Influence of solidification structures on radiation-induced swelling in an additively-manufactured austenitic stainless steel
Influence of solidification structures on radiation-induced swelling in an additively-manufactured austenitic stainless steel
复制标题
DOI：
10.1016/j.jnucmat.2019.06.012
复制
发表时间：
2019-09
影响因子：
3.1
通讯作者：
Gabriel Meric de Bellefon;K. Bertsch;M. Chancey;Y. Wang;Dan Thoma
中科院分区：
文献类型：
--
作者：
Gabriel Meric de Bellefon;K. Bertsch;M. Chancey;Y. Wang;Dan Thoma
金属增材制造为生产核电系统中的结构材料（例如奥氏体不锈钢）提供了潜在的优势。然而，金属增材加工过程中形成的微观结构与传统加工中形成的微观结构明显不同，并且微观结构差异对辐射环境中性能的影响尚未完全量化。使用重离子辐照和透射电子显微镜，研究了高剂量下激光粉末床熔融制造的奥氏体不锈钢的辐射引起的膨胀响应。通过比较 316L 不锈钢在三种微观结构状态（加工态、固溶退火态和完全再结晶态）下的辐射引起的膨胀响应，研究了凝固引起的位错和析出结构的影响。与加工后状态相比，制造状态下的空隙膨胀大约是处理后状态的两倍。在辐射效应的速率理论框架中，制造状态下较高的膨胀可以通过预先存在的位错的中间密度所施加的间隙点缺陷的强下沉偏差来解释。在预先存在的析出物附近，空洞膨胀受到抑制，但制造材料中的析出物密度不足以补偿位错引起的膨胀增加。
Metal additive manufacturing offers potential advantages for producing structural materials, such as austenitic stainless steels, in nuclear power systems. However, the microstructure developed during metal additive processing is notably different from the one developed in conventional processing, and the influence of the microstructural differences on performance in radiation environments has not been fully quantified. Using heavy ion irradiation and transmission electron microscopy, the radiation-induced swelling response of a laser powder-bed fusion-manufactured austenitic stainless steel was investigated at high doses. The influence of solidification-induced dislocation and precipitate structures was studied by comparing the radiation-induced swelling response of a 316L stainless steel in three microstructural states: as-fabricated, solution annealed, and fully recrystallized. Void swelling was approximately twice as pronounced in the as-fabricated state compared to post-processed states. In the framework of the rate theory for radiation effects, the higher swelling in the as-fabricated state can be explained by the strong sink bias for interstitial point defects exerted by the intermediate density of pre-existing dislocations. Void swelling was inhibited in the vicinity of pre-existing precipitates, but the density of precipitates in the as-fabricated material was not enough to compensate for the increase in swelling caused by dislocations.