Study of cascade damage effects detected by dynamic behavior of helium bubbles

(1)氦气泡动态损伤效应的研究高能(100-400keV)自离子辐照Au、Cu、Si、Fe和Fe-Cr合金样品，用10keV氦离子预照射氦泡，并在Argonne国家实验室进行原位IVEM观察，研究了高能自离子辐照过程中气泡的动力学行为。氦气泡可作为叶栅损伤的传感器。研究发现，即使在高温下高能自离子的照射下，大多数气泡仍表现为布朗随机运动，但其迁移率受到抑制。但是，一小部分泡沫被加速了。气泡的压低和加速分别由空位的吸收和与离子的直接碰撞引起。在中温，气泡没有发生随机运动，氦气泡沿位错环的间歇性运动是…在高能自体离子照射下，诱导作用更强。在这些温度下，氦气泡很容易沿着位错线运动。在较低温度下，气泡与位错的相互作用和位错环的一维运动，氦气泡与位错的相互作用较强。结果表明，该小气泡沿位错线和其他方向热运动。气泡可以作为位错中应变场的传感器。研究了在电子辐照或退火过程中，具有1/2&lt；111&gt；的小间隙型位错环的一维运动，发现在一维运动过程中，Burgers矢量向另一个1/2&lt；111&gt；或~lt；100&gt；运动。在较低的温度下，Fe-9Cr中环的数密度增加，这表明它们之间的弹性相互作用可以诱导一维的运动。(3)氦的热脱附谱及其与Fe的微观结构变化的关系，Fe-9CrTDS谱以及相关的微结构变化。在1000℃的恒定加热过程中，观察到五个TDS峰。较低温度下的峰值与位错捕获相关，较高温度下的峰值与气泡向表面的运动和α-伽马相变相关。在Fe-9Cr合金中，铬偏析到气泡或位错环可使TDS峰向高温移动。较少

(1)Study of cascade damage effects detected by dynamic behavior of helium bubblesHigh energy (100-400keV) self-ions were irradiated to Au,Cu,Si,Fe and Fe-Cr alloys specimens, to which helium bubbles were pre-introduced by irradiation with 10keV helium ions, and the dynamical behavior of the bubbles during the irradiation of high energy self-ions was studied by in-situ IVEM observation at Argonne National Laboratory. Helium bubbles can be used as a sensor for the cascade damage. It was found that most of the bubbles showed Brownian type-random motion even under the irradiation with high energy self-ions at high temperature, but their mobility was depressed. But, a small number of the bubble were accelerated. The depression and the acceleration of the bubbles should be caused by absorption of vacancies and by direct collision with ions, respectively. At middle temperatures, random motion of the bubble did not occur and an intermittent motion of helium bubbles along a dislocation loop was … More induced under the irradiation with high energy self-ions. Easy motion of helium bubbles along the dislocation lines at these temperatures was revealed. At lower temperatures, a sporadic motion in a limited region was revealed and this could be caused by direct collision with the cascade damage.(2)Interaction of the bubble with dislocation and one-dimensional motion of dislocation loopsThe interaction of helium bubbles with the dislocation was comparatively strong. It was revealed that the small bubble was thermally mobile along the dislocation line and the other directions. Bubbles can be used as a sensor of the strain field in the dislocation.One-dimensional motion of the small interstitial type dislocation loops with the burgers vector 1/2<111> was studied during annealing or under the electron irradiation and it was revealed that the burgers vector changes to the other 1/2<111> or to <100> during the one-dimensional motion. At lower temperature, the number density of the loops increases in Fe-9Cr and it was suggested that one dimensional motion could be induced by their elastic interaction.(3)TDS(Thermal Desorption Spectroscopy) of helium and its correlation with a change of the microstructure in Fe,Fe-9CrTDS spectra from helium irradiated Fe and Fe-9Cr and the correlated microstructure changes were studied. During a constant heating of the specimen up to 1000℃, five TDS peaks were observed. The peaks at lower temperatures are correlated with the dislocation trapping and ones at higher temperatures are correlated with the bubble motion to the surface and alpha-gamma phase transformation. Chromium segregated to the bubble or dislocation loops could shift the TDS peaks to higher temperature in Fe-9Cr alloy. Less