【摘要】 为了给⁶⁰Co γ辐照条件下硅泡沫垫层的构型设计和工艺优化提供依据,本工作通过材料辐照实验、力学实验和扫描电子显微镜观察等方法,研究了⁶⁰Co γ射线辐照对硅泡沫材料压缩性能的影响,探索了辐照条件下硅泡沫材料的损伤机理,并在此基础上建立了辐照环境条件下多孔硅泡沫材料压缩性能的预测模型,给出了材料压缩模量和断裂应变随辐照剂量的变化规律。结果表明:γ辐照对材料压缩性能的影响较为明显,在预压缩量较低的情况下,辐照后硅泡沫材料力学性能呈先升后降的趋势;当预压缩量超过50%时,辐照后硅泡沫材料力学性能呈先陡后缓的下降趋势。预压缩量为30%、辐照剂量为300 k Gy时,硅泡沫材料的拉伸强度和剪切强度分别增加了69%和84%;而辐照剂量增大到1 000 kGy时,其值分别下降了47%和50%。结合材料宏观性能和细观结构的分析认为,γ辐照引起的交联反应和降解反应是造成硅泡沫材料力学性能改变的主要原因。更多还原

【Abstract】 In order to prove theoretical basis and selecting optimizing design of silicone foamcushion under ⁶⁰Co γ-irradiation conditions,the influence of radiation on the compression properties of silicone rubber foams was studied by several methods,such as the mechanics experiment,irradiation experiment,and scanning electron microscopy（ SEM） analysis,and the damage mechanism were inferred through analysis the irreversible transformation of the indented materials before and after γ-irradiation. Furthermore,a model for the compressive strength prediction of silicone foam cushion was proposed in accordance with irradiation effects,and the variation of compressive modulus and fracture strain with irradiation doses were obtained. The results showed that irradiation dose and pre-strain had significant effects on the properties of silicone rubber foam,and the mechanics property of irradiated silicone rubber foams increased at beginning and then decreased with enhanced γ-radiation dose under low prestrain condition. But the pre-strain exceeded 50%,the mechanics property of irradiated silicone rubber foams firstly decreased rapidly and then slowly with enhanced γ-radiation dose. Tensile strength and shear strength of irradiated silicone rubber foams were enhanced by 69% and 84%,respectively,at a pre-strain of 30% and a radiation dose of 300 kGy. When the radiation dose increased to 1 000 kGy,the value dropped to 47%and 50% of the initial value. Those significant changes provided information for inferring the mechanism of radiation induced cross-linking and degradation reactions of mechanics property of silicone rubber foams. The analysis result of macroscopic properties and microstructure could prove it.更多还原