ABSTRACT

Modeling cluster dynamics or rate theory to describe the microstructural evolution of irradiated materials requires a precise knowledge of the migration energy of a self-interstitial atom (SIA), a product of energetic particle radiation. We measured the evolution of the number density of SIA clusters in electron-irradiated α-iron at low temperatures (110–320 K) by in situ observation using high-voltage electron microscopy. We identified temperature-dependent physical quantities, including (1) the peak density of SIA clusters and (2) the critical defect-free zone thickness in a thin foil specimen, associated with interstitial mobility. By fitting these quantities to the Arrhenius relations derived by rate theory analysis, we obtained estimated interstitial migration energy values of $0.26\pm 0.04$ and $0.30\pm 0.03$ eV for (1) and (2), respectively.

摘要

模拟簇动力学或速率理论来描述受辐照材料的微观结构演化，需要精确了解自填隙原子 (SIA)（高能粒子辐射的产物）的迁移能量。我们通过使用高压电子显微镜的原位观察测量了低温（110-320 K）电子辐照α-铁中SIA簇数密度的演变。我们确定了与温度相关的物理量，包括 (1) SIA 簇的峰值密度和 (2) 薄箔试样中与间隙迁移率相关的临界无缺陷区厚度。通过将这些量拟合到由速率理论分析得出的阿伦尼乌斯关系，我们获得了估计的间隙迁移能量值$0.26\pm 0.04$ 和 $0.30\pm 0.03$ 分别为（1）和（2）的eV。