Assessment of the chemical compatibility between EUROFER and ceramic breeder with respect to fatigue lifetime
Assessment of the chemical compatibility between EUROFER and ceramic breeder with respect to fatigue lifetime
复制标题
评估 EUROFER 和陶瓷增殖剂之间在疲劳寿命方面的化学相容性
DOI：
10.1016/j.fusengdes.2020.111732
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发表时间：
2020
影响因子：
1.7
通讯作者：
R. Knitter
中科院分区：
文献类型：
--
作者：
J. Aktaa;M. Walter;E. Gaisina;M. Kolb;R. Knitter
在具有陶瓷增殖剂的DEMO增殖毯的先进设计中，结构材料EUROFER与陶瓷增殖剂（Li 4SiO 4 + Li 2 TiO 3）的卵石直接接触，导致陶瓷中的组成元素损失，并在操作相关条件下在EUROFER上形成腐蚀层。这种腐蚀对损伤机制的影响是显着影响的表面微观结构的变化，特别是疲劳，需要考虑在受影响的组件的设计，因此在这里报告的工作进行了调查。疲劳试样的EUROFER在不受约束的接触陶瓷增殖卵石暴露在吹扫气体条件下不同的持续时间。暴露后观察到的化学表面侵蚀的特征在于圆形污渍，部分甚至是圆形凹痕，由同心扩散区组成，在长暴露时间的情况下，这些扩散区相遇，形成几乎封闭的腐蚀多层。随后通过在550 °C下进行应变控制低周疲劳（LCF）测试来研究这种攻击对疲劳行为的影响。为了覆盖疲劳寿命的预期分散，进行了足够数量的LCF实验。结果表明，疲劳寿命的显着减少，这在数量上取决于攻击/暴露时间的水平，以及所施加的负载/应变振幅的水平。
In advanced designs of DEMO breeding blankets with ceramic breeder, the structural material EUROFER is in direct contact with the pebbles of the ceramic breeder (Li4SiO4+ Li2TiO3) that results in a loss of constituent elements in the ceramic and the formation of a corrosion layer on EUROFER under operation relevant conditions. The impact of this corrosion attack on damage mechanisms which are significantly influenced by microstructural changes at the surface, in particular fatigue, needs to be considered in the design of affected components and is therefore investigated within the work reported here.Fatigue specimens made out of EUROFER in unconstrained contact to ceramic breeder pebbles were exposed to purge gas conditions for different durations. The chemical surface attack observed after the exposure is characterized by round stains, partly even round dimples, consisting of concentric diffusion zones which meet in case of the long exposure time forming an almost closed corrosion multi-layer. The impact of this attack on the fatigue behavior was subsequently investigated by performing strain-controlled low cycle fatigue (LCF) tests at 550 °C. To cover the scatter expected for the fatigue lifetime, a sufficient number of LCF experiments were conducted. The results show significant reduction of the fatigue lifetime, which quantitatively depends on the level of the attack/exposure time as well as the level of the applied load/strain amplitude.