Moraes Vincent, Riedl Helmut, Fuger Christoph, Polcik Peter, Bolvardi Hamid, Holec David, Mayrhofer P H
Christian Doppler Laboratory for Application Oriented Coating Development at the Institute of Materials Science and Technology, TU Wien, A-1060, Wien, Austria.
Institute of Materials Science and Technology, TU Wien, A-1060, Wien, Austria.
Sci Rep. 2018 Jun 18;8(1):9288. doi: 10.1038/s41598-018-27426-w.
The demand to discover new materials is scientifically as well as industrially a continuously present topic, covering all different fields of application. The recent scientific work on thin film materials has shown, that especially for nitride-based protective coatings, computationally-driven understanding and modelling serves as a reliable trend-giver and can be used for target-oriented experiments. In this study, semi-automated density functional theory (DFT) calculations were used, to sweep across transition metal diborides in order to characterize their structure, phase stability and mechanical properties. We show that early transition metal diborides (TiB, VB, etc.) tend to be chemically more stable in the AlB structure type, whereas late transition metal diborides (WB, ReB, etc.) are preferably stabilized in the WB structure type. Closely related, we could prove that point defects such as vacancies significantly influence the phase stability and even can reverse the preference for the AlB or WB structure. Furthermore, investigations on the brittle-ductile behavior of the various diborides reveal, that the metastable structures are more ductile than their stable counterparts (WB, TcB, etc.). To design thin film materials, e.g. ternary or layered systems, this study is important for application oriented coating development to focus experimental studies on the most perspective systems.
无论是在科学领域还是工业领域，对发现新材料的需求一直是一个持续存在的话题，涵盖了所有不同的应用领域。最近关于薄膜材料的科学研究表明，特别是对于氮化物基保护涂层，计算驱动的理解和建模是一种可靠的趋势引导方法，可用于目标导向的实验。在本研究中，使用了半自动密度泛函理论（DFT）计算，以扫描过渡金属二硼化物，从而表征其结构、相稳定性和力学性能。我们表明，早期过渡金属二硼化物（TiB、VB等）在AlB结构类型中往往在化学上更稳定，而晚期过渡金属二硼化物（WB、ReB等）则优选在WB结构类型中稳定。与此密切相关的是，我们可以证明诸如空位等点缺陷会显著影响相稳定性，甚至可以逆转对AlB或WB结构的偏好。此外，对各种二硼化物的脆韧行为的研究表明，亚稳结构比其稳定对应物（WB、TcB等）更具延展性。为了设计薄膜材料，例如三元或层状体系，本研究对于面向应用的涂层开发非常重要，以便将实验研究集中在最具前景的体系上。
