutectic formation, whereas the welding speed had no influence. A lower rotation speed resulted in a thin, continuous intermetallic layer, whereas a higher speed led to the formation of a massive Mg-Al12Mg17 eutectic microstructure. The formation of eutectic, as an indicative of liquation, may affect the material flow during the process due to decreasing the friction coefficient between the tool and material. The macrostructure analyses showed that the phase evolution as well as the mechanism of material flow are highly affected by liquation.

STRUCTURE AND MECHANICAL PROPERTIES OF Cu/Al6082T6 JOINTS PRODUCED BY WELDING WITH SCANNING ELECTRON BEAM

This study presents the results of the electron-beam welding of pure copper (Cu) and aluminum (Al6082T6) alloy. The effect of the beam power on the phase composition, structure, and microhardness of the welded joints was studied. The power of the electron beam was set to 2400 W, 2700 W, and 3000 W, respectively.The phase composition of the fabricated joints was investigated by X-ray diffraction (XRD). The microstructure and chemical composition were performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively. The mechanical properties of the welded samples wereexamined by microhardness investigation. The results obtained for the microhardness are discussed concerning the applied technological conditions, defined by the power of the electron beam. Furthermore, the possible applications of the obtained welded joints of copper and aluminum Al6082T6 alloy are discussed in the different fields in modern industry.

PGNAA Spectral Classification of Metal With Density Estimations

For environmental, sustainable economic and political reasons, recycling processes are becoming increasingly important, aiming at a much higher use of secondary raw materials. Currently, for the copper and aluminium industries, no method for the non-destructive online analysis of heterogeneous materials are available. The Prompt Gamma Neutron Activation Analysis (PGNAA) has the potential to overcome this challenge. A difficulty when using PGNAA for online classification arises from the small amount of noisy data, due to short-term measurements. In this case, classical evaluation methods using detailed peak by peak analysis fail. Therefore, we propose to view spectral data as probability distributions. Then, we can classify material using maximum log-likelihood with respect to kernel density estimation and use discrete sampling to optimize hyperparameters. For measurements of pure aluminium alloys we achieve near perfect classification of aluminium alloys under 0.25 second.

Finite element method simulation of metal flow during Tubular Channel Angular Pressing (TCAP) of aluminium 7075

ABSTRACT Tubular Channel Angular Pressing (TCAP) is among the upcoming and highly interesting, severe plastic deformation methods (SPD). This technique is reported to be appropriate for the deformation of very large strains in cylindrical tubes. The tube is pressed by a top die in a space between a mandrel and a die containing three shear zones while maintaining the same tube thickness and diameters. To investigate the SPD process in tubular samples, a commercially available pure aluminium alloy (AA7075) was used to evaluate the influence of die geometry, coefficient of friction, pressing speed, die temperature and tube thickness. The average grain size of about 500 nm was attained from 25 μm by extensive grain refinement. The results of Finite Element (FE) indicated that an effective strain of 3 was achieved by correctly choosing the input parameters. The thickness and length of the tube processed by TCAP also exhibited excellent strain homogeneity. The TCAP process can impose large strains because of having three deformation zones. Depending on input parameters selection, this SPD method, therefore, has two major advantages; (i) excellent strain homogeneity and (ii) high effective strain.

高純度アルミニウムおよびA6061アルミニウム合金におけるポアの成長挙動と水素脱離挙動

An increase in the volume fraction of pores in aluminum alloys causes a decrease in the elongation and the strength of alloys. To improve the mechanical properties of aluminum alloys, it is important to understand the growth and shrinkage behavior of pores. In this study, we analyzed the relationship between hydrogen desorption behavior and the growth/shrinking behavior of pores in A6061 alloys and pure aluminum using thermal desorption analysis and synchrotron radiation X-ray tomography. In pure aluminum, the fine pores began to annihilate at temperatures above 500°C and the relatively large pores coarsened. In contrast, the pores shrank with increasing temperature in A6061 alloy. The influence of second-phase particles has been discussed as a possible explanation for the difference in the nature of pores at elevated temperatures in pure aluminum and A6061 alloys. As in the A6061 alloy, much of the hydrogen desorbed from the pores due to heating is released externally from the second-phase particles on the aluminum surface, resulting in pore shrinkage due to the internal pressure drop of pores.

Analysis of mechanical properties enhancement on composites of AA7175 by multi walled carbon nano tube (MWCNT)

Developed to meet the demands of appealing contemporary materials, nanocomposites are polyphase materials that include a matrix and nano-reinforcement. The major types of nanocomposites are as follows. They are categorized as fiber-reinforced nanocomposites, laminar nanocomposites, and particulate nanocomposites based on the reinforcing component, whereas they are classed as metal matrix, ceramic matrix, and polymer matrix nanocomposites based on the matrix ingredient. Due to its advantages over polymer and ceramic matrix, metal matrix nanocomposites (MMNCs) are the most common type of nanocomposites employed in industrial applications. To improve the physical, mechanical, thermal, and electrical properties of conventional materials, nanocomposites are often formed by reinforcing nanoscale tubes, fibres, particles, or sheets. To keep up with technological advancements, drive market changes, and bridge technological gaps by revolutionizing the product, innovative nanocomposites must be used in advanced engineering applications. The high-strength, light-weight aluminium alloy matrix nanocomposites (AMNCs) are able to replace traditional materials to a greater extent in cutting-edge applications including the automotive, aircraft, marine, defense, leisure, and electronic industries. In this study deals with the property enhancement analysis by means of the assistance of Multi Walled Carbon nano tube (MWCNT) nano particles encouragement in AA7175 aluminium alloy. The main focus of this investigation on the tensile related mechanical properties such as tensile strength, percentage of elongation and yield strength. The composites were created with the mass fractions of 5.0 wt%, 4.0 wt%, 3.0 wt%, 2.0 wt% and 1.0 wt% of MWCNT with 95.0 wt%, 96.0 wt%, 97.0 wt%, 98.0 wt% and 99.0 wt% of AA7175 aluminium alloy. These composite mechanical properties were compared with the pure AA7175 aluminium alloy. Among the comparison of these composites values 3.0 wt% of MWCNT produce the greater results on the considered composites. The composite sample recorded high Ultimate Tensile Strength of 431.12 MPa, low Percentage of elongation of 9.58% and high Yield strength of 396.63 MPa.

Distribution of the temperature in friction stir welding of aluminum and copper alloys

Friction stir welded are studied joints of pure copper M1 and aluminum alloy AD1. A technique for measuring the temperature was developed at the points of the weld. The results of measurement temperature are given in friction stir welding at various speeds of rotation of the welding tool (800-1000 rpm), welding speed (25-61 mm/min). The temperature reached in copper is about 60 K higher than in aluminum. The higher cooling rate of copper is due to the greater thermal diffusivity than that of aluminum. The maximum temperature in the copper reached 769 K, which was lower than the melting point of the eutectic in the Al-Cu system (821 K). The residence time above the temperature of formation of intermetallic compounds (623 K) is much shorter than the duration of the thermal cycle (50 s). With an increase in the welding tool rotation frequency from 800 to 1000 rpm, the maximum temperature near the pin increases from 650 to 769 K. At a tool rotation frequency of 800 rpm, the maximum temperature in copper achieved in the cycle is lower than the transition temperature to the superplastic state and is 764 K high heating and free cooling rates (50–145 K/s and 25–50 K/s) of the weld on the side of the copper alloy predetermine the short-term (from 5 to 15 s) stay of the metal in the temperature range of formation of intermetallic phases.