多元素添加制备具有优异力学性能的Ti基非晶薄膜

Preparation of Ti-Based Amorphous Films with Excellent Mechanical Properties by Multi-Element Addition

摘要: 目前MEMS系统在航空航天、电子电力以及生物医学中的广泛应用及发展，导致Ti基合金的力学性能无法适应当前的应用环境。非晶合金因没有晶界、位错等晶体缺陷，因而表现出优异的机械性能。基于此，本文通过磁控共溅射技术，通过控制靶材参数实现调控Zr、V、Nb元素在Ti基薄膜中的成分变化，并成功制出具有完全非晶态结构的Ti80.6Zr6.0V6.9Nb6.5非晶合金薄膜。该非晶合金薄膜与晶态薄膜相比表现出优异的综合性能，包括：1) 优异的力学性能：高的硬度和弹性模量：7.01 GPa，162 GPa；2) 良好的薄膜质量：高的致密性以及低的粗糙度。此外，还解释了该非晶薄膜具有优异力学性能的原因：1) 结构因素：非晶态结构不具备晶界、位错等结构缺陷；2) 变形机制：对于非晶态材料而言，变形机制是以剪切带机制为主，而剪切带的形成是一个复杂过程，需要消耗大量的势能，因此能承受更高的外加载荷。本次研究为Ti基非晶薄膜家族体系研究提供了新的研究思路，也为MEMS系统提供了有希望的候选材料。

Abstract: The current widespread use and development of MEMS systems in aerospace, electronics and power, and biomedicine has resulted in the mechanical properties of Ti-based alloys not being able to adapt to the current application environment. Amorphous alloys exhibit excellent mechanical properties due to the lack of crystal defects such as grain boundary and dislocation. Based on this, in this paper, the compositional changes of Zr, V, and Nb elements in Ti-based thin films are regulated by magnetron cosputtering technique through controlling the target parameters, and Ti80.6Zr6.0V6.9Nb6.5 amorphous alloy thin films with a completely amorphous structure are successfully produced. The amorphous alloy film exhibits an excellent combination of properties compared to crystalline films, including: 1) excellent mechanical properties: high hardness and modulus of elasticity: 7.01 GPa, 162 GPa; and 2) good film quality: high densities as well as low roughness. In addition, the reasons for the excellent mechanical properties of this amorphous thin film are explained: 1) structural factors: the amorphous structure does not possess structural defects such as grain boundaries and dislocations; 2) deformation mechanism: for amorphous materials, the deformation mechanism is dominated by the shear banding mechanism, and the formation of the shear banding is a complex process that consumes a large amount of potential energy, and thus can withstand higher applied loads. The present study provides new research ideas for the study of Ti-based amorphous thin film family systems and promising candidates for MEMS systems.