Phase Field Modeling of β(Ti) Solidification in Ti-45at.%Al: Columnar Dendrite Growth at Various Gravity Levels

2014 ◽  
Vol 790-791 ◽  
pp. 34-39 ◽  
Author(s):  
Alexandre Viardin ◽  
Laszlo Sturz ◽  
M. Apel ◽  
Ulrike Hecht
Keyword(s):  
Mushy Zone ◽  
Phase Field ◽  
Primary Dendrite ◽  
Large Diameter ◽  
Growth Front ◽  
Dendrite Growth ◽  
Dendrite Spacing ◽  
Columnar Dendrite ◽  
Zone Length ◽  
Primary Dendrite Spacing

At present, our understanding of the interaction between melt flow and solidification patterns is still incomplete. In columnar dendritic growth buoyancy driven flow may alter the dendrite tip and spacing selection and consequently the microsegregation of alloying elements. With the aim of supporting directional solidification experiments under hyper-gravity using a large diameter centrifuge (LDC), phase field simulations of β (Ti) dendrite growth have been performed under various gravity conditions for the binary alloy Ti-45at.%Al. The results show that Al segregation at the growth front causes convection rolls around the dendrite tips. The direction of the gravity vector is an essential parameter. When g is opposite to the direction of dendrite growth, increasing gravity leads to a marked decrease of the primary dendrite spacing and to a decrease of the mushy zone length. When g is aligned parallel to the direction of dendrite growth, the primary dendrite spacing and mushy zone length are almost unchanged, however the secondary dendrite arms grow more prominently as the magnitude of g increases.

Crystal Growth during the Solidification Process of Continuous Casting Slab

2011 ◽  
Vol 299-300 ◽  
pp. 282-286
Author(s):  
Shu Ying Chen ◽  
Guang Can Jin ◽  
Xu Dong Yue ◽  
Qing Chun Li ◽  
Guo Wei Chang
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Continuous Casting ◽  
Solid Phase ◽  
Early Stage ◽  
Primary Dendrite ◽  
Dendrite Spacing ◽  
Wave Crest ◽  
Simultaneous Increase ◽  
Primary Dendrite Spacing

Under the condition that the solid-liquid interface bends periodically in continuous casting, the expression of solid-phase growth rate adapting to continuous casting was set up, and then the growth rates were calculated. On this basis, the morphologic of crystal growth and the variation of primary dendrite spacing during continuous casting slabs were studied. The results show that the growth rate is the fastest when solid-phase moves to wave crest within a deformation periodicity, whereas the growth rate is the slowest when the crystal moves to wave hollow. The bigger the bulge size is, the greater the variation amplitude of the growth rate will become. The variation of the growth rate results in the S/L interface to develop towards a planar surface. Because the value is much smaller than the critical value of the transformation from cells to dendrites, and the crystals only grow in the fashion of dendrites. The primary dendrite spacing at wave crest is bigger than the primary dendrite spacing at wave hollow in early stage of columnar crystal growth, and the dendrite spacing at wave crest is basically equal with the dendrite spacing at wave hollow in the late stage of solidification, and they quickly simultaneous increase. Good correlation is obtained between the experimental results and the calculation results of the dendrite arm spacing.

Orientation dependence of primary dendrite spacing

1996 ◽  
Vol 27 (9) ◽  
pp. 2727-2739 ◽  
Author(s):  
CH. A. Gandin ◽  
M. Eshelman ◽  
R. Trivedi
Keyword(s):  
Primary Dendrite ◽  
Orientation Dependence ◽  
Dendrite Spacing ◽  
Primary Dendrite Spacing

Effects of melt flow on the primary dendrite spacing of Pb–Sn binary alloy during directional solidification

2011 ◽  
Vol 320 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Zhixian Min ◽  
Jun Shen ◽  
Zhourong Feng ◽  
Lingshui Wang ◽  
Lei Wang ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Binary Alloy ◽  
Primary Dendrite ◽  
Dendrite Spacing ◽  
Melt Flow ◽  
Primary Dendrite Spacing
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