Numerical modelling of microstructure evolution and dendrite growth in alloy solidification process

2008 ◽  
Vol 33 (1/2) ◽  
pp. 37
Author(s):  
Qingyan Xu ◽  
Bin Li ◽  
Ying Liu ◽  
Baicheng Liu
Keyword(s):  
Numerical Modelling ◽  
Microstructure Evolution ◽  
Solidification Process ◽  
Dendrite Growth ◽  
Alloy Solidification

The Effect of Al-17wt.%Si Alloy Melt Overheating on Solidification Process and Microstructure Evolution

2011 ◽  
Vol 176 ◽  
pp. 29-34 ◽  
Author(s):  
Jaroslaw Piątkowski
Keyword(s):  
Microstructure Evolution ◽  
Solidification Process ◽  
Primary Silicon ◽  
Characteristic Parameters ◽  
Probe Characteristic ◽  
Alloy Solidification ◽  
Silicon Crystals

The effect of overheating on the solidification process and microstructure evolution in AlSi17 silumin was discussed. The alloy melt was held for 40 minutes at 780, 860, 940 and 1020oC, and then cast at a temperature of 780oC to standard ceramic probe. Characteristic parameters of the AlSi17 alloy solidification process, especially Tliq, TE, Tsol, were determined. Examinations of microstructure were also carried out, showing that the higher was the overheating temperature, the higher was the degree of the primary silicon crystals refinement.

Microstructure Evolution in the Atomized Droplets of Mg-9wt%Al Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 1094-1101
Author(s):  
Fei Ding ◽  
Xiao Feng Wang
Keyword(s):  
Droplet Size ◽  
Microstructure Evolution ◽  
Eutectic Reaction ◽  
Solidification Process ◽  
Nucleation And Growth ◽  
Al Alloy ◽  
Microstructure Development ◽  
The Common ◽  
Kinetics Of ◽  
Common Action

A numerical model is developed to describe the kinetics of the microstructure evolution in an atomized droplet of Mg-9wt%Al alloy. The model is coupled with the heat transfer controlling equations to simulate the solidification process of the atomized droplets. The numerical results show that the microstructure development is a result of the common action of the nucleation and growth of grains. The nucleation events take place at a critical supercooling for a given droplet. As the droplet size decreases, the critical supercooling increases significantly. The volume fractions of the phases formed during the period of the recalescence, the segregated solidification and the eutectic reaction are sensitive to the droplet size. It is demonstrated that the developed model describes the microstructure evolution process well.

Dendrite Growth Characteristics and Segregation Control of Bearing Steel Billet with Rotational Electromagnetic Stirring

2017 ◽  
Vol 36 (4) ◽  
pp. 339-346 ◽  
Author(s):  
Yu Xu ◽  
Xiu-Jie Xu ◽  
Zhuang Li ◽  
Tao Wang ◽  
An-Yuan Deng ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Solidification Process ◽  
Bearing Steel ◽  
Dendrite Growth ◽  
Growth Characteristics ◽  
Electromagnetic Stirring ◽  
Secondary Dendrite Arm Spacing ◽  
Steel Billet ◽  
Dendrite Fragmentation ◽  
Equiaxed Grain

AbstractThe effects of rotational electromagnetic stirring (R-EMS) on dendrite growth characteristics and segregation control of bearing steel billet were investigated in continuous casting. The results show that applying R-EMS can promote columnar-equiaxed transition, increase the region of the equiaxed grain from 5 % to 45 %, decrease the secondary dendrite arm spacing (SDAS), and reduce the segregation of both carbon and sulfur. Meanwhile, the fragments of dendrite arms induced by R-EMS are observed. The length of the dendrite fragmentation is approximately 1.5 mm, 7–10 times the SDAS. Some fragments can partially remelt to become effective nuclei, and some fragments survive the solidification process.

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.

Solidification of Al-Pb Alloy under the Effect of Micro-Alloying Element Ti and C

2016 ◽  
Vol 879 ◽  
pp. 2439-2443 ◽  
Author(s):  
Qian Sun ◽  
Hong Xiang Jiang ◽  
Jiu Zhou Zhao
Keyword(s):  
Phase Transformation ◽  
Liquid Phase ◽  
Microstructure Evolution ◽  
Solidification Process ◽  
Miscibility Gap ◽  
Kinetic Behavior ◽  
Number Density ◽  
Alloying Element ◽  
Refinement Efficiency ◽  
Line Temperature

Experiments were carried to investigate the effect of TiC on the solidification process and microstructure of Al-Pb alloys. It is demonstrated that TiC particles are effective inoculants for the nucleation of the Pb-rich droplets during cooling an Al-Pb alloy in the miscibility gap. A model describing the kinetic behavior of TiC particles in the melt and the liquid-liquid decomposition of Al-Pb was developed. The dissolution, coarsening and precipitation processes of TiC particles as well as the microstructure evolution during the liquid-liquid phase transformation of an Al-Pb alloy were calculated. The numerical results indicate that what determines the refinement efficiency of TiC particles on the Pb-rich droplets/particles is the number density of TiC particles in the melt cooled to the binodal line temperature of the Al-Pb alloy. If the number density of TiC particles in the melt before the beginning of the liquid-liquid decomposition is high enough, the addition of TiC causes a refinement of the Pb-rich droplets/particles and promotes the formation of Al-Pb alloys with a well dispersed microstructure.

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