scholarly journals A ternary phase bi-scale FE-model for diffusion-driven dendritic alloy solidification processes

PAMM ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 449-450
Author(s):  
Carla Henning ◽  
Lukas Moj ◽  
Tim Ricken
2002 ◽  
Vol 33 (4) ◽  
pp. 613-623 ◽  
Author(s):  
Ragnvald H. Mathiesen ◽  
Lars Arnberg ◽  
Kjell Ramsøskar ◽  
Timm Weitkamp ◽  
Christoph Rau ◽  
...  

1999 ◽  
Vol 121 (2) ◽  
pp. 430-437 ◽  
Author(s):  
J. W. Gao ◽  
C. Y. Wang

An experimental study has been conducted to investigate the effects of grain transport on the columnar to equiaxed transition (CET) in dendritic alloy solidification. Using the aqueous ammonium chloride solution as a transparent model alloy, experiments were performed in a vertical test cell with cooling from the top, resulting in unidirectional columnar crystals growing downwards. Ahead of the columnar front, equiaxed nuclei were observed to originate mostly by fragmentation of the columnar dendrites in the presence of a thermally driven flow in the melt beneath the columnar mushy zone. Being heavier than the liquid, these fragments fall into the bulk melt where they may grow or remelt. The survived equiaxed crystals finally settle towards the floor and pile up to form an equiaxed bed. The CET occurs when the bottom equiaxed packed bed rises and eventually obstructs the columnar mushy zone growing from the upper surface. Therefore, the CET in the present configuration was predominantly controlled by the sedimentation of equiaxed crystals. A parametric study by varying initial concentration, cooling rate, and superheat was performed.


1985 ◽  
Vol 43 (2) ◽  
pp. 143-158 ◽  
Author(s):  
V. Alexiades ◽  
D. G. Wilson ◽  
A. D. Solomon

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Viera Homolová ◽  
Lucia Čiripová

The isothermal section of the B-Cr-Fe ternary system was studied experimentally at 1353 K. X-ray diffraction and scanning electron microscopy equipped with EDX analyzer were used for determination of phase equilibria and composition of the coexisting phases in the B-Cr-Fe model alloys after long-term annealing (1500–2205 h). Two iron borides FeB and Fe2B, six chromium borides Cr2B, Cr5B3, CrB, Cr3B4, CrB2, and CrB4 and also iron and chromium solid solutions (α(Fe,Cr), α(Cr,Fe), γ(Fe,Cr)) and β-rhombohedral B were observed in the alloys. High solubilities of the third element in binary borides and no ternary phase were found. Based on the experimental results, isothermal section of the B-Cr-Fe system at 1353 K was determined.


2015 ◽  
Vol 779 ◽  
pp. 53-86 ◽  
Author(s):  
A. Plotkowski ◽  
K. Fezi ◽  
M. J. M. Krane

Transient scaling and integral analyses were performed to predict trends in alloy solidification in a rectangular cavity cooled by an isothermal sidewall. The natural convection fluid flow was approximated by a scaling analysis for a laminar boundary layer at the solidification front, and was coupled to scaling and integral analyses of the energy equation to predict the solidification behaviour of the system. These analyses predicted several relevant aspects of the solidification process, including the time required to extinguish the initial superheat and the maximum local solidification time as a function of the system parameters and material properties. These results were verified by comparison to numerical simulations for an Al–4.5 wt% Cu alloy for various initial and boundary conditions and cavity aspect ratios. The analysis was compared to previous attempts to analyse similar fluid flow and solidification processes, and the limitations of the assumptions used for this analysis were discussed.


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