Grain Refinement Efficiency

2021 ◽  
pp. 829-836
Author(s):  
Rein Vainik ◽  
John Courtenay ◽  
Frode Lien
Keyword(s):  
Grain Refinement ◽  
Refinement Efficiency

scholarly journals The Interactions Between Oxide Film Inclusions and Inoculation Particles TiB2 in Aluminum Melt

2021 ◽  
Author(s):  
Jiawei Yang ◽  
Sarina Bao ◽  
Shahid Akhtar ◽  
Yanjun Li
Keyword(s):  
Grain Refinement ◽  
Master Alloy ◽  
Large Fraction ◽  
Oxide Films ◽  
Grain Refiner ◽  
Particle Sedimentation ◽  
Aluminum Melt ◽  
Refinement Efficiency ◽  
Long Time ◽  
Commercial Purity Aluminum

AbstractIn this work, a systematic study on the interactions between aluminum oxide films and TiB2 grain refiner particles and their effect on grain refinement behavior have been conducted. Oxide films were introduced into a commercial purity aluminum melt by adding AA 6061 alloy chips while the grain refiner particles were introduced by adding Al-3T-1B master alloy. Strong sedimentation of TiB2 grain refiner particles was observed in aluminum melt without chip addition during long-time settling. Most of the TiB2 particles were settled and accumulated at the bottom of crucible. In contrast, the sedimentation of TiB2 particles is much less in the melt with the addition of oxide films. A large fraction of TiB2 particles were found to be adhered to the oxide films located at the top part of the crucible, which inhibited the sedimentation of grain refiner particles. TP-1 type tests were also done to study the grain refinement efficiency of Al-3Ti-1B master alloy under different melt cleanliness and settling time. It is found that sedimentation of TiB2 particles greatly reduces the grain refinement efficiency. The introduction of oxide films seems to slightly alleviate the fading effect. This is owing to the strong adherence between the oxide films and TiB2 particles, which leads to a retardation of particle sedimentation.

Enhancing grain refinement efficiency and fading resistance of Al–B master alloys processed by equal channel angular pressing

2018 ◽  
Vol 33 (12) ◽  
pp. 1782-1788
Author(s):  
Kun Xia Wei ◽  
Yan Wei Zhang ◽  
Wei Wei ◽  
Xian Liu ◽  
Qing Bo Du ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Refinement Efficiency ◽  
Master Alloys ◽  
Image Position

Abstract

scholarly journals Effect of Inclusion and Filtration on Grain Refinement Efficiency of Aluminum Alloy

2022 ◽  
Author(s):  
Jiawei Yang ◽  
Yijiang Xu ◽  
Sarina Bao ◽  
Shahid Akhtar ◽  
Ulf Tundal ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Oxide Films ◽  
Pilot Scale ◽  
Ceramic Foam ◽  
Grain Refiner ◽  
Aluminum Melt ◽  
Refinement Efficiency ◽  
Master Alloys ◽  
And Performance

AbstractIt is well known that the filtration efficiency of ceramic foam filters (CFF) on aluminum melt can be significantly reduced by the addition of grain refiner particles under a high inclusion load. Also, it is usually considered that the filtration process has little impact on grain refinement efficiency. In this work, the influence of inclusions and filtration on the grain refinement effect of AA 6060 alloy has been studied. This was done through TP-1 type solidification experiments where the aluminum melt prior to and after the filter during a pilot-scale filtration test was investigated. In the experiments, 80 PPi CFFs were used to filtrate aluminum melt with an ultra-high inclusion load and two addition levels of Al–3Ti–1B master alloys. It is found that both inclusions and filtration significantly reduce the grain refinement efficiency of the grain refiner master alloys. A detailed characterization of the used filters shows that the reduction of grain refinement efficiency is due to the strong adherence of TiB2 particles to the oxide films, which are blocked by the CFF during filtration. A grain size prediction model based on deterministic nucleation mechanisms and dendritic growth kinetics has been applied to calculate the solidification grain size and estimate the loss of effective grain refiner particles during filtration. It is shown that due to the strong adherence between TiB2 particles and oxide films in the melt, the high addition level of aluminum chips also has an influence on reducing the grain refinement efficiency of aluminum melt without filtration. The results of this study extended our understanding of the behavior and performance of inoculant particles in CFF and their interactions with the inclusions.

Influence of MnCO3 Addition on the Grain Refinement of AZ91 Magnesium Alloy

2014 ◽  
Vol 703 ◽  
pp. 56-59
Author(s):  
Xiao Ying Liu ◽  
Hao Ran Geng ◽  
Min Zuo ◽  
Peng Fei Ji
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Az91 Alloy ◽  
Grain Refining ◽  
Az91 Magnesium Alloy ◽  
Refinement Efficiency ◽  
Az91 Magnesium ◽  
Resistance Performance ◽  
Addition Amount

This article reports the effect of MnCO3addition on the grain refinement efficiency of AZ91 magnesium alloy. The results indicate that the addition of MnCO3has excellent grain refining efficiency for AZ91 alloy, which is mainly attributed to the Al4C3particles formed in the melt, besides Mn is indispensable to grain refinement in Al-bearing magnesium alloys. There is an optimal addition amount of 0.6% at 740 °C and the grain size is reduced from 245 to 91 μm. At the same time, the corrosion resistance performance of MnCO3-added AZ91is improved.

Improvement of Grain Refinement Efficiency in Pure Aluminum by Embryos Proliferation

2014 ◽  
Vol 29 (7) ◽  
pp. 826-831 ◽  
Author(s):  
Xiaobo Zhang ◽  
Jing Sun ◽  
Cong Zhou ◽  
Yijie Zhang ◽  
Naiheng Ma ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Pure Aluminum ◽  
Refinement Efficiency

scholarly journals A study on grain refinement of AZ91E magnesium alloy with Al-5TiB₂, AI-Al₄C₃ and ZnO additions

2021 ◽  
Author(s):  
Kenneth Lee
Keyword(s):  
Grain Refinement ◽  
Base Alloy ◽  
Hot Tearing ◽  
Mg Alloys ◽  
Grain Refiner ◽  
Dendritic Microstructure ◽  
Refinement Efficiency ◽  
Average Grain Size ◽  
Refinement Mechanism ◽  
Environmentally Safe

There is great interest in increasing the use of magnesium (Mg) alloys in transportation applications to reduce weight. The use of these alloys would increase if their strength and castability were improved. Through grain refinement, it is possible to achieve significant improvement in specific mechanical properties such as strength and hardness. For aluminum (A1)-containing Mg alloys, a commonly used grain refiner is hexachloroethane (C₂Cl₆). Though effective, C₂Cl₆ use releases harmful chlorinated hydrocarbons. It is therefore desired to find novel grain refiners that are effective and environmentally safe. This thesis focused on the grain refinement of AZ9lE alloy with three refiners: Al-5TiB₂, Al-A1₄C₃ and ZnO. The refiners were chosen due to their known grain refinement efficiency in low-Al Mg or Mg-Zn alloys. Castings with each refiner were made in graphite molds to establish i) the optimum addition levels to achieve the smallest average grain size and ii) the effect of holding time on fading of grain refinement efficiency. These castings ere used to collect thermal data and sectioned for microscopy and hardness testing. Castings were also made with the optimum parameters in a permanent mold specifically designed to investigate hot tearing susceptibility. The results indicated that all three additions enabled grain refinement of the base alloy, and no fading of grain refiner efficiency was observed. These refiners transformed the coarse dendritic microstructure in AZ9lE to one that was equiaxed and globular. At optimal levels, the refinement mechanism was heterogeneous nucleation. Also, hot tearing was significantly decreased with all refiners except for ZnO. The excess Zn from ZnO addition led to an increase in the freezing range, thus increasing the hot tear severity. The hardness of AZ9lE did not increase with ZnO addition as it did with the other two refiners.

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