Molecular dynamics simulation of nanoindentation of Fe3C and Fe4C
Molecular dynamics simulation of nanoindentation of Fe3C and Fe4C
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DOI：
10.1016/j.msea.2013.12.091
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发表时间：
2014-03-12
期刊：
影响因子：
6.4
通讯作者：
Agrawal, Anupam
中科院分区：
文献类型：
--
作者：
Goel, Saurav;Joshi, Suhas S.;Agrawal, Anupam
碳化铁的纳米力学响应的研究非常重要，因为碳化铁的存在极大地影响钢部件的性能和寿命。这项工作通过使用分子动力学模拟探索 Fe3C 和四面体 Fe4C 的纳米压痕，为文献做出了贡献。铁和碳的化学相互作用通过分析键序原子间势（ABOP）能量函数来描述。压痕以50m/s的压痕速度进行，并以5m/s的速度进行重复试验。这两种碳化物的载荷-位移 (P-h) 曲线显示残余压痕深度和最大压痕深度 (h(f)/h(max)) 之比高于 0.7，即不适合应用 Oliver 和 Pharr 方法来评估材料性能的情况。替代评估显示 Fe3C 比 Fe4C 硬得多。吉布斯形成自由能和径向分布函数，加上平均局部温度和冯米塞斯应力的状态表明碳化铁新相的形成。发现这种新相的形成是由于偏应变而不是纳米压痕期间在基材中引起的高温。皇冠版权所有 (C) 2014 由 Elsevier B.V. 出版。保留所有权利。
Study of nanomechanical response of iron carbides is important because presence of iron carbides greatly influences the performance and longevity of steel components. This work contributes to the literature by exploring nanoindentation of Fe3C and tetrahedral-Fe4C using molecular dynamics simulation. The chemical interactions of iron and carbon were described through an analytical bond order inter-atomic potential (ABOP) energy function. The indentations were performed at an indentation speed of 50 m/s and a repeat trial was performed at 5 m/s. Load-displacement (P-h) curve for both these carbides showed residual indentation depth and maximum indentation depth (h(f)/h(max)) ratio to be higher than 0.7 i.e. a circumstance where Oliver and Pharr method was not appropriate to be applied to evaluate the material properties. Alternate evaluation revealed Fe3C to be much harder than Fe4C. Gibbs free energy of formation and radial distribution function, coupled with state of the average local temperature and von Mises stresses indicate the formation of a new phase of iron-carbide. Formation of this newer phase was found to be due to deviatoric strain rather than the high temperature induced in the substrate during nanoindentation. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.