Weak influence of ferrite growth rate and strong influence of driving force on dispersion of VC interphase precipitation in low carbon steels
Weak influence of ferrite growth rate and strong influence of driving force on dispersion of VC interphase precipitation in low carbon steels
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DOI：
10.1016/j.actamat.2020.01.025
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发表时间：
2020-03-01
期刊：
影响因子：
9.4
通讯作者：
Furuhara, T.
中科院分区：
文献类型：
--
作者：
Zhang, Y. -J.;Miyamoto, G.;Furuhara, T.
在迁移的铁素体/奥氏体相间边界处由相间沉淀形成的纳米级合金碳化物的分散预计会受到边界处局部条件的影响，包括铁素体生长速率和沉淀驱动力。通过改变合金成分和转变温度，系统地研究了这两个因素的影响。三维原子探针定量分析表明，当转变温度较低或V含量较高时，VC相间析出物的数量密度较高，尺寸较小。较低的 Mn 或较高的 Si 含量也稍微改善了 VC 的分散性，但通过增加 C 含量几乎保持不变。这种变化与其析出驱动力具有良好的相关性，增大驱动力可以获得更细小的VC析出物。相比之下，在本研究范围内，大多数情况下铁素体生长速率对色散的影响相当小，这可以通过考虑 VC 在铁素体/奥氏体界面迁移的成核动力学来解释。 (C) 2020 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
Dispersion of nano-sized alloy carbides formed by interphase precipitation at migrating ferrite/austenite interphase boundaries is expected to be affected by local conditions at the boundaries, including ferrite growth rate and driving force for precipitation. The effects of these two factors were systematically investigated by changing alloy composition and transformation temperature. Quantitative analyses by using three-dimensional atom probe reveal that VC interphase precipitation becomes higher in number density and smaller in size at lower transformation temperature or with higher V content. The dispersion of VC is also slightly refined by lower Mn or higher Si content, but remains almost unchanged by increasing the C content. Such variations show good correlations with the driving force for its precipitation that finer VC precipitates can be obtained by enlarging the driving force. In contrast, the influence of the ferrite growth rate on the dispersion in most cases is quite small in the range of this study, which can be explained by considering nucleation kinetics of VC at migrating ferrite/austenite interface. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.