Paper Title:

Thermodynamic Calculation of Alpha-Case Formation in Titanium Alloys

Periodical Advanced Materials Research (Volumes 26 - 28)
Main Theme Advanced Materials and Processing
Edited by Young Won Chang, Nack J. Kim and Chong Soo Lee
Pages 519-522
DOI 10.4028/www.scientific.net/AMR.26-28.519
Citation Si Young Sung et al., 2007, Advanced Materials Research, 26-28, 519
Online since October, 2007
Authors Si Young Sung, Bong Jae Choi, Sang Ho Noh, Chang Su Hahn, Yong Mun Ryu, Beom Suck Han, Young Jig Kim
Keywords Alpha Fe2O3, CALPHAD, Casting, Titanium (Ti)
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Abstract

The alpha-case formation mechanism was elucidated for the economic titanium casting. The α-case formation reaction between Ti and Al2O3 mold was examined in a plasma arc melting furnace. The reaction products were characterized by electron probe micro-analyzer and transmission electron microscopy. The α-case generation between Ti and Al2O3 mold was not able to be explained by the conventional α-case formation mechanism, which is known to be formed by the interstitials, especially oxygen dissolved from mold materials. However, from our experimental results and thermodynamic calculations and Calphad modeling (Thermo-calc®), it was confirmed that the α-case is formed not only by an interstitial element but also by substitutional metallic elements dissolved from mold materials. Our newly established α-case formation mechanism will surely lead to a variety of significant applications of the α-case controlled Ti casting.