Materials Physics and Applications Division, MPA-CINT, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Materials Science and Technology Division, MST-8, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Sci Rep. 2017 Jan 16;7:40148. doi: 10.1038/srep40148.
Under irradiation, chemical species can redistribute in ways not expected from equilibrium behavior. In oxide-dispersed ferritic alloys, the phenomenon of irradiation-induced Cr redistribution at the metal/oxide interfaces has drawn recent attention. Here, the thermal and irradiation stability of the FeCr/YO interface has been systematically studied. Trilayer thin films of 90 nm Fe - 20 at.% Cr (1 layer)/100 nm YO (2 layer)/135 nm Fe - 20 at.% Cr (3 layer) were deposited on MgO substrates at 500 °C. After irradiation, Cr diffuses towards and enriches the FeCr/YO interface. Further, correlated with Cr redistributed into the oxide, an amorphous layer is generated at the interface. In the YO layer, the original cubic phase is observed to transform to the monoclinic phase after irradiation. Meanwhile, nanosized voids, with relatively larger size at interfaces, are also observed in the oxide layer. First-principles calculations reveal that Cr substitution of Y interstitials in YO containing excess Y interstitials is favored and the irradiation-induced monoclinic phase enhances this process. Our findings provide new insights that may aid in the development of irradiation resistant oxide-dispersed ferritic alloys.
在辐照下，化学物质可以以非平衡行为所预期的方式重新分布。在氧化物弥散铁素体合金中，金属/氧化物界面处辐照诱导的 Cr 再分布现象引起了人们的关注。本文系统地研究了 FeCr/YO 界面的热稳定性和辐照稳定性。在 500°C 下，将 90nm 的 Fe-20at.%Cr(1 层)/100nm 的 YO(2 层)/135nm 的 Fe-20at.%Cr(3 层)三层薄膜沉积在 MgO 衬底上。辐照后，Cr 向 FeCr/YO 界面扩散并富集。此外，与 Cr 再分布到氧化物中相关，在界面处生成了非晶层。在 YO 层中，观察到原始立方相在辐照后转变为单斜相。同时，在氧化物层中也观察到纳米级的空洞，其在界面处的尺寸相对较大。第一性原理计算表明，在含有过量 Y 间隙的 YO 中，Cr 取代 Y 间隙是有利的，辐照诱导的单斜相增强了这一过程。我们的发现提供了新的见解，可能有助于开发抗辐照氧化物弥散铁素体合金。
