Grain Refinement Mechanism and Effective Nucleation Phase of Al-5Ti-1B Master Alloy

2017 ◽  
Vol 898 ◽  
pp. 1231-1235 ◽  
Author(s):  
Shun Cheng Wang ◽  
Ji Lin Li ◽  
Chun Lei Gan ◽  
Kai Hong Zheng
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Pure Aluminum ◽  
Grain Refiner ◽  
Crystal Nucleus ◽  
Master Alloys ◽  
Refinement Mechanism ◽  
Nucleation Phase ◽  
Heterogeneous Nucleus

The Al-5Ti-1B, Al-10Ti, Al-4B master alloys and TiB2 powder were applied to refine the pure aluminum, respectively. The effects of the TiAl3 phase, TiB2 particle, and AlB2 phase on the grain size of pure aluminum were compared. The grain refinement mechanism of the Al-5Ti-1B grain refiner was studied. The results showed that the TiAl3 phase was an effective heterogeneous nucleus of the α-Al grain. But the TiAl3 phase in the Al-5Ti-1B grain refiner was not the heterogeneous nucleus of the α-Al grain due to its re-melting in the Al melt. The separate TiB2 particle or AlB2 phase was not the heterogeneous nucleus of the α-Al grain. However, the TiB2 coated by the TiAl3 phase can be the effective heterogeneous nucleus of the α-Al grain. The grain refinement mechanism of the Al-5Ti-1B grain refiner can be summarized as follows: when the Al-5Ti-1B grain refiner is added into the Al melt, the TiAl3 phases are re-melted to release the Ti atoms, while the TiB2 particles are remaining in the Al melt. During the solidification of the Al melt, the Ti atoms are segregating on the surface of TiB2 particles to form the TiAl3 phases. The TiB2 particles coated by the TiAl3 phases then reacts with the Al melt to generate α-Al crystal nucleus.

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.

scholarly journals Effect of cooling rates of production process of Al-3%B-3%Sr master alloy on grain refinement and eutectic modification efficiency in cast A356 alloy

2018 ◽  
Vol 192 ◽  
pp. 01036
Author(s):  
Krittee eidhed ◽  
Phisith muangnoy
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Holding Time ◽  
Experimental Result ◽  
Cooling Rates ◽  
Eutectic Modification ◽  
Master Alloys

In this paper, size and morphology of the grain refiner and modifier particles in the Al-3%B-3%Sr master alloy production by using different cooling rates were investigated. Two Al-3%B-3%Sr master alloys were produced with 0.2 and 10°C/s, respectively. The grain refinement and eutectic modification efficiency of the Al-3%B-3%Sr master alloy were tested in casting process of A356 alloy by addition of 4wt.% and holding times for 10-120 min. The experimental result showed that microstructure of the M1 alloy (Slow cooling) consisted of larger solidified particles of AlB2, SrB6 and Al4Sr in the matrix of α-Al compared to the M2 alloy (Rapid cooling). The addition of the M1 alloy in cast A356 alloy, it was found that small grain size and fully modify eutectic silicon were obtained from the holding time in a range of 10-60 min. While the addition of M2 alloy, a small grain size was achieved in shorter holding time in a range of 10-30 min but the eutectic silicon was partly modify. From the thermal analyzed result, solidification of un-modified A356 alloy was changed after addition of Al-3%B-3%Sr master alloy. It was clearly observed that both the undercooling of nucleation and eutectic reaction was reduced and the solidification time was shifted to longer.

Effects of AlN Particles and Electromagnetic Stirring on As-Cast Structure of AZ31 Alloys

2011 ◽  
Vol 675-677 ◽  
pp. 771-774 ◽  
Author(s):  
Song Wei Gu ◽  
Hai Hao ◽  
Can Feng Fang ◽  
Shou Hua Ji ◽  
Xing Guo Zhang
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Grain Growth ◽  
Magnesium Alloys ◽  
Electromagnetic Stirring ◽  
Grain Refiner ◽  
Cast Structure ◽  
Fine Grain ◽  
Refinement Mechanism

A fine grain size generally leads to improved structural uniformity of magnesium alloys. AlN has been identified as a potential grain refiner and electromagnetic stirring may have great effects on microstructure and grain growth. This study will be focused on the effects of AlN particles and electromagnetic stirring on the as-cast structure of AZ31 alloys.The grain refinement mechanism of both methods on magnesium alloy and their interaction effects are also discussed.

The Grain Refinement of Al-Si Alloys and the Cause of Si Poisoning: Insights Revealed by the Interdependence Model

2014 ◽  
Vol 794-796 ◽  
pp. 161-166 ◽  
Author(s):  
Mark A. Easton ◽  
Arvind Prasad ◽  
David H. St. John
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Cost Effective ◽  
Optimum Level ◽  
Grain Sizes ◽  
Relative Contribution ◽  
Master Alloys ◽  
Effective Use ◽  
Special Case

Recent work has extended the Interdependence Model to the prediction of grain size of aluminium alloys when refined by Al-Ti-B master alloys. The relative contribution of Ti solute and TiB2 particles to the as-cast grain size was determined indicating the optimum level of addition required to provide cost effective use of master alloy. This paper quantifies the effect of Al5Ti1B master alloy additions on the grain size of Al-Si alloys. The Al-Si system is a special case where additions of Si above a few percent poison grain refinement resulting in larger grain sizes. Consideration of the complicating effect of Si poisoning on the prediction of the grain size of these alloys and possible approaches to dealing with these complications are presented.

scholarly journals Grain Refinement of AZ91 Magnesium Alloy Induced by Al-V-B Master Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1333 ◽  
Author(s):  
Wang Chang ◽  
Yanping Shen ◽  
Yueying Su ◽  
Long Zhao ◽  
Yunhu Zhang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Comparative Study ◽  
Grain Refinement ◽  
Master Alloy ◽  
Al Alloys ◽  
Az91 Alloy ◽  
Grain Refiner ◽  
Az91 Magnesium Alloy ◽  
Master Alloys ◽  
Az91 Magnesium

It has long been recognized that grain refinement of Mg-Al alloys is difficult, although various methods have been tried. In the present paper, a novel grain refiner, Al-3.4V-1B master alloy, has been developed to refine the as-cast AZ91 alloy. A comparative study on grain refinement effects of Al-3.4V-1B, Al-5V, and Al-3Ti-1B master alloys was performed under the same solidification conditions. It is shown that Al-3.4V-1B master alloy not only has significant grain refinement ability, but also keeps stable anti-fading capacity with holding time up to 2 h. Based on the analysis of grain refinement, VB2 particles introduced by Al-3.4V-1B master alloy are the heterogeneous nuclei for AZ91 alloy.

scholarly journals Development of New Oxide Based Master Alloys and their Grain Refinement Potency in Aluminium Alloys

2015 ◽  
Vol 828-829 ◽  
pp. 23-28 ◽  
Author(s):  
Vadakke Madam Sreekumar ◽  
N. Hari Babu ◽  
Dmitry G. Eskin ◽  
Z. Fan
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Master Alloy ◽  
Aluminium Alloys ◽  
Al Alloys ◽  
Ultrasonic Cavitation ◽  
Size Reduction ◽  
Refinement Efficiency ◽  
Master Alloys

In this study, grain refinement efficiency of a new oxide master alloy based on MgAl2O4 was demonstrated in Al alloys. The grain size of the reference alloy was reduced by 50-60% with the addition of the master alloy and introduction of ultrasonic cavitation. While cooling rate has an influence on the grain size reduction, higher levels of addition of master alloy was found to be not effective in further reducing the grain size.

An Investigation on Grain Refinement Mechanism of Master Alloys Al-Ti, Al-TiC and Al-Ti-C Toward Pure Aluminum

2013 ◽  
Vol 652-654 ◽  
pp. 1072-1075 ◽  
Author(s):  
Wan Wu Ding ◽  
Jiang Tao Zhu ◽  
Wen Jun Zhao ◽  
Tian Dong Xia
Keyword(s):  
Grain Refinement ◽  
Heterogeneous Nucleation ◽  
Pure Aluminum ◽  
Grain Refining ◽  
Nucleation Effect ◽  
Commercially Pure ◽  
Master Alloys ◽  
Refinement Mechanism ◽  
Heat Preservation

The grain refining effects of Al-Ti, Al-TiC and Al-Ti-C master alloys on commercially pure aluminum were compared, and the grain refinement mechanism of TiAl3 and TiC among master alloys was discussed. The results show that: the grain refinement of the master alloys Al-TiC and Al-Ti toward pure aluminum mainly stems from the heterogeneous nucleation role of TiC and TiAl3 particles, but with the extension of heat preservation time of fused mass, its role of heterogeneous nucleation will decline due to dissolution of TiAl3 and aggregation and precipitation of TiC. The preferable grain refinement effects of Al-Ti-C master alloys toward pure aluminum are mainly due to the fact that when TiAl3 and TiC particles are acted commonly as heterogeneous nucleation particles, the heterogeneous nucleation effect of TiC particles will be enhanced because of the presence of TiAl3.

Grain Refinement Mechanism in Al–4B Master Alloy Added Pure Mg

2012 ◽  
Vol 710 ◽  
pp. 161-166 ◽  
Author(s):  
Murugavel Suresh ◽  
Amirthalingam Srinivasan ◽  
Uma Thanu Subramonia Pillai ◽  
Bellambettu Chandrasekhara Pai
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Fluoride Salt ◽  
Boundary Area ◽  
Maximum Reduction ◽  
Alloy Addition ◽  
Refinement Mechanism ◽  
Particle Strengthening

Al–4B master alloy has been prepared by the reaction of fluoride salt KBF4 with molten Al and different amounts of this master alloy (0.5, 1, 1.5 and 2 wt%) has been added to pure Mg to study in detail its effect on the grain refinement of pure Mg. Considerable reduction in grain size from 1300 to 210μm is obtained and maximum reduction is observed with 2 wt% master alloy addition. The grain refinement is caused by both the growth restriction effect of Al and the presence of potent AlB2 nucleant particles. Improvement in mechanical properties is obtained with Al–4B master alloy and is attributed to increase in grain boundary area due to the grain refinement and the particle strengthening due to AlB2.

Grain refinement mechanism of pure aluminum by inoculation with Al–B master alloys

2012 ◽  
Vol 549 ◽  
pp. 136-143 ◽  
Author(s):  
Tongmin Wang ◽  
Zongning Chen ◽  
Hongwang Fu ◽  
Lei Gao ◽  
Tingju Li
Keyword(s):  
Grain Refinement ◽  
Pure Aluminum ◽  
Master Alloys ◽  
Refinement Mechanism

The influence of gadolinium on Al–Ti–C master alloy and its refining effect on AZ31 magnesium alloy

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenxue Fan ◽  
Hai Hao
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Master Alloy ◽  
Cast Alloy ◽  
Az31 Magnesium Alloy ◽  
Synthesis Mechanism ◽  
Refining Effect ◽  
Master Alloys

Abstract Grain refinement has a significant influence on the improvement of mechanical properties of magnesium alloys. In this study, a series of Al–Ti–C-xGd (x = 0, 1, 2, 3) master alloys as grain refiners were prepared by self-propagating high-temperature synthesis. The synthesis mechanism of the Al–Ti–C-xGd master alloy was analyzed. The effects of Al–Ti–C-xGd master alloys on the grain refinement and mechanical properties of AZ31 (Mg-3Al-1Zn-0.4Mn) magnesium alloys were investigated. The results show that the microstructure of the Al–Ti–C-xGd alloy contains α-Al, TiAl3, TiC and the core–shell structure TiAl3/Ti2Al20Gd. The refining effect of the prepared Al–Ti–C–Gd master alloy is obviously better than that of Al–Ti–C master alloy. The grain size of AZ31 magnesium alloy was reduced from 323 μm to 72 μm when adding 1 wt.% Al–Ti–C-2Gd master alloy. In the same condition, the ultimate tensile strength and elongation of as-cast alloy were increased from 130 MPa, 7.9% to 207 MPa, 16.6% respectively.

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