Quantitative measurements of phase equilibria at migrating α/γ interface and dispersion of VC interphase precipitates: Evaluation of driving force for interphase precipitation
Quantitative measurements of phase equilibria at migrating α/γ interface and dispersion of VC interphase precipitates: Evaluation of driving force for interphase precipitation
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DOI：
10.1016/j.actamat.2017.02.020
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发表时间：
2017-04-15
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.
为了使α相变过程中迁移的铁素体(α)/奥氏体（γ）界面形成的纳米级界面相析出物更好地应用于工业，对其弥散的微观组织控制具有重要意义。虽然其降水的驱动力是已知的重要因素之一，但在没有实验支持的文献中对其值的估计仍然存在问题。因此，本研究旨在通过对一系列v合金在不同温度下等温相变的实验研究，定量估计相间析出的驱动力。对α / γ界面C含量的场发射-电子探针微分析（FE-EPMA）表明，可忽略配分局部平衡（NPLE）模型可以很好地解释α / γ相平衡。三维原子探针（3dp）量化的VC间相的数量密度和平均半径与NPLE条件下迁移α / γ界面间相析出驱动力的计算结果具有良好的相关性。从驱动力的角度看，VC的尺寸比预期的要大，这意味着它在迁移的α / γ界面上成核后可能会长大。(C) 2017材料学报Elsevier Ltd.出版。版权所有。
For better industrial application of nano-sized interphase precipitates formed at migrating ferrite (alpha)/ austenite (gamma) interface during alpha transformation, microstructural control on its dispersion is of great significance. Although the driving force for its precipitation was known to be one of the important factors, the estimation on its value in literature without experimental supports was still questionable. Therefore, the present study aimed to quantitatively estimate the driving force for interphase precipitation based on experimental investigation in a series of V-added alloys isothermally transformed at various temperatures. Field emission-electron probe microanalysis (FE-EPMA) on alpha/gamma interfacial C content reveals that alpha/gamma phase equilibria can be well explained by negligible-partition local equilibrium (NPLE) model. Both number density and average radius of VC interphase precipitates quantified by using three-dimensional atom probe (3DAP) show good correlations with the calculated driving force for interphase precipitation at migrating alpha/gamma interface under NPLE condition. Larger size of VC than the expected one from the driving force implies the possible growth after its nucleation at migrating alpha/gamma interface. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.