Numerical Determination of Secondary Arm Spacing of Fe-C as a Function of Cooling Rate and Local Solidification Time

2014 ◽  
pp. 353-360
Author(s):  
Alexandre Furtado Ferreira ◽  
Ingrid Meireles Salvino ◽  
Ever Grisol de Melo
Keyword(s):  
Cooling Rate ◽  
Solidification Time ◽  
Local Solidification Time ◽  
Numerical Determination

Effects of Solidification Parameters on SDAS of A357 Alloy

2008 ◽  
Vol 51 ◽  
pp. 85-92 ◽  
Author(s):  
Juan He ◽  
Jian Min Zeng ◽  
Along Yan
Keyword(s):  
Cooling Rate ◽  
Solidification Time ◽  
Local Solidification Time ◽  
A357 Alloy ◽  
Solidification Condition ◽  
Alloy Casting ◽  
Furan Resin ◽  
Solidification Parameters ◽  
Relationship Of ◽  
The Relationship

In this investigation, experiments were carried out to study the relationship of solidification parameters and the secondary dendrite arm spacing (SDAS) in A357 alloy casting with various thicknesses under the same solidification condition. The results show that the cooling rate decreases as the thickness of specimens increases, the local solidification time increased, and SDAS increased. The relationships between the SDAS and cooling rate and local solidification time under the condition of furan resin self-hardening sand casting were obtained: SDAS = 20.8 tf 0.3, SDAS = 69.34 v -0.3. The mechanical properties have some linear relations with SDAS of A357 alloy after aging heat treatment. The correlations can be expressed: UTS=410.4-0.8SDAS and El%=7.9-0.05SDAS.

scholarly journals Relationship between cooling rate and microsegregation in bottom-chilled directionally solidified ductile irons

2013 ◽  
Vol 49 (3) ◽  
pp. 315-322 ◽  
Author(s):  
W.S. Chang ◽  
C.M. Lin
Keyword(s):  
Heat Transfer ◽  
Cooling Rate ◽  
Solidification Time ◽  
Local Solidification Time ◽  
Mold Surface ◽  
Cooling Curves ◽  
Copper Mold ◽  
Directionally Solidified ◽  
Scheil Equation ◽  
Element Segregation

This study explores the relationship between cooling rate and microsegregation of directionally solidified ductile iron. The unidirectional heat transfer system used in this research is made up of a copper mold kept chilled by circulating water and embedded in the bottom of Furan sand mold. Thermocouples are connected to the computer measuring system to record the cooling curves of the castings at a distance of 0, 30, 60 and 90 mm from the chilled copper mold surface. Alloys including Mn, Cr, Cu, Ni and Ti were added to the specimens. Electron microprobe analysis (EPMA) was employed to examine distribution of elements between the dendrite arms and nodular graphite. Results show that unidirectional heat transfer affects directly the solidification mode and microstructure of the casting. The cooling curves reveal that local solidification time increases with increasing distance from the chilled copper mold surface. Different solidification rates with corresponding microstructure and element segregation were observed in the same unidirectionally solidified casting. Local solidification time was closely related to element segregation. The effective segregation coefficient (Keff) calculated using the Scheil equation was found to vary, according to the stage of solidification. The actual segregation characteristics of complex alloys generally follow the Scheil equation.

Microstructural Characterization and Mathematical Modeling for Determination of Volume Fraction of Eutectoid Mixture of the Cu-8.5wt% Sn Alloy Obtained by Unidirectional Upward Solidification

2020 ◽  
Vol 1012 ◽  
pp. 302-307
Author(s):  
Ricardo Aparecido da Cruz ◽  
Givanildo Alves dos Santos ◽  
Mauricio Silva Nascimento ◽  
Carlos Frajuca ◽  
Francisco Yastami Nakamoto ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Solidification Time ◽  
Fourier Number ◽  
Proposed Model ◽  
Thermal Data ◽  
Order Of Magnitude

The Cu-8.5wt % Sn alloy presents an extensive microsegregation during its solidification. That microsegregation results in the formation of a eutectoid mixture, which is detrimental to subsequent forming processes. This study deals with the influence of solidification time and cooling rate on the microstructure of that alloy. The unidirectional solidification technique allowed the acquisition of thermal data. The optical microscopy enabled the microstructural characterization of the material, the measurement of dendrite arm spacings and the quantification of the volume fraction of the eutectoid mixture. A semi-analytical mathematical model was proposed to estimate the volume fraction of the eutectoid mixture. The model expresses the volume fraction as an implicit function of the Fourier number. The results showed that the microstructure is dendritic and that the characteristic spacings increase with the solidification time between the liquidus and the peritectic temperatures. The data also showed that for higher cooling rates the dendrite arm spacings are smaller and that there is a tendency for the volume fraction of eutectoid mixture in the columnar zone to increase with the Fourier number and to decrease with the cooling rate. The proposed model allowed obtaining values of volume fraction with the same order of magnitude of the experimental data, but with behavior tendency opposite to that observed.

Experimental and Numerical Determination of Micropropulsion Device Efficiencies at Low Reynolds Numbers

2004 ◽  
Author(s):  
Andrew D. Ketsdever ◽  
Michael T. Clabough ◽  
Sergey F. Gimelshein ◽  
Alina Alexeenko
Keyword(s):  
Reynolds Numbers ◽  
Numerical Determination ◽  
Low Reynolds Numbers ◽  
Low Reynolds

scholarly journals Experimental and numerical determination of the optimum configuration of a parabolic wave extinction system for flumes

2021 ◽  
Vol 238 ◽  
pp. 109748
Author(s):  
U. Izquierdo ◽  
L. Galera-Calero ◽  
I. Albaina ◽  
A. Vázquez ◽  
G.A. Esteban ◽  
...  
Keyword(s):  
Numerical Determination ◽  
Optimum Configuration
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