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Thermal and grain-structure simulation in a land-based turbine blade directionally solidified with the liquid metal cooling process

Kermanpur, A ; Sharif University of Technology | 2000

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  1. Type of Document: Article
  2. DOI: 10.1007/s11663-000-0017-z
  3. Publisher: Minerals, Metals & Materials Soc (TMS) , 2000
  4. Abstract:
  5. The thermal field and the grain structure of a cored superalloy turbine blade, which has been directionally solidified with the liquid metal cooling (LMC) process, has been simulated in three dimensions using a cellular automaton (CA) coupled with finite-element (CAFE) model. The cooling induced by the liquid aluminum bath has been replaced by a heat-transfer coefficient, whose temperature- and time-dependence has been adjusted on the basis of natural convection simulations and dimensionless analyses. The simulated grain structure and crystallographic texture have been compared with the microstructure, and the electron back-scattered diffraction (EBSD) results were obtained for a real blade. In both the experiment and the simulation, it has been found that the grains do not exhibit a well-defined 〈001〉 texture, even near the top of the blade, mainly as a result of a concave liquidus surface. In order to improve the texture and decrease the number of stray crystals, the LMC process was then optimized by changing several parameters. The baffle geometry, the liquid bath level, and the thermal conductivity of the ceramic mold were found to be the dominant parameters. Using the optimized design, the effect of the withdrawal rate on the resulting grain structure was investigated
  6. Keywords:
  7. Aluminum ; Thermal conductivity of solids ; Textures ; Superalloys ; Computer simulation ; Solidification ; Liquid metals ; Heat transfer coefficients ; Finite element method ; Crystal microstructure ; Cooling ; Automata theory
  8. Source: Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science, Warrendale ; Volume 31, Issue 6 , 2000 , Pages 1293-1304 ; 10735615 (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s11663-000-0017-z