The Development of a Microgravity Experiment Involving Columnar to Equiaxed Transition for Solidification of a Ti-Al Based Alloy

The authors are members of the integrated project Intermetallic Materials Processing in Relation to Earth and Space Solidification (IMPRESS), funded within the European Framework (FP6). One of the aims of IMPRESS is to develop new alloys and processes for the casting of TiAl-based turbine blades for the next generation of aero and industrial gas turbine engines. Within IMPRESS, two related issues have been identified during the primary solidification stage, namely, segregation and the columnar-to-equiaxed transition (CET). The authors have set out to isolate the effects of thermo-solutal convection, by designing a microgravity experiment to be performed on a European Space Agency platform. This experiment will investigate the CET formation during solidification. It is planned to use a sounding rocket providing a microgravity time of approximately twelve minutes. The results of this microgravity solidification experiment will be used as unique benchmark data for development and validation of new computational models of TiAl solidification. This in turn will produce accurate models and ultimately new robust industrial processes by project partners in the aerospace industry. The evolution of the design of the microgravity experiment is discussed and the results of preliminary ground reference experiments are presented. Future plans and objectives for the project are also highlighted.

[1]  Charles-André Gandin,et al.  Numerical modelling of columnar to equiaxed transition – application to microgravity experiments , 2009 .

[2]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[3]  C. Gandin,et al.  Experimental Study of the Transition from Constrained to Unconstrained Growth during Directional Solidification , 2000 .

[4]  Marcelo de Aquino Martorano,et al.  A solutal interaction mechanism for the columnar-to-equiaxed transition in alloy solidification , 2003 .

[5]  R. Lebed,et al.  Pion form factors in holographic QCD , 2007, 0708.4054.

[6]  J. Hunt,et al.  Steady state columnar and equiaxed growth of dendrites and eutectic , 1984 .

[7]  David J. Browne,et al.  A New Equiaxed Solidification Predictor from a Model of Columnar Growth , 2005 .

[8]  Robert J. Naumann,et al.  An analytical approach to thermal modeling of Bridgman-type crystal growth: I. One-dimensional analysis , 1982 .

[9]  G. Zimmermann,et al.  Microgravity experiments on columnar–equiaxed transition in Al based alloys , 2007 .

[10]  J. A. Spittle.  Columnar to equiaxed grain transition in as solidified alloys , 2006 .

[11]  Chuen-Horng Lin,et al.  Corrigendum to ‘Multi-server system with single working vacation’ [Appl. Math. Modell. (2008), doi:10.1016/j.apm.2008.10.006] , 2009 .

[12]  Alexandru Ioan Ciobanas,et al.  Ensemble averaged multiphase Eulerian model for columnar/equiaxed solidification of a binary alloy: I. The mathematical model , 2007 .