Showing papers on "Aluminium alloy published in 2019"
TL;DR: In this paper, the feasibility of using car scrap aluminium alloy wheels (SAAWs) as the matrix material and spent alumina catalyst (SAC) from oil refineries as reinforcement material was investigated.
126 citations
TL;DR: In this paper, an endeavour has been made to synthesize Al7075 aluminium alloy with reinforcement of B4C and MoS2 as lubricant under various weight percentages of 4, 8% and 12% using stir casting process.
Abstract: The utilization of particulate reinforced aluminium hybrid metal matrix composites is being increased in automotive applications due to its distinct properties. In the present study, an endeavour has been made to synthesize Al7075 aluminium alloy with reinforcement of B4C and MoS2 as lubricant under various weight percentages of 4%, 8% and 12% using stir casting process. The compressive strength, tensile strength, hardness, micro structural analysis and tribological behavior of the synthesized hybrid composites have been analyzed and investigated. From the experimental investigation, it has been observed that the reinforcement particles are uniformly distributed in the matrix alloy as fine dendrites in alumnium solid solutions. The tensile strength, compressive strength, and hardness of the reinforced composites could be increased by adding the reinforcement compared to monolithic alloy. The significant improvement of wear resistance and coefficient of friction of aluminium hybrid composites has been achieved owing to inclusion of solid lubricant (MoS2) along with hard ceramic reinforcement particles (B4C) in the matrix alloy.
113 citations
TL;DR: In this article, an experimentally-based novel alloy development methodology utilising wedge mold casting and laser remelting is proposed, and the processability and properties of the developed alloys can be predicted for SLM.
96 citations
TL;DR: A hierarchical nanostructured aluminium alloy composed of nanograins surrounding by metallic glass shells that has both ultrahigh strength and good ductility is developed.
Abstract: High strength and high ductility are often mutually exclusive properties for structural metallic materials. This is particularly important for aluminum (Al)-based alloys which are widely commercially employed. Here, we introduce a hierarchical nanostructured Al alloy with a structure of Al nanograins surrounded by nano-sized metallic glass (MG) shells. It achieves an ultrahigh yield strength of 1.2 GPa in tension (1.7 GPa in compression) along with 15% plasticity in tension (over 70% in compression). The nano-sized MG phase facilitates such ultrahigh strength by impeding dislocation gliding from one nanograin to another, while continuous generation-movement-annihilation of dislocations in the Al nanograins and the flow behavior of the nano-sized MG phase result in increased plasticity. This plastic deformation mechanism is also an efficient way to decrease grain size to sub-10 nm size for low melting temperature metals like Al, making this structural design one solution to the strength-plasticity trade-off. Strengthening a metallic alloy without sacrificing ductility remains challenging. Here, the authors develop a hierarchical nanostructured aluminium alloy composed of nanograins surrounding by metallic glass shells that has both ultrahigh strength and good ductility.
85 citations
TL;DR: In this paper, a hybrid surface pre-treating method was proposed to improve the CFRTP/Al alloy laser assisted joining strength, and the results showed that the maximum joining strength with this hybrid method was about 260% of that without any surface treating.
Abstract: In order to improve the CFRTP/Al alloy laser assisted joining strength, a hybrid surface pre-treating method was proposed in this paper. This hybrid method is adding PA material in the CFRTP/Al alloy interface and machining microtextures on the Al alloy surface. The joint strength enhancing mechanism with this hybrid method was investigated. The influence of the microtextures’ dimension and the thickness of the added PA material on the CFRTP/Al alloy joining strength was discussed. The result showed that the maximum joining strength with this hybrid method was about 260% of that without any surface treating. The maximum joining strength about 37.5 MPa was obtained as the scanning line space was 0.1 mm in microtextures machining and the thickness of the added PA material was 80 μm.
78 citations
TL;DR: In this paper, four different welds have been prepared to find the material mixing between the similar and dissimilar joints, and the joint interfaces of the welds were investigated by employing an optical microscope and scanning electron microscope.
68 citations
TL;DR: In this paper, a high strength and high ductility die-cast aluminium alloy was developed, which can provide the high yield strength of 321 MPa, the high ultimate tensile strength of 425 MPa and the high ductile of 11.3%.
67 citations
TL;DR: In this paper, an ultrasonic etching process was carried out in alkaline solutions to investigate the influence of NaOH concentration on adhesive bonding characteristics, and an ultra-thin layer of acetone-diluted resin pre-coating (RPC) without hardener was then applied to the etched substrates to seal micro-cavities before adhesive bonding.
Abstract: Adhesive bonding between carbon fibre reinforced plastics (CFRPs) and aluminium alloys is extensively practised to achieve optimum lightweight and reliable structures in the aerospace and automobile industries. In this research, we study pre-treatments of aluminium substrates for stronger adhesion with CFRP. An ultrasonic etching process was carried out in alkaline solutions to investigate the influence of NaOH concentration on adhesive bonding characteristics. An ultra-thin layer of acetone-diluted resin pre-coating (RPC) without hardener was then applied to the etched substrates to seal micro-cavities before adhesive bonding. The single lap shear test was used to evaluate the adhesive bond strength under different surface conditions. The topography and chemistry of treated surfaces were characterised using various surface analytical tools including optical profilometry, scanning electron microscopy and X-ray microanalysis (SEM/EDS), contact angle goniometry and X-ray photoelectron spectroscopy (XPS). Experimental results showed a maximum 91% improvement in bond strength after alkaline etching treatments, which removed the weak passive oxide layers and allowed the formation of thin hydroxide layers through aluminium-water reactions. The wettability of etched specimens was also improved, indicating by their higher surface energy values. Variations of roughness parameters and tomography under different NaOH concentrations also affected the bond strength. The RPC treatments further increased the bond strength of NaOH etched specimens by 8.4–11.6%. The surface treatments reported in this work are very simple and cost-effective for producing durable adhesive joints in industrial applications.
65 citations
23 Jul 2019
TL;DR: In this article, the wear behavior of Al 5052 alloy was analyzed by reinforcing with varying weight percentage of tungsten carbide (1, 3 %, 5%) fabricated using stir casting process.
Abstract: Aluminium 5052 have its various applications in aerospace, fencing, hydraulic tubes and marine components due to their high dimensional stability, light in weight, high strength to weight ratio, economic and elevated stiffness. Since Aluminium alloy (Al 5052) has its application in aerospace and marine industries, its wear properties have to be improved further for better life of the components in its applications. Literature study reveals that studies were not carried out for Al 5052 alloy for improving its wear behaviour. Tungsten carbide (WC) normally used for manufacturing wear-resistant tools, cutting tools, protective coatings and carbide steel because of its wear resistance properties. In this research the wear behaviour of Al 5052 alloy analysed by reinforcing with varying weight percentage of tungsten carbide (1%, 3 %, 5%) fabricated using stir casting process. Taguchi L27 orthogonal array were used to conduct the experiment. Dry sliding wear behaviour is performed by means of Pin-on-disc wear testing apparatus. The process parameters are composition, Speed, Load, Sliding distance and the responses are Coefficient of Friction (CoF) and specific wear rate. Taguchi Signal-to-Noise ratio was carried out to determine best optimal combination to minimize the Coefficient of Friction (CoF) and specific wear rate. From the result it is seen that 5% of tungsten carbide reinforcement gives lower Coefficient of Friction (CoF) and specific wear rate at various parametric condition. To identify the wear track Scanning Electron Microscopic analysis were made and it is analysed that the lesser wear is seen in Al5052 reinforced with 5% of tungsten carbide with constant input parameter. From experiment, the Tungsten carbide improves wear resistance property of Al 5052 alloy with the increase in weight percentage of reinforcement.
64 citations
TL;DR: In this paper, N and S co-doped carbon dots (N, S-CDs) were used as corrosion inhibitors for aluminium alloy and the inhibition performance reached 85% even at 5 mg/L−1.
64 citations
TL;DR: In this paper, a pioneering study investigating the newly developed polymer-aluminium alloy hybrid foam as fillers of thin-walled square tubes made of aluminium alloy, as an alternative to the conventional closed-cell aluminium foams.
Abstract: The paper presents the findings of a pioneering study investigating the newly developed polymer-aluminium alloy hybrid foam as fillers of thin-walled square tubes made of aluminium alloy, as an alternative to the conventional closed-cell aluminium foams. The hybrid foam filled structures were prepared by infiltrating an aluminium alloy open-cell foam with silicone or epoxy inside the thin-walled tubes. Quasi-static and dynamic crush compressive response, deformation and failure modes and energy absorption characteristics of the hybrid foam filled structures were evaluated and compared to the empty tubes and tubes filled with conventional aluminium alloy open-cell foam (with voids). Results show that the deformation of the square thin-walled is improved due to the open-cell foam filler. It stabilises the tube and prevents the unstable global bending mode or a mixed buckling mode that is considered as an inefficient mode from the crashworthiness point of view. The deformation of the hybrid foam filled tubes was accompanied with a progressive folding mode. It was also observed that the polymer fillers caused the rupture of the outer tube at the corners, which results in higher energy apportion but might limit their application. However, it was found that the most efficient hybrid foam filled structures studied, in terms of crashworthiness, were the tubes filled with the epoxy-aluminium alloy hybrid foam. An increase of 610% and 300% in energy absorption and 78% and 51% in specific energy absorption of hybrid foam filled structures with length of 25 mm and 50 mm in comparison to the empty tubes (at strain of 0.7) was noted, respectively.
TL;DR: In this article, the authors investigated the effect of variables such as amount of CNT, amount of wettability agent of Mg and mechanical stirring duration using a robust design of experiment (DOE), namely, Taguchi method.
Abstract: The liquid metallurgical process route for synthesis of multiwalled carbon nanotube–A356 aluminium alloy (MWCNT-A356) composite is suitable for intricate designs and bulk production. In this work, MWCNT-CNT was fabricated through mechanical stir casting followed by thixoforming and modified by T6 (MT6) heat treatment. Hence, the optimisation and effect of variables such as amount of CNT, amount of wettability agent of Mg and mechanical stirring duration were investigated using a robust design of experiment (DOE), namely, Taguchi method, with two factorial levels. The signal-to-noise (S/N) ratio (‘larger is better’), hardness and ultimate tensile strength (UTS) were used as response variables. Results showed that the optimum hardness and UTS values of 106.4 HV and 277.0 MPa, respectively, were obtained from the nanoncomposite subjected to DOE run 4 and containing 0.5 wt.% MWCNT, 0.5 wt.% Mg and 10 min of mechanical stirring. The hardness (76.3%) and UTS (108.4%) improved compared with those of the as-cast A356 alloy. The transformation of the microstructures and the porosity of the as-cast after thixoforming and MT6 modification were also discussed. This work demonstrated the optimised mechanical stir casting parameters for MWCNT-A356 fabrication and the enhanced mechanical properties achieved by thixoforming and heat treatment.
TL;DR: In this paper, an ultrasonic vibration assisted friction stir welding (UVaFSW) assembly was used to produce different aluminum alloy and pure copper joints using an X-ray spectroscopy analysis.
TL;DR: In this paper, a 3D numerical model was developed to describe the keyhole dynamic and melt flow behaviors during laser welding of 5A06 aluminium alloy under sub-mospheric pressures.
TL;DR: In this article, the authors used high resolution imaging and composition analysis via electron microscopy to study the Zr-rich dispersoids in AA7010, a commercial Al-Zn-Mg-Cu alloy, and found that the dispersoids are not of the ideal Al3Zr stoichiometry, and contain Zn up to approximately 15' at%.
TL;DR: In this article, the effect of the ball-burnishing process on the mechanical properties of 2050 aluminium alloy that was previously friction stir welded was described, and the results showed that the ballburnishing treatment enhances the surface properties by increasing the material hardness about 37.5% and by decreasing the average surface roughness from 2.23μm to 0.06μm when a high pressure and a perpendicular burnishing is deployed.
Abstract: This report describes the effect of the ball-burnishing process on the mechanical properties of 2050 aluminium alloy that was previously friction stir welded. This process is a fast, environmentally-friendly and cost-effective surface treatment based on the plastic deformation of the surface irregularities. Consequently, residual stress, material hardening and micro-structural alterations are investigated to improve fatigue strength and wear resistance. The results show that the ball-burnishing treatment enhances the surface properties by increasing the material hardness about 37.5% and by decreasing the average surface roughness from 2.23 μm to 0.06 μm when a high pressure and a perpendicular burnishing is deployed. Additionally, in-depth compressive residual stresses are generated from −315 MPa to −700 MPa depending on the burnishing configuration. Finally, a numerical simulation of the material elastoplastic response is performed to analyze the residual stress continuity in the cross sectional area when using two radial feeds and burnishing pressures. In short, the present study helps to reduce time consumption by selecting the larger radial feed combined with a proper burnishing pressure to ensure the desired quality and compressive residual stress at the surface, which are indices of enhancing the fatigue strength at the nugget zone of the welded area.
TL;DR: In this paper, the authors used optical microscopy, FESEM, XRD and transmission electron microscopy to investigate the metallurgical behavior of the weld joints of AA2014 aluminium alloy.
22 Feb 2019
TL;DR: In this paper, the effects of change in interpass temperature on porosity content and mechanical properties of WAAM parts prepared using DC pulsed GMAW process, with 5356 aluminium consumable wire.
Abstract: Wire arc additive manufacturing (WAAM) technique has revealed the potential of replacing existing aerospace industry parts manufactured by traditional manufacturing routes. The reduced mechanical properties compared to wrought products, the porosity formation, and solidification cracking are the prime constraints that are restricting wide-spread applications of WAAM products using aluminium alloys. An interpass temperature is less studied in robotic WAAM and is the vital aspect affecting the properties of a formed product. This paper highlights the effects of change in interpass temperature on porosity content and mechanical properties of WAAM parts prepared using DC pulsed GMAW process, with 5356 aluminium consumable wire. The samples prepared with different interpass temperatures were studied for the distribution of pores with the help of computed tomography radiography (CT radiography) technique. A WAAM sample produced with higher interpass temperature revealed 10.41% less porosity than the sample prepared with lower interpass temperature. The pores with size less than 0.15mm3 were contributing over 95% of the overall porosity content. Additionally, on a volumetric scale, small pores (<0.15mm3) in the higher interpass temperature sample contributed 81.47% of overall volume of pores whereas only 67.92% volume was occupied in lower interpass temperature sample with same sized pores. The different solidification rates believed to have influence on the hydrogen evolution mechanism. Tensile properties of higher interpass temperature sample were comparatively better than lower interpass temperature sample. For the deposition pattern used in this study, horizontal specimens were superior to vertical specimens in tensile properties.
TL;DR: In this paper, a 3D print device equipped with a cold metal transfer welding source was used to simulate the formation of 3D microstructures of aluminium deposits. And the effects of the travel speed and layer superposition on the transfer mechanisms as well as on the geometrical characteristics of the deposits were discussed for both sets of parameters.
Abstract: 4043 aluminium deposits were elaborated using a 3D print device equipped with a Cold Metal Transfer welding source. Two sets of process parameters leading to different average powers were compared in order to establish the relations between the powers and energies produced and the geometrical characteristics of the deposits. The effects of the travel speed and layer superposition on the transfer mechanisms as well as on the geometrical characteristics of the deposits were discussed for both sets of parameters. Finally, the formed microstructures were analysed and the porosity defects were quantified and discussed with regard to the heat input characteristics and the solidification conditions.
TL;DR: In this article, a series of unified equations for calculating the reduction factors of the material properties at high temperatures are proposed, and they are found to yield more accurate reduction factors for aluminium alloys.
Abstract: Aluminium alloys are being used widely in multiple engineering applications. However, the material properties of aluminium alloys could change significantly at high temperatures. This paper studied the mechanical properties of normal strength aluminium alloy 6063-T5 and high strength aluminium alloy 6061-T6 at elevated temperatures. Tensile tests were conducted at room temperature (24 °C) and high temperatures up to 600 °C. Both steady temperature state tests and transient temperature state tests were used. The yield stress (i.e., 0.2% proof stress), the ultimate stress, the Young's modulus, and the ultimate strain were determined from tests. The measured material properties at different temperatures are compared with the predictions by the American and European specifications. A series of unified equations for calculating the reduction factors of the material properties at high temperatures are proposed herein; they are found to yield more accurate reduction factors for aluminium alloys.
TL;DR: In this article, the friction and wear measurements of AA6082/CaCO3 composite fabricated using Friction Stir Processing (FSP) are reported, and the worn surfaces are examined using Scanning Electron Microscopy (SEM).
TL;DR: In this paper, aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions using Confocal Raman and X-ray photoelectron spectroscopy exp...
TL;DR: In this paper, a regression model was developed to predict the weight loss of composites and checked its adequacy using significance tests, analysis of variance and confirmation tests, and the worn surfaces of composite were investigated using field emission scanning electron microscope and reported with wear mechanisms.
Abstract: Copper-coated steel wires (5 numbers) were uniformly reinforced in AA336 aluminium alloy using squeeze casting process. Microstructure of castings was examined, and dry sliding wear test was performed by considering the factors viz., load (10–50 N), velocity (1–5 m/s) and sliding distance (500–2500 m). Response surface methodology was used to design the experiments by considering three factors, five levels central composite design. A regression model was developed to predict the weight loss of composites and checked its adequacy using significance tests, analysis of variance and confirmation tests. Worn surfaces of composite were investigated using field emission scanning electron microscope and reported with wear mechanisms. Dry sliding wear parameters were optimised for obtaining minimum weight loss. Microstructure of casting showed the reinforcement of steel wires in AA336 aluminium alloy and copper coating on steel wires offered better interface bonding between matrix and reinforcement. Response surface plots revealed that weight loss of composites increased with increasing load and sliding distance. Worn surface of composites showed fine grooves at lower loads and delamination was observed at higher loads. 18.1 N load, 2.41 m/s velocity and 2094 m sliding distance were observed as optimum dry sliding wear parameters for obtaining minimum weight loss.
TL;DR: In this article, fracture modes of dissimilar lap welds produced by friction stir scribe technology were studied under tensile shear loading, and three fracture modes were observed for zone A fracture.
Abstract: Under tensile shear loading, fracture modes of dissimilar lap welds produced by friction stir scribe technology were studied. Three fracture modes were observed. For zone A fracture, the initial cr...
TL;DR: In this paper, two distinct and novel types of aluminium hybrid composites and characterize their mechanical properties and microstructure were introduced and the composite material was processed through the melt-stir casting method and characterized by analyzing their densities, micro hardness, Charpy impact strength, tensile strength and peak elongation.
TL;DR: In this paper, a study of shoulder friction stir processing of high strength thick AA7075 aluminium alloy demonstrated tiny gradient in the microstructure refinement across the thickness, which was attributed to...
Abstract: Stationary shoulder friction stir processing of high strength thick AA7075 aluminium alloy demonstrated tiny gradient in the microstructure refinement across the thickness, which was attributed to ...
TL;DR: In this paper, the microstructure and intergranular corrosion behavior of AA2024-T3 alloy were studied using electron diffraction techniques to correlate stored energy distribution with corrosion propagation path, and it was revealed that Cu tends to segregate at dislocations, resulting in high Cu content of grain with high stored energy.
TL;DR: In this paper, the low velocity impact behavior of thermoplastic fiber metal laminates (FMLs) made of aramid fibre reinforced polypropylene and aluminium alloy Al 5052-H32 was determined using a drop-weight impact tower.
10 Apr 2019
27 Nov 2019
TL;DR: In this paper, additively manufactured high strength aluminium (Al) alloy AA7075 was prepared using selective laser melting (SLM), and the evolution of microstructure and hardness, with the attendant corrosion, were investigated both in the as-produced condition and as a function of artificial ageing.
Abstract: Additively manufactured high strength aluminium (Al) alloy AA7075 was prepared using selective laser melting (SLM). High strength Al-alloys prepared by SLM have not been widely studied to date. The evolution of microstructure and hardness, with the attendant corrosion, were investigated. Additively manufactured AA7075 was investigated both in the “as-produced” condition and as a function of artificial ageing. The microstructure of specimens prepared was studied using electron microscopy. Production of AA7075 by SLM generated a unique microstructure, which was altered by solutionising and further altered by artificial ageing—resulting in microstructures distinctive to that of wrought AA7075-T6. The electrochemical response of additively manufactured AA7075 was dependent on processing history, and unique to wrought AA7075-T6, whereby dissolution rates were generally lower for additively manufactured AA7075. Furthermore, immersion exposure testing followed by microscopy, indicated different corrosion morphology for additively manufactured AA7075, whereby resultant pit size was notably smaller, in contrast to wrought AA7075-T6.