Microstructure Of Aluminum Research Articles

Influence of electropulsing stress aging on electric conductivity, mechanical properties, and microstructure of the AA7150 Al alloy

In the present study, the effect of electropulsing stress aging (ESA) on the electric conductivity, mechanical properties, and microstructure of the AA7150 aluminum (Al) alloys are studied. Experiments are carried out in this regard and obtained results show that as the ESA time increases, the electrical conductivity increases and the strength decreases. Furthermore, the electrical conductivity and ductility of the ESA samples are higher and the strength is lower than that for samples with conventional stress aging (CSA) at the same stress aging time. The evolution of microstructure is analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscope (TEM). The results indicate that the volume fraction of ƞ phase increase with the extension of ESA time. Moreover, it is found that ESA accelerates the formation and growth of ƞ phase. The results of fractography demonstrate that when the as-received samples are treated by ESA, the size and depth of dimples of the ESA samples decrease and the elongation all declines. This study provides the theoretical basis for predicting the electrical conductivity and mechanical properties in electropulsing assisted stress age forming.

A Comparative Assessment on Microstructure, Mechanical and Tribological Behaviour of Light Aluminium–Trialuminide Composites

A Comparative Assessment on Microstructure, Mechanical and Tribological Behaviour of Light Aluminium–Trialuminide Composites

Effect of Dy2O3 content on microstructure and mechanical properties of zirconia-toughened alumina

In this study, the effect of adding Dy2O3 on the microstructure and mechanical properties of zirconia-toughened alumina (ZTA) stabilised by yttrium oxide was investigated. ZTA-Dy2O3 composites with different Dy2O3 contents (0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt%) were prepared by sintering at 1600 °C for 4 h. The phases and structures of the samples were characterised through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dy2O3 formed a solid solution c-DYZ with YSZ, and an appropriate amount of Dy2O3 could refine the grains and contribute to densification. The densities, hardness, flexural strength and toughness all increased and then decreased with increasing Dy2O3 content, reaching maximum values of 99.2%, 1741 ± 19 HV, 449 ± 10 MPa and 5.87 ± 0.42 MPa‧m1/2, respectively, at 3 wt% Dy2O3 content.

Influence of micro graphite particles on the microstructure and wear behaviour of aluminium 6061 alloy composites developed by two step casting process

In the present research, the effect of micron sized graphite addition on the microstructure and wear behaviour of Al6061 alloy has been studied. The Al6061 alloy metal matrix composites reinforced with 6, 9 and 12 varying wt.% of graphite particles were fabricated by novel two step stir cast route which helps in improving the wettability of Al6061 alloy matrix with graphite particles. The created composites were exposed to microstructural studies and wear properties evaluation. Microstructural characterizations of achieved samples were carried out by SEM microscopy, EDS and XRD patterns. The occurrence of graphite particles were confirmed by the XRD patterns. The wear behaviour of Al6061 alloy with 6, 9 and 12 weight percentages of graphite composites were evaluated using pin on disc wear apparatus. All the experiments were conducted by varying applied loads of 1, 3 and 5 kg at 400 rpm sliding speed and varying sliding speeds of 100, 200, 400 and 600 rpm at 5 kg constant load. Wear mechanisms were studied by using SEM micrographs of worn surfaces and wear debris.

Understanding the role of in-flight particle temperature and velocity on the residual stress depth profile and other mechanical properties of atmospheric plasma sprayed Al2O3 coating

This report deals with the influence of particle temperature and velocity on the microstructure, mechanical properties and residual stress depth profile of plasma sprayed alumina coating. The coatings were produced by varying the particle temperature while maintaining a relatively fixed particle velocity, and vice versa. Residual stress profiles were acquired by measuring the stress in successive layers using X-ray Sin2ψ technique. A substantial increase in hardness and indentation modulus by 76% and 64%, respectively were observed with an increase in particle temperature. With an increase in velocity, coating porosity was found to decrease initially. However, at a high velocity, porosity again increased to a limited extent. The mechanical properties were found to depend strongly on porosity. An increase in particle temperature resulted in an increase in the tensile residual stress in the coatings. Moreover, partial recovery of the grit blasted compressive substrate occurred during spraying owing to an annealing effect.

Effect of annealing time on the microstructure and mechanical properties of aluminum added low-density medium manganese steel

The current investigation reports the influence of annealing time on the microstructure, mechanical properties and mechanical stability of austenite in a thermo-mechanically processed medium-Mn (Fe-3.92Al-6.78Mn-1.34Si-0.18C (wt.%)) steel. The specimen annealed at 750 °C for 60 min has better tensile properties than the 30 and 180 min annealed specimen. The combination of higher austenite fraction, higher transformation ratio of austenite and optimum recrystallized fraction lead to the better tensile properties of 60 min annealed specimen. Further, the lower mechanical stability of austenite promotes the transformation-induced plasticity (TRIP) effect, which improves the ductility of the 60 min annealed specimen.

Mechanical Characterization of AA 6061-T6 MIG Welded Aluminum Alloys Using a Robotic Arm

Aluminum alloys are of particular interest in the design of lightweight structures in different applications. Accordingly, welding aluminum alloys (AA) is a critical issue; for example, welding defects could arise during the traditional welding of aluminum alloys. This paper investigates the effects of welding using a robotic arm on the mechanical properties of 6061-T6 Aluminum alloy, as plates joined by Metal Inert Gas (MIG) welding. The tensile behavior and mechanical properties were investigated using tensile testing, hardness testing, and impact testing. The tensile behavior of AA-6061-T6 un-welded and welded specimens showed a decrease in the tensile strength of the welded specimens due to the fusion of the welded zone and the partially melted zone (PMZ). The hardness test showed an increase in the hardness values away from the welded zone, attributed to voids and defects in the welded and HAZ zones. In addition, the impact behavior showed that the maximum impact is in the base metal zone, and the minimum is in the HAZ. Scanning electron microscopy was used to investigate the welded and un-welded Aluminum microstructures. The mechanical properties of AA 6061-T6 Aluminum alloy were sensitive to the novel welding process.

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Microstructural Evolution and Mechanical Properties of Pure Aluminum upon Multi-Pass Caliber Rolling.

The paper presents the microstructure and mechanical property of pure aluminum (Al) fabricated by multi-pass caliber rolling at room temperature. The finite element modeling (FEM) simulation was performed to explore the changes in rolling force, effective stress and strain, and temperature under various rolling passes. As the number of rolling passes increased, the overall temperature, effective stress, and strain gradually increased, while the maximum rolling force decreased. In addition, due to the dynamic recrystallization (DRX), the average grain size reduced from 1 mm to 14 µm with the increase in rolling passes. The dislocation density increased and it gradually evolved into the high-angle grain boundaries (HAGBs). Moreover, the initial cubic texture rotated to the brass component and finally changed to a mixture of Cube and Brass types. The highest tensile yield strength (TYS), ultimate tensile strength (UTS) and elongation (El.) of caliber rolled pure Al (116 MPa, 135 MPa, and 17%, respectively) can be achieved after 13 rolling passes, which mainly attributed to grain refinement.

Microstructure and Eddy-Current Analysis of Aluminum 01570 Welded Joints Obtained by Friction Stir Welding

The article presents the results of studies of aluminum alloys connected by a welded joint obtained by friction stir welding. During this kind of welding a recrystallized fine-grained microstructure is formed in the joint. The pictures of the weld area microstructure are presented, and the eddy current probe signal variations when scanning the joint are shown. The resulting parameter of the eddy current probe was the local electrical conductivity of the weld area. It is demonstrated that the average grain size of the welded joint microstructure varies in the area of weld defects, which was determined by the signal variation of the eddy current probe. The microstructure peculiarities formed in the weld area where the defects are located, and their influence on the mechanical properties of welded joints are discussed. The results of a series of experiments allow concluding about the qualitative characteristics of the obtained welded joints.

Comparison of the Effect of Ni, Mn, Fe, and Si Additives on the Microstructure and Phase Composition of Hypereutectic Aluminum–Calcium Alloys

Comparison of the Effect of Ni, Mn, Fe, and Si Additives on the Microstructure and Phase Composition of Hypereutectic Aluminum–Calcium Alloys

The Effect of Variation of Aluminum Thickness Series 7075 in Heat Treatment Solution on Tensile Strength and Microstructure

This research was conducted to examine the comparison of tensile strength and microstructure between two different aluminum heat treatments. This study aims to compare the microstructure and tensile strength of aluminum 7075 specimens after undergoing solution heat treatment at a temperature of 495°C with soaking time for 30 minutes and experiencing quenching cooling and those without solution heat treatment. The data collection process was carried out by conducting tensile testing and microstructural testing with two specimens each. The test results will be analyzed using tensile strength data and visual microstructure analysis. From the results of the analysis of tensile and microstructural test data, it can be concluded that only the 7075 aluminum specimen with a thickness of 1.4 mm shows the greatest decrease in tensile strength and spread of Mg-Zn and Fe-Al particles, when compared to specimen 7075 with a thickness of 0.6 mm which on the other hand, undergo the separation of Mg-Zn and Fe-Al particles. Meanwhile, the Al 7075 specimen with a thickness of 2.5 mm, the changes that occur only in the diffusion of Mg-Zn particles, which have a slight spread, appear a little faint.

Influence of tool rotational speed on the evolution of microstructure and mechanical properties of precipitation-hardened Aluminium 6061 butt joint during friction stir welding

The present investigation aims to evaluate the influence of varying tool rotational speed (rotation per minute, rpm) on the mechanical properties and microstructural evolution within friction stir welded aluminium alloyAA6061-T6 joints. The effects of rpm underthe constant tool travel speedwere investigated by optical microscopy, field emission scanning electron microscopy (FESEM)and transmission electron microscopy (TEM)observation, tensile, fracture and micro-hardness test. Special attention was paid to the formation and evolution ofprecipitates.Results revealed that the tool rotational speedof 1300 rpmproduces highest hardness reaching to ∼69 HVN at the nugget zone (NZ), which could be attributed to the higher intensity of nano-sized re-precipitation. This specific tool rotational speed of 1300 rpm has been determined to be suitable to achieve the maximum joint efficiency of 70.6%. Significantly, the NZ is characterized with small equiaxed dynamically recrystallized grains. In a noteworthy findings, the NZ showed mostly either free from strengthening precipitate or trace of small tiny re-precipitates, while the thermo-mechanically affected zone (TMAZ) contains coarse precipitates with deformed and dynamically recovered grains. On the other hand, there was obvious grain growth with increasing rpm, substantiating more heat involvement with favourable thermal gradient. The experiment concludes thatthe rotational speed has an considerable effect on the precipitation characteristics, dislocation property and existence of finer second phase intermetallic compounds (IMC),which arethe predominant factors controlling the joint property.

Effect of pulsed laser and laser-arc hybrid on aluminum/steel riveting-welding hybrid bonding technology

The microstructure and properties of aluminum (Al)-steel dissimilar metal riveting-welding joints obtained by the pulse laser and laser-arc hybrid welding methods were investigated. For simple laser beam riveting-welding Al and steel joint, the maximum tensile shear load of the joints was 6.3 kN, as the average laser beam power was about 438 W. The microstructure of the fusion zone (FZ) of the joint was twin martensite (TM), and there were small cracks in the weld. The Al elements were uniformly distributed in a vortex-shaped in the mixed region consisting of QP980 steel, 6061 Al alloy, and Q460 rivet, and the intermetallic compounds (IMCs) at the Al-steel interface had FeAl, Fe2Al5, and FeAl3. For the laser-arc hybrid riveting-welding joint, the maximum tensile shear load of the joint with an average laser power of 160 W and a tungsten inert gas (TIG) current 100 A was 7.25 kN. Lath martensite (LM), ferrite (F), and retained austenite (RA) were generated in the FZ of the joint, and the Al element aggregates in bulk and sporadically distributed in the mixed zone consisting of the steel plate, Al plate, and rivets. Furthermore, the differentiated distribution mechanism of Al element in riveting-welding hybrid joints was discussed in this paper.

Microstructure and Mechanical Properties of Aluminum Alloy/Stainless Steel Dissimilar Ring Joint Welded by Inertia Friction Welding

In recent years, studying the weldability of a dissimilar metal hybrid structure, with the potential to make full use of their unique benefits, has been a research hotspot. In this article, inertia friction welding was utilized to join Φ130 forged ring of 2219 aluminum alloy with 304 stainless steel. Optical observation (OM), electron back scattering diffraction (EBSD), and scanning electron microscopy (SEM) were utilized to examine the joint microstructure in depth. Depending on the research, a significant thermal–mechanical coupling effect occurs during welding, resulting in inadequate recrystallization on aluminum-side thermo-mechanically affected zone (TMAZ) and forming zonal features. The crystal orientation and grain size of each TMAZ region reflect distinct differences. On the joint faying surface, the growth of intermetallic compounds (IMCs) is inhibited by a fast cooling rate and metallurgical bonding characteristics were found depending on the discontinuous distribution of IMCs. The average joint tensile strength can reach 161.3 MPa achieving 92.2% of 2219-O; fracture occurs on aluminum-side base metal presenting ductile fracture characteristics.

Influence of Ti3AlC2 content and load on the tribological behaviors of Ti3AlC2p/Al composites

In this study, Ti 3 AlC 2 particles doped aluminum matrix composites were prepared by ultrasonic agitation casting method. Microstructure, mechanical properties, and tribological properties of pure aluminum and Ti 3 AlC 2p /Al composites were characterized. Influence of different loads (10, 20, 30, and 40 N) and Ti 3 AlC 2 contents (1.0, 2.0, 3.0, and 4.0 wt%) on the tribological behaviors of the composites were studied. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Energy dispersion spectroscopy (EDS), and 3D laser confocal were used to assist the analysis. The results indicated that fine and uniformly microstructure and the optimum comprehensive mechanical properties were exhibited on 2.0 wt%-Ti 3 AlC 2p /Al composites. The abrasive grooves were widened and deepened with an increase in the load. The abrasion performance of composites improved distinctly with the addition of the Ti 3 AlC 2 particles, which changed the wear mechanism from adhesive wear to abrasive wear. The 30 N load and the composites of 2.0 wt% Ti 3 AlC 2 revealed the optimum tribological properties. The improvement of the tribological behavior of composites was attributed to the refinement of microstructure, the improvement mechanical properties and the three dimensional layered Ti 3 AlC 2 phases with self-lubricating properties.

Impact of equal channel angular pressing on aluminium alloys: An overview

SPD is a revolutionary process for converting bulk materials into ultrafine-grained (UFG) structures with outstanding flexibility and strength. ECAP (Equal Channel Angular Pressing) is a widely used SPD methods where workpiece is pass through specific die set. This will exert the significant stresses in materials without affecting their dimensions. In recent years, grain refinement through severe plastic deformation has gained lots of attention in scientific community. The most effective SPD procedures where extremely fine grain sizes and effective mechanical characteristics can be achieved is ECAP. Aluminium and its alloys are the most considered as most significant materials for a wide range of applications such as Manufacturing, Space vehicular system, automobile etc. The goal of this study is to explain the influence of different parameters such as die angle (channel angle, channel curvature), number of passes/ routes over Al alloy-based materials with appreciable reduction in its cross-sectional area. The impact of the Hot and Cold-ECAP procedures on the microstructure, mechanical properties, and wear of aluminium (Al) under load is reviewed in this article.

Efficiency of different commercial TiBAl grain refiners on refinement of pure aluminum cast structures

Industries largely rely on empirical tests to determine what composition and amount of TiBAl grain refiners to add during the casting of aluminum alloy for cast grain structure refinement. TiBAl grain refiners are aluminum master alloys having intermetallic particles within the aluminum matrix, these particles are mainly made of Ti and Al borides, having higher melting point than aluminum matrix. Addition of them to the melt, induces heterogeneous nucleation of aluminum cast grain structures, which promotes solidification of fine equiaxed grains at expense of columnar grain structures. This yields in grain refinement of cast structures, and is beneficial to mechanical and surface treatment properties on the final product. Very often in industrial practice during casting, whether a grain refiner is suitable for a given alloy, the amount to be added in the melt, and what cooling rates to use, are questions remain and reaching the balance becomes a cumbersome practice, and leads to pernicious material’s properties. This study aims to explore the refinement efficiency of three variants of locally supplied TiBAl grain refiners on the microstructure of cast pure aluminum (CPAl). A standard test method of TP-1 was adopted and the efficiency of TiBAl grain refiners was determined according to the average grain sizes. It was found that Al-3Ti-1B alloys from different suppliers yield different grain sizes, however, Al-5Ti-1B alloy has better efficiency than Al-3Ti-1B alloy system on CPAl material. The optimum holding time for CPAl melt at 750℃ is 5 minutes to achieve a fine grain size.

Effect of Friction stir processing parameters on microstructure and microhardness of aluminium based Metal matrix composites

The present article demonstrates the Friction Stir Processing (FSP) of the stir cast Aluminium Alloy based Metal Matrix Composites (MMC). Generally, composites manufactured using the stir casting process tends to have several casting defects along with some agglomeration of reinforcement particles. These defects in stir cast composites can be resolved by implementing FSP. MMC was manufactured using the matrix of aluminium alloy 2014, which was reinforced with different weight percent of Silicon Carbide (SiC) particles (5%, 10% and 15%). FSP was performed by considering two different combinations of rotational speed and transverse speed i.e. (i) 270 rpm and 78 mm/min (First Combination) and (ii) 190 rpm and 50 mm/min (Second Combination). The article discusses the variation in microstructure and microhardness of all the friction stir processed composites and the effects of process parameters were examined. Lastly, the conclusion of the article suggests the best combination of processes parameters for performing FSP of manufactured composites.

The effect of cold rolling on mechanical properties and microstructure of aluminium 6082 T6 joint by friction stir welding process

Cold rolling increases the strain hardening coefficient and improves the material's mechanical strength and formability while maintaining uniform sheet thickness. This paper investigates the effects of cold rolling on the mechanical properties of Aluminum 6082 T6 during the friction stir welding (FSW) process. Aluminum 6082 T6 material was cold rolled to reduce the thickness by 50 percent. Rolled and as-received material were welded by friction stir welding process using the same welding parameters. Welded samples were characterized by optical microscopy. Tensile and hardness tests were conducted on the welded sample. The findings shows a slight difference in tensile strength between rolled and as-received welded sample as it is reported to be 1.7%. Rolled sample was 3.5% more harder on the weld zone than as-received sample.