Influence of magnetic field on ferrite transformation in a Fe–C–Mn alloy
Influence of magnetic field on ferrite transformation in a Fe–C–Mn alloy
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DOI：
10.1016/j.jmmm.2009.07.072
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发表时间：
2009-12
影响因子：
2.7
通讯作者：
G. Zhang;M. Enomoto;N. Hosokawa;M. Kagayama;Y. Adachi
中科院分区：
文献类型：
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作者：
G. Zhang;M. Enomoto;N. Hosokawa;M. Kagayama;Y. Adachi
研究了在8T强磁场中，Fe-0.10质量%C-2.94质量%Mn合金中的铁素体相变动力学。根据扩散控制生长理论，在低过冷度时，缓慢的Mn扩散决定了分配式生长，而在较大过冷度时，无分割式生长是由快速碳扩散控制的。该合金被奥氏体化，并在包含两种生长模式的温度下等温反应。在磁场中，铁素体的形核和生长速度在所有温度下都有所增加，而在较低温度下增加的幅度稍大一些。在缓慢生长区域，由于体心立方Fe固溶体的磁矩和居里温度的影响，除扩散缓慢外，Mn还可能使铁素体相失稳，并部分抵消了相变的加速作用。在磁场作用下，由于铁素体/奥氏体相界面的移动，从慢速生长到快速生长的转变温度预计会升高。
The kinetics of ferrite transformation in a Fe–0.10mass%C–2.94mass%Mn alloy in a strong magnetic field of 8T were studied with regard to alloying element-partitioned and partitionless growth. According to the theory of diffusion-controlled growth, the slow Mn diffusion dictates partitioned growth that occurs at a low undercooling, whereas partitionless growth at a larger undercooling is rate-controlled by fast carbon diffusion. The alloy was austenitized and isothermally reacted at temperatures that encompass the two growth modes. The nucleation and growth rates of ferrite increased at all temperatures in the magnetic field, whereas the amount of increase was somewhat greater at lower temperatures. In the region of slow growth, besides its sluggish diffusion Mn possibly destabilizes the ferrite phase due to the influence on the magnetic moment and the Curie temperature of bcc Fe solid solution, and partially offsets the accelerating effect of transformation. The temperature of transition from the slow to the fast growth is predicted to increase, due to the shift in the ferrite/austenite phase boundaries in the presence of magnetic field.