Journal article
A Pore-Centric Model for Combined Shrinkage and Gas Porosity in Alloy Solidification
Metallurgical and materials transactions. A, Physical metallurgy and materials science, Vol.48(4), pp.1797-1816
01/17/2017
DOI: 10.1007/s11661-016-3940-6
Abstract
A unified model has been developed for combined gas- and shrinkage-induced pore formation during solidification of metal alloys. The model is based on a pore-centric approach, in which the temporal evolution of the pore radius is calculated as a function of cooling rate, thermal gradient, gas diffusion, and shrinkage. It accounts for the effect of porosity formation on the liquid velocity within the mushy zone. Simulations for an aluminum alloy show that the porosity transitions smoothly from shrinkage-induced to gas-induced as the Niyama value is increased. A Blake (cavitation) instability is observed to occur when the porosity is both gas- and shrinkage-driven. A revised dimensionless Niyama curve for pure shrinkage is presented. The experimentally observed gas porosity trend that the pore volume decreases with increasing cooling rate is well predicted. The pore-centric formulation allows the present model to be solved locally, at any point in a casting, during a regular casting simulation.
Details
- Title: Subtitle
- A Pore-Centric Model for Combined Shrinkage and Gas Porosity in Alloy Solidification
- Creators
- Vahid Khalajzadeh - University of IowaKent D Carlson - University of IowaDaniel G Backman - Backman Materials Consulting, LLC, Saugus, USAChristoph Beckermann - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Metallurgical and materials transactions. A, Physical metallurgy and materials science, Vol.48(4), pp.1797-1816
- Publisher
- Springer US
- DOI
- 10.1007/s11661-016-3940-6
- ISSN
- 1073-5623
- eISSN
- 1543-1940
- Language
- English
- Date published
- 01/17/2017
- Academic Unit
- Mechanical Engineering
- Record Identifier
- 9984196550002771
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