Grain boundary precipitation reactions in a wrought Fe-8Al-5Ni-2C alloy prepared by the conventional ingot process
- National Chiao Tung Univ. (Taiwan, Province of China). Inst. of Materials Science and Engineering
Phase transformations in the Fe-8Al-5Ni-2C alloy, prepared by rapid solidification process (RSP), have been studied by Choo and Kim. They showed that the microstructure of the alloy in the as-solidified condition was austenite phase ({gamma}) containing fine ordered L{prime}1{sub 2}-type precipitates. The formation of these fine ordered L{prime}{sub 2}-type precipitates, lying along the <100> directions in the matrix, was attributed to the spinodal decomposition. It was also shown that, on aging at 823 K, the fine ordered precipitates grew and, at the same, {alpha}(ferrite) and {kappa}-carbide formed by a heterogeneous reaction at the {gamma}/{gamma} grain boundaries. With increasing aging time, the heterogeneous reaction became predominant, leading to a two-phase microstructure of {alpha} and {kappa}-carbide in the end. Recently, the authors performed transmission electron microscopy (TEM) observations of the phase transformations in the Fe-8Al-5Ni-2C alloy, prepared by conventional casting process. It was found that the microstructure of the alloy in the as-quenched condition was austenite phase containing fine ordered L{prime}1{sub 2}-type precipitates, similar to the previous results for the as-solidified alloy. However, when the as-quenched alloy was aged at 823 K for a long time, the equilibrium microstructure was observed to be a mixture of ({alpha} + B2 + {kappa}-carbide), rather than {alpha} + {kappa}-carbide as reported by Choo and Kim.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 611595
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 2 Vol. 29; ISSN 1073-5623; ISSN MMTAEB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phase transformations in an Fe-7. 8Al-29. 5Mn-1. 5Si-1. 05C alloy
Spinodal decomposition in Fe-9. 0Al-30. 5Mn-xC alloys