Journal article
Microporosity Prediction and Validation for Ni-based Superalloy Castings
IOP conference series. Materials Science and Engineering, Vol.84(1), p.12003
05/2015
DOI: 10.1088/1757-899X/84/1/012003
Abstract
Microporosityin high performance aerospace castings can reduce mechanical properties and consequently degrade both component life and durability. Therefore, casting engineers must be able to both predict and reduce casting microporosity. A dimensionless Niyama model has been developed [1] that predicts local microporosity by accounting for local thermal conditions during casting as well as the properties and solidification characteristics of the cast alloy. Unlike the well-known Niyama criterion, application of the dimensionless Niyama model avoids the need to find a threshold Niyama criterion below which shrinkage porosity forms - a criterion which can be determined only via extensive alloy dependent experimentation. In the present study, the dimensionless Niyama model is integrated with a commercial finite element casting simulation software, which can now more accurately predict the location-specific shrinkage porosity volume fraction during solidification of superalloy castings. These microporosity predictions are validated by comparing modelled results against radiographically and metallographically measured porosity for several Ni-based superalloy equiaxed castings that vary in alloy chemistry with a focus on plates of changing draft angle and thickness. The simulation results agree well with experimental measurements. The simulation results also show that the dimensionless Niyama model can not only identify the location but also the average volume fraction of microporosity distribution in these equiaxed investment cast Ni-based superalloy experiments of relatively simple geometry.
Details
- Title: Subtitle
- Microporosity Prediction and Validation for Ni-based Superalloy Castings
- Creators
- J Guo - ESI Group (United States)C Beckermann - University of IowaK Carlson - University of IowaD Hirvo - AlcoaK Bell - Airfoils (United States)T Moreland - Airfoils (United States)J Gu - PCC Structurals, Portland, OR, USAJ Clews - PCC Structurals, Portland, OR, USAS Scott - ESI Group (United States)G Couturier - ESI US R&D, Columbia, MD, USAD Backman - Backman Materials Consulting, LLC, Saugus, MA, USA
- Resource Type
- Journal article
- Publication Details
- IOP conference series. Materials Science and Engineering, Vol.84(1), p.12003
- DOI
- 10.1088/1757-899X/84/1/012003
- ISSN
- 1757-8981
- eISSN
- 1757-899X
- Publisher
- IOP Publishing
- Number of pages
- 6
- Language
- English
- Date published
- 05/2015
- Academic Unit
- Mechanical Engineering
- Record Identifier
- 9984196501902771
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