Grain refinement mechanism of nitrogen ion implantation in 7075-T651 aluminum alloy: Insights from the cellular automaton method

Ion implantation can strengthen metal surfaces by inducing grain refinement. However, the refinement mechanism remains unclear, which affects the precise application of the process. To address this, the present study aims to elucidate the dynamic evolution of the microstructure during nitrogen ion i...

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Bibliographic Details
Main Authors: Yelin Zeng, Tingting Jiang, Jinyuan Tang, Jiangping Zhu, Xiaocheng Shen, Yihao Ling
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425021131
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Summary:Ion implantation can strengthen metal surfaces by inducing grain refinement. However, the refinement mechanism remains unclear, which affects the precise application of the process. To address this, the present study aims to elucidate the dynamic evolution of the microstructure during nitrogen ion implantation in 7075-T651 aluminum alloy and analyze the influence of target material parameters on grain refinement. A novel theoretical model was proposed to explain nucleation and growth of new grains by drawing an analogy to dynamic recrystallization. Based on this theory, the cellular automaton model revealed a three-stage grain refinement rate: an initial slow growth, a rapid increase, and a final slowdown. During early ion implantation, parent-phase grain size has little effect on refinement, but smaller grains accelerate refinement in the later stage. The initial dislocation density is positively correlated with the efficiency of grain refinement. Moreover, the study suggests performing shot peening before ion implantation in industrial applications.
ISSN:2238-7854