Post-irradiation tensile properties of the first and second operational target modules at the Spallation Neutron Source
Post-irradiation tensile properties of the first and second operational target modules at the Spallation Neutron Source
复制标题
散裂中子源第一和第二操作目标模块的辐照后拉伸特性
DOI：
10.1016/j.jnucmat.2014.02.037
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发表时间：
2014
影响因子：
3.1
通讯作者：
P. Ferguson
中科院分区：
文献类型：
--
作者：
D. Mcclintock;Bradley J. Vevera;B. Riemer;F. Gallmeier;James W. Hyres;P. Ferguson
在中子产生过程中，散裂中子源（SNS）上的靶模块受到空化侵蚀的破坏，AISI 316L容器材料的力学性能受到高能质子和中子辐射的改变。最近，SNS的第一和第二操作目标模块达到了其使用寿命，从两个目标的光束入口区域采样了盘状样本。用线材放电加工的方法制作了剂量为3 - 7个原子位移（dpa）的拉伸试样，并在室温下进行了测试。本文介绍了从第一和第二操作SNS目标模块中取出的辐照316L容器材料的拉伸性能。结果表明，拉伸强度增加，延伸率下降，类似于先前的散裂辐照316L的结果。在辐照至5.4 dpa的试样中观察到异常大的伸长率，总伸长率为57%，并且在均匀伸长率和总伸长率数据中观察到相当大的分散。在拉伸试验结果中观察到的异常大的伸长和散射的一个可能的解释是所谓的变形波相变诱导的塑性效应。显微表征显示断口表面存在大量富含Al， S, Ca， O和Mg的非金属夹杂物，这可能也是拉伸伸长率结果分散的原因。虽然所有试样都表现出辐射诱发的硬化和延性下降，但所有试样断口表面的主要形貌都是延性微孔隙聚结，所有试样在断裂前都经历了明显的颈缩。这些结果表明，316L在SNS的质子/中子混合辐射环境中，在大约6-7 dpa的辐照下，仍保持了足够的延展性（10-20%的总伸长率），并在延展性大范围内断裂。
During neutron production the target module at the Spallation Neutron Source (SNS) is damaged by cavitation-induced erosion and the mechanical properties of the AISI 316L vessel material are altered by high-energy proton and neutron radiation. Recently the first and second operational target modules at the SNS reached the end of their useful lifetime, and disk shaped specimens were sampled from the beam entrance region of both targets. Tensile specimens ranging in dose from 3 to 7 displacements per atom (dpa) were fabricated from the disk specimens using wire electrical discharge machining and tested at room temperature. This paper presents the tensile properties of the irradiated 316L vessel material removed from the first and second operational SNS target modules. Results show an increase in tensile strength and decrease in elongation values similar to previous spallation irradiated 316L results. Abnormally large elongation, 57% total elongation, was observed in a specimen irradiated to 5.4 dpa and considerable scatter was observed in the uniform and total elongation data. One possible explanation for the abnormally large elongations and scatter observed in tensile test results is the so-calleddeformation wavephase transformation-induced plasticity effect. Microscopy characterization revealed the presence of large nonmetallic inclusions rich in Al, S, Ca, O, and Mg on the fracture surface, which may have also contributed to the scatter in the tensile elongation results. While all specimens exhibited radiation-induced hardening and a decrease in ductility, the predominate topographical morphology on all specimen fracture surfaces examined was ductile microvoid coalescence and all specimens experienced appreciable necking prior to fracture. These findings indicate that 316L retains sufficient ductility (10–20% total elongation) and fractures in a ductile manor after irradiation to approximately 6–7 dpa in the mixed proton/neutron radiation environment at the SNS.