Grain Refinement of AZ91E and Mg-9 WT.% Al Binary Alloys Using Zinc Oxide

Saha, Subrata; Ravindran, C.

doi:10.1007/bf03355600

Cited by 13 publications

(5 citation statements)

References 28 publications

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“…It is hard to conclude that the ZnO particles had totally transformed into Zn solute during the addition and holding process. A recent work was conducted using ZnO particles (0.52 ± 0.38 lm) to refine as-cast AZ91E alloy [17]. Some ZnO cores with 4-5 lm size were observed inside the grains.…”

Section: Discussionmentioning

confidence: 96%

“…Previous works had suggested that the heterogeneous nucleation on the surface of big enough ZnO particle was useful in a short-contact situation before the ZnO had been totally converted into Zn solute in Mg melt [17,25]. However, it was difficult to achieve the short-contact process, because a required holding time to separate the inclusions and slags during the common casting process was necessary to obtain a sound casting.…”

Section: Discussionmentioning

confidence: 99%

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The Effects of ZnO Particles on the Grain Refinement and Mechanical Properties of AZ31 Magnesium Alloys

Liu

Zhang

et al. 2016

Trans Indian Inst Met

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The grain refinement and mechanical properties of AZ31 alloy with ZnO additions were investigated using suction casting method. ZnO addition could provide a more pronounced grain refinement and strengthening effects to the AZ31 alloy than Zn solute addition did. The grain size were well refined from 325 to 220 lm with 1.3 wt% ZnO addition. The grain refining mechanism of ZnO particles (*200 nm) mainly arose from the transformed Zn solute restricting the grain growth and the micro convection by the reaction enthalpy clearing solute suppressed nucleation effects. Meanwhile, the ZnO addition provided uniform solute field and steadly ensured a fine-grain and uniform second phase distribution. With 1.3 wt% ZnO addition, the ultimate tensile strength and yielding tensile strength of suction cast AZ31 alloy were as high as 205 and 66 MPa, respectively. The refining and strengthening mechanism have been discussed in detail.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

The Effects of ZnO Particles on the Grain Refinement and Mechanical Properties of AZ31 Magnesium Alloys

Liu

Zhang

et al. 2016

Trans Indian Inst Met

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“…The liberated Zn is thought to increase solute within the melt providing some growth restriction [154,270]. However, ZnO addition was unable to reduce hot tearing susceptibility in permanent mould castings [271].…”

Section: A221 Aluminum-titanium (Al-ti) Grain Refinersmentioning

confidence: 99%

Inclusion removal and grain refinement of magnesium alloy castings

Elsayed¹

2021

Preprint

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Magnesium alloys show promise to be materials for lightweighting of automotive and aerospace vehicles improving fuel efficiencies and vehicle performance. A majority of magnesium alloy components are produced using casting where susceptibility to forming inclusions and coarse grain sizes could result. Development of effective inclusion removal techniques and better understanding of grain refinement of magnesium alloys could help in improving their mechanical properties to advance them to more structurally demanding applications. This research aimed to develop an environmentally friendly alternative to the grain refinement and inclusion removal capabilities of carbon based hexachloroethane as it releases dioxins, chlorine gas and corrodes foundry equipment. A secondary aim was to pioneer in-situ neutron diffraction to examine the solidification of magnesium alloys. The research involved preparing tensile samples of AZ91E magnesium alloy using permanent mould casting. Inclusion removal was conducted by using filtration and argon gas bubbling. Castings grain refined using hexachloroethane (0.25, 0.50 and 0.75 wt.%) were compared against ex-situ aluminum-silicon carbide and in-situ aluminum-carbon based grain refiners combined with filtration and argon gas bubbling. Further, in-situ neutron diffraction was utilized for phase analysis and fraction solid determination of magnesium-zinc and magnesium-aluminum alloys. There was a significant improvement in yield strength, ultimate tensile strength and elongation with filtration plus argon bubbling, carbon inoculation or both filtration plus argon bubbling and carbon inoculation. The results indicated that the mechanism of the observed ~20% reduction in grain sizes with carbon inoculation (hexachloroethane, ex-situ aluminum-silicon carbide and in-situ aluminum-carbon) was explained through duplex nucleation of Mn-Al and Al-Mg-C-O (likely Al2MgC2) phases. Finally, in-situ neutron diffraction was used to follow the formation of Mg17Al12 eutectic phase in a magnesium-9 wt.% aluminum alloy. For the magnesium-zinc alloys, in-situ neutron diffraction enabled characterization of the effects of zirconium to the fraction solid growth of (1010), (0002) and (1011) α-Mg planes. The societal and environmental impact of this research is significant. There is a clear demonstration of alternatives to the universally used hexachloroethane grain refiner promoting harmful emissions. Improved mechanical properties resulting from new grain refinement and iv inclusion filtration are a major advancement in promoting weight reduction, improved castability and decreased environmental impact for automotive and aerospace industries.

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“…Improvement in mechanical properties of Mg can be achieved through the reinforcement of alloys with hard ceramic particles, producing metal matrix composites (MMC) [64][65][66][67][68][69][70][71].…”

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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Grain Refinement of AZ91E and Mg-9 WT.% Al Binary Alloys Using Zinc Oxide

Cited by 13 publications

References 28 publications

The Effects of ZnO Particles on the Grain Refinement and Mechanical Properties of AZ31 Magnesium Alloys

The Effects of ZnO Particles on the Grain Refinement and Mechanical Properties of AZ31 Magnesium Alloys

Inclusion removal and grain refinement of magnesium alloy castings

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

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