In situ observation of the effect of Al N particles on bainitic transformation in a carbide-free medium carbon steel
来源期刊：International Journal of Minerals Metallurgy and Materials2020年第5期
论文作者：Xiao-jie Zhao Zhi-nan Yang Fu-cheng Zhang
文章页码：620 - 629
摘 要：The bainitic transformation of the steels with different mass fractions of N, ～0.002% and 0.021%, was observed in situ by using high-temperature metalloscope. Micrometer-and nanometer-sized aluminum nitride（AlN） particles were found in the steel with 0.021% N.Grain boundaries, the interior of the grains, and Al N particles were used as initial nucleation sites of bainitic ferrite, and bainitic ferrite subunits served as new nucleation sites to induce secondary nucleation. The lengthening rate of bainitic ferrite varied at different nucleation sites, which was controlled by the repeated nucleation and growth of bainitic subunits. The Al N particles not only provided several nucleation sites, but also increased the autocatalytic effect on the transformation, further shortening the incubation period, promoting the bainitic transformation, and refining the bainitic microstructure.
Xiao-jie Zhao1，Zhi-nan Yang2，Fu-cheng Zhang1
1. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University2. National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University
摘 要：The bainitic transformation of the steels with different mass fractions of N, ～0.002% and 0.021%, was observed in situ by using high-temperature metalloscope. Micrometer-and nanometer-sized aluminum nitride（AlN） particles were found in the steel with 0.021% N.Grain boundaries, the interior of the grains, and Al N particles were used as initial nucleation sites of bainitic ferrite, and bainitic ferrite subunits served as new nucleation sites to induce secondary nucleation. The lengthening rate of bainitic ferrite varied at different nucleation sites, which was controlled by the repeated nucleation and growth of bainitic subunits. The Al N particles not only provided several nucleation sites, but also increased the autocatalytic effect on the transformation, further shortening the incubation period, promoting the bainitic transformation, and refining the bainitic microstructure.
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