离子辐照引起的弥散强化钨内部缺陷的形成和演化机理研究

Tungsten is one of the important candidates as plasma facing components and divertor structure components in nuclear fusion reactors, and its resistance to irradiation has been widely concerned. The optimized dispersion-strengthened tungsten possesses better mechanical strength and toughness and is more resistant to irradiation than pure tungsten. However, there are few researches on the defects and properties in irradiated dispersion-strengthened tungsten, and the effects of dispersoids on the irradiation-induced defects are still unclear. Using the W and He ions provided by 320 kV Multi-discipline Research Platform for Highly Charged Ions and several different measurement technologies, within a wide range of the displacement damage level, this project will systematically study the defects and their evolution as well as mechanical properties in pure tungsten and dispersion-strengthened tungsten irradiated with ions. By comparing with the reported experimental results for pure tungsten, we are trying to explore the effects of dispersoids on the irradiation-induced vacancy-like defects, dislocations, voids and He bubbles etc, as well as the effects of helium on irradiation-induced defects. The law of the hardness change induced by irradiation will be obtained. This study will provide important experimental evidences for the improvement and evaluation of the resistance to irradiation of candidate materials and the application range of the materials for future nuclear fusion reactors.

钨材料是聚变堆中面向等离子体部件和偏滤器结构部件的重要候选材料之一，其抗辐照性能研究一直受到广泛关注。优化设计的弥散强化钨比纯钨具有更好的机械强度和韧性，并可能更抗辐照。但是，辐照弥散强化钨内部的缺陷和性能研究极少，弥散相对辐照缺陷的影响仍不清楚。本项目利用中国科学院近代物理研究所的320kV高压综合实验平台提供的W和He离子和多种测试手段，在较宽的离位损伤范围内系统研究离子辐照弥散强化钨材料内部产生的缺陷及其演化和机械性能。通过与已报道的纯钨的实验结果进行对比，探索分析弥散相对辐照产生的空位型缺陷、位错环、空洞和He泡等缺陷的影响及其机理、以及He对辐照缺陷的影响。获得辐照引起的硬度变化规律。该研究将为未来聚变装置候选材料的抗辐照性能的改进和评价以及材料的应用范围提供重要的实验依据。

钨是未来聚变堆中面向等离子体部件和偏滤器结构部件的重要候选材料之一。由于弥散强化钨具有比纯钨更好的机械强度和韧性等优点，其抗辐照性能受到越来越多的关注。本项目针对聚变堆辐照环境下在材料中引入的离位损伤和He原子沉积效应开展研究。利用中国科学院近代物理研究所的320kV辐照平台提供的Fe和He离子完成了纯钨和弥散强化钨中离子辐照实验。采用多种测试手段测试分析了辐照样品中的空位型缺陷、He泡、表面形貌和表面力学性能。主要结果有：.1）纯离位损伤条件下，弥散强化钨样品中形成空位型缺陷，且其硬度高于未辐照样品的硬度。随着辐照剂量的增加，样品中空位型缺陷的开空间体积减小，纳米硬度先减小后增加。随着辐照温度的增加，样品中空位型缺陷的尺寸变大，纳米硬度减小。.2）室温He离子辐照条件下，纯钨和弥散强化钨损伤峰附近看到了大量He泡的形成；随着辐照剂量的增加，He泡的尺寸和密度增加。辐照温度增加至800℃，整个损伤区域内都观测到了He泡，损伤峰区He泡的尺寸明显增加。两种钨材料中的He泡尺寸和密度无明显差异。.He离子注入导致两种样品的硬度增加。随着辐照剂量的增加，二者的硬度均增加。随着辐照温度的增加，二者的硬度增加峰值基本不变，且硬度峰向表面移动。纯W的硬度增加值比W-ZrC(H2)的高。.高温高流强高剂量He注入条件下，纯W和W-ZrC(H2)的表面形成鼓包。随着剂量的增加，纯钨表面的鼓包密度略有增加；W-ZrC(H2)的表面鼓包无明显变化。.3）与纯钨相比，W-ZrC(H2)中添加的ZrC弥散相减弱了辐照硬化效应，且抑制材料表面发泡。.这些成果为弥散强化钨的抗辐照性能评价提供了重要的参考数据。