Lv Hang, Gao Xinxin, Zhang Kan, Wen Mao, He Xingjia, Wu Zhongzhen, Liu Chang, Chen Changfeng, Zheng Weitao
State Key Laboratory of Superhard Materials, Department of Materials Science and Key Laboratory of Automobile Materials, MOE, Jilin University, Changchun, 130012, China.
School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
Nat Commun. 2023 Aug 10;14(1):4836. doi: 10.1038/s41467-023-40580-8.
Grain boundary engineering is a versatile tool for strengthening materials by tuning the composition and bonding structure at the interface of neighboring crystallites, and this method holds special significance for materials composed of small nanograins where the ultimate strength is dominated by grain boundary instead of dislocation motion. Here, we report a large strengthening of a nanocolumnar copper film that comprises columnar nanograins embedded in a bamboo-like boron framework synthesized by magnetron sputtering co-deposition, reaching the high nanoindentation hardness of 10.8 GPa among copper alloys. The boron framework surrounding copper nanograins stabilizes and strengthens the nanocolumnar copper film under indentation, benefiting from the high strength of the amorphous boron framework and the constrained deformation of copper nanocolumns confined by the boron grain boundary. These findings open a new avenue for strengthening metals via construction of dual-phase nanocomposites comprising metal nanograins embedded in a strong and confining light-element grain boundary framework.
晶界工程是一种通过调整相邻微晶界面处的成分和键合结构来强化材料的通用工具，这种方法对于由细小纳米晶粒组成的材料具有特殊意义，因为在这类材料中，极限强度由晶界而非位错运动主导。在此，我们报道了一种纳米柱状铜膜的大幅强化，该铜膜由嵌入通过磁控溅射共沉积合成的竹状硼框架中的柱状纳米晶粒组成，在铜合金中达到了10.8 GPa的高纳米压痕硬度。围绕铜纳米晶粒的硼框架在压痕作用下使纳米柱状铜膜稳定并强化，这得益于非晶硼框架的高强度以及硼晶界对铜纳米柱的约束变形。这些发现为通过构建包含嵌入强约束性轻元素晶界框架中的金属纳米晶粒的双相纳米复合材料来强化金属开辟了一条新途径。
