Phase Transformations in an Fe-9Al-30Mn-2.5Cr-0.6C Alloy

• Main Authors: Shin-Liang Chen, 陳信良
• Other Authors: Tzeng-Feng Liu
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/74432007636759582730

碩士 === 國立交通大學 === 材料科學與工程系所 === 95 === Phase transformations in an Fe-9Al-30Mn-2.5Cr-0.6C alloy have been examined by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectrometry (EDS). In the as-quenched condition, the microstructure of the alloy was (austenite + ferrite) dual-phases. No precipitate was found within the ferrite phase and austenite phase in the as-quenched specimen, which was confirmed by the electron diffraction method. When the alloy was aged at 650℃, the phase transformation sequence as the aging time increased was found to be [γ + α] → [γ + (α + D03 + M23C6 + M5C2)] → [(γ + κ' carbide) + (α + D03 + β-Mn + M23C6 + M5C2)]. It is noted that, the monoclinic type M5C2 carbide has not been observed by other workers in Fe-Al-Mn alloy systems before. In addition, the coexistence of M5C2 carbide, D03 and β-Mn has also never been reported in the previous literatures. These results are quite different from the previously observations in the Fe-8.8Al-30Mn-6Cr-1.0C alloy and Fe-9.1Al-29.9Mn -2.9Cr alloy.