Abstract The microstructures of SiCf/SiC composites irradiated with 400 keV C+ and then 200 keV He+ at 633 K and annealed post-irradiation at 1073, 1273, and 1473 K for 5 h were analyzed. The SiCf/SiC composites were composed of nanocrystal SiC fibers with 5–25 μm in size, SiC matrix with a columnar crystal structure, and six transition layers (alternate distribution of pyrolytic carbon and SiC layers) between them. Several fine microcracks induced by irradiation appeared at the interfaces and grew during annealing. An irradiation band with a few helium bubbles was formed in the SiC fiber and had a width of approximately 260 nm, which decreased with increase in annealing temperature. Annealing caused the irradiation-induced bubbles to grow and induced a linear arrangement of the bubbles in the SiC fiber. Larger He bubbles were generated at the grain boundary and tended to form microcracks in the SiC matrix. Irradiation did not cause obvious amorphization at 633 K and annealing did not induce nanograin growth. After irradiation, the area fraction and size of carbon packets with graphitic nature in the SiC fiber decreased.

中文翻译：

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C+和He+辐照SiCf/SiC复合材料退火前后的显微组织特征

摘要 对SiCf/SiC 复合材料的微观结构进行了400 keV C+ 和200 keV He+ 633 K 辐照和1073、1273 和1473 K 辐照5 h 后退火处理。SiCf/SiC 复合材料由尺寸为 5-25 μm 的纳米晶 SiC 纤维、具有柱状晶体结构的 SiC 基体和它们之间的六个过渡层（热解碳和 SiC 层交替分布）组成。几个由辐照引起的微裂纹出现在界面处，并在退火过程中生长。在碳化硅光纤中形成了一个带有少量氦气泡的辐照带，其宽度约为 260 nm，随着退火温度的升高而减小。退火导致辐照引起的气泡生长并在 SiC 纤维中引起气泡的线性排列。在晶界处产生较大的 He 气泡，并倾向于在 SiC 基体中形成微裂纹。辐照在 633 K 下没有引起明显的非晶化，并且退火没有引起纳米晶粒的生长。辐照后，碳化硅纤维中具有石墨性质的碳包的面积分数和尺寸减小。