具有辐照缺陷自修复能力的新型金属材料的制备与机理研究

The performance of structural materials in extreme environments of irradiation and temperature must be significantly improved to extend the reliability, lifetime, and efficiency of future nuclear reactors. In reactor environments, damage introduced in the form of radiationinduced defects and helium results in embrittlement and dimensional instability. Therefore, the ability to control radiation-induced point defects and helium bubble nucleation and growth is a crucial first step to improving the mechanical properties of irradiated metals. This calls for novel approaches in designing structural materials that resist radiation damage while maintaining high strength and toughness. Recently, nanolayered metallic composites have been shown to have improved radiation resistance compared with their polycrystalline counterparts. It has been speculated that interfaces may serve as effective sinks for defects. Using nanolayered metallic composites as model systems, we highlight how tailoring the length scales (layer thickness) and interface properties can provide insight into ways of designing radiation damage tolerant structural materials. But how defects interact with interfaces at the atomic scale is far from understood, we perform in situ investigations on the evolution of microstructures during ion irradiation by a transmission electron microscope (TEM)–implanter/accelerator interface facility and a slow positron beam apparatus. We will perform MD simulations to investigate cascade-induced defect. The research results of this project will provide experimental and theoretical basis for developing new reactor materials.

在核反应堆的中子辐照、高温和应力存在的环境中，需要具有足够耐高温、耐腐蚀、抗辐照、长寿命的新材料。面对第四代核能系统和聚变堆提出的新要求，许多现在已在使用的不锈钢、锆合金、镁合金、铝合金等材料将不再符合要求，必须要有创新的思想，使其具有强抗辐照和自修复性能。本项目基于微纳结构缺陷自我修复的概念，研究探索具有抗辐照自愈能力的金属多层膜材料。对研制的金属多层膜材料进行氢、氦和重离子辐照，通过本单位独特的透射电镜离线与原位观察，结合正电子湮没谱学，深入了解缺陷与纳米晶界的相互作用，从原子尺度上揭示金属多层膜抗辐照自愈能力的机理，研究其在极端条件下的力学性能的演变过程及规律。为核反应堆内结构材料的选取、改良和升级提供理论指导和基础数据，设计开发出具有自主知识产权的先进的抗辐照实用型材料。

本项目基于微纳结构缺陷自我修复的概念，研究探索具有抗辐照自愈能力的金属多层膜材料。取得如下进展：.1..研究了CrN/AlTiN多层膜随着周期的减小，抗辐照性和耐腐蚀性有明显的提高。.2..用热动力学,有限原子尺寸效应，阴影效应解释了V/Ag多层膜的生长机制.纳米压痕测试表明柱状结构会降低薄膜的硬度。.3..通过界面的“吸收-释放”机制与间隙原子复合、湮灭解释了辐照后多层膜层状结构依然存在，即使在最大损伤处。辐照后气泡多分布在界面处，但是大周期膜内的He气泡尺寸明显大于小周期膜。.4..制备了Cu/ graphene多层膜结构材料，通过He离子辐照实验，结果表明Cu/ graphene多层膜结构材料能明显提高抗辐照能力。