Effect of cooling rate after solution treatment on subsequent phase separation during aging of Fe-Cr alloys: A small-angle neutron scattering study
Effect of cooling rate after solution treatment on subsequent phase separation during aging of Fe-Cr alloys: A small-angle neutron scattering study
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DOI：
10.1016/j.actamat.2017.06.001
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发表时间：
2017-08
期刊：
影响因子：
9.4
通讯作者：
Xin Xu;J. Odqvist;M. Colliander;S. King;M. Thuvander;A. Steuwer;P. Hedström
中科院分区：
文献类型：
--
作者：
Xin Xu;J. Odqvist;M. Colliander;S. King;M. Thuvander;A. Steuwer;P. Hedström
研究了固溶处理后冷却速度对Fe-Cr二元合金初始组织的影响，以及初始组织对后续时效过程中相分离的影响。采用小角中子散射法研究了合金体中纳米尺度的成分波动，并与Cahn-Hilliard-Cook （CHC）模型的模拟结果进行了比较。所研究的合金表现出不同的相分离机制，当Cr含量较高时，有利于独立分解（SD），固溶处理后缓慢冷却导致的初始Cr成分波动降低了相分解动力学，而当Cr含量较低时，有利于成核和生长，相分解动力学更快。无论合金的标称Cr成分如何，在748 K下延长时效至300 h后，对于更非随机的初始组织，相分解总是更大。对fe - 40wt .% Cr合金进行SD分解的实验结果与冷却过程和随后的初始时效（小于10 h）的CHC模型在定性上基本一致。然而，必须改进建模方法，以便对整个SD过程进行精确的定量建模，包括粗化。
The effect of cooling rate after solution treatment on the initial structure of concentrated binary Fe-Cr alloys and the effect of the initial structure on phase separation during subsequent aging has been investigated. The nano-scale compositional fluctuations in the bulk of the alloys are studied using small-angle neutron scattering and the results are compared with simulations using the Cahn-Hilliard-Cook (CHC) model. The alloys investigated represent different mechanisms of phase separation and at higher Cr content, when spinodal decomposition (SD) is favored, the initial Cr compositional fluctuations due to slow cooling after solution treatment reduce the kinetics of phase decomposition, whereas, at lower Cr composition when nucleation and growth is favored, the kinetics of phase decomposition is more rapid. Regardless of the nominal Cr composition of the alloy, the phase decomposition after extended aging up to 300 h at 748 K is always larger for the more non-random initial structure. The CHC modeling of the cooling process and subsequent initial aging (below 10 h) is in reasonable qualitative agreement with the experimental results for the Fe-40 wt.% Cr alloy decomposing via SD. However, the modeling approach must be refined for accurate quantitative modeling of the full SD process, including coarsening.