Segregation of Cr at tilt grain boundaries in Fe–Cr alloys: A Metropolis Monte Carlo study
Segregation of Cr at tilt grain boundaries in Fe–Cr alloys: A Metropolis Monte Carlo study
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DOI：
10.1016/j.jnucmat.2010.11.024
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发表时间：
2011-01
影响因子：
3.1
通讯作者：
D. Terentyev;Xu He;E. Zhurkin;A. Bakaev
中科院分区：
文献类型：
--
作者：
D. Terentyev;Xu He;E. Zhurkin;A. Bakaev
本文采用Metropolis蒙特卡罗（MMC）方法，采用等温-等压统计系综，研究了Cr含量从5%到14at.%不等的bcc Fe-Cr合金的晶界偏析。考虑了不同的< 110 >倾斜晶界：Σ19{331}， Σ9{221}， Σ3{111}， Σ3{112}， Σ11{113}， Σ9{114}，取向角在26 ~ 141°范围内变化。采用两波段经验多体势在300-900K温度范围内进行了系统的MMC模拟。结果表明，取代态Cr对GB核的结合能主要由GB界面结构决定，在0.05 ~ 0.35 ev范围内变化。此时，结合能随GB过剩体积的增大而增大。MMC模拟结果表明，温度、合金成分和GB结构的共同作用会导致Cr的局部原子重排或偏析。研究了温度和GB结构对α′粒子局部原子重排和析出的影响。
In this work, the Metropolis Monte Carlo (MMC) method employing the isothermal–isobaric statistical ensemble is applied to investigate segregation at grain boundaries in bcc Fe–Cr alloys with varying Cr content from 5 to 14at.%. Several different 〈110〉 tilt grain boundaries, namely: Σ19{331}, Σ9{221}, Σ3{111}, Σ3{112}, Σ11{113}, Σ9{114} with misorientation angle varying in the range 26–141° were considered. Systematic MMC simulations were performed employing a two band empirical many-body potential in the temperature range 300–900K. It was found that the binding energy of substitutional Cr to the GB core is essentially determined by the structure of the GB interface and varies in the range 0.05–0.35eV. At this, the binding energy increases with the GB excess volume. MMC simulations revealed that either a local atomic rearrangement or segregation of Cr at the considered GBs occurs depending on the combination of temperature, alloy composition and GB structure. Influence of temperature and GB structure on the local atomic rearrangement and precipitation of α′ particles is demonstrated.