The study of phase transformations of a Fe-12 Mn-4 Al-1.3 C steel

• Main Authors: Wei-Lin Ciou, 邱韋霖
• Other Authors: Wei-Chun Cheng
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/bm7s8w

碩士 === 國立臺灣科技大學 === 機械工程系 === 104 === Mn-Al steels have the potential to substitute some of the commercial Ni-Cr stainless steels. For the development of Mn-Al stainless steels, phase transformations of the steels provide the basic information for the research and development department. Our methods of studying the phase transformations of the Fe-11.7 Mn-4.3 Al-1.3 C steel include that heating the steel at 1100℃, cooling to room temperature, and isothermally holding at low temperatures. The results of our study show that the spinodal decomposition occurs in the steel after heating at and cooling from 1100℃as follows: γ → γ' + γ'' where γ is the high temperature austenite and (γ' + γ'') are low temperature austenite phase, and precipitation reaction occurs after isothermal holding at temperature below 750℃. κ-carbide appears in the austenite as either grain boundary or cellular precipitates. At temperature below 700℃ the cellular precipitates are composed of lamellar austenite, κ-carbide, M3C carbide, and ferrite. Besides, the lamellar κ-carbide grains are always accompanied with austenite twins in austenite matrix.