Al Alloy Materials Research Articles

Easily Applicable Superhydrophobic Composite Coating with Improved Corrosion Resistance and Delayed Icing Properties

Mitigating the adverse effects of corrosion failure and low-temperature icing on aluminum (Al) alloy materials poses significant research challenges. The facile fabrication of bioinspired superhydrophobic materials offers a promising solution to the issues of corrosion and icing. In this study, we utilized laboratory-collected candle soot (CS), hydrophobic fumed SiO2, and epoxy resin (EP) to create a HF-SiO2@CS@EP superhydrophobic coating on Al alloy surfaces using a spray-coating technique. Various characterization techniques, including contact angle meter, high-speed camera, FE-SEM, EDS, FTIR, and XPS, were employed to investigate surface wettability, morphologies, and chemical compositions. Moreover, a 3.5 wt.% NaCl solution was used as a corrosive medium to evaluate the corrosion resistance of the uncoated and coated samples. The results show that the capacitive arc radius, charge transfer resistance, and low-frequency modulus of the coated Al alloy significantly increased, while the corrosion potential (Ecorr) shifted positively and the corrosion current (Icorr) decreased by two orders of magnitude, indicating improved corrosion resistance. Additionally, an investigation of ice formation on the coated Al alloy at −10 °C revealed that the freezing time was 4.75 times longer and the ice adhesion strength was one-fifth of the uncoated Al alloy substrate, demonstrating superior delayed icing and reduced ice adhesion strength performance.

An energy-CP-combined model for predicting the fatigue life of polycrystalline materials under high cycle and very high cycle fatigue

A fatigue life prediction model in the high to very high cycle fatigue (VHCF) regime of as-received 7075-T6 Al alloy material is proposed. The relative parameters in the life prediction model are obtained by crystal plasticity finite element (CPFE) framework. The modified Ohno-Wang constitutive model is embedded into the CPFE model considering the evolution of back stress during the cyclic loading. In the life prediction model, the range of energy efficiency factors is validated by verifying the plastic strain energy density (PSED) with fatigue experimental data. The fatigue experiments are performed using an ultrasonic fatigue system to validate the fatigue life prediction model. The predicted life is estimated using the maximum and minimum energy efficiency factors, it is found that the life prediction model can accurately predict the VHCF life. It is found that 72.8%–81.3% of the experimental fatigue life can be captured using the proposed model. Moreover, the localized deformation in the grain scale can be well-captured considering the heterogeneity of mechanical properties.

Influence of carbon fiber failure mode caused by TiO2 coating on the high temperature tensile strength of carbon fiber reinforced 7075 Al alloy composites

To enhance the mechanical properties of carbon fiber (CF) reinforced 7075 Al alloy material at high temperature conditions, TiO2 coating was prepared on the surface of CF by chemical vapor deposition. The composites were prepared by hot pressing sintering and hot extrusion methods. The evolution of the compositional components of the composite interface was investigated. The density, hardness, and tensile strength of the samples were measured, and the strength/density ratio of the samples was calculated at 150 °C. The results indicate that the tensile strength of coated CF reinforced composite (535 MPa) was increased by 21.3% and 5.7% compared to the tensile strength of 7075 Al alloy (441 MPa) and uncoated CF reinforced composite (506 MPa), respectively. Furthermore, the strength/density ratio of the composite also increased with the addition of TiO2 coating. The enhancement of coating on CF on tensile strength is attributed to the transformation of CF failure mode.

Plasma electrolytic oxidation treatments for bimetallic substrates enabling sustainable procedures for automotive painting

Magnesium- or Aluminium based lightweight alloys are increasingly utilized in the automotive sector. To ensure corrosion protection of these lightweight alloys, plasma electrolytic oxidation (PEO) can be utilized to from protective layers in an efficient manner on those lightweight alloy materials. In real vehicles often a blend of joined materials is used and it must be evaluated if the joined material combinations can be subjected directly to corrosion protection treatments or if separated treatments are necessary for different materials, which would significantly enhance production costs. In this study we investigate the feasibility of the PEO process for already joined Al-alloy and Mg-alloy materials. Special focus is put on the compatibility with subsequent cathodic dip coating (CDC) processes and the corrosion resistance of the coated materials was evaluated, which is highly relevant for applications in vehicles. We provide characterization of the formed PEO layers and could demonstrate different layer formation behaviour and composition, depending on the alloy material. It could be also shown that Mg-alloy and Al-alloy materials joined by gluing and riveting can be subjected to the PEO process, resulting in effective, simultaneous protective layer formation on both materials. Finally, it is demonstrated that the joined and PEO treated materials exhibit excellent compatibility with the cathodic dip coating process and that previous PEO treatment results in better corrosion resistance also for cathodic dip coated samples.

Study on wear properties of 7075 aluminum alloy by laser alloying imitating shell surface structure with different unit spacing

Based on observation of shell surface structures of wear-resistant organisms in the nature, Al–Ni "soft-hard interphase" nonsmooth bionic "shell" surface were prepared by adding alloy element Ni into the surface of 7075 Al alloy through laser alloying. Thereby, the wear resistance of 7075 Al alloy materials was significantly improved.By laser alloying and adding alloying element Ni to the surface of 7075 aluminum alloy, the "soft and hard alternating" non smooth bionic surface with different Al Ni unit spacing were prepared. Therefore, the wear resistance of 7075 aluminum alloy material is significantly improved.When the unit spacing was 3 mm, the wear resistance of bionic samples was optimized. In comparison with the untreated samples, the weight loss due to wear declined by 82.14% in the treated samples. Moreover, the stress distribution in the wear process of bionic samples was simulated by ABAQUS finite element simulation software. Together with the microstructure and phase changes of alloyed layers, the wear resistance mechanism of bionic alloyed samples was further analyzed.

Effects of material transfer evolution on tribological behavior in CuCrZr alloy paired with 7075 Al alloy under current-carrying

This study investigated the effects of material transfer evolution on the tribological behavior of a CuCrZr alloy paired with the 7075 Al alloy under current-carrying using a self-developed block-pin wear tester. The microstructure, material transfer behavior, tribological characteristics, and wear mechanism of the worn surfaces were examined. The results indicated that mechanical and electrical wear were the primary wear mechanisms, and a large amount of the Al alloy material was transferred to the worn surface. The material transfer was caused by the adhesion of debris and the splashing of the Al alloy sample. The material transfer process affected the tribological behavior; the final stable Al alloy layer on the worn surface reduced and stabilized the coefficient of friction.

Numerical analysis of sandwich panels under high-velocity impact

Composites are gaining importance in aircraft structures, due to their high specific strength, stiffness, and low weight. There are different types of composites used in aircraft structures out of which carbon fiber reinforced polymer (CFRP) serves best in the aircraft industry. Half of the weight of the Boeing 787 is made of CFRP and other composites that reduced the weight of the aircraft by 20% as compared to the conventional design with aluminum alloy. Similar to CFRP the recent trend focused on the usage of sandwich structures in aircraft design. Sandwich structure is a composite material made of the lightweight thick core placed between the thin face sheets made of CFRP or Glass fiber reinforced polymer. During service, aircraft panels are subjected to severe structural, aerodynamics loads, and impact loads. These loads cause severe damage to the structure that affects the residual strength. The impact is the more susceptible damage in composite panels. In this paper, a numerical impact analysis of the sandwich panel is carried out. There are different parameters that influence the impact strength of sandwich panels are face sheet material, core material, and thickness of the core. In this paper, finite element-based parametric analysis is carried out by varying face sheet materials such as CFRP, GFRP, Al alloy, Ti alloy, and core materials (such as honeycomb structure and PVC foam). Further, in this work, the combined MADM method using TOPSIS and AHP is applied to find out the optimal face sheet material for the sandwich panel. The attribute data for applying the MADM method is obtained from finite element analysis (FEA).

Investigation on Cavitation-Erosion Damage with the Cavitation Amplitude of Al Alloy Materials in Seawater

Recently, 5000 series and 6000 series Al alloys have been used as hull materials for small and medium-sized ships because of their excellent weldability, corrosion resistance, and durability in marine environments. Al ships can navigate at high speed due to their light weight. However, cavitation-erosion problems cause reducing durability of Al ship at high speed. In this investigation, 5052-O, 5083-H321, and 6061-T6 Al alloy materials were used to evaluate the damage characteristics with amplitude (cavitation strength). As a result of the electrochemical experiments, the corrosion current density and corrosion potential of 6061-T6 in seawater were 8.52 × 10-7 A/cm2 and -0.771 V, respectively, presenting the best corrosion resistance. The cavitation-erosion experiment showed that 5052-O had the lowest hardness value and cavitation-erosion resistance. 5052-O also had a very short incubation period. As the experiment progressed for 5052-O, pitting formed and grew in a short time, and was observed as severe cavitation-erosion damage that surface detached. Among the three specimens, 5083-H321 presented the highest hardness value and the damage rate was the smallest after the initiation of pitting.

Investigation of material impact on Truck frame design through Structural Analysis

The truck chassis core purpose is to support the payload due to the various components located on it. The chassis was encountered to dynamic vibration due to the road irregularity and excitation of vibrating mechanisms, when the vehicle is moving on the road. Chassis helps to keep the automobile rigid and stiff. This paper investigates the material impact on the truck frame design. Two different materials were analysed on the heavy truck frame through finite element analysis. The Al alloy and Structural steel materials were applied on for channel cross-section of the truck frame. The results were compared and the best truck chassis material was identified with lower stress and deflection.

Uncertainty of the Analytical Values in Laser-induced Plasma Optical Emission Spectrometry for Element-based Sorting of Commercial Aluminum Alloys.

This paper describes uncertainty ranges of the analytical values by laser-induced breakdown spectrometry (LIBS), in order to realize an element-based sorting of commercial Al alloys whose chemical compositions are varied depending on the kind. For this purpose, calibration factors and their standard errors between the emission intensity and the content of major alloyed elements were estimated using a series of standard reference materials of Al alloys. From the result of LIBS analysis, Al alloy samples, labeled as A1050, A1100, A2017, A2024, A5052, A5083, and A6061, were actually classified into the kinds of Al alloy for which the chemical compositions have been standardized by the Japanese Industrial Standards. The sorting was successfully conducted, although several of them could not be classified into a particular alloy type. This was not due to the analytical precision of LIBS but due to a similarity of the chemical composition between several types of the Al alloy. For comparison, a similar sorting procedure was carried out using the analytical result by ICP-OES, which gave the same conclusion as the LIBS. In fact, ICP-OES requires sample pretreatment and dissolution and thus cannot be applied to on-site/in-line analysis, whereas LIBS can provide a rapid response of analytical values. Accordingly, the LIBS analysis may be actually applied for sorting Al alloy materials in detail.

Ablation behavior of SiCp/AA2024 composites irradiated by a single-pulse nanosecond laser

In this study, homogenous Al alloy and SiC materials and SiCp/AA2024 composites with mean particle diameters of 5 μm and 30 μm were irradiated by a single-pulse nanosecond fiber laser with a 200 ns pulse width and 1064 nm wavelength. Using a laser pulse, regular circular heat-affected zones (HAZ) were formed in the homogenous materials. For the composites, an Al allloy matrix was melted and sputtered, and the SiC particles bulged when irradiated by the laser pulse. According to the measured results, the HAZ increased with the pulse energy density in a logarithmic pattern. Nonlinear fitting results demonstrated that the damage thresholds of the composites and SiC homogenous materials were the lowest and highest, respectively. SiCp/AA2024 composites with different mean particle diameters exhibited similar damage thresholds. The measured etching depths of the SiC particles and Al alloy matrix were smaller than the respective values of the homogenous materials. Thermal simulation results revealed that thermal-mechanical coupling occurred between the SiC particles and Al alloy matrix. The SiC particles in the composite heated more rapidly under a nanosecond laser, and the heat was then transferred to the matrix. Large SiC particles constrained the matrix’s molten pool, which accelerated its gasification but hindered further etching.

Cold-Rolling Strain Hardening Effect on the Microstructure, Serration-Flow Behaviour and Dislocation Density of Friction Stir Welded AA5083

5083 aluminium (Al) alloy materials have extensive structural applications in transportation industries because of their high strength-to-weight ratio and corrosion resistance. However, under conventional fusion weldings, these materials are limited by their porosity, hot cracking, and distortion. Herein, friction stir welding (FSW) was performed to join a similar AA5083 alloy. A post-weld cold-rolling (PWCR) process was applied on joint samples at different thickness-reduction percentages (i.e., 10%, 20%, and 40%) to identify the effect of strain hardening on the microstructure and mechanical properties of the friction-stir-welded joint of AA5083 while considering the serration-flow behaviour at stress–strain curves and dislocation density of the post-weld cold-rolled (PWCRed) samples. FSW induced a 20% reduction in the tensile strength of the joint samples relative to the base metal. PWCR also reduced the average grain size at the nugget zone and base metal because of the increase in plastic deformation imposed on the samples. Furthermore, PWCR increased the dislocation density because of the interaction among dislocation stress fields. Consequently, the tensile strength of the friction-stir-welded joint increased with the increased cold-rolling percentage and peaked at 403 MPa for PWCRed–40%, which significantly improved the serration-flow behaviour of stress–strain and welding efficiency up to 123%.

Effect of Pre-Cyclic Stress on Fatigue Crack Propagation Behavior of Key Structural Al Alloy Materials Used in High Speed Trains

Effect of Pre-Cyclic Stress on Fatigue Crack Propagation Behavior of Key Structural Al Alloy Materials Used in High Speed Trains

PENGARUH MEDIA PENDINGIN DAN WAKTU TUNGGU TERHADAP POROSITAS, KEKERASAN DAN STRUKTUR MIKRO MATERIAL AL PADUAN (RONGSOKAN) MENGGUNAKAN METODE PENGECORAN EVAPORATIVE

The purpose of this research is to know the effect of cooling media and holding time to porosity, hardness and micro structure of Al alloy material (scrap) using evaporative casting method. The method used in this research is the experimental method of smelting Al Alloy piston scrap and poured at 700°C in Styrofoam pattern mold with 10 and 15 minutes holding time, then cooled with medium air, brine, and water of PDAM for 30 minutes. The material used is excavator aluminum alloy (scrap) izumi piston with silicon aluminum alloy (Al-12% Si). The highest hardness value obtained from the results of cooling casting with the brine cooling medium for 10 minutes that is equal to 217,996 kg / mm2 average HV. At porosity, the highest value was obtained at holding time of 15 minutes with PDAM water cooling medium 5.088% against raw material. While the result of visual observation with 50x magnification of microstructure of specimen to raw material, Si material in raw material has significant length increase. The conclusion of the research results is that re-casting with variations of cooling medium and waiting time will increase hardness and increase porosity, except on brine cooling medium. Keywords: MTTR, MTTF, RCM (Reliability Centered Maintanance)

Explicit Dynamic Analysis of Tensional & Torsional Propagations on Composite Material with Dog Bone Shaped Testing Specimen

In general the composite are made by percentage of mixed or arrangement or concentration of material properties to increase the strength and advantages of the materials. Toeliminate the holding and gluing problems making the direct tensile strength test hard and torsional momentum loads to be applied, a new method of testing specimens prepared using 3d designing CATIA software to make the dog bone shape is assessed whether it could be applied to determine accurate direct tensile strength values and torsional loads over al alloy materials. In the project, i here considered 3 conditions, High percentage of aluminum alloy and low percentage of the silicon, Low percentage of aluminum alloy and high percentage of the silicon and Balanced percentage of aluminum alloy and silicon A series of modeling and analysis was performed using finite element method (ansys workbench) to investigate the deformation and stress to change of effect by material properties. A proper mechanical material property of the specimens was suggested and ideal failure of the dog bone shaped specimens was determined according to the results obtained from this study.

Flow analysis of materials in friction stir welding

AbstractThe aim of this study was to analyze the flow behavior of materials in friction stir welding (FSW) of magnesium (Mg) alloy to aluminum (Al) alloy materials at a low rotational speed of 300 rpm and at a low welding speed of 50 mm/min. It was observed that during the dissimilar welding at 300 rpm, some of the material of the advancing side (AS) rotated almost 360° and transferred to the position just behind the previous position, i.e. initial AS position and some of the material of leading edge region transferred to the trailing edge region and such a change continued. Material transfer takes place layer by layer from front to back portions of the FSW tool; a thin layer of material adhered to the tool in the front portion for every half rotation and transferred to the back portion of the tool and this repeated in subsequent rotations. Wrinkle formation began at the front side of the forward moving tool and as the material transferred to backside they became an onion ring pattern, and this was inevitable because the formation of onion rings instantly in the backside region of the tool was clearly impossible.

The effect of welding speed on mechanical and microstructural properties of 5754 Al (AlMg3) alloy joined by laser welding

5754 (AlMg3) alloys have advantages such as good strength, perfect corrosion resistance and cold forming in addition to the low specific density. Because of these advantages, they are commonly used in automotive, chemical and food industries, and especially in the vessel and yacht industry. However, in spite of having such important and common areas of usage, it is very difficult to join Al and its alloys by traditional welding methods. This study focused on joining of 5754 Al alloy materials, which are hard to be joined by the traditional welding methods but have common areas of usage, by using the laser welding method. Laser welding method has many advantages such as the low heat input, deep penetration, low residual stress, and distortion compared to traditional welding methods. For this purpose, 3 mm thick 5754 Al alloy sheets were joined by using the laser welding method. The welding processes was carried out selecting three welding speeds (3, 4.8, and 6 m min−1). The macrostructure, microstructure, hardness, tensile, and impact strength properties of the samples taken from the welded joints were examined. It was observed that micro-porosity and micro-void defects formed in the microstructure of the weld metal. The rate and size of these defects increased with increasing welding speed. The increase in the welding speed decreased the amount of the accumulated metal and the penetration rate. The mechanical properties were also negatively affected by the increase in the welding speed.

Deformation Control by VSR Technique on Al alloy Thin-Walled Components

Initial residual stress and machining stress of Al-alloy materials are the main factors that cause the deformation of Al-alloy thin-walled components. According to the theory of plastic yield and analysis of the stress-deformation characteristics in materials, the component is treated by using vibration stress relief (VSR) technology under three different aging of 30 min, 60 min and 90 min, after that the deformation are measured by coordinate machine respectively. The results of experiment present that, based on the balance of structural stress, after VSR aging 30 min, the component comes to deformation and becomes flatter than one before VSR. Similarly, as for complicated thin-walled component, the VSR aging time to achieve this effect mentioned above is about 90 min. The research manifests that VSR has a positive impact on deformation control of component even if structural stress level is extremely low in material.

Comparison of Electrochemical Behaviors between FSW and MIG Joints for 6082 Aluminum Alloy

Electrochemical corrosion behaviors of friction stir welding (FSW) and MIG (mixed inert gas) welding joints of 6082 Al alloy and parent material 6082 Al alloy were investigated in a solution of 0.2 mol/L NaHSO3 and 0.6 mol/L NaCl, by potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) observation. Results show that the corrosion rate of the FSW joint is less than those of MIG joint and the parent material; the corrosion potential of the FSW joint is more positive than those of MIG joint and the parent material; the corrosion current density of the FSW joint is less than those of MIG joint and the parent material; the polarization resistance of the FSW joint is greater than those of MIG joint and the parent material. EIS Nyquist loops indicate that an inductive arc exist on the complex plane. SEM observation shows that a few shallow pits occurs on the surface of the FSW joint; however, a large number of deeper pits appear on the surface of the parent materials and MIG joint.

Effects of rotation speed and time in potentiostatic experiment in seawater for 5083-H116 Al alloy

Aluminum acts as sacrificial anode and corrosion protection with Al₂O₃ formation. If the same current on material for Al ships with steel ships supplies, the more hydrogen would be occurred, that result is bring about over-protection. For this reason, the damage by hydrogen embrittlement leads to the serious accident. In this study, we evaluate electrochemical behavior with rotation speed of 5083-H116 Al alloy material for Al ship in seawater. To examine the electrochemical characteristics with rotation speed and its effects on performance, experiments were conducted at four rotation speed. Results of experiments, the corrosion current density and damage were increased by applying the rotation speed compared to static state.