Liu Wenbo, Ji Yanzhou, Tan Pengkang, Zang Hang, He Chaohui, Yun Di, Zhang Chi, Yang Zhigang
Department of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
Materials (Basel). 2016 Feb 6;9(2):105. doi: 10.3390/ma9020105.
Nanostructured (NS) materials may have different irradiation resistance from their coarse-grained (CG) counterparts. In this review, we focus on the effect of grain boundaries (GBs)/interfaces on irradiation induced microstructure evolution and the irradiation tolerance of NS materials under irradiation. The features of void denuded zones (VDZs) and the unusual behavior of void formation near GBs/interfaces in metals due to the interactions between GBs/interfaces and irradiation-produced point defects are systematically reviewed. Some experimental results and calculation results show that NS materials have enhanced irradiation resistance, due to their extremely small grain sizes and large volume fractions of GBs/interfaces, which could absorb and annihilate the mobile defects produced during irradiation. However, there is also literature reporting reduced irradiation resistance or even amorphization of NS materials at a lower irradiation dose compared with their bulk counterparts, since the GBs are also characterized by excess energy (compared to that of single crystal materials) which could provide a shift in the total free energy that will lead to the amorphization process. The competition of these two effects leads to the different irradiation tolerance of NS materials. The irradiation-induced grain growth is dominated by irradiation temperature, dose, ion flux, character of GBs/interface and nanoprecipitates, although the decrease of grain sizes under irradiation is also observed in some experiments.
纳米结构（NS）材料与其粗晶（CG）对应物相比可能具有不同的抗辐照性能。在本综述中，我们关注晶界（GBs）/界面在辐照诱导的微观结构演变中的作用以及NS材料在辐照下的辐照耐受性。由于GBs/界面与辐照产生的点缺陷之间的相互作用，系统地综述了金属中空位耗尽区（VDZs）的特征以及GBs/界面附近空位形成的异常行为。一些实验结果和计算结果表明，NS材料由于其极小的晶粒尺寸和大体积分数的GBs/界面而具有增强的抗辐照性能，这些GBs/界面可以吸收和消除辐照过程中产生的可移动缺陷。然而，也有文献报道，与块状材料相比，NS材料在较低辐照剂量下抗辐照性能降低甚至非晶化，因为GBs也具有多余的能量（与单晶材料相比），这可能导致总自由能发生变化，从而导致非晶化过程。这两种效应的竞争导致了NS材料不同的辐照耐受性。辐照诱导的晶粒生长受辐照温度、剂量、离子通量、GBs/界面和纳米析出相的特性支配，尽管在一些实验中也观察到辐照下晶粒尺寸的减小。
