Effect of Eutectic Reaction Induced by Pr on Microstructure in Semisolid A356 Alloy

2011 ◽  
Vol 322 ◽  
pp. 361-364
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu ◽  
Yong Mei Hu

Semisolid A356 alloy, which is grain-refined by Pr, was prepared by low superheat pouring. The effects of grain-refined by Pr on the morphology and the grain size of the primary α-Al in semisolid A356 alloy are researched. The results indicate that semisolid A356 alloy with particle-like and rosette-like primary α-Al can be prepared by low superheat pouring from liquid A356 alloy grain-refined by Pr. The grain size and particle morphology of primary α-Al in A356 alloy are markedly improved by 0.3wt% Pr. The refining mechanism of Pr on the morphology and the grain size of the primary α-Al in semisolid A356 alloy were delved.

2011 ◽  
Vol 311-313 ◽  
pp. 666-669
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu ◽  
Yong Mei Hu

The semisolid A356 alloy slurry, which was grain-refined by Y2O3, was manufactured by low superheat pouring. The effects of grain-refine on the morphology and the grain size of the primary phase in semisolid A356 alloy were researched. The results indicated that semisolid A356 alloy contained Y2O3 with particle-like and rosette-like primary phases could be prepared by low superheat pouring. The grain size and particle morphology of primary phase in semisolid A356 alloy were markedly improved by Y2O3. The refining mechanism of Y2O3 on the morphology and the grain size of the primary α phase in semisolid A356 alloy was delved.


2010 ◽  
Vol 97-101 ◽  
pp. 1003-1007 ◽  
Author(s):  
Zheng Liu ◽  
Wei Min Mao

The semi-solid A356 alloy slurry is prepared by compound process, and the effect of the compound process on morphology and size of primary α-Al in A356 alloy is researched. The results indicate that the compound process remarkably affects the morphology and the size of primary α-Al. Primary α-Al with particle-like is distributed uniformly in A356 alloy, and there is no the transient area of change in structure morphology. Compared with the samples prepared by low superheat pouring and slightly electromagnetic stirring, the nucleation rate, morphology and grain size of primary α-Al in A356 alloy are markedly improved by the compound process. The mechanism of refining grain in the compound process is probed.


2012 ◽  
Vol 424-425 ◽  
pp. 77-80
Author(s):  
Zheng Liu ◽  
Mei Yan Huang ◽  
Kai Cao ◽  
Hong Biao Xu

Semisolid A356 alloy was prepared by low superheat pouring. The effects of La as a kind of refinement on the size and morphology of the primary phase in semisolid A356 alloy were researched. The results indicated that semisolid A356 alloy contained certain La addition with particle-like and rosette-like primary phase could be prepared by low superheat pouring. The size and morphology of primary phase in A356 alloy are markedly improved by the suitable addition of La. The refining mechanism of La on the size and morphology of the primary phase in semisolid A356 alloy were concerned with the eutectic reaction induced by La in the alloy.


2010 ◽  
Vol 139-141 ◽  
pp. 693-697 ◽  
Author(s):  
Xiao Mei Liu ◽  
Zheng Liu ◽  
Yong Mei Hu

Semi-solid A356 alloy slurry grain-refined by Al-La master alloy is prepared by low superheat pouring. The effects of La on the morphology and size of primary grain in semi-solid A356 alloy are researched. The results indicate that the semi-solid A356 alloy slurry with particle-like and rosette-like primary grains can be prepared by low superheat pouring. The size and morphology of the primary grain in semi-solid A356 alloy are markedly improved by La. The refining mechanism of La on the morphology and size of the primary grain in semi-solid A356 alloy is delved. The eutectic reaction of Al-La binary alloy provides the effective nuclei for formation of the primary grains in semi-solid A356 alloy.


2010 ◽  
Vol 152-153 ◽  
pp. 1745-1750
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu ◽  
Wei Min Mao

The semi-solid A356 alloy slurry is prepared by slightly electromagnetic stirring with Ti-based refiner. The effects of the refiner on the morphology and the grain size of the primary phase in the slurry are researched. The results indicate that the slurry with particle-like and rosette-like primary phases can be prepared by slightly electromagnetic stirring with the refiner. Compared with the A356 alloys without the refiner, the grain size and particle morphology of primary phase as well as the distribution of the grain with particle-like or rosette-like along radial in the ingot in A356 are markedly improved by the refiner.


2016 ◽  
Vol 877 ◽  
pp. 114-120
Author(s):  
Zheng Liu ◽  
Li Na Xu ◽  
Jia Yi Zhang ◽  
Guang Zhu Bai ◽  
Xiao Mei Liu

Based on the green and saving concept, a complex process preparing semisolid alloy slurry was developed, which was composed of the low superheat pouring and low frequency electromagnetic stirring. The semisolid A356-La slurry was prepared by the complex process, and the microstructure of the semisolid A356-La alloy was researched under the different preparing parameters in the complex process, such as the pouring temperature, electromagnetic stirring frequency, stirring time and micro-addition of La. The results indicated that it was feasible to reduce the addition of La and consumption of energy during the preparation of semisolid alloy slurry by optimizing the preparing parameters in the complex process. The suitable preparing parameters were obtained by the experiment, in which the pouring temperature was 630 °C, the frequency of electromagnetic stirring was 30 Hz, and the stirring time was 8 s. When semisolid A356 alloy slurry added 0.3 wt% La was prepared by the suitable preparing parameters in the complex process, the refining effects on microstructure in the semisolid A356-0.3La alloy was indistinguishable with that of the conventional addition amount of 0.6 wt% La in semisolid A356 alloy prepared by low superheat pouring.


2011 ◽  
Vol 409 ◽  
pp. 373-378
Author(s):  
H. Takano ◽  
Mitsuaki Furui ◽  
Susumu Ikeno ◽  
Tomoyasu Yamaguchi ◽  
Seiji Saikawa

Our recent studies showed that continuous and cellular precipitates are covered with the whole of crystal grain in age hardable AM60 magnesium alloy cast into permanent molds, which have the average grain size of 75-85μm. Also, continuous precipitation is generated nearby grain boundary in the same alloys cast into sand molds, which have the average grain size of 138-147μm. It’s thought that permanent mold castings have the age hardening behavior of intragranular precipitation participation type that is influenced by continuous precipitates. It’s also thought that sand mold castings have the age hardening behavior of grain boundary participation type that is influenced by cellular precipitates. In this study, AM60 magnesium alloy with larger grain size was used to detect the grain size dependence of microstructure and aging behavior. In the microstructure of as-cast condition, the larger the grain size, it was shown that the none-equilibrium crystallized β phase with eutectic reaction during the solidification between liquidus and solidus temperatures becomes large-size. In the age hardening curves, the peak hardness values become higher with decreasing of grain size.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6018
Author(s):  
Bandar Alzahrani ◽  
Mohamed M. El-Sayed Seleman ◽  
Mohamed M. Z. Ahmed ◽  
Ebtessam Elfishawy ◽  
Adham M. Z. Ahmed ◽  
...  

In the current investigation, additive friction stir-deposition (AFS-D) of as-cast hypoeutectic A356 Al alloy was conducted. The effect of feeding speeds of 3, 4, and 5 mm/min at a constant rotational speed of 1200 rpm on the macrostructure, microstructure, and hardness of the additive manufacturing parts (AMPs) was investigated. Various techniques (OM, SEM, and XRD) were used to evaluate grain microstructure, presence phases, and intermetallics for the as-cast material and the AMPs. The results showed that the friction stir deposition technique successfully produced sound additive manufactured parts at all the applied feeding speeds. The friction stir deposition process significantly improved the microstructure of the as-cast alloy by eliminating porosity and refining the dendritic α-Al grains, eutectic Si phase, and the primary Si plates in addition to intermetallic fragmentation. The mean values of the grain size of the produced AMPs at the feeding speeds of 3, 4, and 5 mm/min were 0.62 ± 0.1, 1.54 ± 0.2, and 2.40 ± 0.15 µm, respectively, compared to the grain size value of 30.85 ± 2 for the as-cast alloy. The AMPs exhibited higher hardness values than the as-cast A356 alloy. The as-cast A356 alloy showed highly scattered hardness values between 55 and 75.8 VHN. The AMP fabricated at a 3 mm/min feeding speed exhibited the maximum hardness values between 88 and 98.1 VHN.


2020 ◽  
Vol 62 (11) ◽  
pp. 1147-1152
Author(s):  
Serhat Acar ◽  
Kerem Altug Guler

Abstract In this study, low superheat casting and cooling slope casting processes were carried out with A356 and A380 aluminum alloys in order to obtain feedstocks with near globular microstructures. Castings were conducted at 20 °C above of the liquidus temperature for both processes and molten alloys were cast through a copper cooling slope with two different lengths (350 mm and 650 mm) and two different tilt angles (30° and 60°). In order to evaluate the significance of boron nitride coating on cooling slope, castings in short slope were carried out under both coated and uncoated conditions. Microstructural examinations and hardness measurements were carried out. According to obtained results, cooling slope casting caused superior microstructural properties as compared to low superheat casting, especially for A356 alloy. 30° tilt angle was found more efficient in order to obtain a more globular microstructure for A356, while, on the other hand, the tilt angle of 60° was detected more favorable in that manner for A380. Obtained grain size measurements were slightly improved with the employment of short slope and coating was found beneficial especially for A356 alloy. The measured hardness values did not display any significant difference in the same alloy type except in the low superheat cast A356 specimen, which was obtained with coarser microstructure.


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