吉林大学张侃等：空位工程和压应力实现HfB2薄膜的超硬特性及其原子尺度机制

2025-11-27 16:12:22 作者：中国科学材料来源：中国科学材料分享至：

刀具防护膜在极端条件下服役，对硬度要求极高。过渡金属二硼化物（TMB₂）因其TM-B和B-B强共价键而展现出应用潜力，但在保持简单二元结构的同时实现超硬仍具挑战。

近日，吉林大学张侃教授等人在Science China Materials发表研究论文，以HfB₂为例，揭示了硼空位填充与平面压应力协同提升硬度的机制。

本文要点

1) 制备了具有(001)择优取向的亚化学计量比的HfB_2-x、化学计量比的HfB₂及受压应力作用的HfB₂薄膜。

2) 纳米压痕结果显示，硬度由HfB_1.90的33.0 ± 1.1 GPa提升至HfB₂的40.5 ± 0.4 GPa，并在-3.67 GPa压应力下进一步增至45.7 ± 1.1 GPa。

3) 理论计算表明，空位填充增加了承载键数目并通过电荷积累强化B-B键，而压应力则通过缩短B-B键长进一步增强其强度。

本工作阐明了TMB₂中空位与应力调控的原子尺度机制，并提出了一种无需掺杂即可实现超硬防护膜的简便可扩展途径。本论文收录于“2026新锐科学家”专刊。

Figure 1. (a) XRD patterns ranging from the HfB_1.90-100V film to the HfB_2.00-200V film; (b) experimental and theoretical values of lattice constant c; typical pole figure of the HfB_2.00-100V film along (c) the [001] direction and (d) [101] direction, presented in 2D and 3D views.

Figure 2. (a–c) HR-TEM images, (d–f) corresponding IFFT images of the HfB_1.90-100V film, the HfB_2.00-100V film, and the HfB_2.00-200V film.

Figure 3. (a) Bonding pattern of the HfB₂ structural unit under the indentation shear strains along the (001)[100] direction at the peak stress compared with the unstrained equilibrium structure. (b) Stress responses to indentation shear strain in the (001)[100] shear-slip direction of HfB_1.89-0σ, HfB_1.94-0σ, HfB₂-0σ, HfB₂-2σ, and HfB₂-4σ. (c) Structural snapshots of HfB₂-0σ along the [001] direction at equilibrium and after the drop in indentation shear stress.

Figure 4. (a) Numbering of B atoms in the (001) plane. (b) Evolution of B–B bond lengths in the (001) plane under (001) [100] indentation shear strain for HfB_1.89-0σ, HfB_1.94-0σ, HfB₂-0σ, HfB₂-2σ, and HfB₂-4σ. (c) Statistics of the total number of B–B bonds and the number of broken B–B bonds within the (001) plane region shown in (a) under the indentation shear strain.