Formation of the solidified microstructure of Mg–Al–Zn alloy under a low-voltage pulsed magnetic field

2011 ◽  
Vol 26 (14) ◽  
pp. 1688-1695 ◽  
Author(s):  
J.W. Fu ◽  
Y.S. Yang

Abstract

2013 ◽  
Vol 423-426 ◽  
pp. 725-729
Author(s):  
Xiao Hua Xie ◽  
Quan Zhou ◽  
Cheng Bo Xiao ◽  
Xin Tang

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.


2010 ◽  
Vol 654-656 ◽  
pp. 428-431
Author(s):  
Yuan Sheng Yang ◽  
Xiao Ping Ma ◽  
Ying Ju Li

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.


2011 ◽  
Vol 399-401 ◽  
pp. 2139-2143
Author(s):  
Quan Zhou ◽  
Le Ping Chen ◽  
Jian Yin

The solidified structure refinement of Al-4.5%Cu under the action of low-voltage pulsed magnetic field (LVPMF) was investigated in the paper. The influences of different pulse voltage and pouring temperature on solidified structure of Al-4.5%Cu alloy were studied. The results show that solidified structure of Al-4.5%Cu alloy can be refined greatly by LVPMF processing. The dendrite growth is restrained and the microstructure is changed from larger dendrite grains to smaller nondendritic grains, and with certain parameters, the equiaxed, non-dendritic grains are gained in the alloy. With the increase of pulse voltage, grain size of the alloy decreases, and the primary phase degrades from developed dendrites into rose-like or spherical crystals. The decrease of pouring temperature enhances the refinement effect of LVPMF processing. With 150 V pulse magnetic field treatment, grain size of the alloy decreases, primary phase degrades and refines gradually with the decrease of pouring temperature.


2013 ◽  
Vol 652-654 ◽  
pp. 2413-2417 ◽  
Author(s):  
Quan Zhou ◽  
Yang Cao ◽  
Le Ping Chen

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.


2013 ◽  
Vol 821-822 ◽  
pp. 877-882
Author(s):  
Xiao Hua Xie ◽  
Le Ping Chen ◽  
Cheng Bo Xiao ◽  
Xin Tang

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.


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