Intergranular Segregation in the Pressure Vessel Steel of a Commercial Nuclear Reactor Studied by Atom Probe Tomography
Intergranular Segregation in the Pressure Vessel Steel of a Commercial Nuclear Reactor Studied by Atom Probe Tomography
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DOI：
10.2320/matertrans.m2013133
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发表时间：
2013-11-01
影响因子：
1.2
通讯作者：
Gerard, Robert
中科院分区：
文献类型：
--
作者：
Toyama, Takeshi;Nagai, Yasuyoshi;Gerard, Robert
采用激光辅助原子探针层析成像技术（APT）研究了核反应堆压力容器（RPV）钢中溶质/杂质的偏析和晶界析出。在商用核反应堆中辐照到0.83 × 10（19）n.cm（-2）中子剂量的反应堆压力容器监视试验样品（低剂量）和5.1 x 10（19）n.cm（-2）（高剂量），分别对应于类似于5年和类似于30年的在职暴露。低剂量辐照后，晶界上出现了C、P和Mo的偏聚现象。在高剂量辐照后，观察到Si和Mn以及C，P和Mo的偏聚。单层覆盖的P估计是小于晶间脆化的建议水平。在小角度晶界上还观察到C、P和Mo沿沿着排列的位错线的偏聚。然而，在那里没有检测到Si和Mn的偏析。在晶界上、沿着位错线和基体中观察到铜纳米析出物。比较了这些CNP中的尺寸和溶质杂质富集。
Solute/impurity segregation and precipitation at grain boundaries (GBs) in a nuclear reactor pressure vessel (RPV) steel were investigated using laser-assisted atom probe tomography (APT): RPV surveillance test specimens irradiated in a commercial nuclear reactor to neutron doses of 0.83 x 10(19)n.cm(-2) (low-dose) and 5.1 x 10(19)n.cm(-2) (high-dose), corresponding to in-service exposure of similar to 5 and similar to 30 years, respectively. The segregation of C, P and Mo was found on GBs after the low-dose irradiation. The segregation of Si and Mn as well as C, P and Mo was observed after the high-dose irradiation. The monolayer coverage of P is estimated to be less than a suggested level for intergranular embrittlement. The segregation of C, P and Mo was also observed along parallel array of dislocation lines in small-angle grain boundaries. However, no segregation of Si and Mn was detected there. Copper-nano precipitates (CNPs) were observed on the GBs, along the dislocation lines and in the matrix. The sizes and the solute-impurity enrichment in these CNPs are compared.