The diffusion mechanism of carbon in iron plays a vital role in carburization processes, steel fabrication, and metal dusting corrosion. In this paper, using the kinetic activation-relaxation technique (k-ART), an off-lattice kinetic Monte Carlo algorithm with on-the-fly catalog building that allows to obtain diffusion properties over large time scales taking full account of chemical and elastic effects coupled with an EAM potential, we investigate the effect of pressure on the diffusion properties of carbon in $85.{91}^{\circ }\langle 100\rangle$ symmetric tilt grain boundaries (GB) of $\alpha$-iron up to a pressure of 12 kbar at a single temperature of 600 K. We find that, while the effect of pressure can strongly modify the C stability and diffusivity in the GB in ways that depend closely on the local environment and the nature of the deformation, isotropic and uniaxial pressure can lead to opposite and nonmonotonous effects regarding segregation energy and activation barriers. These observations are relevant to understanding of the evolution of heterogeneous materials, where variations of local pressure can alter the carbon diffusion across the material.

中文翻译：

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α-铁的85.91∘〈100〉对称倾斜晶界上压力对碳扩散的影响

碳在铁中的扩散机制在渗碳过程，钢铁制造和金属粉尘腐蚀中起着至关重要的作用。在本文中，使用动力学活化松弛技术（k-ART），一种具有动态目录构建的非晶格动力学蒙特卡洛算法，该算法可在充分考虑化学和弹性的情况下获得较大时间范围内的扩散特性效应与EAM势结合，我们研究了压力对碳在碳纳米管中扩散特性的影响$85。{91}^{\circ }〈100〉$ 的对称倾斜晶界（GB） $\alpha$-在600 K的单一温度下将铁加压至12 kbar的压力。我们发现，虽然压力的影响可以强烈地改变GB中C的稳定性和扩散性，但其方式密切依赖于当地环境和碳的性质。变形，各向同性和单轴压力会导致与偏析能和激活势垒相反且非单调的影响。这些观察结果与理解异质材料的演化有关，局部压力的变化会改变碳在整个材料中的扩散。