Microstructure-Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al–Si (A390) Alloy

Kim, Soo Bae; Cho, Young Hee; Jung, Jae Gil; Yoon, Woon‐Ha; Lee, Young Kook; Lee, Jung Moo

doi:10.1007/s12540-018-0150-3

Cited by 20 publications

(8 citation statements)

References 29 publications

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“…furthermore. According to Reference [46], ultrasound can promote the diffusion of solute elements in the matrix, increasing the solid solubility of the matrix to the solute elements, which also explains the observed microstructure of UST ingots, and the reduction of coarse secondary phases. The increase in ingot yield strength using UST is likely due to an increase in solute, which leads to solid-soluble reinforcement in the casting state.…”

Section: Mechanical Propertiesmentioning

confidence: 95%

Effects of High-Intensity Ultrasound on the Microstructure and Mechanical Properties of 2195 Aluminum Ingots

Jiang

et al. 2021

Metals

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The microstructural refinement of 2195 aluminum alloy ingots is particularly important for improving their industrial applications and mechanical properties. Combined with vacuum casting and inert gas protection, scalable high-strength ultrasonic melt processing (USMT) technology was used to manufacture 2195 aluminum alloy cylindrical ingots. Then, the influence of USMT on the main microstructural components (primary α-Al grains, secondary phase network, and precipitated particles) was studied. Our experiments show that the main microstructure of the ingot was improved after the introduction of ultrasound. Compared to the ingot formed without USMT, the size and morphology of the primary α-Al phase were optimized. The agglomeration of coarsening secondary phases can be alleviated, and the large layered secondary phase network becomes discontinuous throughout the ingot under USMT. At the same time, the mechanical properties of the solidified aluminum alloy ingots were also tested, and comparisons were made between samples formed with and without USMT. The results show that the stress concentration caused by the large area of coarse secondary phase in the ingot leads to the decrease of mechanical properties.

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Section: Mechanical Propertiesmentioning

confidence: 95%

Effects of High-Intensity Ultrasound on the Microstructure and Mechanical Properties of 2195 Aluminum Ingots

Jiang

et al. 2021

Metals

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“…It has been reported that the narrow size distribution of refiner particles after UST of Zr added to Mg [6] and Al-Ti-B [67], Al-Zr, Al-Zr-Ti [63] added to Al alloys results in better grain refinement. The refinement of blocky and needle shape primary intermetallic phases such as Al 3 Ti [63,68], Al 3 (Zr, Ti) [63,69], primary Si [70,71,72] and β/δ-Al-Fe-Si [24,25] phases is an added advantage of UST that further improves the mechanical properties of the cast alloys. Figure 7 shows a summary of the common intermetallic phases encountered in commercial Al alloys and their refinement after UST.…”

Section: Ust Applied To the Liquid Meltmentioning

confidence: 99%

Ultrasonic Processing for Structure Refinement: An Overview of Mechanisms and Application of the Interdependence Theory

et al. 2019

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Research on ultrasonic treatment (UST) of aluminium, magnesium and zinc undertaken by the authors and their collaborators was stimulated by renewed interest internationally in this technology and the establishment of the ExoMet program of which The University of Queensland (UQ) was a partner. The direction for our research was driven by a desire to understand the UST parameters that need to be controlled to achieve a fine equiaxed grain structure throughout a casting. Previous work highlighted that increasing the growth restriction factor Q can lead to significant refinement when UST is applied. We extended this approach to using the Interdependence model as a framework for identifying some of the factors (e.g., solute and temperature gradient) that could be optimised in order to achieve the best refinement from UST for a range of alloy compositions. This work confirmed established knowledge on the benefits of both liquid-only treatment and the additional refinement when UST is applied during the nucleation stage of solidification. The importance of acoustic streaming, treatment time and settling of grains were revealed as critical factors in achieving a fully equiaxed structure. The Interdependence model also explained the limit to refinement obtained when nanoparticle composites are treated. This overview presents the key results and mechanisms arising from our research and considers directions for future research.

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“…Microstructural refinement and modification are possible using a modified casting process, which involves creating disturbances in melt during solidification. Disturbances in melt during solidification are produced by various methods such as ultrasonic vibration, 11,12 electromagnetic vibration, 13,14 and mechanical vibration. 15,16 Each of these vibration methods has shown promising results in terms of grain refinement and improvement in mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Changes and Quality Improvement of Al7Si0.2Mg (356) Alloy by Die Vibration

2020

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The influence of amplitude and frequency of die vibration during solidification on microstructural evolution of Al-7Si-0.2Mg (356, LM-25) alloy was studied. The amplitude of die vibration was varied from 0.0 to 1.05 mm at 50 Hz frequency, and the frequency was changed from 30 to 50 Hz at a amplitude of 0.75 mm. Structural examination and quality of the casting were evaluated in terms of porosity at various processing conditions. Vibration modified and refined structure during gravity die casting of the alloy. Macrostructure of casting prepared in vibrating die consisted of fine equiaxed grains. In contrast, macrostructure of casting produced in stationary die typically consisted of columnar grains at the periphery and equiaxed grains at the center. Die vibration resulted in microstructure of mixed type comprising of globular and dendritic primary a-Al with interdendritic eutectic Si particles. On the contrary, microstructure of casting produced in stationary die consisted of dendritic a-Al structure and eutectic Si particles. In addition, die vibration reduced secondary dendritic arms spacing (SDAS) to 18.98 lm from 34.38 lm obtained without vibration. Since SDAS is a measure of cooling rate, its reduction due to die vibration implies an increase in cooling rate of casting. This is attributed to the forced convection effect generated by die vibration. Consequently, the higher cooling rate owing to the die vibration reduced microsegregation of Si and Mg in the casting. Further, structural modification and refinement due to die vibration improved the quality of casting significantly in terms of porosity.

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Microstructure-Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al–Si (A390) Alloy

Cited by 20 publications

References 29 publications

Effects of High-Intensity Ultrasound on the Microstructure and Mechanical Properties of 2195 Aluminum Ingots

Effects of High-Intensity Ultrasound on the Microstructure and Mechanical Properties of 2195 Aluminum Ingots

Ultrasonic Processing for Structure Refinement: An Overview of Mechanisms and Application of the Interdependence Theory

Microstructural Changes and Quality Improvement of Al7Si0.2Mg (356) Alloy by Die Vibration

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