Kinetic Monte Carlo simulation of phase-precipitation versus instability behavior in short period FeCr superlattices

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• 作者：F.J. Rodrí ; guez-Martí ; nez^a ; J.F. Castejó ; n-Mochó ; n^a ; ^{jfcastejon@ucam.edu} ; P. Castrillo^a ; R. Berenguer-Vidal^a ; I. Dopico^b ; I. Martin-Bragado^b
• 关键词：FeCr alloys ; Superlattices ; Kinetic Monte Carlo ; Spinodal
• 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：393
• 期：Complete
• 页码：135-139
• 全文大小：2683 K
• 卷排序：393

文摘

The structural evolution of FeCr superlattices has been studied using a quasi-atomistic Object Kinetic Monte Carlo model. Superlattices with different spatial periods have been simulated for anneal durations from few hours to several months at 500 °C. Relatively-long period superlattices stabilize into Fe-rich and Cr-rich layers with compositions close to those of bulk α and α′ phases. In contrast, superlattices with very short periods (4, 5, 6 nm) are observed to undergo instability and, for long annealing times, evolve into three-dimensionally decomposed regions, in qualitative agreement to recent experimental observations. The instability onset is delayed as the spatial period increases, and it occurs via interface roughness. This evolution can be explained as a minimization of the free-energy associated to the α/α′ interfaces. A comprehensive description of the evolution dynamics of FeCr-based structures is obtained with our model.