Papers by Keyword: Aluminium

Abstract: Using of metal matrix composite coating is a promising approach for improving the surface properties of a component against the mechanical and environmental attacks especially wear and corrosion. Laser cladding (LC), also known as direct energy deposition (DED), is an additive manufacturing (AM) technique, able to perform coating, repair worn parts, manufacturing and prototyping. In this work, pure Al and a mixture of multi-ceramic Al-15SiC-15Al₂O₃ coatings were successfully deposited on Al-based substrate. The quality of the deposited clads was evaluated according to macro-graphic, microstructure, and microhardness characteristics. The microscopic inspection of the multi-ceramic coatings showed a slight dilution of SiC particles. Also, XRD investigation revealed a formation of Al₄C₃ carbide. Besides SiC and Al₂O₃ hard phases, this yielded an increase in matrix microhardness about 180% (from 75 to 212 Hv_0.05) as compared to pure Al clads, indicating a great improvement in the mechanical properties of the composite cladded coating.

Abstract: Metals are prone to wear through the separation of wear debris particles as well as the plastic displacement of surface and near-surface material. Particle sizes range from millimetres to nanometres. Erosion is the gradual, layer-by-layer destruction of a metallic object's surface brought on by mechanical pressure or electrical discharges. Metals erode as a result of surface friction, wear, cavitation, and the influence of powerful gas or liquid currents on a surface. Jet engines, nuclear reactors, steam turbines, and boilers might all suffer damage from erosion. By enhancing process technology or unit design, using better materials, and applying heat treatment, it is possible to strengthen the resistance of components against erosion. AlSi10Mg is a hypoeutectic alloy that may be additively manufactured due to its limited solidification range, which reduces hot cracking susceptibility during cooling. Complex bulk and open-cell structures with outstanding strength ratio (strength-to-weight ratio) and good formability may be created using additive manufacturing of aluminium alloys, particularly AlSi10Mg. Carbon, manganese, sulphur, silicon, phosphorus, chromium, nickel, copper, and niobium are all present in the pH grade of 17-4. This combination of high strength and corrosion resistance benefits a 17-4 PH stainless steel grade. It may be utilised effectively in a variety of applications due to its high tensile strength and exceptional corrosion resistance.Powder bed fusion is one of the most mature metal additive methods, and as such, it benefits from decades of industrial expertise. PBF can satisfy demands of creating a new component and need to iterate on ideas quickly or are searching for a more efficient procedure to produce sophisticated components. Material waste is reduced because building the part layer by layer reduces the majority of the waste associated with subtractive manufacturing processes. Any surplus powder is collected and recycled when the item is finished. This review researches about the wear and erosion behaviour of Al-Si Alloy and steels printed using additive manufacturing methods. Finally, the findings of this review are summarised, and recommendations are made for future research aimed at resolving current issues and advancing technology.

Abstract: An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al³⁺ ions at all temperatures. Iron undergoes dissolution to the Fe²⁺ or the Fe³⁺ ions and copper undergoes dissolution to the Cu⁺ or the Cu²⁺. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1%, freezing point equals -22°C, pH 6.5–7.5) at room temperature and 100°C. The average charges of copper, iron, and aluminium ions were calculated using Faraday’s law of electrolysis at electric current density 3,000 A/m² (or 30 A/dm²): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100°C. The main condition was z_Al=3. We concluded that calculations of the average metal ions charges, z_Fe and z_Cu, were correct since z_Al=3. The result is as follows: the Al³⁺, the Fe²⁺, and the Cu⁺ ions dissolve into concentrated NaCl solution in water at room temperature; the Al³⁺, the Fe²⁺, the Cu⁺ and the Cu²⁺ ions (50%/50%) dissolve into the solution at temperature 100°C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100°C (and, obviously, up to 180°C) like “zeroth Arrhenius law”. The spherical anode effect is greater than the cylindrical anode effect in 1.5 times.

Abstract: Compared to discrete manufacturing, sheet material is produced in a continuous manufacturing process with several dimension and volume changes. This includes thickness reduction by rolling and width and length changes by slitting and cross-cutting. Along the process chain, this happens several times using different manufacturing facilities, where each work step is usually followed by coiling. Each of these machines records high-frequent production data in a time-based manner. General research topics in this field [1, 2] aim to assign the time-based records to the related section of the alloy sheet (length-based). This paper deals with challenges concerning the identification of strips and the assignment of the corresponding process data. In a particular application, the coil orientation for each process step is calculated and documented for a given part of the production process. This is a necessary precondition for further process data assignment. Furthermore, the effort for certain manual tasks can be reduced by using the calculated coil orientation.

Abstract: The adhesive strength and degradation behavior of the Al/resin interface was investigated under high temperature and high humidity conditions. The adhesive strength of the joint without aging was approximately 14 MPa. The value is the same as the Cu/resin joint. With progress of aging at 85°C in 85%R. H., the strength decreased rapidly in the early aging stage and decreased gradually by further aging. The strength of the Al/resin joint was inferior to that of the Cu/resin joint after aging. The fracture mainly occurred in the interface of the joint. The result of Fourier transform infrared spectroscopy analysis for the fracture surface showed that water absorption in the Al/resin joint occurs by aging and causes the degradation of the strength.

Abstract: Shot-peening (SP) is one of the severe surface plastic deformation (SSPD) processing techniques. Due to large plastic strain by the SP, the SP for metallic materials forms crystallographic texture on the peened surface. Since the crystallographic texture formed by the SP depends on the dislocation slip, it can be expected that this texture is affected by stacking fault energy (SFE) of the materials. However, effects of the SFE on the crystallographic texture formed on the peened surface by the SP is not clear. In this study, crystallographic textures of pure Al (higher SFE) and Al-10 mass%Mg alloy (lower SFE) formed by the SP are investigated. When the pure Al is SPed, {001}+{111} double fiber texture with the <001> and <111> directions parallel to the plane normal direction of the peened surface is obtained. On the other hand, in the case of Al-10 mass%Mg alloy with the SFE close to the pure Cu, {110} fiber texture is formed as well as the pure Cu. Therefore, it is found that the crystallographic texture formed by the SP is influenced by the SFE.

Abstract: Aluminium and titanium are currently in demand as lightweight materials. However, their combination is challenging due to their significantly different thermo-mechanical properties. Here, solid-state joining processes such as Friction Stir Welding open up new opportunities. Within this study, four commercial aluminium alloys (AA2024, AA5754, AA6056 and AA7050) were welded to Ti6Al4V. The results show a direct relationship between the solidus temperature of the aluminium alloys, the process temperature, energy input and resulting lap-shear strength. Regardless of the process parameters, AA5754 and AA6056 with higher solidus temperatures (600 °C and 555 °C) show superior bonding strength compared to AA2024 and AA7050, having a lower solidus temperature of 500 °C and 490 °C, respectively. Therefore, it is assumed that the maximum process temperature, proportional to the solidus temperature, has a major influence on the bonding. This, conversely, would imply that there is a physical limitation in the achievable joint strength between aluminium and titanium alloys as the required process temperature would exceed the solidus temperature of certain alloys. This assumption is verified for AA7050 by systematic variation of the rotation speed and therefore process temperature.

Abstract: In the ultrasonic bonding process, oxides existing on the metal surfaces are removed, and bonding is achieved by bringing clean surfaces to be in contact with each other. However, the bonding process with microstructure variation is not well understood due to experimental difficulties. In this study, using a newly developed sample holder, which enables ultrasonic bonding in a TEM, we directly observed the bonding process at the nanoscale. The bonding process of Au foils with a clean surface was investigated and compared to that of Al foils with a stable oxide film, a bonding inhibitor, on the surface. During the Al ultrasonic bonding process, the nanoparticles generated dispersed over the entire bonding interface and finally formed a fine grain region at the interface. In contrast, in Au bonding, the nanoparticles generated tended to accumulate at the local area of the Au surface and form bridge-like connections between Au foils. It was considered that these differences in bonding behavior were caused by the surface conditions of the materials to be bonded.

Abstract: This study utilized friction stir welding for butt joining of A1050 and C1020 plates, investigating the effects of cold rolling and annealing on the structure of the bonding interface and the hardness of the materials. The experiments revealed successful joint formation with minimized copper dispersion in aluminum and the formation of intermetallic compounds. Cold rolling resulted in increased hardness without significant crack propagation along the bonding interface. Annealing effectively reduced the difference in hardness, indicating that copper recrystallizes earlier than aluminum.

Abstract: Maize husk (MH) particulates at wt.% composition of 5% and 10%, and particle sizes of 150 and 300 um were added to the microstructure of 1170 aluminium alloy (Al) and analysed for their effect on the corrosion resistance of the maize husk reinforced aluminium composites Al/MH in 3.5% NaCl, 0.00625 M H₂SO₄ and 3.5% NaCl/0.00625 M H₂SO₄ solution by weight loss method. Protection performance results obtained at 264 h of exposure shows the MH particulates significantly enhanced the corrosion resistance of the Al/MH at 5 wt.% comp./150 um particle size (45%) and 5% wt./300 um particle size (30%) in 3.5% NaCl solution at 264 h. In 0.00625% H₂SO₄ solution, MH particulates significantly weakened the corrosion resistance of the Al/MH composites at all MH wt.% comp./particle sizes. Protection performance data at 264 h varied from-58.77% to 8.77 % which are significantly below the threshold 20% protection performance values. However, in 3.5% NaCl/0.00625% H₂SO₄, protection performance data above 20% threshold was obtained for Al/MH composites at 10% wt. comp./300 um particle size, 5% wt. comp./150 um particle size and 10% wt. comp./300 um particle sizes (22.58%, 38.71% and 29.03%). Results from ANOVA statistical method shows MH particulate wt.% comp./particle size is the important determinant factors influencing the protection performance results of Al/MH composites compared to exposure time with statistical relevance factor values of 36.53%, 77.98% and 18% from the electrolytes. The proportion of data above 20% protection performance for CB and CS particulates in 3.5% NaCl solution is 0% at margins of error of 0%. The corresponding values in 0.05 M H₂SO₄ solution are 15.18% and 15.32% at margins of error of 40% and 43% while the values from 3.5% NaCl/0.05 M H₂SO₄ solution are 14.78% and 15.5% at margins of error of 35% and 50%. The proportion of data above 20% protection performance for Al/MH composite in 3.5% NaCl solution is 30% at margins of error of 14.2%. The corresponding values in 0.00625 M H₂SO₄ solution are 15% at margins of error of 15.42% while the values from 3.5% NaCl/0.00625 M H₂SO₄ solution are 63% at margins of error of 15%.