Grain boundary precipitation behaviors in an Fe-9.8Al-28.6Mn-0.8Si-1.0C alloy
- National Chiao Tung Univ., Hsinchu (Taiwan, Province of China). Inst. of Materials Science and Engineering
The phase transformations in Fe-Al-Mn-C alloys have been extensively studied by many workers. Based on their studies, it is seen that when an alloy with a chemical composition in the range of Fe-(8--11) wt pct Al- (28--35) wt pct Mn-(0.8--1.3) wt pct C was solution heat-treated and then quenched, the microstructure was single austenite ({gamma}) phase. When the as-quenched alloy was aged at temperatures ranging from 550 C to 750 C for short times, fine (Fe,Mn){sub 3}AlC carbides ({kappa}{prime}-phase) having an L{prime}1{sub 2}-type structure were observed to appear within the austenite matrix, but not on the austenite grain boundaries. However, when the aging time was increased within this temperature range, a {gamma} {yields} {alpha} (ferrite) + {kappa} transition, or a {gamma} {yields} {alpha} + {beta}-Mn transition (11--13), or a {gamma} {yields} {alpha} + {kappa} + {beta}-Mn transition occurred on the austenite grain boundaries. The {kappa} phase is also an (Fe,Mn){sub 3}AlC carbide, which was formed on the grain boundary as a coarse particle. Recently, the present workers performed transmission electron microscopy observations on the microstructures of the Fe-9.8Al-28.6Mn-0.8Si-1.0C alloy after being solution heat-treated, quenched and then aged at 600 C. In the as-quenched condition, the microstructure of the alloy was single austenite phase. After being aged at 600 C for short times, fine (Fe,Mn){sub 3}AlC carbides were observed within the austenite matrix and no grain boundary precipitates could be detected.
- OSTI ID:
- 186772
- Journal Information:
- Scripta Materialia, Vol. 34, Issue 1; Other Information: PBD: 1 Jan 1996
- Country of Publication:
- United States
- Language:
- English
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