SiC材料的氦离子辐照损伤研究
发布时间：2019-01-16 14:17
【摘要】：材料问题一直是制约未来先进核能发展的主要瓶颈之一。先进核能装置处于高温、高通量中子辐照等恶劣环境中,中子辐照不但可以在材料中引起严重的位移损伤,同时中子引起的核嬗变反应在材料中产生了大量的He原子。He原子在材料中具有低的溶解度,在高温下发生迁移聚集成He泡。位移损伤和He掺杂行为导致材料微观结构变化和宏观性能下降,进而影响反应堆的运行安全。烧结Si C是一种具有高熔点、高耐腐蚀性、高热导率、低热膨胀系数和低中子反应截面的陶瓷材料,被认为是有潜力的可用于先进核能装置的候选材料之一。目前国内外主要研究的是单晶Si C,对于多晶烧结Si C的研究相对缺乏、不系统。论文对多晶烧结Si C的He离子辐照损伤进行了初步研究,作为对比,对单晶6H-Si C中的He行为也做了较深入研究。针对不同温度不同注量下He离子辐照引起的Si C材料宏观性能和微观结构的变化,采用多种测试手段对两种Si C材料He离子辐照损伤进行了研究,主要结论如下:1.单晶6H-Si C中He行为研究。拉曼散射光谱结果表明:高注量室温下辐照会使晶体出现非晶化;高温下辐照伴随着晶体缺陷的恢复过程,氦泡的存在会抑制缺陷恢复。高分辨XRD结果表明:高注量室温下辐照,曲线出现了漫散射;高温下辐照,随着注量的增大,近表面应变和最大应变峰向小角度方向移动。2.烧结Si C中He行为研究。拉曼散射光谱结果表明:随着注量的增加拉曼峰强度不断减小,这与损伤层吸收系数的增大有关。纳米压痕结果表明:高注量室温下辐照,非晶层包壳效应引起辐照样品纳米硬度低于未辐照样品;600℃高温下辐照时,随着注量的增加纳米硬度逐渐增加,这是间隙型位错环所引起的。TEM结果表明:He泡在晶粒内和晶界处的密度和形貌与He离子辐照剂量有关。3.对比研究烧结Si C和单晶6H-Si C中的He行为。相同辐照条件下,6H-Si C的拉曼光谱出现了Si-Si键的振动模式;烧结Si C显示出更大的硬度差;He泡更容易在烧结Si C中形核和长大。
[Abstract]:Material problem has been one of the main bottlenecks restricting the development of advanced nuclear energy in the future. Advanced nuclear power plants are in harsh environments such as high temperature and high throughput neutron irradiation. Neutron irradiation can not only cause serious displacement damage in materials, At the same time, the neutron induced nuclear transmutation produced a large number of He atoms in the materials. The He atoms have low solubility in the materials and migrate and aggregate into He bubbles at high temperature. Displacement damage and He doping behavior lead to the change of microstructure and the decrease of macroscopic performance of the material, which will affect the safety of the reactor. Sintered Si C is a kind of ceramic material with high melting point, high corrosion resistance, high thermal conductivity, low thermal expansion coefficient and low neutron reaction cross section. At present, the main research at home and abroad is single crystal Si C, the study of polycrystalline sintering Si C is relatively scarce and not systematic. In this paper, the radiation damage of He ions in polycrystalline sintered Si C has been studied. As a comparison, the He behavior in single crystal 6H-Si C has also been studied. Aiming at the changes of macroscopic properties and microstructure of Si C materials induced by He ion irradiation at different temperatures and different doses, the damage of He ion irradiation on two kinds of Si C materials was studied by a variety of test methods. The main conclusions are as follows: 1. Study on He behavior in single Crystal 6H-Si C. The Raman scattering spectra show that irradiation at high flux room temperature will lead to the crystallization of the crystal, and the existence of helium bubble will inhibit the defect recovery when the irradiation is accompanied by the recovery process of the crystal defect at high temperature. The results of high resolution XRD show that diffuse scattering appears at room temperature, and the peak of near surface strain and maximum strain shift to small angle with the increase of flux at high temperature. 2. Study on He behavior in sintered Si C. The Raman scattering spectra show that the intensity of Raman peak decreases with the increase of the flux, which is related to the increase of the absorption coefficient of the damaged layer. The results of nanocrystalline indentation show that the nanocrystalline hardness of irradiated samples is lower than that of unirradiated samples due to the cladding effect of amorphous layer at high Fluence at room temperature. When irradiated at 600 鈩，
本文编号：2409721
[Abstract]:Material problem has been one of the main bottlenecks restricting the development of advanced nuclear energy in the future. Advanced nuclear power plants are in harsh environments such as high temperature and high throughput neutron irradiation. Neutron irradiation can not only cause serious displacement damage in materials, At the same time, the neutron induced nuclear transmutation produced a large number of He atoms in the materials. The He atoms have low solubility in the materials and migrate and aggregate into He bubbles at high temperature. Displacement damage and He doping behavior lead to the change of microstructure and the decrease of macroscopic performance of the material, which will affect the safety of the reactor. Sintered Si C is a kind of ceramic material with high melting point, high corrosion resistance, high thermal conductivity, low thermal expansion coefficient and low neutron reaction cross section. At present, the main research at home and abroad is single crystal Si C, the study of polycrystalline sintering Si C is relatively scarce and not systematic. In this paper, the radiation damage of He ions in polycrystalline sintered Si C has been studied. As a comparison, the He behavior in single crystal 6H-Si C has also been studied. Aiming at the changes of macroscopic properties and microstructure of Si C materials induced by He ion irradiation at different temperatures and different doses, the damage of He ion irradiation on two kinds of Si C materials was studied by a variety of test methods. The main conclusions are as follows: 1. Study on He behavior in single Crystal 6H-Si C. The Raman scattering spectra show that irradiation at high flux room temperature will lead to the crystallization of the crystal, and the existence of helium bubble will inhibit the defect recovery when the irradiation is accompanied by the recovery process of the crystal defect at high temperature. The results of high resolution XRD show that diffuse scattering appears at room temperature, and the peak of near surface strain and maximum strain shift to small angle with the increase of flux at high temperature. 2. Study on He behavior in sintered Si C. The Raman scattering spectra show that the intensity of Raman peak decreases with the increase of the flux, which is related to the increase of the absorption coefficient of the damaged layer. The results of nanocrystalline indentation show that the nanocrystalline hardness of irradiated samples is lower than that of unirradiated samples due to the cladding effect of amorphous layer at high Fluence at room temperature. When irradiated at 600 鈩，
本文编号：2409721
本文链接：https://www.wllwen.com/kejilunwen/huagong/2409721.html
