The Effects of Electromagnetic Stirring on Solidification Structure and Macrosegregation of Pb-Sn Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 1447-1452 ◽  
Author(s):  
Qian Zhao ◽  
Xing Guo Zhang ◽  
Can Feng Fang ◽  
Nan Zhang ◽  
Yan Bo Han ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Primary Phase ◽  
Solidification Structure ◽  
Grain Refining ◽  
Technological Parameters ◽  
Technical Parameters ◽  
Composition Segregation ◽  
Stirring Time ◽  
Equiaxed Grains ◽  
Magnetic Field Condition

The effects of different electromagnetic field and technological parameters on the microstructure and composition segregation of Pb-80%Sn alloy were studied. The results show that, both rotating and spiral magnetic field can improve the composition segregation ,refine grains of alloy. Moreover,the spiral magnetic field is more effective on improving composition homogenization and grain refining. The electromagnetic force distribution of spiral magnetic field is more helpful to form a well stirring in a larger zone and promote the formation of equiaxed grains, and the direction of the grain arrangement is much smaller. The technical parameters of spiral magnetic field have been optimized. It is found that, under the spiral magnetic field condition, when stirring time and exciting current exceeded a critical value, the size of the primary phase became larger. Therefore, there existed an optimum value of magnetic stirring parameters for the homogenization of component and refinement of grains.

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.

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.

scholarly journals Optimization of tablet formulation containing ginger dry extract

2020 ◽  
Vol 33 (2) ◽  
pp. 90-93
Author(s):  
Walid A.A. Malek ◽  
Olena Anatoliivna Ruban ◽  
Olga V. Kutova ◽  
Nataliia A. Herbina
Keyword(s):  
Tablet Formulation ◽  
Regression Equations ◽  
Diabetes Treatment ◽  
Optimal Composition ◽  
European Pharmacopoeia ◽  
Technological Parameters ◽  
Mathematical Methods ◽  
Dry Extract ◽  
Technical Parameters ◽  
Effective Drugs

AbstractIntroduction. Diabetes mellitus is one of the world’s most common diseases, therefore the development and introduction of new effective drugs for diabetes treatment into clinical practice is an important task for the health systems of many countries of the world.Aim. The aim of our work was to determine and substantiate the quantitative ratio of excipients for the development of the optimal composition of directly compressible ginger dry extract tablets.Materials and methods. To choose the optimal composition of tablets containing ginger dry extract, the effect of various quantitative ratios of the excipients Kollidon K30 and Neusilin UFL 2 on tablet mass pharmaceutical technical parameters, determined by established methods, was studied. For processing the experimental data, mathematical methods were used: design of experiment, regression analysis and a technique based on the theory of vector optimization.Results. The interrelation between factors that were studied and technological parameters of tablet mass and compressed tablets were analyzed using regression equations.Conclusions. The studies conducted allowed to chose the optimal composition of ginger dry extract tablets: ginger dry extract – 60%, Galen IQ 721 – 34.5%, Kollidon K30 – 3.5%, Neusilin UFL 2 – 1%, calcium stearate – 1%. The chosen tablet formulation is characterized by pharmaceutical technical parameters meeting the requirements of the European Pharmacopoeia and the State Pharmacopoeia of Ukraine.

scholarly journals Effect of cooling rate on microstructure of B2-NiSc intermetallics

2019 ◽  
Vol 39 (3) ◽  
pp. 236-242
Author(s):  
Zhipeng Yuan ◽  
Hao Chen ◽  
Hongbao Cui ◽  
Yatao Chang ◽  
Xuefeng Guo
Keyword(s):  
Thin Plate ◽  
Volume Fraction ◽  
Solidification Rate ◽  
Centrifugal Casting ◽  
Critical Dimension ◽  
Eutectic Structure ◽  
Primary Phase ◽  
Solidification Structure ◽  
Second Phase ◽  
Lamellar Eutectic Structure

Ni-50at%Sc alloy was prepared by centrifugal casting method. Volume fraction, the actual content of B2-NiSc and second phase Ni2Sc in alloy were analyzed with an Image-Pro Plus software. The cooling rates for the solidified thin plate with thickness of 2.65mm, 1.2mm, 0.75mm and 0.35 mm are 1164, 2570, 4112 and 8811 K·s1, respectively. It is found that d=0.5 mm was an critical dimension which corresponds to an abrupt change in the solidification rate. It is also found that (Ni2Sc+NiSc)eutectic was dispersed at grain boundary or between dendritic arms due to the loss of Sc element during melting. While d＞0.5mm (corresponding to the thin plate with thickness of 0.75mm, 1.20mm and 2.65 mm), the solidification structure consists of primary phase B2-NiSc and (Ni2Sc+NiSc)eutectic. While d ＜ 0.5mm (corresponding to the thin plate with thickness of 0.35 mm), the solidification structure is composed of fine globular B2-NiSc and relatively small amounts of (Ni2Sc+NiSc)eutectic. Based on the phase volumetric analyzing of the microstructure with an Image-Pro Plus software, the loss of Sc element during melting was about 3.01~3.10 at%. The eutectic NiSc in the lamellar eutectic structure together with the primary phase B2-NiSc form a larger single phase NiSc, while Ni2Sc with the form of particles is distributed on the grain boundaries after (970 ℃, 72 h) homogenization heat treatment.

scholarly journals Can an interplanetary magnetic field reach the surface of Venus?

2018 ◽  
Vol 36 (6) ◽  
pp. 1537-1543
Author(s):  
Yasuhito Narita ◽  
Uwe Motschmann
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Activity ◽  
Interplanetary Magnetic Field ◽  
Field Condition ◽  
Diffusion Time ◽  
Field Reversal ◽  
Magnetic Diffusion ◽  
The Magnetic Field ◽  
Magnetic Field Condition

Abstract. We address the question of whether there is a possibility of an interplanetary magnetic field reaching Venus' surface by magnetic diffusion across the ionosphere. We present a model calculation, estimate the magnetic diffusion time at Venus, and find out that the typical diffusion timescale is in a range between 12 and 54 h, depending on the solar activity and the ionospheric magnetic field condition. The magnetic field can thus permeate Venus' surface and even its interior when the solar wind is stationary (i.e., no magnetic field reversal) on the timescale of half a day to several days.

Effect of Rotating Magnetic Field on Microstructure Evolution of Pb-Bi Alloys

2011 ◽  
Vol 311-313 ◽  
pp. 600-608
Author(s):  
Zhao Chen ◽  
Xiao Li Wen ◽  
Chang Le Chen
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Microstructure Evolution ◽  
Solidification Process ◽  
Nucleation And Growth ◽  
Primary Phase ◽  
Rotating Magnetic Field ◽  
Growth Behaviour ◽  
Solidification Behaviour ◽  
40 Hz

Solidification behaviour of Pb-Bi alloys under rotating magnetic field (RMF) was investigated experimentally to understand the effect of the frequency of RMF on the nucleation and growth behaviour. It was found that, as the increase of the rotating frequency, the grains are fragmented and refined gradually until a transition from columnar to equiaxed microstructures happens at a rotating frequency of 40 Hz. Moreover, the Bi concentration of the primary phase decreases and macrosegregation is eliminated effectively with RMF. These are due to the effect of RMF on the nucleation, growth and fluid flow in the solidification process.

Removal of Chromium and Nickel Ions from Synthetic Solution by the Ferrite Process

2010 ◽  
Vol 113-116 ◽  
pp. 2251-2254 ◽  
Author(s):  
Xiao San Song ◽  
San Fan Wang ◽  
Jiong Yuan Lu
Keyword(s):  
Heavy Metals ◽  
Hydrothermal Reaction ◽  
Technological Parameters ◽  
Reaction Conditions ◽  
Nickel Ions ◽  
Leaching Toxicity ◽  
Stirring Time ◽  
Synthetic Solution ◽  
Optimum Reaction ◽  
Leaching Procedure

Pollution with Cr (VI) and Ni (II) waste water is frequently encountered together in practice, and the ferrite process carves out a new way for the treatment of wastewater contaminated by heavy metals. The purpose of this study is to investigate the treatment of Cr (VI) and Ni (II) wastewater by the ferrite process.In this paper, the ferrite process of Cr (VI) and Ni (II) synthetic solution by hydrothermal reaction and its technological parameters was sdudied. The most optimum reaction conditions were explored: pH=9.0, temperature=70°C, stirring time=40min, stirring speed=120 rpm. Leaching toxicity of heavy metals from Ni–Cr ferrite prepared in the experiment was much lower than the regulated limit of Toxicity Characteristic Leaching Procedure (TCLP), indicating that Ni–Cr ferrite had a better chemical stability. Therefore, the ferrite process is a feasible method with respect to the removal of chromium and nickel ions from wastewater.

Sign in / Sign up

Export Citation Format

Share Document