Influence of SiC Particles on the Grain Refinement of an Mg-Al Alloy

2009 ◽  
Vol 618-619 ◽  
pp. 445-448 ◽  
Author(s):  
Andreas Schiffl ◽  
Mark Easton
Keyword(s):  
Grain Size ◽  
Phase Equilibria ◽  
Grain Refinement ◽  
Al Alloys ◽  
Al Alloy ◽  
Grain Refiner ◽  
Sic Particles ◽  
Ternary Carbides

SiC particles are effective grain refiners in Mg-Al alloys. Several investigations, from different researchers, into their effect on a range of alloys with different Al contents has been undertaken and it has been found that the greatest reduction in grain size occurs in alloys having low Al contents. Performing grain refinement studies on a range of alloy contents also allows for further investigation into the mechanisms of grain refinement. It was found that the size of the SiC particles is also important in magnesium grain refinement. However, the presence of Mg2Si in the microstructure and the consideration of phase equilibria suggest that SiC can transform into other binary or ternary carbides. If such carbides are formed, they may also act as an effective grain refiner for Mg-Al alloys. In this study, the possibility of formation of new carbides (Al4C3, Al2MgC2, Mn7C3, Mg2C, Mg2C3, Al2CO etc.) and their ability to be good grain refiners for Mg-Al alloys is discussed.

Control of Grain Size and Texture in Al Alloys Utilizing Friction Stir Processing

2007 ◽  
Vol 539-543 ◽  
pp. 3769-3774 ◽  
Author(s):  
Toshiya Shibayanagi ◽  
Masaaki Naka
Keyword(s):  
Grain Size ◽  
Aluminum Alloys ◽  
Grain Refinement ◽  
Grain Growth ◽  
Rotation Speed ◽  
Al Alloys ◽  
Abnormal Grain Growth ◽  
Texture Development ◽  
Al Alloy ◽  
Friction Stir

The present paper deals with the control of microstructure of friction stir processed aluminum alloys focusing on grain refinement, thermal stability at elevated temperature and texture development in some aluminum alloys such as 5083, 6061 and 7075 commercial aluminum alloys. 3mm thickness plates of 5083, 6061 and 7075 Al alloys were friction stir processed/welded with several rotation speeds and travelling speeds. Optical microscopy revealed the grain refinement in the stirred zone of each alloy and the average grain size decreased with decreasing rotation speed under various travelling speeds. Annealing of the joints brought about abnormal grain growth at temperatures higher than 773K for 5083 alloy. Critical temperature of the abnormal grain growth tended to decrease as the rotation speed decreased for the fixed travelling speed. Dissimilar joining of 5083 Al alloy to 6061 Al alloy also showed abnormal grain growth when annealed at 773K. A peculiar texture development of 7075 Al joint showing (111)//ND-oriented grains existing throughout the nugget was revealed by EBSP analysis.

scholarly journals Novel grain refinement of AZ91E magnesium alloy and the effect on hot tearing during solidfication

2021 ◽  
Author(s):  
Abdallah Elsayed
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Hot Tearing ◽  
Grain Refining ◽  
Grain Refiner ◽  
Structural Applications ◽  
Hot Tearing Susceptibility

For the A1-5Ti-1B grain refiner, the addition of 0.1 wt.% provided a 68 % reduction in grain size as compared to the unrefined AZ91E alloy at a holding time of five minutes. Grain growth restriction by TiB₂ particles was the source of grain refinement. With the addition of A1-5Ti-1B, only a small reduction in hot tearing susceptibility ws observed because large TiA1₃ particles bonded poorly with the eutectic and blocked feeding channels.The addition of 1.0 wt.% A1-1Ti-3B provided a grain size reduction of 63% as compared to the unrefined AZ91E alloy at a holding time of five minutes. The grain refinement with A1-1Ti-3B addition was attributed to a combination of TiB₂ grain growth restriction and A1B₂ nucleating sites. A significant reduction in hot tearing susceptibility was observed with A1-1Ti-3B addition as a result of a higher cooling rate and shorter local soldification time as compared to the AZ91E alloy. The reduction in hot tearing susceptibility was attributed to the good interface between eutectic and TiB₂ particles. Both grain refiners demonstrated a good resistance to fading during the holding times investigated. In addition, the AZ91E + A1-5Ti-1B and AZ91E + A1-1Ti-3B castings showed much fewer dislocation networks as compared to the untreated AZ91E casting.The development of efficient A1-Ti-B refiners can also improve castability of magnesium alloys. In addition, the fade resistant A1-Ti-B grain refiners can reduce operating costs and maintain productivity on the foundry floor. Thus, magnesium alloy with A1-Ti-B treatment have the potential for more demanding structural applications in the automobile and aerospace industries. Vehicle weight in the aerospace and automotive industries directly impacts carbon emissions and fuel efficiency. An increase in the use of lightweight materials for structural applications will result in lighter vehicles. Low density materials, such as magnesium (1.74 g/cm³) are a potential alternative to aluminium (2.70 g/cm³), to reduce component weight in structural applications.However, current magnesium alloys still do not have adequate mechanical properties and castability to meet the performance specifications of the automotive and aerospace industries. Grain refinement can significantly improve mechanical properties and reduce hot tearing during permanent mould casting. Recently, Al-Ti-B based grain refiners have shown potential in grain refining magnesium-aluminum alloys such as AZ91E. This study investigates the grain refining efficiency and fading of A1-5Ti-1B and A1-1Ti-3B in AZ91E magnesium alloy and their subsequent effect on hot tearing.The grain refiners were added at 0.1, 0.2, 0.5 and 1.0 wt.% levels. For the grain refinement and fading experiments, the castings were prepared using graphite moulds with holding times of 5, 10 and 20 minutes. For the hot tearing experiments, castings were produced representing the optimal addition level of each grain refiner. The castings were prepared using a permanent mould with pouring and mould temperatures of 720 and 180 ºC, respectively. The castings were characterized using SEM, TEM, optical microscopy and thermal analysis.

Influence of Stacking Fault Energy on the Microstructures and Grain Refinement in the Cu-Al Alloys during Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 379-384 ◽  
Author(s):  
X.H. An ◽  
Shi Ding Wu ◽  
Z.F. Zhang
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Al Alloys ◽  
Stacking Fault ◽  
High Recovery ◽  
Angular Pressing ◽  
High Recovery Rate ◽  
Refinement Mechanism ◽  
Stacking Fault Energies

The microstructural evolution and grain refinement of Cu-Al alloys with different stacking fault energies (SFEs) processed by equal-channel angular pressing (ECAP) were investigated. The grain refinement mechanism was gradually transformed from dislocation subdivision to twin fragmentation with tailoring the SFE of Cu-Al alloys. Concurrent with the transition of grain refinement mechanism, the grain size can be refined into from ultrafine region (1 m~100 nm) to the nanoscale (<100 nm) and then it is found that the minimum equilibrium grain size decreases in a roughly linear way with lowering the SFE. Moreover, in combination with the previous results, it is proposed that the formation of a uniform ultrafine microstructure can be formed more readily in the materials with high SFE due to their high recovery rate of dislocations and in the materials with low SFE due to the easy formation of a homogeneously-twinned microstructure.

Wear Resistance of Pre-ECAP Annealing A356 Al Alloy with 1.5 Wt.% TiB2

2019 ◽  
Vol 961 ◽  
pp. 118-125
Author(s):  
Muhammad Syukron ◽  
Zuhailawati Hussein ◽  
Abu Seman Anasyida
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Optical Microscopy ◽  
Al Alloys ◽  
Wear Testing ◽  
Al Alloy ◽  
Hardness Distribution ◽  
Grain Refiner ◽  
Ecap Processing

The combination of heat treatment, addition of grain refiner and ECAP processing is used to improve mechanical properties and wear resistance of A356 Al alloys with 1.5 wt.% TiB2. The alloys were grouped into as-cast and pre-ECAP annealing. The alloys were characterized with hardness and wear testing, optical microscopy and SEM. The ECAP processing was done through BA route for 4 passes and it improved hardness, distribution of TiB2 and Si particles in the aluminium matrix and increased wear resitance of pre-ECAP annealing specimen.

Practical Considerations on the Application of Ultrasonic Treatment to Mg-Al Shape Castings

2013 ◽  
Vol 765 ◽  
pp. 255-259
Author(s):  
Eraldo Pucina ◽  
Geoff de Looze ◽  
Dacian Tomus ◽  
Mark A. Easton ◽  
Andreas Schiffl ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Ultrasonic Treatment ◽  
Solidification Front ◽  
Al Alloys ◽  
Grain Refining ◽  
Fine Grain ◽  
Effective Form

This paper investigates the use of ultrasonic treatment on the grain refinement of Mg-Al alloys in castings similar to commercial gravity castings. It shows that it is a very effective form of grain refinement but it is limited spatially and by the advancing solidification front if partially-solidified product is washed into the die. It was found that the best way to obtain a homogeneous fine grain size through-out the casting was to combine a grain refining addition, SiC, with ultrasonic treatment during the initial stages of solidification.

Theoretical and Practical Considerations of Grain Refinement of Mg-Al Alloys

2005 ◽  
Vol 488-489 ◽  
pp. 299-302 ◽  
Author(s):  
L. Lu ◽  
Arne K. Dahle ◽  
John A. Taylor ◽  
David H. StJohn
Keyword(s):  
Grain Refinement ◽  
Magnesium Alloys ◽  
Al Alloys ◽  
Experimental Results ◽  
Grain Refiner ◽  
Carbon Based

The fundamentals of grain refinement are reviewed with particular focus on magnesium alloys. This is followed by considerations of the theoretical and practical aspects of grain refinement of Mg-Al alloys by carbon-based grain refiners. Finally, experimental results using Al4C3 as a potential grain refiner are presented and discussed.

Significance of High Rate Superplasticity in Metallic Materials

1990 ◽  
Vol 196 ◽  
Author(s):  
Norio Furushiro ◽  
Shigenori Hori
Keyword(s):  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
Grain Refinement ◽  
Fine Particles ◽  
High Strain ◽  
High Rate ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Al Alloy

ABSTRACTIt has been expected that “High rate superplastic materials” will be developed for industrial applications. The Dorntype equation for high temperature deformation suggests that strain rate can be increased if the grain size is decreased. This means that grain refinement can effectively establish high strain rate superplastic materials.It is well known that a high degree of grain size refinement will result from the addition of zirconium to Al-base alloys. Powder-metallurgical processing with rapidly solidified powders is also available for the improvement of superplasticity by both the refinement of the solidified structure and the maintenance of the stable fine structure of a 7475 Al alloy during recrystallization and deformation. Therefore. P/M 7475 Al alloys containing Zr up to 0.9 wt% were selected as candidate specimens. The objective of the present paper includes the clarification of the role and the effective amount of Zr to obtain high strain rate superplastic materials. As a result, the addition of 0.3%Zr or more is effective in grain refinement of the P/M 7475 Al alloy. However, alloys containing 0.7 and 0.9 wt%Zr only show superplasticity at 793K. The optimum strain rate is shifted to a higher range with increasing Zr. The alloy of 7475 Al-0.9%Zr shows the maximum elongation of 900% at the remarkably high strain rate of 3.3×10−1 s−1.The deformation mechanism of such high stain rate superplasticity will be discussed briefly, by considering the effect of the fine particles of Zr on superplastic behavior.

Estimation of Crystalline Size of Deformed 5251 Al Alloy Using PALT and XRD Techniques

2013 ◽  
Vol 337-338 ◽  
pp. 11-18
Author(s):  
M. Abdel-Rahman ◽  
Ahmed G. Attallah ◽  
M. El-Sayed ◽  
A.A. Ibrahim ◽  
A.A. Akel ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Al Alloys ◽  
Radioactive Isotopes ◽  
Crystalline Size ◽  
Al Alloy ◽  
Solid Materials ◽  
Deformation Effect ◽  
Powerful Technique ◽  
Xrd Techniques

Certain radioactive isotopes decay by emitting positrons, and the positrons can be used to probe the structure of solid materials. For example, one can investigate the grain size due to deformation in a metal. XRD is also a powerful technique for detection the defects introduced into a metal and for investigating the microstructure of a deformed metal. In this paper we shall investigate the plastic deformation effect on the grain size of 5251 Al alloys using two different techniques, PALT and XRD. The study shows a significant effect of the plastic deformation on the grain size which decreases as the deformation increases.

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.

Eco-Friendly Grain Refinement for A3003 Alloy

2009 ◽  
Vol 620-622 ◽  
pp. 89-92
Author(s):  
Hoon Cho ◽  
Jae Hong Ha ◽  
Byoung Soo Lee ◽  
Sung Ho Chang ◽  
Je Sik Shin
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Grain Growth ◽  
Heterogeneous Nucleation ◽  
Aluminum Matrix ◽  
Graphite Crucible ◽  
Holding Time ◽  
Ti Alloy ◽  
Grain Refiner ◽  
Prolonged Holding

Eco-friendly grain refinement of A3003 alloy was studied by addition of non-toxic Al-Ti alloy because of toxic-fluorine in Al-Ti-B alloys which used as a representative grain refiner for aluminum and its alloys. TiAl3 phase in Al-Ti alloy bring to decrease grain size of A3003 alloy. But, grain growth occurred with prolonged holding time due to the solution of Ti into aluminum matrix. In contrast, lasting grain refinement of A3003 alloy was occurred in graphite crucible. It can be mentioned that carbon comes from graphite crucible was combined with Ti solute in aluminum melt and then TiC acts as a heterogeneous nucleation for A3003 alloy.

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