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The heat transfer coefficient, including interfacial heat transfer coefficient (IHTC) and convective heat transfer coefficient (CHTC), plays a pivotal role in the thermal dynamics of hot gas forming processes. This parameter can determine the temperature field, thereby affecting the deformation and mechanical properties of the material to improve productivity. In this paper, we present an innovative experimental apparatus designed to measure the temperature evolutions of the aluminum specimen and the die during the hot gas forming processes. This apparatus is capable of simultaneously measuring IHTC and CHTC. Using the inverse finite element method, the simulated temperature histories are matched with empirical data and the best-fit values are adopted as indicative of IHTC and CHTC. This study identified the effects of contact pressure and die temperature on IHTC, as well as the impact of gas pressure on CHTC. In addition, a predictive model was developed to forecast the IHTC and CHTC at varying contact pressures and die temperatures with a prediction accuracy surpassing 0.95. By leveraging the predictive model presented in this paper, users can modulate contact pressure and die temperature based on specific production needs to achieve a targeted temperature profile. This method offers enhanced precision in managing the temperature field of the workpiece during hot gas forming experiments, thereby refining the temperature distribution. Moreover, it optimizes the formability and microstructural attributes of the material, ultimately leading to improved mechanical characteristics. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical and wear properties of AA6061 composites reinforced with monosynthesized Al2TiO5 particles. Bottom pouring and stir casting were employed to achieve uniform dispersion of Al2TiO5. Five composite samples were fabricated with varying Al2TiO5 weight percentages (wt%) (0, 1, 2, 3, and 3.5) while maintaining a constant stirring speed of 400 rpm. Tensile strength, impact energy, and microhardness were evaluated according to ASTM standards. Wear rate and coefficient of friction (CoF) were measured using a Pin-on-Disc apparatus on samples prepared through ASTM G99. Composites reinforced with 2 wt% and 3.5 wt% Al2TiO5 exhibited the highest tensile strength (215.96 MPa) and impact strength (12.6 J), respectively. Microhardness increased significantly in samples 6R1 (75.37 HV), 6R2 (83.75 HV), and 6R3 (91.6 HV) compared to 6R0 (71.52 HV) and 6R3.5 (72.26 HV). Based on the finding that 1, 2, and 3 wt% Al2TiO5 reinforcement improved hardness, RSM optimization was applied to these compositions to further adapt the wear rate and CoF. Field emission scanning electron microscopy (FESEM) was used to examine the worn surface morphology of the composites and understand how Al2TiO5 particles influence wear mechanisms. The 3 wt% Al2TiO5 reinforced composite demonstrated an 83.5% increase in wear resistance compared to other samples under a 10 N load and 1600 m sliding distance. [ABSTRACT FROM AUTHOR]

The present paper deals with the simulation of the horizontal centrifugal casting process to produce AA6061-15wt% B4C functionally graded composite with its experimental validation. A hollow functionally graded composite cylinder of dimension OD 110 mm × ID 77 mm × L 110 mm is fabricated under the centrifugal speed of 1200 rpm. Simulation work has been performed on ANSYS FLUENT. Boron carbide (B4C) reinforcement particle distribution is validated against the simulation results at the different zones of as-cast functionally graded aluminum matrix composite (FGAMC). Experimental results as the volume fraction of B4C particles at outer (34%), middle (20%), and inner (2.5%) zones closely align with simulated findings at outer (32.5%), middle (18%), and inner (1.8%) zones, confirming the efficacy of the simulation model. Microhardness testing reveals a correlation between particle distribution gradient and hardness, with values decreasing radially inward from 472 to 57 HV. Further casting quality is assessed by density and porosity measurement. The density and porosity gradients are also observed along the radial direction of as-cast FGAMC. The highest tensile strength of 224 MPa was observed for the higher particle-concentrated region. [ABSTRACT FROM AUTHOR]

Due to their outstanding corrosion resistance, mechanical characteristics and low specific density, AA5083 and AA6061-T6 Al alloys are used in the aerospace, automotive and marine sectors. Joining such dissimilar Al alloys using conventional fusion welding techniques is very challenging. In contrast, laser beam welding (LBW) is a non-conventional welding technique that is promising to weld dissimilar materials. The viability of welding dissimilar AA5083 and AA6061-T6 joints using fibre laser welding are examined herein. The effect of laser power and welding speed on the morphological, microstructural, microhardness and tensile strength of the welded joints was assessed and revealed that increasing welding power resulted in deeper keyhole penetration. Microporosities were formed due to Mg evaporation and shrinkages; however, the existence of these porosities did not show significant effect on the tensile strength. The microhardness values indicate that the welds were harder than the AA6061 and AA5083 base metals. This is explained by the existence of Mg2Si phase in the AA5083-AA6061 dissimilar junction in addition to the grain size circumstances. The fracture examination showed brittle fracture pattern that is regarded to the formation of brittle intermetallic compound (IMC) phases of Mg2Si, in addition to the inter-dendritic brittle phases of other sites as they were frequently inter-granular. [ABSTRACT FROM AUTHOR]

The present study investigates the research conducted on friction stir welding of aluminium alloys AA6061. The experiments were conducted under optimal parametric settings, and the specimens were subsequently subjected to post-processing techniques such as heat treatment and shot peening. The enhancement of weldment strength is contingent upon secondary processing, eliminating internal stress and improving surface qualities. Subsequently, the weldment will undergo mechanical testing and tribometer testing. The conventional testing protocol was implemented to assess the hardness, yield, and tensile strength. The wear and friction test examined the effects of various process factors. The load conditions were set at 10, 30, 50, and 70 N, while the sliding distance was set at 700 m and 1400 m. The experiments were carried out in dry sliding conditions at room temperature and the resulting data were recorded as average values. The welded AA6061 samples exhibited superior hardness and ultimate tensile strength, with the highest average values observed after heat treatment and subsequent shot peening. Attributed to the strengthening effect and achieving an ultra-fine grain size. The results of this inquiry indicate that the yield strength and ultimate tensile strength of the welded sample were significantly increased by heat treatment and shot peening. In particular, when compared to the as-welded AA6061 aluminium alloy sample, the sample's yield and ultimate tensile strength were 39.49 % and 38.7 % greater, respectively. The tribometer test revealed that a rise in load and sliding distance results in an increase in wear rate and a drop in the coefficient of friction. Under a load of 70 N and a sliding distance of 1400 m. s, the heat-treated and shot-peened AA6061 specimen showed a 27.3 % lower wear rate and a 29.6 % lower coefficient of friction compared to the as-welded AA6061 specimen.

Aluminum Hybrid Metal Matrix Composites (Al-HMMCs) are contemporary materials that blend aluminum with additional reinforcing elements to enhance their mechanical, thermal, and other properties. These materials find applications across various sectors including the aerospace industry, automotive sector, military and defence, marine industry, as well as manufacturing industries. In this research, AA6061, zirconium dioxide (ZrO2) and boron carbide (B4C) have been selected as the matrix and reinforcement materials. AA6061/ZrO2/B4C (Al-HMMCs) is manufactured using Ultrasonic-assisted stir casting. The process parameters of ultrasonic assisted stir casting were optimized with the help of Taguchi optimization technique. The melting temperature (700, 750 and 800 ºC), stirring speed (10, 15 and 20 minutes) and AA6061/xwt.%B4C/xwt.%ZrO2 ( 6, 8 and 10) are selected as input parameters for optimization. The reinforcements ZrO2 and B4C are weighed by equally sharing by wt.% The micro hardness was selected as response parameter and it was determined by using Vickers micro hardness tester. The L9 Orthogonal Array (OA) was employed for optimization of input parameters of ultrasonic assisted stir casting. Taguchi results showed that medium level of melting temperature (750 ºC), higher level of stirring speed (300 rpm), lower level of stirring duration (10 minutes) and medium level of wt.% of ZrO2 and B4C (8wt.%) were the optimized combination of input process parameters of ultrasonic assisted stir casting for fabricating AA6061 HMMC. The AA6061/xwt.%B4C/xwt.%ZrO2 (x = 0,4,6,8 and 10) HMMCs were manufactured by utilizing optimized process parameters. The micro hardness of AA6061/xwt.%B4C/xwt.%ZrO2 (x = 0,4,6,8 and 10) was determined. . From the obtained hardness tests, it was observed that the hardness of AA6061 HMMCs was enhanced up to addition of 8wt. % of B4C and ZrO2 and decreased the hardness while adding 10wt.% of B4C and ZrO2. The better AA6061/8wt.%ZrO2/8wt.%B4C HMMC undergone X-ray Diffraction Analysis (XRD) and Scanning Electron Microscope (SEM) testing to identify elements and examine the microstructure. The high peak of ZrO2, B4C and Al was obtained in 71.4, 35.68 and 37.81 2 theta values respectively. The SEM image of ultrasonic aided stir cast AA6061 based composite was confirmed the uniform distribution of zirconium di oxide and boron carbide reinforcements. There was no oxide formation on the surface of the stir casted AA6061 composites due to the execution of casting process in the inert environment. The casted AA6061/8wt.%ZrO2/8wt.%B4C surface of the composite exhibits no porosity occurrence due to the impact of usage of ultrasonic vibrator to prevent the formation of holes due to escape of unwanted gases. Subsequently, corrosion tests were conducted on the AA6061 HMMC in various corrosive environments such as NaOH, HCl, H2SO4, and NaCl to evaluate its electrochemical behavior. The surfaces of corroded specimens were analyzed using SEM and Energy Dispersive Spectroscopy (EDS). The research findings indicate that AA6061 composites exhibit the highest corrosion resistance when immersed in a NaCl medium. This enhanced resistance was attributed to the medium's lower corrosion potential, stronger charge transfer resistance (Rct), and lower double-layer capacitance (Cdl) compared to alternative environments. Additionally, SEM analysis illustrated that the incorporation of B4C and ZrO2 ceramics results in the formation of protective barrier layers, further enhanced their corrosion resistance. ZrO2 particles were attracted and neutralized the corrosive ions and electrons, thereby reducing corrosive activity on the AA6061 aluminium matrix.

This paper focuses on the plastic strain hardening behaviors of 6061 aluminum alloy (AA6061), considering its dependence on strain rate and temperature. Quasi-static tensile tests were conducted over a wide temperature range (20 °C-300 °C), and the digital image correlation technique was used to capture the deformation process of specimens. Additionally, the uniaxial compressive mechanical response of AA6061 was tested utilizing quasi-static compression and split Hopkinson pressure bar experiments over a wide range of strain rates (0.001 s−1–6000 s−1). Experimental results showed that the flow stress decreased and increased nonlinearly with temperature and strain rate, respectively. A modified Johnson–Cook (MJC) model was developed by incorporating a temperature-dependent strain softening term, along with corrections to the temperature and strain rate product terms, to reproduce the nonlinear dependence. Furthermore, the MJC model was proven to be able to accurately reproduce the deformation of the specimens tested in Taylor impact experiments (strain rates up to 105 s−1), suggesting its effectiveness for interpolating and extrapolating stress-strain relationships. This model provides applicable modeling for materials with nonlinear rate sensitivity and temperature sensitivity, and it is expected to be applied in engineering problems involving ultra-high strain rates.

The present work aims to study the effect of the 316 stainless steel reinforcement volume fraction during friction surfacing of AA6061 on the AA5083 alloy by tool's rotation, traverse speed, and feeding rate of 1000 rpm, 150 mm/min, and 100 mm/min to improve the tribological and mechanical behaviors of deposited layers. It was found that a fully bonded interface without any void or defect at the bonding interface was formed between the deposited layer and substrate. It was also found that an increase in the number of holes from one to two in the tool resulted in the betterment of the strength of the coating layer by about 18% from 219 MPa to 259 MPa that can be attributed to the complete bonding between the deposited layer/substrate and better scattering of 316 stainless steel reinforcements.

Bu çalışmada sürtünme karıştırma yöntemi ile AA6061 alüminyum alaşımı ve farklı oranlarda TiB2/Nano Grafen/B4C takviyeli hibrit yüzey kompozitleri üretilmiş ve mekanik özellikleri ile mikroyapı analizleri yapılmıştır. AA6061 altlığı üzerine 2 mm sabit aralıklarla 3 mm çapında ve 1.5 mm derinliğinde delikler açılmış, açılan bu deliklere farklı oranlarda karıştırılmış TiB2/Nano Grafen/B4C tozları doldurulmuştur. Takviye tozları ultrasonik ve mekanik olarak karıştırılmıştır. Sürtünme Karıştırma yöntemi ile 7 farklı takviye oranında hibrit yüzey kompoziti aynı profilde karıştırıcı uç kullanılarak sabit hızda üretilmiştir. Üretilen kompozitlerin çekme dayanımları, farklı yüklerdeki aşınma dirençleri ve sertlikleri belirlenmiştir. Ayrıca optik ve SEM mikroskoplar ile mikroyapı, kırık yüzey ve aşınma yüzeyi analizleri ile element haritalaması yapılmıştır. En düşük çekme dayanımı takviyesiz alaşımda elde edilirken TiB2, nano grafen ve B4C ilaveli yüzey kompozitlerin dayanımı artmıştır. Mikroyapılarda herhangi bir gözenek ve boşluk tespit edilmemiştir Kırık yüzeylerde takviye elemanı arttıkça gevrek kırılmaların meydana geldiği görülmüştür.

Friction stir welding is a type of welding that creates friction using a stirring tool while the work-pieces are held together in the welding joint configuration. Friction stir welding is a solid-state welding process. It is one of the efficient ways of joining technology of materials. The friction forces at a microscopic level to change the inner structure of metal properties and it is done by using the kinetic energy of friction in welding methods. This work is majorly carried out to optimize the process parameters like tool rotational speed, Feed, ultimate tensile strength of friction stir welded joint on AA6061 and AA6082 alloy. Welding speed and temperature variation in the workpiece during the welding is recorded for different trials. Failure analysis was carried out for different fractured surfaces by using Scanning Electron Microscope (SEM) revels ductile fracture due to micro void coalescence. The maximum ultimate tensile strength was at a speed of 900 rpm, feed 31.5 mm/min indicates high joint efficiency. Welding speed is more at the feed 90mm/min. Maximum rise in the temperature is at speed 2000 rpm and feed 90 mm/min. [ABSTRACT FROM AUTHOR]

This study investigates the new surface development on AA6061 and AA5086 alloys considering the wire-arc additive manufacturing technique as a direct energy deposition (DED) process of wire. Two different quantities of MWCNTs, i.e., 0.01 (low) and 0.02 (high) g, with a constant nickel (Ni) weight (0.2 g) were pre-placed in the created square patterns. ER4043 filler was used as a wire for additive deposition, and an arc was generated through a tungsten inert gas (TIG) welding source. Furthermore, hardness and pin-on-disk wear-testing methods were employed to measure the changes at the surfaces with the abovementioned inducements. This work was designed to illustrate the hardness and the offered wear resistance in terms of mass loss of the AA6061 and AA5086 aluminum alloys with the function of nano-inducements. Two sliding distance values of 500 m and 600 m were selected for the wear analysis of mass loss from tracks. A maximum increase in hardness for AA6061 and AA5086 alloys was observed in the experiments, with average values of 70.76 HRB and 74.86 HRB, respectively, at a high mass content of MWCNTs. Moreover, the tribological performance of the modified surfaces improved with the addition of MWCNTs with Ni particles in a broader sense; the modified surfaces performed exceptionally well for AA5086 compared to AA6061 with 0.02 and 0.01 g additions, respectively. The system reported a maximum of 38.46% improvement in mass loss for the AA5086 alloy with 0.02 g of MWCNTs. Moreover, the morphological analysis of the developed wear tracks and the mechanism involved was carried out using scanning electron microscope (SEM) images. [ABSTRACT FROM AUTHOR]

The deformation behavior and microstructure of 6061 aluminum alloy processed by severe plastic deformation (SPD) using biaxial alternate forging that can evaluate the forming limit and mechanical properties of alloys, simultaneously, were investigated in this study. A finite element (FE) analysis on the biaxial alternating forging process, considering the strain-hardening coefficient and forging pass of the material, was conducted. When the strain-hardening coefficient is 0, an average effective strain of 440% was found within a diameter of 4 mm in the core of the workpiece after eight passes, while it was 300% at the same pass number when the strain-hardening coefficient was 0.2. The average effective strain estimated from the FE analysis was about 264% after eight passes of forging, which is considered to be a level of SPD that significantly exceeds the elongation of the raw material. As a result of the tensile test according to the forging pass, after two passes, the strength of the material could be gradually improved without significant degradation of elongation. Even though a large strain of 264% was found after eight passes were applied, deformed grains and twins with no recrystallized structure in optical microstructures with different forging passes were found. [ABSTRACT FROM AUTHOR]

Most engineering problems are complicated, and developing mathematical models for such problems requires understanding the phenomena through experiments. It is well known that as processing parameters with assigned levels increase, so does the number of experiments. By minimizing the number of experiments, Taguchi's method of experimental design will help to furnish the idea of full factorial experimental design. Taguchi's method is more appropriate for single-objective optimization problems and needs modifications while dealing with multi-objective optimization problems. Aluminum alloys are in great demand in today's automotive and aerospace sectors due to their low density, good corrosion resistance, and excellent machinability. The material is subjected to a constrained groove pressing (CGP) process to obtain microstructural grain refinement with enhanced mechanical behavior. This paper considers AA6061 material having major alloys such as silicon and magnesium. For this work, 3 CGP process parameters (viz., displacement rate, plate thickness and number of passes) are assigned 3 levels to each parameter, acquired the test data, viz., grain size (gs), micro hardness (hs), and tensile strength (σult) based on L9 orthogonal array of Taguchi. Using a modified version of Taguchi's methodology, it is possible to estimate the range of grain size (gs), micro hardness (hs), and tensile strength (σult) for effective combinations of the CGP processing parameters and validate the results with existing test data. A more dependable and simpler multi-objective optimization procedure is used to choose the optimal CGP processing parameters. [ABSTRACT FROM AUTHOR]

A step die made of H13 steel was utilized in this investigation cast aluminum alloy AA6061 at a pressure of 95 MPa in sections measuring 3 mm, 6 mm, 9 mm, 12 mm, and 15 mm in thickness. Surface temperatures during the squeeze casting process, as well as temperatures at distances of 3 mm, 6 mm, and 9 mm from the inner wall of the die, were recorded using K-type thermocouples. Utilizing the inverse method to solve 1-D heat conduction equations, we successfully determined the interfacial heat transferring coefficients (IHTC) and the interfacial heat flux (IHF) of the cast and die surface. The calculations revealed that with the commencement of squeeze casting, there was a significant rise in the IHTC for each of the five sectional steps. These IHTC reached their peak before they began to decline. The peak range of IHTC incrementally increased with the section thickness, from the 3 mm of Step 1 up to the 15 mm of Step 5. Moreover, the rate at which the IHTC reached its peak and then stabilized at a low level was slower for steps with greater thicknesses. [ABSTRACT FROM AUTHOR]

The utilization of aluminium alloy composite materials is increased progressively in automotive, aerospace, and sports allocations due to their distinct physical and mechanical properties. The conventional metal joining process is not suitable for joining the composite material. The present work of silicon carbide (SiC) compacted aluminium alloy (AA6061) composite surface is joined by friction stir welding (FSW) process under the rotational speed of 800, 1200, and 1600 rpm. Influences of tool rotational speed on welding interface quality mechanical and fatigue properties of AA6061/SiC composite surface are evaluated. The internal defect area of the weld joint is detected by radiograph inspection, and its surface morphology is analyzed through the Scanning Electron Microscope (SEM) apparatus. It revealed that the coarse aggregated inter-metallic structure with an effective interface of weldment was observed. The 1200 rpm (rotational speed) performed AA6061 composite found enhanced yield and tensile strength of 23.7% and 25.66% improvement compared to the yield and tensile strength of weldment operated under 800 rpm rotational speed. The hardness of composite weldment is increased significantly with increased tool rotational speed. The maximum hardness of 88HV is by 1200 rpm performed weld joint. Sample 3 performed higher fatigue life (1.8 × 106 cycles) without failure. [ABSTRACT FROM AUTHOR]

Solid-state additive friction stir deposition (AFSD) is a thermomechanical-based additive manufacturing technique. For this study, AFSD was utilized to produce aluminum alloy 6061 (AA6061) blocks with varying layer thicknesses (1 mm, 2 mm, and 3 mm). The mechanical properties were assessed through uniaxial tensile tests and Vickers microhardness measurement, and statistical analysis was employed to investigate differences among data groups. The results revealed that the deposition layer thickness influences tensile properties in the building (Z) direction, while the properties in the X and Y directions showed minor differences across the three AFSD blocks. Furthermore, variations in tensile properties were observed depending on the sample orientation in the AFSD blocks and its depth-wise position in the part in the building direction. The microhardness values decreased non-linearly along the building direction, spread across the width of the part's cross-section, and highlighted that the deposition layer thickness significantly affects this property. The 1 mm block exhibited lower average microhardness values than the 2 mm and 3 mm blocks. The temperature histories and dynamic heat treatment are influenced by the deposition layer thickness and depend on the location of the point being studied in the part, resulting in variations in the microstructure and mechanical properties along the building direction and across the part's width. [ABSTRACT FROM AUTHOR]

Aluminium alloys are widely used in automotive and aerospace fields due to their material properties such as low density and high strength. In this experimental performance, AA2024, AA6061, and AA7075 alloy materials were cut in desired form by water jet (angle value ranges: between 0.0 and1.0 by 0.10 increments) processes. The fellow T6 heat treatment step was determined for the waterjet cut samples (Treatment for 2 h at 510°C followed by aging at 160°C for 1-h periods up to 15 h). After dissolution and after each hour of aging heat treatment, the hardness and vibration properties of the samples were investigated. FESEM, EDS, MAP, and microhardness data were obtained to determine the effects of applied heat treatments. As a result of the experiments, it was observed that the applied aging heat treatments increased the hardness, while no significant difference in vibration occurred. In addition, it has been shown experimentally and analytically that the natural frequency values of the beam can be changed by changing the cross-sectional angle of the beam. The experimental and analytical analyzes of the built-in beams were close to each other. The reason for the difference between them is the use of the Euler-Bernoulli beam in the analytical analysis and the neglect of the shear forces. [ABSTRACT FROM AUTHOR]

There is accelerating demand for energy-absorbing structures fabricated from lightweight materials with idealized, near-constant force responses to simultaneously resolve the engineering challenges of vehicle mass reduction and improved occupant safety. A novel compounded energy dissipation system composed of AA6061-T6 and AA6061-T4 tubing subjected to hybrid cutting/clamping and H130, H200 and H250 PVC foam compression was investigated utilizing quasi-static experiments, finite element simulations and theoretical modeling. Identical structures were also subjected to axial crushing to compare with the current state of the art. The novel cutting/foam crushing system exhibited highly stable collapse mechanisms that were uniquely insensitive to the tube/foam material configuration, despite the disparate material properties, and exceeded the energy-absorbing capacity and compressive force efficiency of the axial crushing mode by 14% and 44%, respectively. The simulated deformation profiles and force responses were consistent with the experiments and were predicted with an average error of 12.4%. The validated analytical models identified numerous geometric/material configurations with superior performance for the compounded AA6061/PVC foam cutting/foam crushing system compared to axial crushing. An Ashby plot comparing the newly obtained results to several findings from the open literature highlighted the potential for the compounded cutting/foam crushing system to significantly outperform several alternative lightweight safety systems. [ABSTRACT FROM AUTHOR]

The improved mechanical properties of AA6061 make it ideal for a wide range of industries, including aerospace, nuclear, defense, and marine. The development of empirical relationships for optimizing the parameters that influence the fabrication of AA6061/B4Cp composite is vital for using this composite in the above applications. In this study, the composites are fabricated using FSP by reinforcing B4C particles in AA6061 plates. In order to optimize the experimental conditions, a central composite rotatable design (CCRD) matrix with four factors and five levels was used. The response surface methodology (RSM) has been used to develop empirical relationships between process parameters such as tool rotational speed, traverse feed, tool tilt angle, penetration depth, and output factors such as yield strength, ultimate tensile strength (UTS), % of elongation, microhardness, and wear rate. Microstructural characterization of AA6061/B4Cp composites has been done in order to examine the effect of process parameters on the composite properties. The fabricated composites showed a maximum yield strength of 135 MPa, a UTS of 172 MPa, % elongation of 8.1, a microhardness of 179 VHN, and a minimum wear rate of 0.001185 mm3/m. Upon analyzing the wear surface and wear debris of the composites, it was found that abrasion is the predominant wear mechanism. These experiments result in increased wear resistance for nuclear, defense and aerospace parts. [ABSTRACT FROM AUTHOR]

Wire-electric discharge machining offers a number of benefits in comparison to traditional manufacturing processes likewise, no obvious mechanical cutting traces also hard and rigid materials can be processed perfectly in WEDM. Since, aluminum alloys are used in aerospace, shipbuilding, breathing gas cylinders for scuba diving, surgical components and automotive industry for their high-strength-to-weight ratio, accurate shapes and dimensions. Through this method, complicated structures made of aluminum alloy are produced in a single setup with incredibly tight tolerances. The present investigation explores WEDM for AA6061 to optimize different process variables for attaining performance measures in terms of maximum MRR and minimum SR. Taguchi’s L18 OA matrix, S/N ratio, ANOVA and Grey Relational Analysis were employed to optimize SR and MRR. It has been noted from ANOVA that pulse on time and peak current are the most influential aspects for MRR and SR with their contributions of 13.33% and 16.25% respectively. Further, the best possible considered parameters setting has been established by applying GRA for MRR and SR are, pulse on time-50µs, pulse off time-13µs and peak current-4 amp.

In the current study, friction stir surface processing (FSSur.P) was carried out to alter the surface microstructure of 6061 aluminum alloy using a pinless friction stir tool. The impact of rising tool rotational speed from 400 to 1200 rpm while keeping tool traveling speed constant at 250 mm/min on surface microstructure, mechanical properties, and corrosion resistance was explored in detail. The microstructural findings revealed a significant reduction in grain size, in addition to a remarkable improvement in microhardness of processed samples. Approximately 44% increase in microhardness, compared to unprocessed counterpart was achieved at the lowest rotation speed. The corrosion behavior of the processed samples as well as the base sample was evaluated after 15 days of exposure to 3.5% NaCl using several electrochemical methods such as potentiodynamic polarization technique (PDP), linear polarization method (LPR) and electrochemical impedance spectroscopy (EIS) approach. All electrochemical techniques results demonstrated an excellent agreement where the unprocessed sample showed poor corrosion resistance with corrosion current density of (Icorr.) of 3.22 μA, whereas the sample processed at the highest tool rotating speed exhibited superior corrosion resistance with Icorr. of approximately 0.057 μA. Based on results it was found that increasing tool rotational speed has minimum effect on grain size, as well as microhardness; with best improvement achieved at lowest rotational speed or minimum heat input. On the other hand, the corrosion resistance was found to improve with increasing tool rotational speed. The use of pinless tool had a great impact on simplifying the process and achieve required surface enhancement without altering the subsurface material.

Due to their distinctive qualities, ultra-lightweight alloys like AA6061 and AZ31B find use in a variety of significant applications. However, they are challenging to fusion weld due to incompatible metallurgical properties that result in significant cooling stresses and solidification defects like hot cracking and porosity. To address the problems brought on by the fusion welding process, solid state technology is employed to combine various materials. The goal of this study is to pinpoint the impacts of friction stir spot welding process variables on shear fracture stress, including rotation speed, plunge rate, dwell period, and shoulder to pin diameter ratio. At a rotational speed of 1000 rpm, a plunge rate of 16 mm/min, a dwell time of 5 min, and a tool shoulder to pin diameter ratio of 2.5, the FSSW joint encounters a greater shear fracture strain. According to the hook height, width, and initiation point, an appropriate fracture load was discovered, which improved the mechanical and metallurgical qualities of the joints.

This work investigates the efficacy of high-pressure torsion (HPT), as a severe plastic deformation mechanism for processing plain and silicon-carbide-reinforced AA6061, with the broader objective of using the technique for improving the properties of lightweight materials for a range of objectives. The interactions between input variables, such as the pressure and equivalent strain (εeq) applied during HPT processing, and the presence of SiCp and response variables, like the relative density, grain refinement, homogeneity of the structure, and the mechanical properties of the AA6061 aluminum matrix, were investigated. Hot compaction (HC) of the mixed powders followed by HPT were employed to produce AA6061 discs with and without 15% SiCp. The experimental findings were then analyzed statistically using the response surface methodology (RSM) and a machine learning (ML) approach to predict the output variables and to optimize the input parameters. The optimum combination of HPT process parameters was confirmed by the genetic algorithm (GA) and ML approaches. Furthermore, the constructed ML and RSM models were validated experimentally by HPT processing the same material under new conditions not fed into the models and comparing the experimental results to those predicted by the model. From the ML and RSM models, it was found that processing the AA6061/SiCp composite HPT via four revolutions at 3 GPa produced the highest mechanical properties coupled with significant grain refinement compared to the HC condition. ML analysis revealed that the equivalent strain induced by the number of revolutions was the most effective parameter for grain refinement, whereas the presence of SiCp played the highest role in improving both the hardness values and the compressive strength of the AA6061 matrices. [ABSTRACT FROM AUTHOR]

Surface roughness plays an essential role in friction surfacing deposition as a smooth substrate surface polishes both consumable and substrate tools, resulting in a lack of deposition. Hence, an attempt is made to investigate the effect of substrate surface roughness while friction surfacing of AA6061-T6 coating on CR01 low carbon steel and its performance is compared through push-off strength. It is revealed that with an increase in substrate surface roughness, more rubbing action occurs between consumable tool and substrate, which results in higher heat generation and reduction in deposition thickness. The grain refinement is observed at the coating region due to dynamic recrystallisation, which results in fine grain microstructure. The substrate with Ra roughness values 1.5-2.5, 5.5-6.5 and 7.5-8.5 μm showed 26, 32 and 45 MPa push-off strength, respectively. Hence, it is inferred that the push-off strength increases substantially with an increase in the substrate surface roughness. [ABSTRACT FROM AUTHOR]

This paper provides the first description of residual stress distributions in a 66-mm-thick AA6061 deposit produced by additive friction stir deposition (AFSD). The AFSD process is being quickly developed as a solid-state additive manufacturing technique. Residual stresses in additively manufactured components can affect the susceptibility to fracture and fatigue, so there is a need to understand the residual stress distributions in the AFSD deposits. In this research, a large (194 × 49 × 66 mm) AA6061 deposit was produced using AFSD to study the residual stress distributions through its thickness. Three components of residual stresses were independently measured using neutron diffraction on the VULCAN instrument at Oak Ridge National Laboratory. At the starting end and the center region in the AA6061 deposit, the longitudinal residual stresses were generally tensile and ranged between − 5 and 91 MPa, and were consistently larger than the transverse residual stresses, ranging between − 5 and 76 MPa. The balancing compressive residual stresses were present at the finishing end of the deposit between − 127 and − 46 MPa. Residual stresses were homogeneously distributed throughout the deposit except at the top few layers (top 10 mm), which were exposed to the least number of thermal cycles from the AFSD process. The measured residual stresses in the AFSD AA6061 deposit were still significant in light of the low yield strength of AFSD AA6061 in its as-deposited state. [ABSTRACT FROM AUTHOR]

This work aims to join sheets of carbon steel to aluminum alloy AA6061. A lap joint arrangement was used with a joint lap area of dimensions * 25 25 mm . The joining procedure was carried out using a rotating tool of 10 mm shoulder diameter. Three process parameters, with three levels for each parameter, were selected to investigate their effects on joints quality. The parameter’s levels for each experiment were designed using the design of the experiment method (DOE). The results indicated that the two materials were joined by a mechanical interlock at an interface line, without formation of intermetallic compounds. The shear force of the joint reached an ultimate value of. 482kN . The shear force of the joint improved by increasing plunging depth of the tool. Samples of minimum shear force value failed by a pull-outing aluminum metal from the carbon steel specimen. Samples of higher shear force value exhibited a shear mode of fracture. Increasing the rotating speed and decreasing pre-heating increased the process temperature.

Low-enriched uranium (LEU) alloyed with 10% Mo (U-10Mo) is being considered as a promising alternative to oxide-based dispersion fuel with high-enriched uranium for use in research reactors. The configuration of this proposed LEU monolithic LEU fuel plate consists of a U-10Mo plate-type fuel foil with a 25 μm zirconium interlayer barrier clad with an aluminum alloy (AA6061). In certain research reactors, the clad AA6061 is coated with a boehmite layer to prevent corrosion. The boehmite layer has a high-pH passivation range, which makes it resistant to oxidation. Boehmite is usually formed on the AA6061 surface by autoclave processing. Before the boehmite layer is added, the surface of the AA6061 is cleaned using techniques such as polishing and wet etching. In this study, we use multimodal analysis to examine how pretreatment of AA6061 using polishing followed by alkaline etching affects the chemical composition of the boehmite layer. X-ray photoelectron microscopy (XPS), transmission electron microscopy (TEM), and x-ray diffraction (XRD) were used to study the chemical changes in the boehmite layer caused by alkaline etching pretreatment. XPS provides quantitative analysis for the Al:O ratio as well as oxidation states present on the surface, which suggests slight oxidation of the boehmite surface after alkaline etching of the AA6061 surface. We further explored this suggested oxidation of the boehmite surface using high-resolution transmission electron microscopy with selected area electron diffraction (SAED) and grazing incidence x-ray diffraction (GI-XRD), which suggested only a small amount of aluminum oxide at the surface. The multimodal analysis and imaging yielded new insights for optimizing boehmite growth on AA6061 for research reactors.

Friction stir welding (FSW) is a popular method for creating dissimilar material joints in the aerospace and automotive industries. This work proposes a new FSW derivative process: butted friction stir forming (BFSF). BFSF has the distinction of joining two abutting workpieces to a lapped third workpiece. Additionally, the process does not require modification to traditional FSW equipment and tooling. In this study, BFSF combines two workpieces of aluminum alloy 6061-T6 in a butt weld configuration throughout the process. As the FSW tool traverses, it travels over preformed, threaded holes in low carbon ASTM A36 hot rolled steel at regular spacing. Downward force combined with the stirring action of the tool displaces material into the hole, filling the threads and forming a mechanical interlock. Testing of various screw sizes and thread pitches allowed the determination of the optimal joint configuration. Aluminum die-cut bolts of each size established a point of comparison for base material strength. Of the sizes tested, the ANSI metric M profile M9-1.25 screw had the highest mechanical strength. In cross-tensile testing, the average failure load was 3915 N. Shear testing produced a failure load of 5749 N. The M9-1.25 formed screws had a 33.6% decrease in strength compared to the die-cut bolts. While this strength reduction is higher than is often experienced in traditional FSW, the results of this study are a valid proof of concept for further development in BFSF methods. [ABSTRACT FROM AUTHOR]

Cryogenic rolling is one of the essential severe plastic deformation processes to manufacture high-strength aluminum sheets with excellent formability limits. The present work characterizes the formability of AA6061 for cryogenic rolling before and after artificial aging. Nakajima method based on ISO standard is used to measure formability. Samples are aged in the range of 100 °C to 150 °C. Artificial aging at 150 °C is found to be the optimum temperature for achieving a good combination of strength and formability. Over the course of artificial aging, strength improved up to 40%, where the original value of 250 MPa for cryo-rolled condition increased to 350 MPa after 50 h of aging at 150 °C, and the formability of the cryo-rolled sample improved especially for multi-axial forming condition. [ABSTRACT FROM AUTHOR]

Friction surfacing is a solid-state metal deposition technology, which has potential application in additive manufacturing. In this paper, multilayer of AA6061 deposition was fabricated on 316L steel plate by friction surfacing. The morphology, temperature field, axial force, microstructure, and mechanical properties of the deposition were analyzed. It was found that with the increase of substrate surface roughness, the thickness of deposition increased, the width decreased, and the bonding strength increased. The grain size increased and the hardness decreased from the top layer to the bottom layer of the deposition as a result of reheating by subsequent layer surfacing process. The bonding strength between the substrate and deposition decreased when the number of layers increased. [ABSTRACT FROM AUTHOR]

The current study mainly focused on evaluating the dry sliding wear performance of centrifugally casted functionally gradient AA6061–8 vol% B4C composite using response surface methodology (RSM). A cylindrical functionally graded material (FGM) component was produced with the combination of stir and horizontal centrifugal casting techniques. Metallographic characterization by scanning electron microscope has confirmed the gradual variation of B4C particles from external to internal periphery of FGM. B4C concentration and microhardness value were found to be maximum in outer and minimum in inner zone. A mathematical model is established for the outer zone of FGM to estimate response-specific wear rate considering applied load, sliding velocity, and sliding distance as wear parameters. Dry sliding wear tests were performed utilizing a pin-on-disk equipment in accordance with the central composite design of experiments. The high determination coefficient (R2 = 0.9981) indicates the derived model's quality of fit. Furthermore, the optimal wear parameter condition was estimated using response optimizer, ensuing a predicted specific wear rate of 1.8051 × 10–5 mm3/N-m. The validation test was conducted under optimum conditions, and the determined specific wear rate value by the experiment was found as 1.8843 × 10–5 mm3/N-m, indicating reasonable accuracy between predicted and experimental specific wear rates. The morphology of worn-out surface for optimized conditions was analyzed with the help of scanning electron microscopy (SEM) images and energy-dispersive spectroscopy (EDS). [ABSTRACT FROM AUTHOR]

In the current study, friction stir surface processing (FSSur.P) was carried out to alter the surface microstructure of 6061 aluminum alloy using a pinless friction stir tool. The impact of rising tool rotational speed from 400 to 1200 rpm while keeping tool traveling speed constant at 250 mm/min on surface microstructure, mechanical properties, and corrosion resistance was explored in detail. The microstructural findings revealed a significant reduction in grain size, in addition to a remarkable improvement in microhardness of processed samples. Approximately 44% increase in microhardness, compared to unprocessed counterpart was achieved at the lowest rotation speed. The corrosion behavior of the processed samples as well as the base sample was evaluated after 15 days of exposure to 3.5% NaCl using several electrochemical methods such as potentiodynamic polarization technique (PDP), linear polarization method (LPR) and electrochemical impedance spectroscopy (EIS) approach. All electrochemical techniques results demonstrated an excellent agreement where the unprocessed sample showed poor corrosion resistance with corrosion current density of (Icorr.) of 3.22 mA, whereas the sample processed at the highest tool rotating speed exhibited superior corrosion resistance with Icorr. of approximately 0.057 mA. Based on results it was found that increasing tool rotational speed has minimum effect on grain size, as well as microhardness; with best improvement achieved at lowest rotational speed or minimum heat input. On the other hand, the corrosion resistance was found to improve with increasing tool rotational speed. The use of pinless tool had a great impact on simplifying the process and achieve required surface enhancement without altering the subsurface material. [ABSTRACT FROM AUTHOR]

Due to their distinctive qualities, ultra-lightweight alloys like AA6061 and AZ31B find use in a variety of significant applications. However, they are challenging to fusion weld due to incompatible metallurgical properties that result in significant cooling stresses and solidification defects like hot cracking and porosity. To address the problems brought on by the fusion welding process, solid state technology is employed to combine various materials. The goal of this study is to pinpoint the impacts of friction stir spot welding process variables on shear fracture stress, including rotation speed, plunge rate, dwell period, and shoulder to pin diameter ratio. At a rotational speed of 1000 rpm, a plunge rate of 16 mm/min, a dwell time of 5 min, and a tool shoulder to pin diameter ratio of 2.5, the FSSW joint encounters a greater shear fracture strain. According to the hook height, width, and initiation point, an appropriate fracture load was discovered, which improved the mechanical and metallurgical qualities of the joints. [ABSTRACT FROM AUTHOR]

The deformation behavior and microstructure of 6061 aluminum alloy processed by severe plastic deformation (SPD) using biaxial alternate forging that can evaluate the forming limit and mechanical properties of alloys, simultaneously, were investigated in this study. A finite element (FE) analysis on the biaxial alternating forging process, considering the strain-hardening coefficient and forging pass of the material, was conducted. When the strain-hardening coefficient is 0, an average effective strain of 440% was found within a diameter of 4 mm in the core of the workpiece after eight passes, while it was 300% at the same pass number when the strain-hardening coefficient was 0.2. The average effective strain estimated from the FE analysis was about 264% after eight passes of forging, which is considered to be a level of SPD that significantly exceeds the elongation of the raw material. As a result of the tensile test according to the forging pass, after two passes, the strength of the material could be gradually improved without significant degradation of elongation. Even though a large strain of 264% was found after eight passes were applied, deformed grains and twins with no recrystallized structure in optical microstructures with different forging passes were found.

This study aims to evaluate the effect of HSS drill tool coatings, namely single-layer TiN, single-layer AlCrN, and double-layer AlTiN + TiSiXN (Durana), on the surface roughness and cylindricity of AA6061 (90 wt%)/C (5 wt%)/ZrO _2 (5 wt%) hybrid composite material processed by the stir casting method. The fabricated sample was examined for the uniform particle distribution of reinforcements using Scanning Electron Microscope. The drilling operation was carried out on the fabricated in a CNC machining center by setting the spindle speeds of 800, 1200, and 1600 rpm, depths of cut of 0.5, 1, and 1.5 mm, and feeds of 50, 100, and 150 mm/rev. An orthogonal array (L _27 ) designed by Taguchi’s method was used as the design of the experiment for the optimization of the best cutting parameters and coating. Surface roughness and cylindricity errors were determined for the 27 experimental runs. Field emission scanning electron microscopic (FESEM) examination and Energy Dispersive Spectroscopy (EDS) were used to analyze the surface integrity and elemental composition, respectively. The results revealed that Durana had a significant effect on the surface substrate with minimum surface roughness (R _a ) of 1.666 μm and obtained the minimum cylindricity error for the parameters of depth of cut 0.5 mm, spindle speed of 1200 and feed of 100 mm rev ^−1 .

In this study, Friction stir welding (FSW) of AA6061 shows the importance of machining parameters such as tool rotational speed (TRS), feed rate (FR) and Tool Pressure angle (TPA). The machining performance has been measured through the ultimate tensile strength (UTS) and Vickers hardness (VH). The Taguchi’s philosophy has been considered in designing the experiment. The machining characteristics were analyzed using the main effect plot and analysis of variance (ANOVA). A principal component analysis (PCA) based composite principal component (CPC) has been used to optimise multi-response. The TRS has been found to be the most significant parameter for obtaining the optimum parameter setting. The performance has been enhanced using ANN technique of the process.