Poirier is P.I. of two NASA-sponsored research grants on the effects of
convection on the microstructure and macrosegregation in directionally
solidified (DS) castings. This is done by comparing the solidified
structures of DS-castings that have been made on earth and the same made
in the low-gravity environment of the International Space Station
(ISS). Accompanying the experimental results are computer simulations of
the solidification. The earth-based experiments are carried out by
Professor S.N. Tewari at Cleveland State University (CSU); computer
simulations are led by Professor R.G. Erdmann and Professor Poirier at the University of Arizona (UA). The UA-CSU team is also working with Dr.
R. Grugel at NASA-MSFC on characterizing the microstructures with
advanced techniques in image analysis and microscopy. During 2010 and
2011, two DS castings were processed on the ISS, returned to earth, and
are being studied. Additional ISS-experiments are anticipated with
processing in 2013 and/or 2014.