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 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.

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 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 effect of pulsed magnetic field on solidified microstructure of superalloy IN718

2009 ◽  
Vol 24 (10) ◽  
pp. 3174-3181 ◽  
Author(s):  
Xiaoping Ma ◽  
Yingju Li ◽  
Yuansheng Yang
Keyword(s):  
Magnetic Field ◽  
Delay Time ◽  
Mold Wall ◽  
Joule Heat ◽  
Pulsed Magnetic Field ◽  
Exciting Frequency ◽  
Refinement Mechanism ◽  
Grains Refinement ◽  
Exciting Voltage ◽  
Refinement Effect

The refinement mechanism of pulsed magnetic field (PMF) was discussed by experimental investigation, and the effects of exciting frequency, exciting voltage, and delay time of PMF on grains refinement of superalloy were studied. The experimental results show that, as exciting frequency or exciting voltage is increased, the grains are refined. However, the grains become coarse when frequency increases further. As delay time of PMF increases, the grain size increases. The refinement effect of PMF is attributed to the detachment of heterogeneous nuclei on the mold wall and subsequently separation of nuclei in the melt. The Joule heat can prolong the continuous nucleation process. However, the refinement effect will be impaired if the Joule heat is strong enough to remelt the detached nuclei.

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 Mg97Y2Cu1 Alloy Solidified with Pulsed Direct Current Magnetic Field

2013 ◽  
Vol 842 ◽  
pp. 279-283
Author(s):  
Shui Lin Tan ◽  
Quan Zhou ◽  
Jia Bin Fu ◽  
Hao Fu
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Grain Refinement ◽  
Direct Current ◽  
Mold Temperature ◽  
Pulse Voltage ◽  
Pouring Temperature ◽  
Pulsed Direct Current ◽  
Equiaxed Grains ◽  
Current Magnetic Field

The influences of different pulse voltage, discharging frequency, pouring temperature and mold temperature on marostructure of Mg97Y2Cu1alloy under pulsed direct current magnetic field (PDCMF) were studied and the related mechanism was also discussed. The results show that grains of Mg97Y2Cu1alloy can be refined greatly by PDCMF treatment. Macrostructure of the alloy is changed from coarsened grains to complete fine equiaxed grains. When the pulse voltage is at 0-250V, grain size of the alloy decreases dramatically as pulse voltage increases. When the discharging frequency is at 1-10Hz, grain size of the alloy increases firstly, then decreases, and the turning point is 5 Hz. The change of grain size is not obvious, when the discharging frequency increases from 1 Hz to 5 Hz. When the discharging frequency reaches 10 Hz, the effect of grain refinement is the best. When the mold temperature is at 20-600°C or the pouring temperature is at 660-750°C, grain size of the alloy with PDCMF treatment decreases grossly with the increase of the mold temperature or the pouring temperature. The higher the pouring temperature or the mold temperature, the better the effect of grain refinement with PDCMF treatment.

Grain refinement of pure aluminum by direct current pulsed magnetic field and inoculation

2014 ◽  
Vol 24 (5) ◽  
pp. 1295-1300 ◽  
Author(s):  
Hang CHEN ◽  
Jin-chuan JIE ◽  
Ying FU ◽  
Hong-jun MA ◽  
Ting-ju LI
Keyword(s):  
Magnetic Field ◽  
Grain Refinement ◽  
Direct Current ◽  
Pure Aluminum ◽  
Pulsed Magnetic Field

Effects of Compound Treatment of Pulsed Magnetic Field and Mechanical Vibration on Solidified Structure of Mg97Y2Cu1 Alloy

2014 ◽  
Vol 1061-1062 ◽  
pp. 17-22
Author(s):  
Hao Zhang ◽  
Quan Zhou ◽  
Sen Zhang
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Volume Fraction ◽  
Mechanical Vibration ◽  
Mold Temperature ◽  
Pulse Frequency ◽  
Pulse Voltage ◽  
Pulsed Magnetic Field ◽  
Second Phase ◽  
Pouring Temperature

The influences of different pulse voltage, pulse frequency, pouring temperature and mold temperature on solidified structure of Mg97Y2Cu1alloy reinforced by long-period ordered structure with compound treatment of pulsed magnetic field and mechanical vibration were studied. The results show that grains of the alloy can be refined greatly with compound treatment. Primary phase degrades from developed dendrites into rosette-shaped crystal. Distribution of second phase is more uniform and continuous, and its volume fraction increases. When the pulse voltage is at 0-280V or the pulse frequency is at 1-10Hz, grain size of the alloy decreases dramatically as pulse voltage or pulse frequency increases. When the pouring temperature is at 660-750°C or the mold temperature is at 20-600oC, grain size of the alloy with compound treatment decreases grossly with the increase of the pouring temperature or the mold temperature.

scholarly journals Numerical Simulation of Grain Refinement of Pure Copper Solidified under Pulsed Magnetic Field

2019 ◽  
Vol 37 ◽  
pp. 537-540
Author(s):  
Xiaohui Feng ◽  
Yi Zhang ◽  
Jingpeng She ◽  
Lihong Li ◽  
Min Zhong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Grain Refinement ◽  
Pure Copper ◽  
Pulsed Magnetic Field
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