Effect of frequency and intensity of rotating magnetic field on the microstructures of Pb-Sn alloys

Wen

2014

AMR

Self Cite

The solidification behaviors of Sn-Zn alloy under rotating magnetic field (RMF) with different magnetic intensities and different rotating frequencies were investigated, and the velocity of the convection induced by RMF was calculated. It is found that the trunk length of the precipitated phase reduces with the increase of magnetic intensity and rotating frequency, and the precipitated-phase distribution is more uniform. The tangential rate increases with increasing the magnetic intensity and rotating frequency, and reaches the maximum value at about 0.55r0. All the results indicate that the solidification microstructure is attributed to the effect of RMF on the nucleation, temperature fluctuation and fluid convection in the solidification process. It predicts that RMF presents obvious advantages on controlling solidification microstructure.

Section: Resultsmentioning

confidence: 99%

Effect of Rotating Magnetic Field on Fluid Convection and Microstructure during Directional Solidification of Sn-Zn Alloy

Wen

2014

AMR

Self Cite

“…During the experiment, the specimens were put into a 13 mm ID × 15 mm OD ×160 mm specification quartz tubes of a self-design device, as shown in Ref. [15], and 10 ml silicon oil was injected into the tubes to prevent the specimens from being oxidized. Then, the specimens were heated up to 50 K above liquidus temperature and held for 30 minutes.…”

Section: Methodsmentioning

confidence: 99%

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

Wen

2011

AMR

Self Cite

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.

“…The grain size and distribution of the particles formed in the melt are obviously improved by the melt convection, particles spin as well as the collision and friction between them. Furthermore, with the increasing of probability of collision and aggregation between the particles, the size of the grain becomes coarse again [12]. The analysis indicates that there is a critical value of magnetic field intensity.…”

mentioning

confidence: 89%

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

Zhao

Zhang

Fang

et al. 2012

AMR

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.