Revealing the Mechanisms for the Nucleation and Formation of Equiaxed Grains in Commercial Purity Aluminum by Fluid-Solid Coupling Induced by a Pulsed Magnetic Field

2020 ◽  
Author(s):  
J.C. Jie ◽  
S.P. Yue ◽  
J. Liu ◽  
D. StJohn ◽  
Y.B. Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Pulsed Magnetic Field ◽  
Commercial Purity ◽  
Commercial Purity Aluminum ◽  
Equiaxed 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.

Solidification Structure of 6063 Alloy under Pulsed Magnetic Field

2015 ◽  
Vol 817 ◽  
pp. 355-359
Author(s):  
Shi Chao Liu ◽  
Hang Chen ◽  
Jun Jia Zhang ◽  
Peng Fei Wang ◽  
Jin Chuan Jie ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Temperature Field ◽  
Pulse Frequency ◽  
Dendrite Growth ◽  
Pulsed Magnetic Field ◽  
Solidification Structure ◽  
Cold Wall ◽  
Average Grain Size ◽  
Equiaxed Grains

The influences of pulsed magnetic field (PMF) on solidification structure of 6063 alloy were studied in this article. The results show that solidification structure of 6063 alloy can be refined with the application of PMF. The dendrite growth restrained and the macrostructure changed from large dendrite grains to fine equiaxed grains. The grain size decreased when the voltage increased from 0V to 600V. However, when the pulse frequency increased from 5Hz to 15Hz, the average grain size decreased continuously until reached a limit, and then the grains coarsened with further increase of the pulse frequency. The vibration caused by PMF not only made the temperature field of the melt uniform ,but also brook off the initial solidified grains formed on the cold wall of the mold, and spurs the grains to move to the center of melt which can be acted as nuclei.

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.

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.

Microstructural Refinement Process of Pure Magnesium by Pulse Magnetic Field Treatment

2011 ◽  
Vol 189-193 ◽  
pp. 3964-3967
Author(s):  
Bin Wang ◽  
Ming Li Sun ◽  
Jing De Chen ◽  
Yong Bin Wei
Keyword(s):  
Magnetic Field ◽  
Pulse Magnetic Field ◽  
Pulsed Magnetic Field ◽  
Bulk Liquid ◽  
Microstructural Refinement ◽  
Average Grain Size ◽  
Columnar Grains ◽  
Refinement Process ◽  
Inner Diameter ◽  
Equiaxed Grains

The effects of pulsed magnetic field on the solidified structure of pure Mg were investigated. Fine uniform equiaxed grains are acquired in the whole ingot from the PMF treatment, in contrast with the coarse columnar grains observed in conventional casting, and the average grain size is refined to 260 m with a 5Hz PMF treatment. The mould size also affects the grain refinement and the most suitable inner diameter of the cylindrical mould is set at 50mm. Pulsed magnetic field increases melt convection during solidification, and the violent agitation causes warmer liquid to fracture the tip of columnar dendrites or to break off dendrite branches and promote the formation of an equiaxed structure, with the broken pieces transported into the bulk liquid acting as nuclei.

Effect of Pulsed Magnetic Field on Structure Refinement of Pure Magnesium

2010 ◽  
Vol 154-155 ◽  
pp. 46-49
Author(s):  
Bin Wang ◽  
Ming Li Sun ◽  
Qiang Wei
Keyword(s):  
Magnetic Field ◽  
Structure Refinement ◽  
Pure Magnesium ◽  
Pulsed Magnetic Field ◽  
Processing Parameter ◽  
Microstructural Refinement ◽  
Optimal Processing ◽  
Average Grain Size ◽  
Columnar Grains ◽  
Equiaxed Grains

A pulsed magnetic field (PMF) was introduced into the solidification of pure magnesium and the effect of structure refinement is investigated. The results show that remarkable microstructural refinement is achieved when the pulsed magnetic field is applied. The morphology is characterized as the columnar grains at the periphery and equiaxed grains at the core. The average grain size in the center of ingot is refined to 260m at the optimal processing parameter (5Hz, 200V). The pulsed magnetic field increases melt convection during solidification, as a result, the stress fractures the dendrites inwards from the mould wall, and the fractured dendrites act as nuclei, so the big columnar grains are prohibited.

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