Chen Hui, Wang Yu, Zheng Jianshu, Zhao Chengzhi, Li Qing, Wei Xin, Zhang Boning
AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China.
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Materials (Basel). 2025 Apr 15;18(8):1805. doi: 10.3390/ma18081805.
Nano-precipitates play a vital role in the development of ultra-high strength steels (UHSSs). In recent decades, the B2-NiAl phase, which forms highly coherent interfaces with the BCC-Fe matrix, has attracted significant attention for enhancing the strength of UHSSs. However, direct experimental investigation of alloying elements-specifically their atomic distribution and the resulting effects on the interfacial bonding strength of nano-precipitates-remains challenging. This study uses density functional theory (DFT)-based first-principles calculations to investigate the role of alloying elements in modifying interfacial characteristics. Six elements-Al, Ni, Co, Cr, Mo, and C-are introduced at various occupation sites within the coherent interface model to calculate the formation energy. The predicted preferential distribution of solid-solution atoms aligns well with experimental findings. Stable configurations of alloying segregation are selected for first-principles rigid tensile fracture tests along the <001> direction. Electronic structure analysis reveals that Co, Cr, and Mo segregation enhances interface strength due to solute-induced high charge density and the preservation of bonding characteristics of bulk phases at the interface. The results offer valuable insights and practical guidance for developing novel ultrahigh-strength structural steels strengthened by B2-NiAl.
纳米析出相在超高强度钢（UHSSs）的发展中起着至关重要的作用。近几十年来，与体心立方铁（BCC-Fe）基体形成高度共格界面的B2-NiAl相，在提高超高强度钢强度方面引起了广泛关注。然而，对合金元素进行直接实验研究——特别是它们的原子分布以及对纳米析出相界面结合强度的影响——仍然具有挑战性。本研究采用基于密度泛函理论（DFT）的第一性原理计算方法，来研究合金元素在改变界面特性方面的作用。在共格界面模型中的不同占位位置引入六种元素——铝（Al）、镍（Ni）、钴（Co）、铬（Cr）、钼（Mo）和碳（C）——以计算形成能。预测的固溶体原子优先分布与实验结果吻合良好。选择合金偏析的稳定构型，沿<001>方向进行第一性原理刚性拉伸断裂试验。电子结构分析表明，钴、铬和钼的偏析由于溶质诱导的高电荷密度以及界面处体相键合特性的保留而增强了界面强度。这些结果为开发由B2-NiAl强化的新型超高强度结构钢提供了有价值的见解和实际指导。
