Mechanisms of oxidation of pure and Si-segregated α-Ti surfaces
Mechanisms of oxidation of pure and Si-segregated α-Ti surfaces
复制标题
DOI：
10.1016/j.apsusc.2018.08.253
复制
发表时间：
2019
影响因子：
6.7
通讯作者：
S. Bhattacharya;R. Sahara;S. Suzuki;Kyosuke Ueda;T. Narushima
中科院分区：
文献类型：
--
作者：
S. Bhattacharya;R. Sahara;S. Suzuki;Kyosuke Ueda;T. Narushima
利用第一性原理分子动力学，我们确定了α-Ti表面氧化的机制。Si偏析抑制了Ti中α-case的形成，这也得到了实验的证实。从金属原子到气体分子的电荷转移驱动了纯α-Ti（0001）和si分离α-Ti（0001）表面的初始氧化阶段，而在后期阶段，氧化通过氧气渗透到板坯中进行。氧化网络的生长强烈依赖于表面钛原子的氧化态。si分离材料表面形成TiOx(0.5 ≤x≤ 1)，对应于Ti原子的+1.5氧化态，阻碍了材料中氧化物的生长。模拟和实验清楚地表明，即使在高温下，Si也能减少氧进入Ti。本文所进行的鉴定、理解和控制高温下钛表面氧化机制的主要和关键步骤，有望帮助设计出具有更好抗氧化性的新合金。
Using first-principles molecular dynamics, we identified the mechanisms of the oxidation of α-Ti surfaces. Si segregation was found to suppress α-case formation in Ti, which was also confirmed experimentally. Charge transfer from the metal atoms to the gas molecules drives the initial stages of oxidation on the pure and Si-segregated α-Ti (0001) surfaces, while during the later stages, oxidation proceeds via oxygen penetration into the slab. Growth of the oxide network was strongly dependent on the oxidation state of the surface Ti atoms. Oxide growth in the Si-segregated material was retarded with the formation of TiOx(0.5 ≤x≤ 1) on the surface, which corresponds to the +1.5 oxidation state of the Ti atoms. The simulations and experiments clearly showed that Si reduces the ingress of oxygen into Ti, even at high temperatures. The primary and critical steps of identifying, understanding, and controlling the mechanisms of oxidation of Ti surfaces at high temperatures, as performed here, are expected to aid the design of new alloys with improved oxidation resistance.