Grain Refinement Performance of Al Cast Using Machining Chips

2010 ◽  
Vol 654-656 ◽  
pp. 1444-1447 ◽  
Author(s):  
Yoshimi Watanabe ◽  
Kenichi Tabushi ◽  
Hisashi Sato ◽  
Eri Miura-Fujiwara
Keyword(s):  
Cooling Rate ◽  
Grain Refinement ◽  
Nucleation Site ◽  
Grain Refiner ◽  
Metallic Mold ◽  
Refinement Effect

In this study, grain refinement performance of as-cast Al using machining chip of Al instead of the grain refiner is investigated. At first, the machining chips of pure Al are placed in metallic mold. Then, pure Al melt is inserted into the mold with the machining chips. From the microstructure of the as-cast Al using the machining chips, it is found that this machining chip in mold can induce grain refinement of as-cast Al. The increment of the Al chips enhances the grain refinement of the as-cast Al. Moreover, it is shown that preheating the mold can reduce the pore inside as-cast Al using the machining chips. This grain-refinement effect by the machining chips would come from the enhancement of cooling rate and the role of the nucleation site. Therefore, it is concluded that the machining chips of Al can enhance the grain refinement of as-cast Al.

The Role of Fe on the Grain Refinement of High Purity Aluminium

2012 ◽  
Vol 538-541 ◽  
pp. 2264-2268 ◽  
Author(s):  
Yi Jie Zhang ◽  
Nai Heng Ma ◽  
Brian J. McKay ◽  
Xian Feng Li ◽  
Hao Wei Wang
Keyword(s):  
Grain Refinement ◽  
High Purity ◽  
Solute Concentration ◽  
Grain Structure ◽  
Grain Refiner ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
Solid Liquid Interface ◽  
Solid Liquid

The role of Fe on the grain refinement of high purity aluminium (HPAl) was investigated after adding commercial Al-5Ti-1B grain refiner rod. Experimental results show that with a 0.08% Fe addition, the grain structure at chill zone of the HPAl sample changes from coarse to fine equiaxed grains. More importantly, the grain size observed at the centre of the HPAl sample decreased from 500±50µm to 206±30µm. The improvement has been attributed to the interfacial segregation and solute concentration of the Fe at the solid-liquid interface.

Grain refinement effect of a pulsed magnetic field on as-cast superalloy K417

2009 ◽  
Vol 24 (8) ◽  
pp. 2670-2676 ◽  
Author(s):  
Xiaoping Ma ◽  
Yingju Li ◽  
Yuansheng Yang
Keyword(s):  
Magnetic Field ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Mold Wall ◽  
Thermal Control ◽  
Pulsed Magnetic Field ◽  
Refinement Process ◽  
Melt Convection ◽  
Melt Cooling ◽  
Refinement Effect

The grain refinement effect of a pulsed magnetic field on superalloy K417 was studied. The experimental results show that fine equiaxed grains are acquired with proper thermal control under the pulsed magnetic field. The refinement effect of the pulsed magnetic field is affected by the melt cooling rate and the melt superheating. The refinement effect of the pulsed magnetic field is attributed to the dissociation of nuclei from the mold wall by melt vibration and the subsequent dispersion of nuclei by melt convection. The Joule heat and the melt convection caused by the pulsed magnetic field may defer the formation of solidified shell, which prolongs the continuous refinement process. The decrease of melt cooling rate reduces the number of nuclei produced on the mold wall but prolongs the duration for the nuclei to depart from the mold wall and disperse in the melt, which enhances the refinement effect of the pulsed magnetic field. The increase of melt superheating lessens the survival probability of the nuclei in the melt, which weakens the refinement effect of the pulsed magnetic field.

Grain Refinement and Nuclei Formation Mechanism of Ni-Based Superalloy K417 with Low Voltage Pulsed Magnetic Casting

2010 ◽  
Vol 654-656 ◽  
pp. 428-431
Author(s):  
Yuan Sheng Yang ◽  
Xiao Ping Ma ◽  
Ying Ju Li
Keyword(s):  
Magnetic Field ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Formation Mechanism ◽  
Low Voltage ◽  
Experimental Results ◽  
Pulsed Magnetic Field ◽  
Melt Flow ◽  
Refinement Mechanism ◽  
Refinement Effect

Low Voltage Pulsed Magnetic Casting (LVPMC) is developed for grain refinement castings in recent years. This paper investigates the grain refinement effect of LVPMC on superalloy K417 and deals with the effects of cooling rate and superheating on grain refinement, as well as grain refinement mechanism. The experimental results show that the grains in the alloy are equiaxed and refined to 60 m averagely. The melt flow and Joule heat during solidification are modeled and simulated to reveals the grain refinement mechanism. It is considered that the melt vibration and convection caused by the pulsed magnetic field, as well as cooling rate and superheating contribute to the refinement of solidified grains.

scholarly journals The Role of Grain Refiner in the Nucleation of AlFeSi Intermetallic Phases During Solidification of a 6xxx Aluminum Alloy

2019 ◽  
Vol 50 (11) ◽  
pp. 5242-5252 ◽  
Author(s):  
A. Lui ◽  
P. S. Grant ◽  
I. C. Stone ◽  
K. A. Q. O’Reilly
Keyword(s):  
Grain Refinement ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Primary Phase ◽  
Al Alloy ◽  
Grain Refiner ◽  
Phase Selection ◽  
Type Size ◽  
6Xxx Series

Abstract Primary grain refinement using inoculant additions and intermetallic compound (IMC) phase selection are critical aspects in the solidification of commercial aluminum alloys, controlling the final mechanical properties in service. Although there have been studies which suggest there are explicit interactions between the two phenomena, they have yet to be fully elucidated. Here, through study of intermetallic phase particles extracted from an inoculated casting, key features relating to the nucleation of different intermetallic phases via eutectic reactions are recognized and explained. In particular, rake-like IMCs are identified as initiation points for the deleterious $$\beta $$ β -AlFeSi IMC phase in a model 6xxx series Al alloy. A mechanism is proposed for how $${\text{TiB}}_{2}$$ TiB 2 inoculant particles, which are commonly used for primary phase refinement, play a role in enhancing the nucleation of intermetallic phases during eutectic reactions at the liquid/$$\alpha $$ α -Al interface in the final stages of solidification. The implication of this mechanism is that, after the event of primary grain refinement, any unused $${\text{TiB}}_{2}$$ TiB 2 inoculant particles could be contributing to IMC formation thereby affecting the overall type, size, and distribution of intermetallic phases in the solidified alloy.

Preparation of Al-Ti-N Master Alloy Grain Refiner for Al

2012 ◽  
Vol 452-453 ◽  
pp. 721-725
Author(s):  
Z.Q. Wang ◽  
C.J. Chen
Keyword(s):  
Grain Refinement ◽  
Powder Mixture ◽  
Master Alloy ◽  
Induction Furnace ◽  
Grain Refiner ◽  
Refinement Effect ◽  
Al Matrix

An Al-Ti-N master alloy was prepared through the addition of AlN and Ti powders into pure Al melt heated in an induction furnace. This master alloy shows a higher grain refinement effect for pure Al than Al-Ti due to the formation of TiN and/or AlxTiyNz particles in the Al matrix. DTA, SEM and XRD results suggest that TiN and/or AlxTiyNz particles start to form at about 970°C during heating the Al-Ti-AlN powder mixture.

The Effect of Grain Refinement and Cooling Rate on the Hot Tearing of Wrought Aluminium Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 1675-1680 ◽  
Author(s):  
Mark Easton ◽  
John F. Grandfield ◽  
David H. StJohn ◽  
Barbara Rinderer
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Aluminium Alloys ◽  
Grain Morphology ◽  
Hot Tearing ◽  
Grain Refiner ◽  
Cooling Rates ◽  
High Cooling Rates ◽  
Hot Tearing Susceptibility

Using modifications to the Rappaz-Drezet-Gremaud hot tearing model, and using empirical equations developed for grain size and dendrite arm spacing (DAS) on the addition of grain refiner for a range of cooling rates, the effect of grain refinement and cooling rate on hot tearing susceptibility has been analysed. It was found that grain refinement decreased the grain size and made the grain morphology more globular. Therefore refining the grain size of an equiaxed dendritic grain decreased the hot tearing susceptibility. However, when the alloy was grain refined such that globular grain morphologies where obtained, further grain refinement increased the hot tearing susceptibility. Increasing the cooling decreased the grain size and made the grain morphology more dendritic and therefore increased the likelihood of hot tearing. The effect was particularly strong for equiaxed dendritic grain morphologies; hence grain refinement is increasingly important at high cooling rates to obtain more globular grain morphologies to reduce the hot tearing susceptibility.

The role of cooling rate on microstructure in a sand-cast Al-Cu–Ag alloy containing high amounts of TiB2

2021 ◽  
pp. 1-9
Author(s):  
Lucas Ravkov ◽  
Bradley Diak ◽  
Mark Gallerneault ◽  
Peter Clark ◽  
Giuseppe Marzano
Keyword(s):  
Cooling Rate ◽  
Sand Cast

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.

Role of Ti and Y in the nucleation of the primary α-Al of Al7075–Ti–Y natural composites and influence of ultrasonic vibration

2021 ◽  
Vol 112 (8) ◽  
pp. 652-664
Author(s):  
Xiao-Hui Chen ◽  
Lei Liu ◽  
Jinbo Li ◽  
Fayun Zhang
Keyword(s):  
Reaction Kinetics ◽  
Grain Refinement ◽  
Ultrasonic Vibration ◽  
Nano Particles ◽  
Influencing Mechanism ◽  
Ultrasonic Time ◽  
Natural Composites ◽  
Corrosion Pits ◽  
Main Factor

Abstract Al7075–Ti–Y natural composites were prepared by using a combination of ultrasonic vibration and casting. The effects of titanium (Ti) and yttrium (Y) on the nucleation of primary α-Al were studied and the influencing mechanism of Y on the TiAl3 formation was analysed. Furthermore, a reaction kinetics model of TiAl3 under ultrasonic vibration was established. The results showed that the uniformly distributed TiAl3 and Al3Y nano-particles resulted in grain refinement. Y changed the morphology of TiAl3 and the appearance of corrosion pits was related to the fact that Y was dissolved within the TiAl3 structure to form Ti(Al,Y)3. The established model revealed that ultrasonic vibration significantly promoted the formation of TiAl3, and that ultrasonic time was the main factor affecting its growth.

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