增材制造316L不锈钢辐照硬化行为的温度效应研究  

Temperature effect of irradiation hardening behavior of 316L stainless steel by additive manufacturing

作　　者：付崇龙 李健健[1] 白菊菊 林俊[1] FU Chonglong;LI Jianjian;BAI Juju;LIN Jun(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049

出　　处：《核技术》2022年第9期23-32,共10页Nuclear Techniques

基　　金：国家自然科学基金(No.12175301);中国科学院前沿重点项目(No.QYZDY-SSW-JSC016);兰州重离子研究装置支持(No.HIR2021PY007);上海市自然科学基金项目(No.22ZR1474800)资助。

摘　　要：利用500 keV氦离子在不同辐照温度(350~800℃)下对选区激光熔化(Selective Laser Melting,SLM)成形的316L不锈钢进行了辐照,研究了增材制造材料硬化行为的温度效应。通过纳米压痕测试发现,SLM 316L不锈钢的辐照硬化随温度的升高而降低,样品的硬化程度从350℃的71.65%下降最高温度时的23.62%,呈现高温硬化回复的行为。透射电镜(Transmission Electron Microscope,TEM)结果表明:辐照造成的微观缺陷主要是氦泡和位错环,两者数密度和尺寸随温度的变化趋势一致,即随着温度的升高,平均数密度稳步下降,而尺寸逐渐增大,但相比之下,氦泡的温度敏感性要略高于位错环。利用弥散强化模型,计算了氦泡及位错环对辐照硬化的贡献,得到的计算值与纳米压痕测试获得的实验值随温度的变化趋势是一致的,表明SLM 316L不锈钢中辐照缺陷与辐照硬化行为具有紧密联系。分析两种缺陷分别对辐照硬化的贡献可知,除了最高温度以外,氦泡对辐照硬化的贡献都要高于位错环,并且随着辐照温度的上升氦泡数密度急剧下降带来的辐照硬化程度降低与实际辐照硬化趋势更加吻合,而位错环对辐照硬化的贡献随温度的变化较小,这与氦泡具有更高的温度敏感性一致。总体来说,辐照温度升高时,SLM 316L不锈钢中辐照缺陷数密度的下降是辐照硬化高温回复行为的主要原因。[Background] The additive manufacturing(AM) technology is expected to apply to the field of advanced nuclear energy because of its unrivalled design freedom and short lead times. However, the irradiation resistance of the AM materials needs to be studied. One of the key scientific problems is the irradiation hardening behavior of the AM materials under irradiation environment. As a candidate nuclear material, 316L stainless steel(SS) produced by selective laser melting(SLM, a very important AM technology of metals) is selected as the study object. [Purpose] This study aims to investigate the irradiation hardening behavior and the irradiation defects evolution of the SLM 316L SS as function of temperature. [Methods] The SLM 316L SS was irradiated by 500 keV helium ions at different irradiation temperatures(from 350 ℃ to 800 ℃) to explore the temperature effect of hardening behavior. The irradiation dose of each sample was 1.5×10^(16) ions·cm. The irradiation hardening and irradiation defects were characterized by nanoindentation and transmission electron microscopy(TEM) respectively.The contribution of helium bubbles and dislocation loops to irradiation hardening was calculated using the dispersed barrier hardening(DBH) model. [Results] The results of the nanoindentation test show that the irradiation hardening degree of SLM 316L SS decreases from 71.65% at 350 ℃ to 23.62% at the highest temperature, suggesting an obvious irradiation hardening recovery with the temperatures increasing. The observation of TEM indicates that helium bubbles and dislocation loops are the main micro defects caused by the ion irradiation. The evolution trend of the two types of irradiation defects with temperature is the same whilst the helium bubble’s contribution to the irradiation hardening is slightly higher than that of dislocation loops except at the highest temperature. With the increase of temperature, the average number density of the two defects decreases steadily with the increase of diameter, but the helium bubbles

关 键 词：增材制造 316L不锈钢 辐照硬化 氦泡 位错环 

分 类 号：TL99[核科学技术—核技术及应用]