Cavitation mechanism of ultrasonic melt degassing
Abstract
The real melt always contains non-wettable fine inclusions which are potential nuclei for cavitation and degassing. This paper deals with the nature of ultrasonic degassing and the industrial application of a relevant technology.
References (11)
- E.A Hiedemann
Metallurgical effects of ultrasonic waves
J Acoust Soc Am
(1954) - A.E Crowford
Ultrasonic Engineering
(1955) - G.I Eskin
Ultrasound in Metallurgy
(1960) - J Campbell
Effects of vibration during solidification
Int Met Rev
(1981) - G.I Eskin
Ultrasonic Treatment of Molten Aluminium
(1988)
Cited by (230)
Effect of electromagnetic stirring on degassing and mechanical properties of M174 heat-resistant alloy
2024, Journal of Materials Research and TechnologyMany experimental results confirm that electromagnetic stirring (EMS) has a good purification effect on the melts, either degassing or removing inclusions, but the mechanism of electromagnetic purification still needs to be further explored. This paper takes M174 alloy as an example, and carries out a more in-depth study on the purification effect of electromagnetic field on the basis of numerical simulation, focusing on the amount of hydrogen present in the ingot, the enhancement effect of electromagnetic field stirring on the mechanical properties of the melt was investigated in terms of the treatment temperature, and the current intensity during electromagnetic stirring. The results show that the tensile strength and elongation of the alloy reached 195.3 MPa and 0.69% after electromagnetic stirring at a current intensity of 60 A, which are very close to the theoretical properties of the alloy of 200.3 MPa and 0.74%, respectively. At the same time, the effect of electromagnetic stirring on the presence of oxides and double oxide film in the melt is slightly explored.
Enhancement of the corrosion resistance of the Mg alloy ZW61 by dual-frequency ultrasonic vibration
2024, Journal of Magnesium and AlloysUltrasonic vibration was introduced into the casting of quasicrystal-reinforced magnesium alloy ZW61. The microstructure, mechanical properties, and corrosion resistance were studied. The dual-frequency ultrasonic field (DUF) treatment reduced the α-Mg grain size from 502 µm to 69 µm, and the aggregated lamellar I-phase was refined into tiny dot-like shapes with a smaller area fraction. Static corrosion and electrochemical tests indicated that DUF decreased the corrosion rate from 10 mm·y−1 to 3 mm·y−1 with a denser protective oxide film. DUF not only significantly enlarged the effective cavitation area but also reduced the dependence of transient cavitation on the initial bubble radius. The ratio Rmax3/tc was used to qualitatively characterize the cavitation strength, and cavitation dynamics calculations indicated that DUF had higher cavitation strength compared to single-frequency ultrasonic field (SUF). An equation for corrosion rate versus microstructural parameters (grain size, second phase fraction, potential difference) was developed, which could well predict the corrosion rate of magnesium alloy ZW61 without and with different ultrasonic vibrations.
Recent advances and future trend of aluminum alloy melt purification: A review
2024, Journal of Materials Research and TechnologyAluminum, the most produced non-ferrous metal in the world, is highly regarded for its light weight, high specific strength, and excellent thermal conductivity. With the continuous development of aerospace, precision electronics, photovoltaic semiconductors and other emerging strategic industries, the demand for high-performance aluminum alloys is also booming. The paper discusses recent advances in aluminum alloy melt purification, focusing on the development of conventional purification treatment and novel purification treatment of aluminum alloy melt. The advantages and disadvantages of adsorption purification, non-adsorption purification and integrated purification are also summarized. Additionally, the article points out the shortcomings of the current research on aluminum alloy melt purification and gives an outlook on the future research direction.
Achieving material diversity in wire arc additive manufacturing: Leaping from alloys to composites via wire innovation
2024, International Journal of Machine Tools and ManufactureMulti-material components featuring high performance and design flexibility have attracted considerable attention, providing solutions to meet the performance demands of high-end equipment components. Achieving material diversity in additive manufacturing (AM) is a fundamental step towards manufacturing multi-material components. Wire arc additive manufacturing (WAAM), an important branch of AM technology, boasts notable advantages in the efficient and customized preparation of large-scale parts due to its high deposition efficiency and unrestricted forming size. However, achieving material diversity in WAAM, constrained by its reliance on wire-form raw materials, has emerged as a compelling challenge. Wire innovation, including multiple, stranded, and cored wires, have furnished solutions to this challenge. To this end, this review provides an overview of the current developments in WAAM via wire innovation and suggests future research directions, aiming to serve as a reference for the further advancement of WAAM. Initially, the article introduces several WAAM printing forms, their manufacturing features, printable materials and inherent manufacturing limitations, and the intermixing of metal constituents of WAAM, prior to highlighting the advantages and necessity of achieving material diversity. Subsequently, the exposition of multi-wire-arc AM demonstrates its utility in the preparation of binary or ternary alloys, inclusive of intermetallic compounds and functionally graded materials, responding adeptly to the deficiencies of conventional WAAM, which is limited to single-material printing. The merits and progression of stranded-wire-arc AM for high-entropy alloy production are synthesized and debated, especially given that creating components with multiple metal elements via multi-wire-arc AM customarily confronts the constraint of necessitating more intricate manufacturing equipment and processes. Further, the review explores the recently developed cored-wire-arc AM technology, which actualizes the manufacturing of composite materials, amalgamating metals and non-metals, to remedy the issues encountered with standard WAAM, incapable of realizing non-metallic material printing. Considering machine tools as an important means to achieve material diversity in WAAM, we expand on the current machine tool architecture and its corresponding design tools. Finally, the current research status on WAAM via wire innovation is summarized and potential future research directions are proposed.
Sonochemical synthesis of lignin nanoparticles and their applications in poly (vinyl) alcohol composites
2024, International Journal of Biological MacromoleculesLignin is a common and abundant byproduct of the pulp and paper industry and is generally burned to produce steam. Opportunities exist to acquire greater value from lignin by leveraging the properties of this highly conjugated biomacromolecule for applications in UV absorption and polymer reinforcement. These applications can be commercialized by producing value-added lignin nanoparticles (LNPs) using a scalable sonochemical process. In the present research, monodisperse LNPs have been synthesized by subjecting aqueous dispersions of alkali lignin to acoustic irradiation. The resulting particle size distribution and colloidal stability, as determined by dynamic light scattering, transmission electron microscopy and zeta potential analysis, of LNPs can be adjusted by varying the solution pH and ultrasonication energy. As-synthesized LNPs with a mean diameter of 204 nm were incorporated into poly (vinyl) alcohol (PVA) to prepare thin and flexible nanocomposite films using a simple solvent casting method. The addition of 2.5 wt% LNP increased the material's Sun Protection Factor up to 26 compared to 0 for neat PVA, while maintaining light transmission above 75 % in the visible spectra. In addition, the tensile strength and elastic modulus of the PVA nanocomposites improved by 47 % and 36 %, respectively. The presence of LNP also enhanced the thermal stability of the materials. Significantly, the proposed sonochemical process may be generally applicable to the synthesis of a range of naturally-derived LNPs for a variety of value-added applications.
Ultrasonic effects with different vibration positions on gas tungsten arc wire additive manufactured aluminum nanocomposite
2023, Journal of Manufacturing ProcessesUltrasonically assisted gas tungsten arc based wire additive manufacturing (UA-GTAAM) of TiB2 nanoparticle-reinforced AA7075 aluminum metal matrix nanocomposite (MMNC) was conducted with the UA probe directly immersed in the molten pool. This work focuses on the UA effects with different probe positions on the UA-melt interactions and the resulting microstructure. In situ high-speed imaging reveals melt pool surface ripples induced by UA. More refined surface ripples, corresponding to a faster melt flow, are observed with the UA probe immersed deeper into the melt. This condition also leads to a lighter etched color under optical microscope, which is related to a more homogeneous microstructure with less eutectic phase at grain boundaries. Electron backscatter diffraction (EBSD) analysis was employed for grain orientation and nanoparticle distributions, where the lower Confidence Index (CI) served as an indicator for intragranular nanoparticle segregation. The EBSD results show a strong (110) texture in the conventional WAAM builds. High-resolution backscattered electron (BSE) imaging reveals nanoparticles tend to segregate into preferred (001) and (111) grains. UA suppresses the epitaxial growth of (110) grains and promotes a more randomly orientated microstructure. Accordingly, more (001) and (111) grains are available to accommodate nanoparticles and promote a more homogeneous dispersion.