Ultrasonic Casting Research Articles

Improved mechanical properties of GNPs/Al composites by eliminating alumina and obtaining a strong bonded GNPs-Al direct contact interface and Mg-rich phases

The interface between Graphene Nanosheets and Aluminum (GNPs-Al) without carbide and transition layers is referred to as a direct-contact GNPs-Al interface. In this work, the GNPs-reinforced aluminum matrix composites are fabricated by ultrasonic casting process. The interfacial structure of GNPs-Al is investigated using transmission electron microscopy, and the strength of the fabricated direct-contact GNPs-Al interface is analyzed. The results identified the presence of weak amorphous aluminum oxide at the original GNPs-Al interface. The direct contact GNPs-Al interface was obtained by introducing Mg. The migration of Al atoms formed an Al/C mixing zone between GNPs-Al, which led to the enhancement of the interface strength. The average UTS value has improved by about 20.5% due to the optimization of the interface structure. The enhancement of strength at the same toughness is achieved by the load transfer of GNPs, bridging, and the enhancement of dislocation storage capacity by the Mg-rich phase. The present work provides a new reference for the reinforcement of cast aluminum alloys by GNPs.

Ultrasonic Cast Bonding of Sheet Steel to Aluminum in a Metal Mold

Ultrasonic Cast Bonding of Sheet Steel to Aluminum in a Metal Mold

Effect of ultrasonic power on degassing and microstructure of large-scale 7085 aluminum alloy ingots

In this work, five sets of large-scale 7085 Al alloy ingots (diameter 830 mm × length 3600 mm) were manufactured by introducing different ultrasonic powers (0–750 W) in the Direct-Chill (DC) casting process. The difference among the ultrasonic degassing, the α-Al grains, elemental segregation and eutectic phase with ultrasonic treatment were investigated. The results indicated that with the increase of ultrasonic power, the efficiency of ultrasonic degassing was gradually improved, which was decreased from 0.085 cm3/100 g to 0.056 cm3/100 g in ingot center part. The grain size was also dramatically refined, in which the grain refinement rate reached 38.2%, 42.8% with 550 W, 750 W power, respectively. The segregation of alloying elements (Zn, Mg, Cu) in the ingot was significantly suppressed, which the maximum positive deviations ∆C of Zn, Mg, and Cu were reduced by 59.5%, 55.9%, and 60.8%, respectively. In addition, the new Al14Cu2Fe3 (α−Fe) phase was the first to be discovered in the low power state and the coarse eutectic phase was more refined in the high power. The mechanisms of degassing, grain refinement and suppression of macroscopic segregation during ultrasonic casting were further revealed by calculating the acoustic energy density (I).

Study on chemical corrosion properties of titanium alloy in 2A14 aluminum melt

Titanium alloy radiation rods have excellent physical and chemical properties compared to other materials, and are commonly used for ultrasonic casting of 2A14 aluminum alloy. However, titanium alloys are chemically corroded in high-temperature aluminum melts for a long time, making it difficult to precisely regulate the elemental composition during casting. In order to better understand the high-temperature chemical corrosion mechanism of titanium alloy radiation rods, this research looks into the corrosion morphology, weight loss, surface roughness, and reaction layer. The study’s findings suggest that the rate of chemical corrosion of titanium alloy in high-temperature aluminum melt is often inversely correlated with the degree of roughness, with the degree of roughness changing nonlinearly during the corrosion process. Titanium alloy weight loss rates with roughness Ra0.4 μm, Ra7.2 μm, Ra9.5 μm and Ra9.8 μm are 0.16 mg per min, 0.25 mg per min, 0.37 mg per min and 0.29 mg per min, respectively. The corrosion product of the chemical corrosion process is TiAl3, which is granular. Under varying roughness conditions, the solid-liquid interface of Al/Ti emerges reactants after 4 min, and the TiAl3 reaction layer arises after 12 min. Furthermore, the reaction layer with little roughness is flat and compact, whereas the reaction layer with great roughness is loose and contains many faults. At the same time, the growth rate of the reaction layer decreases slightly. And the greater the surface roughness, the greater the TiAl3 reaction layer grows at the titanium alloy matrix.

Investigation on synergetic effect of non-contact ultrasonic casting and mushy state rolling on microstructure and hardness of Al–Si–Al2O3 nanocomposites

AbstractThe present work elucidates a novel way of processing Al–Si–Al2O3 bulk nanocomposites. The novel approach includes synergetic effect of non-contact ultrasonication and mushy state rolling for achieving appreciable uniformity in the distribution of nanoparticles in the metal matrix. A systematic study on the distribution of particles, the resultant microstructure, and also the resultant hardness in the nanocomposite has been presented. It is shown that the current methodology has resulted in enhanced distribution of nanoparticles in the metal matrix as compared to the earlier versions in the field. The structure of the nanocomposites has been explained on the basis of cavitation phenomena and particle pushing during solidification. The work also includes simulation using the Fluent platform to estimate the time available before the initiation of solidification to carry out effective deagglomeration and distribution of nanoparticles in the liquid melt using ultrasonic cavitation. Although the non-contact ultrasonic casting has resulted in a nearly uniform deagglomeration of nanoparticle clusters, a small number of agglomerates were present at the grain boundaries. Hence, the as-cast nanocomposites were deformed in the mushy state condition. An attempt has been made to explore the feasibility of enhancing the distribution of nanoparticles in the Al–Si matrix through semisolid state rolling. The synergetic effect has resulted in enhancement of the hardness of the material by 37%.

Numerical Modeling and Experimental Validation of TiC Nanoparticle Distribution During the Ultrasonic Casting Process of 2219 Aluminum Matrix Nanocomposites

In this work, a two-dimensional model of 0.9 wt% TiC nanoparticle-reinforced 2219 aluminum nanocomposites fabricated by a high-intensity ultrasonic casting technique was established. The TiC nanoparticle distribution in 2219 aluminum melts was investigated using the multiphase computational fluid dynamics ultrasonic cavitation model accounting for turbulent flow. And the variable interaction between nanoparticles and melts was analyzed by Ansys’s Fluent Dense Discrete phase Model According to the simulation results, the ultrasonic power had a significant effect on the distribution of TiC nanoparticles in aluminum melt. The appropriate ultrasonic power has a promoting effect on the dispersion of nanoparticles. Due to the impact of ultrasonic streaming, the number of nanoparticles in the center position was lower than that in the edge position of the molten pool. Moreover, casting experiments were carried out to verify the efficacy and accuracy of the simulation. The average grain size in the center position was smaller than that in the edge position. TEM and SEM were used to analyze the distribution of TiC nanoparticles. They were more evenly distributed in the center position of the ingot than those in the edge part. Besides more nanoparticles were agglomerated in the edge. The experimental results were mostly consistent with the simulation results.

Effect of ultrasonic field on the microstructure and mechanical properties of sand-casting AlSi7Mg0.3 alloy

Abstract The injection of ultrasonic wave into a melt during casting can refine grain size, improve grain distribution, and thereby enhance casting performance. The available studies on ultrasonic-assisted casting are mostly about inserting a transducer directly into the melt. Such a method is not suitable for sand casting. Therefore, the study of ultrasonic sand casting by indirectly injecting ultrasonic waves into an aluminum alloy melt through a sand mold was proposed and carried out in this study. The effects of ultrasonic waves of different powers at different solidification stages on the microstructure and mechanical properties of the melt were studied. Compared to conventional sand casting, the samples prepared by ultrasonic sand casting have finer grains and better grain distribution, as well as higher mechanical properties. Moreover, the sample’s performance improves to different levels when the same ultrasonic wave is injected at different periods, when compared to the injection of ultrasonic waves with different powers in the same period.

Insight of high-entropy alloy particles-reinforced 2219 Al matrix composites via the ultrasonic casting technology

The microstructure and mechanical properties of metallic composites can be favorably modified by the introduction of various reinforcing particles. Different contents of high-entropy AlCoCrFeNi alloy particles (HEAps) were individually injected into the 2219 Al alloys via ultrasonic casting technology. Some irregular HEAps were observed along the grain boundaries. They served as reinforcing factors and provided numerous potential heterogeneous nucleation sites on the α-Al matrix. The average grain size of the HEAps-reinforced aluminum matrix composites (HEAps/AMCs) reduced dramatically from 136.08 μm (0 wt%) to 34.95 μm (1.5 wt% HEAps). Several rich-Al, Co, Fe, Cr, Ni, Cu elements with needle-shaped phases accompanied by some distinctive plate-like precipitates were observed in the Al matrix. Additionally, the optimal addition of HEAps was approximately 1.5 wt%, for any excess was detrimental to the microstructure and properties. The HEAps had a substantial influence on the mechanical properties, namely 1.5 wt% corresponding to the optimum tensile strength (217.4 MPa), and 3 wt% ascribing to the maximum micro-hardness (120.5 HV). The primary strengthening mechanisms were explored, revealing the grain refinement, solute, and precipitate strengthening to be the dominant factors. However, ∆ σ CTE and ∆ σ EMM showed very limited contribution. Meanwhile, ∆ σ Load , ∆ σ WH1 , and ∆ σ WH2 offered marginal increments to the yield strength. Theoretically, a novel strengthening model was established, and the yield strength of the HEAps/AMCs in an optimal HEAps addition range was effectively predicted. • AlCoCrFeNi HEAps/2219 Al matrix composites are fabricated via ultrasonic casting. • HEAps were stochastically distributed along the grain boundaries. • Novel model was established to predict the yield strength of HEAps/AMCs.

Strengthening Mechanisms in Carbon Nanotubes Reinforced Metal Matrix Composites: A Review

Carbon nanotubes (CNTs)-reinforced metal matrix composites are very attractive advanced nanocomposites due to their potential unusual combination of excellent properties. These nanocomposites can be produced by several techniques, the most reported being powder metallurgy, electrochemical routes, and stir or ultrasonic casting. However, the final mechanical properties are often lower than expected. This can be attributed to a lack of understanding concerning the strengthening mechanisms that act to improve the mechanical properties of the metal matrix via the presence of the CNTs. The dispersion of the CNTs is the main challenge in the production of the nanocomposites, and is independent of the production technique used. This review describes the strengthening mechanism that act in CNT-reinforced metal matrix nanocomposites, such as the load transfer, grain refinement or texture strengthening, second phase, and strain hardening. However, other mechanisms can occur, such as solid solution strengthening, and these depend on the metal matrix used to produce the nanocomposites. Different metallic matrices and different production techniques are described to evaluate their influence on the reinforcement of these nanocomposites.

Understanding the influence of ultrasonic streaming on solidification of AZ80 magnesium alloy during direct-chill casting using a transient coupling modeling

In this modeling, the influence of ultrasonic streaming on physical fields during direct-chill (DC) casting of AZ80 magnesium alloy is investigated by a transient 2D axisymmetric mathematical model, which couples the ultrasonic field, fluid flow and temperature field using COMSOL Multiphysics software. The influences of input acoustic pressure, inserted depth and shape of ultrasonic horn on physical fields are discussed systematically. Compared with the DC casting, the ultrasonic casting (UC) has more turbulent melt flow, uniform temperature gradient, and shallow liquid sump. The acoustic streaming driving force dramatically changes the melt flow and temperature distribution. The increase of input acoustic pressure from 0.2 MPa to 2.2 MPa enlarges the affected area of ultrasonic streaming. However, a further increase of input acoustic pressure to 4.2 MPa has sight effects on physical fields. With the increase of inserted depth of ultrasonic horn from 10 mm to 50 mm, the circulation caused by ultrasonic streaming is enlarged. The convex surface of the ultrasonic horn promotes the transverse flow of melt compared with the flat horn. Therefore, the transverse temperature gradient and depth of liquid sump are decreased.

Design of metal casting mold for ADC 12 aluminium alloy with assistance of 20 kHz ultrasonic vibration

Metal mold casting is widely used in industry because of higher accuracy than sand casting and lower cost than diecasting. Metal mold casting can yield products with complex shapes and adjustable cooling rate. In this work, designing and fabrication of 20 kHz ultrasonic assisted mold casting using 20Cr steel are studied. Some major components such as motor, heater power, melting chamber are selected and calculated. Model for heating and pouring the ADC 12 alloy is designed. Samples with and without ultrasonic vibration are investigated using 3D laser scan.

Role of Ti and Y in the nucleation of the primary α-Al of Al7075–Ti–Y natural composites and influence of ultrasonic vibration

Abstract Al7075–Ti–Y natural composites were prepared by using a combination of ultrasonic vibration and casting. The effects of titanium (Ti) and yttrium (Y) on the nucleation of primary α-Al were studied and the influencing mechanism of Y on the TiAl3 formation was analysed. Furthermore, a reaction kinetics model of TiAl3 under ultrasonic vibration was established. The results showed that the uniformly distributed TiAl3 and Al3Y nano-particles resulted in grain refinement. Y changed the morphology of TiAl3 and the appearance of corrosion pits was related to the fact that Y was dissolved within the TiAl3 structure to form Ti(Al,Y)3. The established model revealed that ultrasonic vibration significantly promoted the formation of TiAl3, and that ultrasonic time was the main factor affecting its growth.

Processing and performance assessment of particulate TiB2 reinforced aluminum MMC developed via a novel hybrid ultrasonic casting system

ABSTRACT The production of aluminum metal matrix composites (AMMCs) has been a great challenge for commercial sectors and the research fraternity. Over the past few decades, many modifications and hybrid techniques have been designed and developed by the researchers to address the manufacturing issues and reduce the production cost in developing AMMCs. In this regard, there is a need to address fundamental issues such as wettability and uniform distribution of particles across the matrix. Due to the poor mixing of particles, the materials’ hardness, strength, and wear properties are affected. In the present research, aluminum-titanium diboride metal matrix composite (Al-TiB2 MMC) has been synthesized by developing a novel hybrid liquid processing technique. The performance efficacy of the novel hybrid experiment setup has been determined through the computational fluid dynamics (CFD) approach. Metallography has been done to demonstrate the uniformity of TiB2 phase in aluminum. Mechanical and wear behavior of the Al-TiB2 MMC have been subsequently assessed and compared with conventional processing technique. The results obtained in the current study are promising and demonstrate the potential benefits of the novel hybrid liquid processing system from an industrial standpoint.

Role of Ti and Y in the nucleation of the primary α-Al of Al7075–Ti–Y natural composites and influence of ultrasonic vibration

Abstract Al7075–Ti–Y natural composites were prepared by using a combination of ultrasonic vibration and casting. The effects of titanium (Ti) and yttrium (Y) on the nucleation of primary α-Al were studied and the influencing mechanism of Y on the TiAl3 formation was analysed. Furthermore, a reaction kinetics model of TiAl3 under ultrasonic vibration was established. The results showed that the uniformly distributed TiAl3 and Al3Y nano-particles resulted in grain refinement. Y changed the morphology of TiAl3 and the appearance of corrosion pits was related to the fact that Y was dissolved within the TiAl3 structure to form Ti(Al,Y)3. The established model revealed that ultrasonic vibration significantly promoted the formation of TiAl3, and that ultrasonic time was the main factor affecting its growth.

ANN-GA based parametric optimization of Al-TiB2 metal matrix composite material processing technique

Over the years, aluminum metal matrix composites (AMMCs) have transitioned into a viable replacement for traditional metals due to their exceptional strength-to-density ratio, higher modulus, excellent wear resistance, and anti-corrosive properties. An economical and efficient technique that uniformly distributes reinforcement particles into liquid aluminum can further widen the industrial applicability of AMMCs. In this work, particulate titanium diboride (TiB2) is reinforced into pure aluminum (Al) to produce Al-TiB2 MMC via a novel hybrid ultrasonic casting route. Three-level process parameters are implemented to obtain the optimal process parameters. Artificial neural network (ANN) is employed to develop predictive models. Using genetic algorithm (GA), single-objective optimization is carried to minimize casting porosity. Optimal values for minimum porosity are obtained through the integrated ANN-GA approach. The experimental validation is done by assessing the microstructure, density, hardness, and tensile behavior of the Al-TiB2 MMC ultrasonically cast using the optimal parametric combination. The results delineate the promising benefits that industries may receive by adopting the hybrid ultrasonic casting and an integrated ANN-GA approach for developing AMMCs.

Scalable ultrasonic casting of large-scale 2219AA Al alloys: Experiment and simulation

An ultra-large 2219 Al alloy ingot (i.e., 1.38 m in diameter and 4.6 m in length) was manufactured using a direct-chill casting technique assisted by four ultrasonic sonotrodes. Then, the effects of ultrasonication on the matrix grains, the α-Al/θ-Al2Cu eutectic structures and the macrosegregation of Cu were experimentally determined. Using numerical simulation, the distribution of physical fields (i.e., the liquid fraction, the temperature gradients and the velocity field) in the sump was simulated and compared between the ingots with and without ultrasonication. After introducing ultrasonication, grain refinement occurred due to the increased cooling rate generated by the accelerated heat transfer in the sump. Meanwhile, the macrosegregation of the major element (Cu) was relieved, which was mainly attributed to the effect of ultrasound-forced convection. Besides, eutectic growth was restricted in the narrowed mushy zone under ultrasound. As a result, eutectic agglomerations were accordingly reduced. The relevant mechanisms were discussed in terms of the experimental results and simulation.

Role of ultrasonic treatment on microstructure, mechanical and tribological behavior of 2D boron nitride reinforced aluminum composites

Abstract This paper presents the first report of ultrasonic treatment (UST) assisted casting of independent 2D layered hexagonal boron nitride (hBN) reinforced aluminum matrix composites. A linear enhancement of nucleation density is obtained with treatment time from 0 to 90 s from dispersion of hBN platelets by UST. Outstanding grain refinement of 72% from 375.3 to 103.6 μm is obtained from UST for 90 s. The corresponding nanohardness is 709.2 MPa, a hardening of 36% due to symbiotic refinement and dispersion contributions. Anchoring and orientation of hBN platelets dictate that the elastic modulus improved up to 150% by ultrasonication for 90 s. The exfoliated 2D reinforcement layers reduce the coefficient of friction during sliding wear by 15% and loss of worn material by 46% in these composites. The mechanism of dispersion, improvement of properties, and quantitative correlations constitute a step of advancement towards understanding the role of 2D particle morphology and dimensionality on the ultrasonic casting of metal matrix composites.

Investigation on Ultrasonic Cavitation Erosion Behaviors of Al and Al-5Ti Alloys in the Distilled Water

Al and Al-5Ti alloys were manufactured by an ultrasonic casting method with a new device, and their ultrasonic cavitation erosion behaviors of Al and Al-5Ti alloys in the distilled water were clarified. The damage mechanism was analyzed by macro photograph, scanning electronic micrograph and three-dimensional morphology, and the results demonstrate that Al-5Ti alloys have better cavitation erosion resistance than Al in terms of the mass loss and the surface damage. The deformation mechanism of Al and Al-5Ti alloys under cavitation erosion is mainly dislocation slip, and the Al3Ti phase enhances the cavitation erosion resistance of Al-5Ti alloys. In addition, the maximum depth of cavitation pits in the Al-5Ti sample is less than that in the Al sample for 31.3%.

Analytical Review of Reinforcement Addition Techniques during Ultrasonic Casting of Metal Matrix Composites

A fundamental understanding of second‐phase reinforcement addition techniques during ultrasonic casting is necessary for the advancement of metal matrix composite manufacturing technology. This review evaluates the comparative efficacy of various addition techniques for incorporating reinforcements under the framework of ultrasonic processing. The evolution of these techniques over time is deciphered in light of the scientific background behind challenges, principles, and methods. Their role in the improvement of microstructure and properties of the composites, intertwined with ultrasonic treatment, is delineated. Techniques introducing greater kinetic disorder during solidification, such as “Stirring” and “Gas‐Assisted Injection” are found to be superior for reinforcement addition. More significant enhancement of microstructural and mechanical characteristics is also obtained in composites manufactured by the techniques with higher kinetics. This culminates in the identification of the limitations and perspectives on the progress of research in this scope. This analytical review of second‐phase reinforcement addition techniques operates as a tool for researchers to steer the advancement of future procedures and therefore metal matrix composite manufacturing technology.

Effects of Ultrasonic Bending Vibration Introduced by an L-Shaped Ultrasonic Rod on the Microstructure and Properties of a 1060 Aluminum Alloy Strip Formed by Twin-Roll Casting.

In order to achieve the industrial application of ultrasonic energy in the continuous casting and rolling production of aluminum alloy, a new type of L-shaped ultrasonic rod was used to introduce an ultrasonic bending vibration into the aluminum melt in the launder during the horizontal twin-roll continuous casting and rolling process of a 1060 aluminum alloy. The effects of the ultrasonic bending vibration on the microstructure and properties of the 1060 aluminum alloy cast rolling strip and its subsequent cold rolling strip were studied experimentally, and the effect of the ultrasonic-assisted refining with different amounts of Al-Ti-B refiner was explored. The results show that under the same addition amount of Al-Ti-B refiner, the ultrasonic bending vibration can refine the grains of the cast rolling strip, make the distribution of precipitates more uniform, reduce the slag inclusion defects, and improve the mechanical properties to a certain extent. The microstructure and properties of the ultrasonic cast rolling strip with 0.18 wt% Al-Ti-B refiner or 0.12 wt% Al-Ti-B refiner are better than those of the conventional cast rolling strip, but the microstructure and properties of the ultrasonic cast rolling strip with 0.09 wt% Al-Ti-B refiner are slightly worse than those of the conventional cast rolling strip. Moreover, after cold rolling, the effect of the ultrasonic bending vibration on the improvement of the microstructure and properties of the aluminum alloy strip is inherited. A comprehensive analysis shows that the use of ultrasonic energy in this paper cannot completely replace the effect of the Al-Ti-B refiner, but it can reduce the addition amount of the Al-Ti-B refiner by 1/3.