Atomic diffusion

Atomic diffusion

Imperfections and Diffusion

Published in Yip-Wah Chung, Monica Kapoor, Introduction to Materials Science and Engineering, 2022

In polycrystalline solids, grain boundaries become a preferred path for atomic diffusion. Generally, because of the more open nature of grain boundaries, the activation energy for diffusion along grain boundaries is lower than that in the bulk.

Effect of Gradient Nanostructure on Plasma Sulfonitrocarburizing of 42MnCr52 Steel

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Journal Information

Published in Tribology Transactions, 2020

X. H. Zhao, Y. Q. Zhao, D. S. Xu, C. H. Hu

A graphical model is proposed to explain the diffusion of sulfur, nitrogen, and carbon in the PSNC specimen and USRP + PSNC specimen (Fig. 8). After USRP, grains are refined to different degrees at different vertical distances, thereby generating many grain boundaries. In addition, a large number of nonequilibrium defects are generated during the plastic deformation process. High-density nonequilibrium defects increase the surface activity and further enhance the adsorption of active atoms in surface (Tong, et al. (36)). A large number of grain boundaries may act as fast atomic diffusion channels (Vetterick, et al. (17); Lu, et al. (18)). Therefore, the above characteristics induced by USRP would help to promote the diffusion of elements, following the conclusion that surface nanocrystallization can improve the surface structure, increase surface activity, and promote the diffusion of elements.

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Imperfections and Diffusion

Effect of Gradient Nanostructure on Plasma Sulfonitrocarburizing of 42MnCr52 Steel