Synergistic Effect of In-Situ Al-7075/Al3Ti Metal Matrix Composites Prepared via Stir-Assisted Ultrasonic Melt Processing Under Dynamic Nucleation

Sujith, S.; Kim, Han‐Soo; Mulik, Rahul S.; Park, Hyeonwoo

doi:10.1007/s12540-021-01143-y

Cited by 20 publications

(2 citation statements)

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“…Ultrasonic treatment (UST) has recently emerged as an effective means for the refinement of metals and alloys [55,54,[110][111][112]. The process entails the application of high-intensity ultrasonic vibration to the liquid metal using a sonotrode.…”

Section: Introductionmentioning

confidence: 99%

Grain Refinement of Az91e Magnesium Alloy Through Ultrasonic Treatment, Inoculation and Hybrid Processing for Improvements to Microstructure and Mechanical Properties

Emadi

2024

Preprint

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<p>Light metals are gaining increased attention due to ecological sustainability concerns and consequent strict emission regulations. Magnesium (Mg) has the potential to replace aluminum (Al) and steel components, which can reduce emissions through lightweighting. However, widespread implementation of Mg is hindered by its low mechanical properties. As a means for improving the mechanical properties of cast alloys, ultrasonic processing has shown increasing promise within the past years. As well, grain refinement and reinforcement with ceramic particles can also improve the properties of cast alloys. This dissertation examines the effects of ultrasonic treatment (UST), grain refinement with Œ±-Al 2 p3rticles, and their combination to produce hybrid refined castings on the microstructure and mechanical properties of cast Mg alloys. To evaluate the effects of UST, the molten alloys were subjected to 60 to 240 s of sonication at a frequency and amplitude of 20 kHz and 15 ¬µm, respectively. Vibrational amplitudes ranging from 1.25 to 15 ¬µm were also investigated. Sonication time was found to improve the mechanical properties of the alloy relative to the base condition. In addition, vibrational amplitudes up to 7.5 ¬µm were able to refine the secondary phases of the alloy. In both cases, the improvement was attributed to the refinement of the Mg grain structure and secondary phases. Grain refinement with Al2O3 was performed with mechanical stirring (MS) and addition levels ranging from 0.25 to 2 wt.%. The highest levels of improvement for ultimate tensile strength and ductility were achieved through 0.5 wt.% Al2O3 addition. Moreover, hybrid refined samples were prepared by combining 1 wt.% Al2O3 addition and UST. The hybrid samples displayed improved mechanical properties relative to the base alloy and the samples prepared with MS. This was attributed to the finer grain size, and enhanced inoculant distribution. Thus, significantly improved mechanical properties of Mg alloys are facilitated by UST, grain refinement with Al2O3 and hybrid processing. These processes have the potential to replace higher density Al and iron-based components, with consequent energy efficiency and environmental and ecological benefits.</p>

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Section: Introductionmentioning

confidence: 99%

Grain Refinement of Az91e Magnesium Alloy Through Ultrasonic Treatment, Inoculation and Hybrid Processing for Improvements to Microstructure and Mechanical Properties

Emadi

2024

Preprint

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“…According to one theory, coherent crystallographic orientation should reduce the interfacial energy between the nuclei and the matrix in an efficient nucleate. A different approach, the free-growth model, places more emphasis on the size of the nuclei particles and suggests that, in order for the nucleation to proceed properly, an efficient nucleus particle should be larger than a crucial threshold value [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Zr as an Alternative Grain Refiner in the Novel AlSi5Cu2Mg Alloy

Bolibruchová,

Matejka,

Širanec

et al. 2024

Metals

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Al-Si-Cu-Mg alloys are among the most significant types of aluminum alloys, accounting for 85–90% of all castings used in the automotive sector. These alloys are used, for example, in the manufacturing of engine blocks and cylinder heads due to their excellent specific strength (ratio of strength to specific weight) and superior castability and thermal conductivity. This study investigated the effect of using Zr as an alternative grain refiner in the novel AlSi5Cu2Mg cylinder head alloy. The microstructure of this alloy could not be refined via common Al-Ti-B grain refiners due to its specifically designed chemical composition, which limits the maximum Ti content to 0.03 wt.%. The results showed that the addition of Zr via the AlZr20 master alloy led to a gradual increase in the solidus temperature and to the grain refinement of the microstructure with the addition of as little as 0.05 wt.% Zr. The addition of more Zr (0.10, 0.15, and 0.20 wt.%) led to a gradual grain refinement effect for the alloy. The presence of Zr in the AlSi5Cu2Mg alloy was reflected in the formation of Zr-rich intermetallic phases with acicular morphology. Such phases acted as potent nucleants for the α-Al grain.

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