Further comments on “An investigation of the precipitation-hardening process in aluminum alloy 2219 by means of sound wave velocity and ultrasonic attenuation” (original) (raw)
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Today, in the industry of aluminum, the D. C. casting of billets and slabs is playing the major role. The producers of these slabs and billets are many. The end users of the product are OEMs. The degassing technology for producing these aluminum slabs and billets is provided by very few. There are two types of degassing methods currently in use. One of these, vacuum degassing, is used primarily in the steel industry and thus not generally used in the aluminum industry. The second method, generally employed in the aluminum industry, is rotary degassing, which uses finely dispersed argon, chlorine, fluorine to remove dissolved hydrogen and various salts from melt. The challenges associated with producing aluminum are reducing porosity due to hydrogen precipitation during casting through degassing processes; which generates detrimental effects on mechanical properties of alloy castings and removing impurities like; the Ca, Mg salts etc. from the molten metal. Looking at the degassing systems provided by these players, are going to be obsolete as the environment norms will become stricter in the next decade, because of the use of Fluorine and Chlorine for removing the Ca, Mg, etc. impurities from the molten metal as the ozone layer is getting depleted and process becomes more cumbersome and hazardous. So, the innovation in the technology is needed; which leads research interest on development of the ultrasonic degassing as a better option. During this research authors would be using ultrasonic technology over existing technology to compare the results of conventional degasser units available in the market such as LARSTM, SNIFTM, STASTM - ACDTM, AlpurTM, MDUTM etc., and would be finding out the better operating parameters of ultrasonic equipment for the process for replacement of Fluorine and Chlorine based old technology with Ultrasonic Technology. This research paper should underpin improvement in the process and hence improved hardness of material by elimination of the fluorine and chlorine usage by replacing it with ultrasonic technology with suitable mechanical design, metallurgical criteria and thermal analysis consideration. During the entire research and development authors had carried out various operations like Research on thermal and metallurgical behavior of the molten metal and alloys, Comparison of results achieved using ultrasonic technique over existing technique, Formulation of conclusion; making ultrasonic technique a proven technology, and Identifying the further scope of research and development. With the experiments carried out, authors found significant improvement in hardness of the material produced by ultrasonic degassing as compared with the hardness of material produced by conventional degassing.
Influence of Thermal Treatments on Precipitation Hardening of Aluminum 2024
Influence of Thermal Treatments on Precipitation Hardening of Aluminum 2024, 2024
The artificial aging of Aluminum 2024, a critical aerospace alloy, represents a complex metallurgical process with significant implications for material performance. This study systematically investigates the precipitation hardening mechanisms through comprehensive thermal treatments at varying temperatures (178°C, 190°C, and 200°C) and durations, alongside natural aging. By analyzing hardness variations, microstructural transformations, and precipitate evolution, we reveal the intricate relationships between aging conditions and mechanical properties. Our research demonstrates that the precipitation sequence involving-Guinier-Preston zones, θ" and θ' phases, and and S phases evolution-plays a pivotal role in material strengthening. The 190°C treatment emerged as optimal, providing a stable hardening window with peak hardness maintained for up to 12 hours. Comparative analyses between artificial and natural aging processes highlight the superiority of controlled thermal treatments in accelerating precipitate formation and improving mechanical properties. The study provides an understanding of how temperature, time, and microstructural evolution interact to optimize the alloy's performance.
Today, in the industry of aluminum, the D. C. casting of billets and slabs is playing the major role. The producers of these slabs and billets are many. The end users of the product are OEMs. The degassing technology for producing these aluminum slabs and billets is provided by very few. There are two types of degassing methods currently in use. One of these, vacuum degassing, is used primarily in the steel industry and thus not generally used in the aluminum industry. The second method, generally employed in the aluminum industry, is rotary degassing, which uses finely dispersed argon, chlorine, fluorine to remove dissolved hydrogen and various salts from melt. The challenges associated with producing aluminum are reducing porosity due to hydrogen precipitation during casting through degassing processes; which generates detrimental effects on mechanical properties of alloy castings and removing impurities like; the Ca, Mg salts etc. from the molten metal. Looking at the degassing systems provided by these players, are going to be obsolete as the environment norms will become stricter in the next decade, because of the use of Fluorine and Chlorine for removing the Ca, Mg, etc. impurities from the molten metal as the ozone layer is getting depleted and process becomes more cumbersome and hazardous. So, the innovation in the technology is needed; which leads research interest on development of the ultrasonic degassing as a better option. During this research authors would be using ultrasonic technology over existing technology to compare the results of conventional degasser units available in the market such as LARSTM, SNIFTM, STASTM - ACDTM, AlpurTM, MDUTM etc., and would be finding out the better operating parameters of ultrasonic equipment for the process for replacement of Fluorine and Chlorine based old technology with Ultrasonic Technology. This research paper should underpin improvement in the process and hence improved hardness of material by elimination of the fluorine and chlorine usage by replacing it with ultrasonic technology with suitable mechanical design, metallurgical criteria and thermal analysis consideration. During the entire research and development authors had carried out various operations like Research on thermal and metallurgical behavior of the molten metal and alloys, Comparison of results achieved using ultrasonic technique over existing technique, Formulation of conclusion; making ultrasonic technique a proven technology, and Identifying the further scope of research and development. With the experiments carried out, authors found significant improvement in hardness of the material produced by ultrasonic degassing as compared with the hardness of material produced by conventional degassing.
Effect of Ultrasonic Processing on a Direct Chill Cast AA6082 Aluminium Alloy
Light Metals 2017, 2017
For many years now, ultrasonic melt treatment (UST) has proven itself to promote grain refinement in aluminium alloys. The current work presents cavitation-aided grain refinement obtained on commercial AA6082 DC-cast billets. Grain refinement was achieved while applying UST in the crucible away from the sump, prior to casting. Since in high strength alloys, Zr and Ti are commonly present as alloying elements for anti-recrystallization and corrosion resistance properties, their as well as UST parameters influence on the microstructure are studied and presented. Primary Al 3 (Zr 1-x-y ,Ti x , Si y) intermetallics were found in the centre of the α-Al grains. This suggests that UST may have forced the nucleation and refinement of primary intermetallics influencing the subsequent solidification process when Al 3 (Zr 1-x-y , Ti x , Si y) act as nucleation sites.
Investigating ultrasound-induced acoustic softening in aluminum and its alloys
Ultrasonics, 2020
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The international journal of advanced manufacturing technology/International journal, advanced manufacturing technology, 2024
Ultrasonic additive manufacturing (UAM) is an advanced joining technique that utilizes ultrasonic vibrations to bond layers of metal foil together. UAM offers several benefits over traditional manufacturing methods, including enhanced design flexibility and reduced material waste, and its potential applications in various industries such as aerospace, automotive, and biomedical engineering are being actively explored. The study employs a nanoindentation apparatus to investigate the effect of the UAM process on the local mechanical properties of the bonded interface, along with changes in microstructure, which were investigated using scanning electron microscopy and electron back-scattered diffraction. The results revealed a significant correlation between material hardness and local plasticity. EBSD has revealed that the grain size distribution of Al far from the interface contains 57% of the grains less than 3 µm in size, while at the interface this number rises to approximately 78%, indicating that the average grain size decreases as it approaches the interface. This result is consistent with nanoindentation results that demonstrated a gradual change in the hardness of Al foil far from the interface to close to the interface (the maximum penetration depth near the interface was 500 nm less than far from the interface). Both EBSD and nanoindentation disclose the effect of work hardening close to the interface, which is related to dislocation accumulation with a density of 8.6 × 10 −10 cm −2 beneath the interface. The consistency of hardness and Young's modulus with the pole figures and microscopic images demonstrated that plasticity flow and fine grain distribution would only occur in the vicinity of the interface in the softer metal region. Although the harder metal did not exhibit plasticity or recrystallization, the hardness, and Young's modulus map indicated the formation of a layer of small grains close to the interface on the aluminum side owing to strain hardening and dynamic recrystallization.
Elastic characterization by Ultrasonic waves of the unstandardized polycrystalline alloy 42500
A B S T R A C T The objective of this work is to determine the impact of the temper heat treatment (150, 160, 170, 180, 190, 200,220 and 240) °C on the evolution of the main elastic and structural properties of the alloy foundry AlSi7Zn3Cu2Mg (42500). This alloy will be subjected to precipitation hardening. This is one of the most successful methods to considerably improve the mechanical properties of the alloy, this allows choosing the compromise of high resistances while maintaining satisfactory ductility. The mechanical properties are governed by the combination of four factors: heat treatments, molding process, chemical composition and the shape of the specimen used. We used mainly four techniques namely: The ultrasonic method for the determination of the elastic characteristics, the Brinell hardness HB and the micro hardness Hv to identify the stress field, the Kcv resilience to provides information on fracture mode, brittleness and the impact resistance, and finally to completely identify the alloy, it will be followed by its metallography, microstructure and fracture surface in resilience. The purpose of this work is to study the structural hardening of the alloy AlSi7Zn3Cu2Mg (42500) by considering ten states: crude of casting noted: F taken as reference state. To improve the mechanical characteristics obtained from the crude of castingstate, a structural hardening heat treatment is carried out, the addition of magnesium is necessary in order to make the alloy sensitive to this specific heat treatment T46.
Transactions of the Indian Institute of Metals, 2014
An experiment was conducted to characterize microstructural and mechanical behavior of AA6061 alloy during an artificial aging treatment through destructive and ultrasonic nondestructive techniques. Identical aluminum plates of AA6061-T6 aluminum alloy were solutionized at &800 K, followed by quenching and artificial aging at 493 K up to 8 h. The microstructural evolution was analyzed using scanning electron microscopy. The variations in hardness, yield stress, and ultimate tensile strength with respect to aging time were discussed. Besides, ultrasonic parameters velocity and attenuation were measured and correlated with the microstructural evolution as well as certain mechanical properties. The ultrasonic measurements showed a good correlation with the microstructural features and mechanical properties of the alloy during aging, whereby an excellent correlation was found between the longitudinal wave velocity and strength properties of the aged specimens. The longitudinal wave velocity was found to be directly related to the hardness with a correlation coefficient of 0.99.
Nfluence of Nanostructuration on the Sound Velocity in Aluminum AL_99.50
European Journal of Materials Science and Engineering, 2017
The paper aims to determine the influence of nanostructure on sound velocity, to severe plastic deformation by cold multiaxial forging of aluminum. The deformation process is discontinuous and comprises deformation processes defining a severe plastic deformation cycle. Thus, a number of 7 determinations were performed for each sample, corresponding to the first 12 cycles of severe plastic deformation. As a result of the analysis of the results, it can be deduced that the area of passages 3, 4 and 5 represents, in fact, precisely the transition zone between micrometric granulation and mesoscopic (ultrafine) granulation, which is only
Metals, 2019
In this study, ultrasonic vibration (USV) was evaluated in preparation of Al–8wt.%Cu alloys at a lab-scale. Moreover, the role of Ti–6Al–4V sonotrode erosion and its contribution in grain refining were analyzed. Based on the experimental conditions/parameters, it was found that the amount of impurities and the associated porosity were significantly reduced in USV treated alloys. Furthermore, USV reduced the time needed for dissolving the alloying element Cu, nevertheless, the best dissolving of Cu in this study was not possible without introducing further holding time. As a result of using a titanium-based sonotrode, a noticeable content of Ti was found in the ultrasonically treated alloys due to sonotrode erosion under USV. The dispersion of TiAl3 promoted, as a main factor, a grain refining effect at relatively constant and high melt temperature, other possible mechanisms of grain refining have been discussed.