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Title: A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials

Abstract

The aim of the model presented in this paper is to capture the difference in solidification behaviour of long and short freezing materials. The shrinkage defects in short freezing materials tends to be internal, as porosity, while in long freezing materials these defects tend to be external in the form of surface depressions. To achieve this, a pressure drop based 3-D feeding flow model has been developed to evaluate shrinkage defects for casting alloys. A continuum formulation is used to describe the transport of mass, energy and momentum. It is assumed that during solidification the driving force for flow is shrinkage. A Darcy type source term has been included in the momentum equation to account for flow resistance in the mushy zone. A VOF free surface model has been used to describe shrinkage defects, i.e., external surface depressions and internal shrinkage porosities, while ensuring mass conservation. The model is used to calculate the shrinkage in a simple casting. The results shows internal and outside shrinkage defects depending on the freezing range of the metal. Short freezing range results mainly in internal shrinkage whereas the long freezing range results in external shrinkage. The expected shrinkage features are well described by themore » present model.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. FEUP - Faculdade de Engenharia da Universidade do Porto, R.Dr.Roberto Frias s/n, 4200-110 Porto (Portugal)
  2. WTCM Foundry Center, Research Center of Belgium Metalworking Industry9052 Zwijnaarde, Gent (Belgium)
  3. UGent - University of Ghent, Technologiepark Zwijnaarde 903, Gent (Belgium)
Publication Date:
OSTI Identifier:
21057331
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 908; Journal Issue: 1; Conference: NUMIFORM '07: 9. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17-21 Jun 2007; Other Information: DOI: 10.1063/1.2740951; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; CASTING; DEFECTS; FLOW MODELS; FREEZING; METALS; NUMERICAL ANALYSIS; POROSITY; PRESSURE DROP; SHRINKAGE; SOLIDIFICATION; SURFACES; ZONES

Citation Formats

Reis, A., Duarte, J. F., Santos, A. D., Magalhaes, A. B., Xu Zhian, and Houbaert, Y.. A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials. United States: N. p., 2007. Web. doi:10.1063/1.2740951.
Reis, A., Duarte, J. F., Santos, A. D., Magalhaes, A. B., Xu Zhian, & Houbaert, Y.. A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials. United States. doi:10.1063/1.2740951.
Reis, A., Duarte, J. F., Santos, A. D., Magalhaes, A. B., Xu Zhian, and Houbaert, Y.. Thu . "A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials". United States. doi:10.1063/1.2740951.
@article{osti_21057331,
title = {A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials},
author = {Reis, A. and Duarte, J. F. and Santos, A. D. and Magalhaes, A. B. and Xu Zhian and Houbaert, Y.},
abstractNote = {The aim of the model presented in this paper is to capture the difference in solidification behaviour of long and short freezing materials. The shrinkage defects in short freezing materials tends to be internal, as porosity, while in long freezing materials these defects tend to be external in the form of surface depressions. To achieve this, a pressure drop based 3-D feeding flow model has been developed to evaluate shrinkage defects for casting alloys. A continuum formulation is used to describe the transport of mass, energy and momentum. It is assumed that during solidification the driving force for flow is shrinkage. A Darcy type source term has been included in the momentum equation to account for flow resistance in the mushy zone. A VOF free surface model has been used to describe shrinkage defects, i.e., external surface depressions and internal shrinkage porosities, while ensuring mass conservation. The model is used to calculate the shrinkage in a simple casting. The results shows internal and outside shrinkage defects depending on the freezing range of the metal. Short freezing range results mainly in internal shrinkage whereas the long freezing range results in external shrinkage. The expected shrinkage features are well described by the present model.},
doi = {10.1063/1.2740951},
journal = {AIP Conference Proceedings},
number = 1,
volume = 908,
place = {United States},
year = {Thu May 17 00:00:00 EDT 2007},
month = {Thu May 17 00:00:00 EDT 2007}
}
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  • ABS>The observed shrinkage of the diffraction pattern in p-p, but not in pi /sup -/--p, scattering is considered. Representation of the pi /sup -/-p differential cross section in terms of the Pomeranchuk trajectory alone is shown to give good agreement with diffraction data. In p-p scattering the Pomeranchuk term determines the low momentum transfer behavior of the cross section, while at about 10 Bev/c the term due to omega exchange (not present in pi /sup -/-p) becomes important. omega -exchange is also present in K/sup plus or minus /-p scattering; this diffraction pattern should show shrinkage similar to the p-pmore » and p-p shrinkage. (D.C.W.)« less
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