脉冲激光亦或电子束辐照对SUS316 L奥氏体不锈钢中空位扩散的影响

利用激光-超高压电子显微镜系统在500℃对SUS316L奥氏体不锈钢进行了电子束辐照和脉冲激光-电子束双束同时辐照(以下简称:同时辐照),通过观察和分析辐照后自由晶界处无空洞区域以及元素偏析,以电子束辐照结果为标准,对比研究了同时辐照对空位扩散的影响.结果表明:同时辐照后的无空洞区域宽度为48±16 nm,小于电子辐照的71±27 nm;不论在偏析程度还是偏析宽度上,同时辐照条件下Cr和Ni的偏析都小于对应的电子束辐照;同时辐照下空位的扩散通量仅为电子束辐照的45.7%.通过分析得出,和电子辐照相比,同时辐照促进了空位与间隙原子的再结合,限制空位向尾闾扩散,进而造成流入尾闾的空位数量减少,极大地抑制了辐照偏析与肿胀.脉冲激光-电子束双束同时辐照可以为探索抑制肿胀方法提供新的思路.

Effect of pulsed-laser and/or electron irradiation on vacancy diffusion in SUS316 L austenitic stainless steel

Electron irradiation and simultaneous pulsed-laser and electron dual-beam irradiation were performed using laser high voltage electronic microscopy ( HVEM) at 500℃, and the void-denuded zone ( VDZ) and radiation-induced segregation ( RIS) near the random grain boundary were observed and analyzed after irradiation. Compared to electron irradiation, the effect of simultaneous pulsed-laser and electron dual-beam irradiation on vacancy diffusion was investigated. The results show that the width of VDZ after simultaneous pulsed-laser and electron dual-beam irradiation is 48 ± 16 nm which is smaller than the VDZ width of 71 ± 27 nm after electron irradiation. Both the magnitude and width of Cr and Ni segregation under simultaneous pulsed-laser and electron dual-beam ir-radiation are lower than those under electron irradiation. The ratio of vacancy flux of simultaneous pulsed-laser and electron dual-beam irradiation to that of electron irradiation is 45. 7%. Compared to electron irradiation, the vacancy flux flowing into point defect sinks is lower owing to enhanced recombination between vacancies and interstitial spaces under simultaneous pulsed-laser and electron dual-beam irradiation. This has the effect of suppressing RIS and void swelling. Therefore, simultaneous pulsed-laser and electron dual-beam irradiation is expected to provide new insights into the suppression of void swelling.