Chen Y, Yu K Y, Liu Y, Shao S, Wang H, Kirk M A, Wang J, Zhang X
Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, USA.
Department of Materials Science and Engineering, China University of Petroleum-Beijing, Beijing 102246, China.
Nat Commun. 2015 Apr 24;6:7036. doi: 10.1038/ncomms8036.
Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation induces significant damage in the form of dislocation loops and voids in irradiated materials, and continuous radiation often leads to void growth and subsequent void swelling in metals with low stacking fault energy. Here we show that by using in situ heavy ion irradiation in a transmission electron microscope, pre-introduced nanovoids in nanotwinned Cu efficiently absorb radiation-induced defects accompanied by gradual elimination of nanovoids, enhancing radiation tolerance of Cu. In situ studies and atomistic simulations reveal that such remarkable self-healing capability stems from high density of coherent and incoherent twin boundaries that rapidly capture and transport point defects and dislocation loops to nanovoids, which act as storage bins for interstitial loops. This study describes a counterintuitive yet significant concept: deliberate introduction of nanovoids in conjunction with nanotwins enables unprecedented damage tolerance in metallic materials.
极端辐射环境下的材料性能是未来核反应堆设计的核心。辐射会在被辐照材料中以位错环和空位的形式造成显著损伤，持续辐射通常会导致低堆垛层错能金属中的空位生长及随后的空位肿胀。在此我们表明，通过在透射电子显微镜中进行原位重离子辐照，纳米孪晶铜中预先引入的纳米空位能有效吸收辐射诱导的缺陷，同时纳米空位逐渐消除，从而提高了铜的辐射耐受性。原位研究和原子模拟表明，这种显著的自愈能力源于高密度的相干和非相干孪晶界，这些孪晶界能迅速捕获点缺陷和位错环并将其传输至纳米空位，而纳米空位则充当间隙环的存储库。本研究描述了一个违反直觉但意义重大的概念：与纳米孪晶相结合有意引入纳米空位可使金属材料具备前所未有的损伤耐受性。
