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.

The origin of nuclei and the refinement mechanism for solidified superalloy IN718 under pulsed magnetic field

2009 ◽  
Vol 24 (12) ◽  
pp. 3689-3692 ◽  
Author(s):  
Xiaoping Ma ◽  
Yingju Li ◽  
Yuansheng Yang
Keyword(s):  
Magnetic Field ◽  
Grain Refinement ◽  
Mold Wall ◽  
Mold Temperature ◽  
Experimental Results ◽  
Pulsed Magnetic Field ◽  
Mold Surface ◽  
Refinement Mechanism ◽  
Equiaxed Grains ◽  
Refinement Effect

The grain refinement effect of a pulsed magnetic field on superalloy IN718 was investigated. The experimental results show that fine equiaxed grains are acquired under the pulsed magnetic field. The refinement effect of the pulsed magnetic field is affected by the mold temperature. And the mixed grains are found in the solidified microstructures under the pulsed magnetic field. The origin of nuclei under the pulsed magnetic field is from the mold wall because of the rough mold surface, the undercooling, and the melt vibration, which all contribute to the refinement of solidified grains.

Effect of Low-Voltage Pulsed Magnetic Field on Solidified Structure of Superalloy K4169

2013 ◽  
Vol 423-426 ◽  
pp. 725-729
Author(s):  
Xiao Hua Xie ◽  
Quan Zhou ◽  
Cheng Bo Xiao ◽  
Xin Tang
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Low Voltage ◽  
Pulse Frequency ◽  
Pulse Voltage ◽  
Experimental Results ◽  
Pulsed Magnetic Field ◽  
Equiaxed Grains ◽  
Dendritic Structures ◽  
Refinement Effect

Effects of different pulse voltage and frequency on solidified structure of superalloy K4169 under low-voltage pulsed magnetic field (LVPMF) were investigated in this paper, and the related mechanism was also discussed. The experimental results show that grain of superalloy K4169 can be refined greatly by LVPMF treatment during the course of solidification. Growth of dendrite is restrained and primary grain is changed from large dendrites to smaller equiaxed grains. When the pulse voltage is at 0-280V, grain size of the alloy decreases as pulse voltage increases, and primary dendrites are fractured from well-developed dendrites into fine equiaxed grains and non-dendritic structures. When the pulse frequency is at 0-5Hz, the increase of pulse frequency enhances the refinement effect of LVPMF processing. With the increase of the pulse frequency, grain size of the alloy increases.

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 of 6061 Alloy by Low-Voltage Pulsed Magnetic Field Treatment

2013 ◽  
Vol 652-654 ◽  
pp. 2413-2417 ◽  
Author(s):  
Quan Zhou ◽  
Yang Cao ◽  
Le Ping Chen
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Low Voltage ◽  
Mold Temperature ◽  
Primary Phase ◽  
Pulse Voltage ◽  
Pulsed Magnetic Field ◽  
Magnetic Field Treatment ◽  
Spherical Crystals ◽  
Refinement Effect

The influences of different pulse voltage and mold temperature on solidified structure of 6061 alloy under low-voltage pulsed magnetic field (LVPMF) were studied. The results show that grain of 6061 alloy can be refined greatly by LVPMF treatment. The dendrite growth is restrained and the microstructure is changed from larger dendrite grains to smaller nondendritic grains. When the pulse voltage is at 0V-300V, grain size of the alloy decreases as pulse voltage increases, and the primary phase degrades from developed dendrites into rose-like or spherical crystals. When the mold temperature is at 20°C-600°C, the decrease of mold temperature enhances the refinement effect of LVPMF processing. With the decrease of the mold temperature, grain size of the alloy decreases.

Grain Refinement of Superalloy K4169 with Low-Voltage Pulsed Magnetic Field Treatment

2013 ◽  
Vol 821-822 ◽  
pp. 877-882
Author(s):  
Xiao Hua Xie ◽  
Le Ping Chen ◽  
Cheng Bo Xiao ◽  
Xin Tang
Keyword(s):  
Magnetic Field ◽  
Low Voltage ◽  
Mold Temperature ◽  
Primary Phase ◽  
Pulsed Magnetic Field ◽  
Pouring Temperature ◽  
Average Grain Size ◽  
Magnetic Field Treatment ◽  
Equiaxed Grains ◽  
Refinement Effect

The influences of different pouring temperature and mold temperature on solidified structure of superalloy K4169 under low-voltage pulsed magnetic field (LVPMF) were investigated in the paper. The experimental results show that solidified structure of superalloy K4169 under LVPMF can be refined greatly with appropriate cooling rate of the alloy. The dendrite growth is restrained and the microstructure is changed from larger dendrite grains to smaller equiaxed grains. When the pouring temperature is at 1380 °C-1530 °C or the mold temperature is at 1000 °C-1300 °C, the increase of pouring temperature or mold temperature enhances the refinement effect of LVPMF processing. With the increase of the pouring temperature or the mold temperature, average grain size of the alloy decreases and the primary phase degrades from developed dendrites into equiaxed crystals under the LVPMF.

Grain refinement of as cast superalloy K4169 solidified with low voltage pulsed magnetic field

2014 ◽  
Vol 18 (sup4) ◽  
pp. S4-352-S4-356 ◽  
Author(s):  
Y. F. Teng ◽  
X. H. Feng ◽  
Y. J. Li ◽  
Y. S. Yang
Keyword(s):  
Magnetic Field ◽  
Grain Refinement ◽  
Low Voltage ◽  
Pulsed Magnetic Field ◽  
Cast Superalloy
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