Grade Aluminum Alloy Research Articles

Monometallic motor-axial bearings of diesel locomotives: replacing bronze with complex aluminium alloy

Introduction. Replacing the material of monometallic motor-axial bearings currently manufactured from bronze to aluminium alloy is advisable to improve traffic safety due to the higher reliability and efficiency of such bearings.Materials and methods. This article studies the materials of monometallic motor-axial bearings, bronze and the proposed complex aluminium-tin alloys. Mechanical properties are determined by standard methods: tensile strength, relative elongation (ductility), Brinell hardness, impact strength. Antifriction properties (abradability, score resistance, wear resistance of the antifriction alloy and the steel associated with it, the heating temperature of the steel surface and the coefficient of friction) were determined according to the methods of the Railway Research Institute approved by JSC Russian Railways on the SMTs-2 friction machine. Bronze and three grades of aluminium alloys were tested with M-14V2 diesel oil, and bronze, B16 babbitt and one grade of aluminium alloy were tested with axial oil.Results. This research shows the possibility of replacing bronze with complex-alloyed aluminium alloys both in terms of economic indicators and antifriction properties. A comparison of mechanical properties is carried out, in most of which aluminium alloys are found superior or not inferior to bronze. The exception is ductility, in terms of which bronze surpasses the proposed alloys.Discussion and conclusion. According to the complex of service characteristics obtained in laboratory studies, it seems expedient to replace bronze with complex aluminium antifriction alloy. The final decision on such a replacement could be made after bench and operational tests of motor-axial bearings on diesel locomotives.

Thermomechanical and Material Flow Analysis during Friction Stir Welding of Marine Grade Aluminum Alloy 5083

_ This research aims to depict the thermal history, residual stress distribution, axial force applied, and material flow behavior on aluminum alloy 5083 (AA5083) plates, during the friction stir welding (FSW) process. This alloy finds most its use in shipbuilding industries and for marine constructions. It has been developed using an explicit, fully coupled thermomechanical nonlinear finite element (FE) analysis approach. The analysis was performed to simulate the effect of three stages, namely plunging, dwelling, and welding, of the FSW process. The ABAQUS/Explicit program was used for the computational modeling. To build a reliable and computationally efficient FE model, features such as arbitrary Lagrangian-Eulerian (ALE) formulation, adaptive meshing/ remeshing approach, mesh sensitivity analysis, and mass scaling have been introduced. The interaction between the tool bottom surface and the plate top surface was defined using a finite sliding and a sticking property. A Coulomb friction model with a temperature-dependent coefficient of friction (COF) was used to describe the tool-workpiece interaction. In addition, a small experiment was done with the following process parameters; a rotating tool speed of 875 rpm, a traverse speed of 60 mm/min, and a tool tilt angle of 0° to produce a defect-free butt joint to validate the numerically generated thermal profiles. The temperature was found slightly higher on the advancing side (AS). Residual stress distribution created over the whole width of the plates was also investigated. Introduction The introduction of friction stir welding (FSW) process by The Welding Institute in 1991 (Thomas 1991) drew much attention. During fusion welding of 5 mm AA5083 plates, the heat input should be very high. Because of this high input, a higher thermal gradient is produced, which leads to the formation of several intermetallic compounds (IMCs). Because of this IMC formation, the strength of the welded joint is reduced. However, the steep thermal gradient produced leads to the formation of finer microstructure near the weld bead and coarser along the base metal region. These results in the heterogeneity of the weld bead microstructure leading to less efficiency and accuracy of the weldment.

Metal Matrix Composite Fabricated with 5000 Series Marine Grades of Aluminium Using FSP Technique: State of the Art Review

Aluminium metal matrix composites have been shown to make significant contributions to the area of new materials and have become widely accepted in high-tech structural and functional applications such as those in the aircraft, automobile, marine, mineral, defence, transportation, thermal management, automotive, and sports and recreation fields. Metal matrix composites are manufactured using a variety of manufacturing processes. Stirring casting, powder metallurgy, squeezing casting, in situ processes, deposition techniques, and electroplating are part of the manufacturing process used in the manufacture of aluminium-metal matrix composites. Metal matrix composites that use friction stir processing have a distinct advantage over metal matrix composites that use other manufacturing techniques. FSP’s benefits include a finer grain, processing zone homogeneity, densification, and the homogenization of aluminium alloy and composite precipitates. Most metal matrix composite investigations achieve aluminium-metal matrix composite precipitate grain refinement, treated zone homogeneity, densification, and homogenization. This part of the work examines the impact of reinforcing particles, process parameters, multiple passes, and active cooling on mechanical properties during the fabrication of 5000-series aluminium-metal matrix composites using friction stir processing. This paper reports on the available literature on aluminium metal matrix composites fabricated with 5xxx series marine grade aluminium alloy using FSP.

Neutron capture of UO2 targets prepared by spin-coating assisted combustion synthesis

Two uranium dioxide (UO2) targets of (414 ± 23) nm and (1092 ± 93) nm thicknesses were prepared on 6061 aluminum alloy and puratronic grade aluminum backing materials. The targets were deposited with a novel method combining spin coating and solution combustion synthesis (SCS). The target layers consisted of small (3–7 nm) UO2 grains and uniformly distributed ultra-small (1–3 nm) pores. The prepared targets were tested at the Los Alamos National Laboratory’s LANSCE facility for neutron irradiation damage and suitability for neutron capture experiments. The samples showed no signs of target material loss after the irradiation. However, irradiation caused a significant increase in the grain size (4–10 nm), as well as upward mass diffusion and coalescence of the pores due to the thermal spikes. The magnesium in the aluminum 6061 alloy backing also diffused into the UO2 layer during neutron irradiation. The structural changes in the target after the irradiation do not affect the data from neutron capture. The new method can be used more broadly to prepare other actinide targets for nuclear physics experiments.

Effect of Ti, Sr, and B Addition on the Fluidity of A356.2 Grade Aluminum Alloy

Effect of Ti, Sr, and B Addition on the Fluidity of A356.2 Grade Aluminum Alloy

Degradation Induced by thermal and chemical impacts on matrix codes installed on brass and aluminium alloy parts by laser

To be securely readable, barcodes and matrix ID codes that are installed on metallic or non-metallic surfaces should be of high contrast both immediately after installation and throughout the life of the product that carries them. However, utilizing the product in hot and harsh environments (in acids, alkalis, etc.) may lead to its structural degradation and, consequently, affect the contrast of the codes making them poorly readable with the help of optical devices. The efficiency of such degradation is also governed by the product material. This paper describes the results of a study that looked at the degradation of matrix codes installed by lasers on products made of L63 brass grade and D16 aluminium alloy following thermal and chemical impacts. It is shown that the thermal resistance temperature of laser-installed ID codes for brass is 200 oC, while barcodes installed on the aluminium alloy remain readable when heated up to 600 oC. A major change is noted with regard to the effect produced by 2% acid solutions on codes installed on brass. In the case of the aluminium alloy, a 2% solution of sulphuric acid did not affect the contrast of the codes. When treated with alkaline solutions, a brass surface with a code turned dark, the contrast of the codes degraded significantly and the code became poorly readable. At the same time, alkali produced but a slight effect on the contrast of codes installed on the aluminium alloy.

Influence of magnetic-abrasive processing on roughness of flat products made of AMts grade aluminum alloy

The widespread use of AMts grade aluminum alloy in industry is due to its physical and mechanical properties and high weldability. For most products, high requirements are placed on surface roughness, including the surface of the edges of products subjected to special preparation before welding to ensure a high-quality welded joint. However, achieving the required roughness values is technologically quite laborious. As a finishing method of processing in order to ensure a given value of roughness, the method of magnetic-abrasive processing (MAP) is widely used, which makes it possible to significantly reduce the surface roughness. However, the dependence of the process of forming the surface roughness of products made of the AMts grade aluminum alloy on technological parameters of processing has not been previously established. In this regard, the article presents the results of experimental studies of the influence of MAP factors (the value of magnetic induction B, T; processing time t, min; workpiece rotation frequency n, min–1; workpiece feed along the pole pieces S, mm/min) on the formation surface roughness (Ra) of flat products made of AMts grade aluminum alloy. Based on the research results, polynomial functions have been compiled that enable to estimate the degree of influence of each processing parameter on surface roughness, as well as to determine the rational values of these parameters necessary to achieve its required level. The selected rational values make it possible to form the surface roughness of pro ducts made of AMts grade aluminum alloy in the range of Ra = 0.23÷0.31 μm, which is 6 times lower than the original one. A mathematical model has been created for the formation of surface roughness depending on the processing parameters, which makes it possible to comprehensively assess the effect of these parameters on the process. The model confirms the conclusion made on the basis of the analysis of polynomial functions and shows that the greatest influence on the formation of surface roughness is exerted by the feed rate of the workpiece along the pole-pieces and the magnitude of the magnetic induction.

Comparative analyses and investigations of chamfered and honed-edge tool geometries on tool wear, chip morphology, residual stresses and end-burr formation

Cutting simulations for chamfered-edge and honed-edge tools for rough-to-semi finishing operations in machining an aerospace grade aluminum alloy AA2024 have been presented in this work. A finite element based approach has been developed to comprehend and investigate the relative effects of various cutting edge geometries on chip morphology, end-burr and residual stresses. Additionally, the role of chip-breaker geometry in segmentation and fragmentation has been thoroughly examined. Moreover, to estimate the expected wear in different sections of the tool, stress fields have been plotted. Furthermore, effects of chamfered-tool' macroscopic parameters: chamfer-length and chamfer-angle on various aspects of cutting process have been discussed. Presented coupled temperature-displacement numerical model has been validated for various results concerning chip morphology, cutting forces and segmentation frequency with previously performed experimental work. Finally, recommendations are made for proper selection of tool-geometry for better tool life, surface integrity and lesser burr formation in machining AA2024.

Effect of Tool Geometry and Turning Parameters on Cutting Force during Ultra-Precision Diamond Machining of Rapidly Solidified Aluminum (RSA) Alloy 6061

The most important goal of advanced diamond machining is to improve precision and product integrity. Cutting force could have a strong effect on diamond machining performance and hence, it can be used as an indicator for monitoring tool condition for achieving successful machining. Moreover, diamond machining process parameters such as cutting speed, depth of cut and feed rate may strongly influence the process outcomes in terms of surface roughness and tool failure. Diamond machining parameters have a significant role on the cutting force values, and machine-tool stability during ultra-high precision machining that makes use of a natural diamond cutting tool. The main objective of this research work is to investigate the effect of cutting speed, feed rate, depth of cut and nose radius on the cutting force generated during diamond turning of a rapidly solidified aluminum alloy grade called RSA 6061. The effect of nose radius and cutting parameters on cutting force during the ultra-high precision diamond turning process was monitored. The study shows that low speed, low depth of cut and an increase in feed rate at large nose radius consequently results in increase in the cutting force.

Combined electron-ion-plasma treatment of 40Cr steel surface

Complex alloying, combining in a certain sequence the saturation of surface layer of material with atoms of metals and gases, is now widely used in most industrialized countries of the world. The present work is devoted to the revelation and analysis of dependences of element and phase composition, defect substructure, mechanical (microhardness) and tribological (wear resistance and friction coefficient) properties changes of alloying carbon steel subjected to combined treatment including the saturation of the sample surface layer by aluminum and subsequent nitriding. The material used for the study was AISI 5135 steel, which in the initial state has a structure represented by ferrite grains and pearlite grains of lamellar morphology. The combined modification was carried out in a single vacuum space on the TRIO setup with the chamber dimensions of 600×600×600 mm3 equipped by switching unit for realization of elion (electron and ion) mode of treatment. Aluminizing was carried out at the temperature of 963 К during 4 h. The cathode of electroarc evaporator was made of A7 grade aluminum alloy (98.8 % Al). Subsequent nitriding of aluminized layer was carried out at the temperature of 803 К during 2 h. It was established that the modified layer with the thickness of 70 μm is formed as a result of the combined treatment. It is demonstrated that the combined steel modification is accompanied by the formation of multiphase submicro- and nanostructure state including aluminum nitrides, iron and chromium nitrides and aluminides. It is revealed that the steel hardness is maximal on the modification surface and it exceeds by 3 times that of the initial steel. Wear resistance under the dry conditions decreases after the combined modification.

Modeling of Surface Topography after Milling with a Lens-Shaped End-Mill, Considering Runout

The paper presents a method of forecasting the product surface topography after five-axis machining with a lens-shaped end-mill. Surface roughness is one of the key parameters considered when assessing the effectiveness of the machining process, especially in the aviation, automotive, tooling and medical equipment industries. The developed method, the first published, presented in the paper is based on the analytical equations of the trajectory of the cutting edge motion, on the basis of which the cutter action surface is generated. The developed model takes into account: cutting depth, cutting width, feed, lead angle and radial runout. Experimental studies were conducted using three different materials: 40HM steel, Al7035 aluminum alloy and Ti Grade 5 titanium alloy. Various values of the cutting width parameters and different feeds were used in the tests. Based on the results of the experimental tests, an empirical model (response surface model) was determined and was then used to verify the simulation model. The simulation results and the results of experimental tests were compared and conclusions were drawn regarding the developed models. The developed models supported by numerical simulation can be used to approximately estimate the influence of the width of cut and feed on selected height characteristics and of the geometric structure of the surface (GSS) after machining with a lens-shaped end-mill in terms of the process parameters adopted in the tests. It was found that the influence of the on the and is greater for small values of . The effect of is greater with lower values. The cutting width has the greatest influence on and , and and the interaction of these parameters has the least influence.

Buckling and post-buckling of thin-walled stiffened panels: modelling imperfections and joints

This paper explores the effect of different modelling strategies to represent geometrical imperfections and joints in flat thin-walled stiffened panels during buckling and post-buckling. Compression tests were performed on aircraft grade aluminium alloy panels jointed to L-shape stiffeners using rivets with digital image correlation used to monitor out-of-plane deformations, mode shape changes and failures such as stiffener debonding. Experiments were replicated using finite element analysis employing different levels of complexity to model geometric imperfections and joints. The advantages and limitations of these strategies are discussed and recommendations are made.

Friction Stir Welding of Dissimilar Aluminium Alloys for Vehicle Structures

Welding process in vehicle structures has gained importance, especially for better strength and mechanical properties. Hence, there is vast research going on in the domain of newer welding techniques. Friction Stir Welding (FSW) is one of them. FSW is used in this research to join two different grades of aluminium alloys by varying the process parameters. The process parameters are optimized based on the Design of Experiments (DoE) and the Taguchi techniques. From the experimental findings for different process parameters, the optimized set of conditions involving the normal, transverse forces and the torque are determined. Further, the process methodology is validated.

Comparative Studies on Normal and Pulsed Cold Metal Transfer Welding of Aerospace Grade Aluminum Alloy 2024

Abstract Aluminum alloy 2024 (AA2024) sheets are mostly used in the fuselage and wings of the aircraft and structural applications; it is because of better fatigue resistance and high strength. The joining of AA2024 through gas metal arc welding (high heat input) is complicated because of hot cracking (solidification cracking), softening of the heat-affected zone (HAZ), and formation of porosity. However, these problems could be minimized by employing cold metal transfer (CMT) (low heat input) welding. The ultimate aim of the present research is to compare the metallurgical integrity and mechanical properties of the butt-welded AA2024 through normal CMT (N-CMT) and pulsed mode CMT (P-CMT) methods. The fine-grain structure observed in the P-CMT contributed better mechanical properties compared to N-CMT. The segregations of magnesium, silicon, and copper have revealed the intermetallic compounds such as aluminum-copper (2:1), Al2CuMg, magnesium silicide, and tetracopper silicide. This results in an intergranular fracture of both N-CMT and P-CMT joints. Besides, P-CMT exhibited a higher ultimate tensile strength and % elongation than the N-CMT. Also, the joint efficiencies of N-CMT and P-CMT were 64 % and 68 %, respectively. Furthermore, the hardness value in HAZ of N-CMT (93 HV) was inferior to P-CMT (126 HV). Hence, P-CMT is recommended for joining AA2024 compared to N-CMT.

Significant reinforcement of mechanical properties in laser welding aluminum alloy with carbon nanotubes added

Laser welding 2A12 (Chinese grade) aluminum alloy with carbon nanotubes (CNTs) added was carried out, and the mechanism of CNTs strengthening joints was explored in detail. Firstly, to achieve the same penetration depth, single laser welding and laser welding with CNTs require speeds of 40 mm/s and 60 mm/s respectively. The addition of CNTs increases the welding efficiency by 50%. Furthermore, the maximum tensile strength of the joint with CNTs increased by 45.5% to 326 MPa. Fracture analysis showed that the significant improvement in the mechanical properties of the joint was partly due to the CNTs reducing the pore size by an order of magnitude. Then, phase analysis reveals that a large number of precipitated phases increase the dislocation density and provide a basis for dislocation strengthening. The failure mode of CNTs is pulled out and the HRTEM test found that the CNTs are dispersed in the aluminum matrix. Indicating that the CNTs in the weld are tightly bonded to the surrounding Al matrix and load transfer from the matrix to CNTs is improved. This work provided an idea of laser welding aluminum with high efficiency and significantly enhanced mechanical properties. Finally, the process window for laser welding 2A12 aluminum alloy has also been established.

Warm sheet metal forming of energy-absorbing elements made 7075 aluminum alloy in the hardened state T6

The article covers experimental research on the forming of products made of 7075 aluminum alloy. This aluminum alloy grade is characterized by high strength, but due to its low formability in T6 temper, its use in the stamping processes of complex structural elements is limited. The authors have manufactured a U-shaped element at an elevated temperature and determined the optimal parameters of the process. Conventional heating of the sheet and shaping it at the temperature of 100 and 150 °C allowed to obtain a product of high strength similar to the T6 state, above 540 MPa. Due to the excessive springback of the sheet during forming, these products were characterized by a large deviation of the shape geometry, exceeding the allowable values of + / − 1 mm. Only the use of an alternative method of heating the sheet to temperatures of 200 and 240 °C (between plates at 350 °C, heating time 2 min, heating rate 1.8 °C/s) allowed to obtain a product that meets both the strength and geometric requirements. The determined optimal process’ parameters were later transferred to the stamping process of elements of a more complex shape (lower part of the B-pillar). The sheet was heated up and formed in the previously pre-heated tools. In the subsequent series of tests, the heating method and the blank’s temperature were being analyzed. In the case of the foot of the B-pillar, it was necessary to lower the initial blank temperature to 200 °C (heating in a furnace with a temperature of 340 °C, heating speed 0.5 °C/s). The appropriate combination of the process parameters resulted in the satisfactory shape deviation and reaching the product’s strength comparable to the strength of the material in as-delivered T6 temper. Using electron microscopy, it was verified that the structure of the finished product contained particles MgZn2 that strongly strengthen the alloy. The obtained results complement the data on the possibility of using 7075 aluminum alloy to produce energy-absorbing elements of motor vehicles.

Metallographic analysis of in-house developed marine grade aluminum alloy AA5086friction stir welds

A friction stir welding (FSW) setup was developed and performed trial experiment on marine grade aluminum alloy 5086 in the present work. The input parameters were traverse speed (56 and 80 mm/min) and spindle speed (750 and 1000 rpm). From study it was observed that the spindle speed has an immense influenced on joint formation compared to feed speed. The rotational speed of 750 rpm produced defect joints due to inadequate welding heat generation and joints without defect were achieved at 1000 rpm spindle speed. The metallographic analysis and mechanical testing were conducted for the defect-free weld joints.

Finite element simulation of liquid nitrogen temperature rolling of marine grade aluminium alloy 5754

Now days, numerical approaches are becoming an efficient practical tool for the analysis of elastoplastic behavior of various engineering materials. Present study elaborates about the numerical investigation of liquid nitrogen temperature (LNT) plate rolling operation of marine grade aluminium alloy 5754 (AA 5754) by finite element method. To serve this purpose, commercially available ANSYS software package has been utilized to perform LNT-rolling simulation. In literature, it is well documented that LNT-rolling immensely increases mechanical strength through grain refinement technique. During rolling at liquid nitrogen temperature, the dynamic recovery process is inhibited which leads in accumulation of high rate of dislocation defects. Consequently, with due rolling these accumulated dislocations attributed towards formation of ultrafine grain (UFG) structure. The aim of this work is to formulate an efficient method to numerically investigate the deformation characteristics of AA 5754 during LNT-rolling. Geometrical and experimental parameters like roller diameters, dimensions of flat plate, roller speed, friction coefficient etc. are incorporated in the preprocessor module of ANSYS software. An optimized meshed domain is selected for simulation of 40% thickness reduction of AA 5754. The temperature effect and corresponding stress distribution in the flat plate of AA 5754 is well captured and comparative analysis with the experimental practices has been successfully carried out. Numerical results obtained in the form of uniform thickness reduction, elastoplastic stress and strain contour plots, pressure force exerted by roller etc. are in good agreement with the experimental rolling operation.

Locating Cracks in 1050 Aluminium Alloy by Digital Image Correlation

In this paper deformation of commercial 1050 grade aluminum alloy is studied by digital image correlation (DIC) technique using open-source software, Ncorr. For this purpose, samples of aluminum alloy were subjected to uniaxial deformation under a scanning electron microscope (SEM) till the initiation of crack. Intermittently images were captured during deformation and by using DIC technique, variations in the microstructure of the deformed samples were identified in terms of displacement. Using these displacements, normal strains Exx, Eyy, and Exy shear strain were estimated to subpixel accuracy. By superimposing the region of crack and distribution of strains in the microstructures, it was possible to show that near the crack, strains not only attain high values but also show large fluctuations. Various aspects relating to the nature of strain distribution are discussed in the paper.

Study on the weldability of AA2519 armor grade aluminium alloy

This paper describes series of studies concerned with welding of Sc-modified AA2519 at the Military University of Technology. The modification of AA2519 alloy contains a higher concentration of scandium and zirconium and it has been developed in The Institute of Non Ferrous Metals, Light Metals Division in Skawina. The examination involves friction stir welding (FSW) and laser beam welding (LBW) of 5 mm thick AA2519-T62 extrusion. FSW process parameters were: 600 rpm tool rotation speed, 100 mm/min welding velocity, 4.8 mm depth plunge, and MX Triflute tool type. The used LBW parameters were as follows: 3.2 kW laser power, 1.1 m/min welding velocity, 0.2 mm laser beam width, 10° laser beam inclination angle, 10 L/min shielding gas (argon) flow with the laser beam focused on the workpiece surface (f=0). In this work selected results have been presented containing some problems and features typical for investigated joints. Butt joints produced by FSW and LBW have been compared in terms of microstructure (grains), microhardness distribution, joint efficiency, localization of failure, etc. The basic features of weld zones have been discussed together with the distributions of microhardness on the joint’s cross-sections. Both welding techniques cause a reduction of microhardness in the weld zone, but the drop from the base material’s value (135-140 HV0.1) is far higher in the case of LBW (85-90 HV0.1) than FSW (120 HV0.1). The established values of joint efficiency were 80% (376 MPa) and 66% (314 MPa) for FSW and LBW, respectively. The FSW joints tend to fail in the thermo-mechanically affected zone and LBW in the fusion zone.