Positron annihilation lifetime spectroscopy (PALS) was performed to characterize the interfacial nanostructure between the oxide particles and ferritic matrix in two types of oxide dispersion strengthened (ODS) alloys: FeCr dispersed with Y-Ti oxide nanoparticles and FeCrAl dispersed with Y-Al oxide nanoparticles. The spectra were precisely fitted and decomposed into three components with two trapping rates. Bulk lifetime approached the theoretical value of 107 ps by taking into account the positron trapping at two types of defects. Structural characterization was performed by coincidence Doppler broadening and high-resolution transmission electron microscopy (HRTEM), revealing that two-trapping defect clusters were closely associated with Y-Ti or Y-Al oxide particles. Trapping was not detected in the non-ODS alloys. Based on Kuramotos advanced theoretical work, the shorter annihilation lifetime (179–194 ps) could be ascribed to positron trapping at vacancies and divacancies localized under the misfit dislocations associated with Y-Ti or Y-Al oxide particles. The longer annihilation lifetime (301–323 ps) could be attributed to Ar-filled gas bubbles precipitated at the oxide particle-matrix interfaces. These results of PALS analyses were consistent with the HRTEM characterization.

中文翻译：

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FeCr 和 FeCrAl 氧化物弥散强化 (ODS) 合金的正电子湮灭寿命光谱

正电子湮没寿命谱 (PALS) 表征了两种氧化物弥散强化 (ODS) 合金中氧化物颗粒和铁素体基体之间的界面纳米结构：分散有 Y-Ti 氧化物纳米颗粒的 FeCr 和分散有 Y-Al 氧化物纳米颗粒的 FeCrAl 。光谱被精确拟合并分解为具有两种捕获率的三个分量。考虑到两种缺陷处的正电子俘获，体寿命接近 107 ps 的理论值。通过重合多普勒展宽和高分辨率透射电子显微镜 (HRTEM) 进行结构表征，表明双俘获缺陷簇与 Y-Ti 或 Y-Al 氧化物颗粒密切相关。在非消耗臭氧层物质合金中未检测到捕获。根据 Kuramoto 的先进理论工作，较短的湮没寿命（179-194 ps）可归因于与 Y-Ti 或 Y-Al 氧化物颗粒相关的失配位错下的空位和双空位处的正电子捕获。较长的湮灭寿命（301-323 ps）可归因于在氧化物颗粒-基体界面处沉淀的充满Ar的气泡。 PALS 分析的这些结果与 HRTEM 表征一致。