| Title |
Research Papers / Transformations : Crystallographic Features of 9R Precipitate in Fe-0.15C-1.5Mn-1.5Si-1.0Cu Alloy ( 1 ) 1 . Precipitation Characteristics of Cu Precipitate |
| Authors |
이태호(Tae Ho Lee),이창길(Chang Gil Lee),오창석(Chang Seok Oh),김성준(Sung Joon Kim),최병학(Byung Hak Choe) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
Precipitation characteristics and crystallographic features of 9R precipitate in Fe-0.15C-1.5Mn-1.5Si-1.0Cu (all in weight percent) alloy were investigated utilizing conventional and high-resolution transmission electron microscopy (TEM). The modulated or tweed structure which contained bumpy morphology and distinguished striations perpendicular to [100]_α direction was observed at the early stage of aging at 500℃. The precipitates with banded structure were found to be lying parallel to the {110)_α planes within ferrite matrix after aging at 500℃ for 10 hours and it was confirmed from the HRTEM investigations that this banded contrast from the precipitate corresponded to the intervariant boundary of twinned 9R precipitate. After electron irradiation, it was founded that the close-packed (009)_9R planes rotated and aligned more closely with matrix {110}_α planes and the regular stacking faults on every third (009)_9R planes were eliminated. This 9R-to-3R transformation was due to the relaxation of elastic strain produced by the bcc-to-9R martensitic transformation. |