Columnar to Equiaxed Transition in Peritectic TiAl Based Alloy Studied by a Power-Down Technique

摘要: Columnar to equiaxed transition (CET) was studied in a peritectic TiAl-based alloy with chemical composition Ti-45.1Al-4.9Nb-0.25C-0.2B (at.%). Solidification experiments were conducted Bridgman-type apparatus using cylindrical moulds made of high-purity Y2O3. The methodology containing appropriate etching and observations under flat light stereo-microscope used identify the morphology primary β phase grains position CET samples˰ All samples prepared by power down-technique showed sharp CET. measured from beginning sample depends on applied cooling rate increases approximately 65 115 mm decreasing 50 15 K/min. Based terrestrial experiments, future work focused microgravity hypergravity numerical modeling is proposed. A Bridgman furnace front tracking method will be complement experimental results here as part European Space Agency GRADECET programme. This input directly into planned experiments.