Fe-Al-C 계 주철의 흑연화에 관한 결정학적 고찰 = Crystallographic study on the Graphitization of Fe-Al-C system Cast Iron

다국어 초록 (Multilingual Abstract)

For the purpose of investigating the graphitization mechanism of Al alloyed cast iron, Fe-Al-C system alloy was melted in high frequency induction furnace by changing the aluminum content, and crystallographically discussed the structure of Fe-Al-C cast iron.
The results obtained in this work are summarised as follows.
1. With increasing the aluminum contents, in low aluminum range (0-4 wt.%), the mean and maximum graphite length were increased, and perovskite type carbide dud not appear.
2. Graphitization mechanism at the low aluminum range is thought to be controlled not only by decrement of iron-carbon bond energy and increment of carbon-carbon bond energy owing to the ionization energy difference between aluminum and carbon, but also by the rise of austenite-graphite eutectic temperature-
3. At the medium aluminum range (6-16 wt.%), the amount of carbide was increased with increasing the aluminum content, which is thought to be deduced from the fact that Al atom can not be the second nearest neighbor atoms each other in Fe₃ Al ordering.
4. As the aluminum content came to the vicinity of stoichiometric number of Fe₃ Al, carbide took the form of dendrite.
5. Graphitization ability at the high aluminum range (over 20 wt.%) is thought to be due to the decrement of the number of octahedral sites for carbon which is followed by FeAl ordering.