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Metallurgical and Materials Transactions A

, Volume 50, Issue 2, pp 757–771 | Cite as

Real-time X-ray Radiography and Computational Modeling of Shrinkage Porosity Formation in Aluminum Alloy Castings

  • Vahid Khalajzadeh
  • David D. Goettsch
  • Christoph Beckermann
Article
  • 82 Downloads

Abstract

The formation of shrinkage porosity in an A356 aluminum alloy wedge casting is investigated using real-time video radiography. An image processing technique is developed to quantify the amount of porosity observed in the video. The transient temperature field is obtained using casting simulation. The results show that initially, sinks develop in the low solid fraction regions on the surface of the wedge. Once the surface becomes sufficiently solid to be rigid, the subsequent solidification shrinkage is accommodated by internal porosity. The internal porosity is found to nucleate and grow in the central part of the wedge where the solid fraction is the lowest. A computational model is developed to predict the formation of the surface sinks and the internal porosity. The model is validated using the experimental measurements and a parametric study is performed to investigate the sensitivity of the predictions to changes in the model parameters.

Notes

Acknowledgments

The authors wish to thank Anil Sachdev, Gene Tuohy, Mike Walker, and Jason Traub for their support of the foundry real-time X-ray room at GM R&D and the work on this project.

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Copyright information

© The Minerals, Metals & Materials Society and ASM International 2018

Authors and Affiliations

  • Vahid Khalajzadeh
    • 1
  • David D. Goettsch
    • 2
  • Christoph Beckermann
    • 1
  1. 1.Department of Mechanical and Industrial EngineeringUniversity of IowaIowa CityUSA
  2. 2.GM Manufacturing Engineering, Global Propulsion System CenterPontiacUSA

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