Cai Junfeng, Han Wentuo, Wan Farong, He Jianchao
Institute of Special Environments Physical Sciences, Harbin Institute of Technology, Nanshan District, Shenzhen 518055, China.
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Materials (Basel). 2022 Oct 17;15(20):7257. doi: 10.3390/ma15207257.
Oxide-dispersion-strengthened (ODS) steels, which contain nano-scale Y-Ti-O particles, are being considered for high-temperature radiation environments of nuclear reactors. It is important to accurately characterize the structure of grain boundaries and understand the behavior of segregation at grain boundaries in ODS steels during irradiation. The effect of heavy ion irradiation at 700 °C on Nanostructured Ferritic Alloy 14YWT was investigated using Atom Probe Tomography. Enrichment of Cr occurs at the grain boundaries as well as at nano oxide particle surfaces in the unirradiated sample. The enrichment of Ti and Y at a grain boundary corresponds with Y-Ti-O nano oxide particles with larger size compared to those in the grain, and the Cr enrichment is particularly accentuated at these larger nano oxide particles. The segregation of W occurs at the grain boundaries that are without nano oxide particles. O is segregated at grain boundaries without oxide particles after irradiation. The segregation behavior of Cr, W, Ti, and Y at the grain boundary in the irradiated samples is similar to that in the unirradiated sample. The nano oxide particles embedded in the grain boundary are a primary reason for the increase in Cr segregation at the grain boundary.
含有纳米级Y-Ti-O颗粒的氧化物弥散强化（ODS）钢正被考虑用于核反应堆的高温辐射环境。准确表征ODS钢晶界结构并了解辐照过程中晶界处的偏析行为非常重要。使用原子探针断层扫描研究了700℃下重离子辐照对纳米结构铁素体合金14YWT的影响。在未辐照样品中，Cr在晶界以及纳米氧化物颗粒表面富集。晶界处Ti和Y的富集与尺寸比晶粒中更大的Y-Ti-O纳米氧化物颗粒相对应，并且在这些较大的纳米氧化物颗粒处Cr的富集尤为明显。W的偏析发生在没有纳米氧化物颗粒的晶界处。辐照后，O在没有氧化物颗粒的晶界处偏析。辐照样品中晶界处Cr、W、Ti和Y的偏析行为与未辐照样品中的相似。嵌入晶界的纳米氧化物颗粒是晶界处Cr偏析增加的主要原因。
