Micromechanical testing of irradiated nuclear fusion materials

辐照核聚变材料的微机械测试

• 批准号: 1993924
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1993924
• 关键词: Micromechanical; testing; irradiated; nuclear; fusion

Any future nuclear fusion power systems rely on the development of materials which can withstand some of the most extreme engineering environments. These include temperatures up to 1500oC, high fluxes of high energy neutrons and effects of gaseous elements produced by transmutation and implantation from the plasmas. Due to efforts to minimise the production of nuclear waste by such reactors the elements which may be used in structural components is limited and in many cases there is a lack of understanding of the basic deformation processes occur in ether pure materials or alloys and importantly how these are effected by temperature, radiation damage and gas content. Due to the long time periods required for neutron irradiation campaigns, plus the associated cost and difficulty of working with active materials there is a need to develop robust methods for the characterisation of irradiated materials on the microscale. There are two advantages to this. Firstly it allows the maximum data return from small volumes of neutron irradiated materials. Secondly it allows the use of heavy ion irradiation to mimic neutron damage. In this case while the damage is similar to that of neutrons and can be built up in much shorter time frames the damage is only over a few 10's of microns. This precludes the use of traditional mechanical testing methods. While the methods required for understanding micro-scale plastic deformation are well developed micro-fracture testing has lagged behind. This project will build upon the expertise in the MFFP and Micromechanics groups on high temperature frcature testing at the micro and nano-scale. Facilities include two high temperature nanoindenters (-50oC to 950oC), high temperature microhardness (RT to 1500oC) and dedicated FIB-SEM and FEG-SEM with EBSD as well as high performance modelling stations. Both nanoindentation, micro-compression and micro-bend experiments will be used to study elastic-plastic fracture in tungsten and tungsten alloys. Understanding brittle failure of these alloys is key for the safe design of critical fusion reactor components such as the divertor. Currently diverter designs assume tungsten as the plasma facing components. However there is minimal understanding (only two previous studies-both lacking full experimental details in the published form) on the effect of irradiation damage on the brittle to ductile transition temperature in tungsten.HR-EBSD and TKD will be used to study the dislocation deformation structures produced around the crack tips during testing and to inform crystal plasticity based finite element and discrete dislocation dynamics models. The new science will concern both the development of robust elastic-plastic fracture testing methodologies as well as a the fuller understanding of the underlying physics of deformation in tungsten and tungsten alloys both before and after heavy irradiation or gas implantation. The work will include collaboration with CCFE-UKAEA through the fusion CDT.EPSRC theme and research area is Energy

任何未来的核聚变动力系统都依赖于能够承受一些最极端工程环境的材料的开发。这些包括高达1500摄氏度的温度、高通量的高能中子以及等离子体嬗变和注入产生的气体元素的影响。由于努力减少这种反应堆产生的核废料，可用于结构部件的元素受到限制，并且在许多情况下，缺乏对醚纯材料或合金中发生的基本变形过程的理解，以及重要的是，这些变形过程如何受到温度，辐射损伤和气体含量的影响。由于中子辐照活动所需的时间较长，加上与活性材料相关的成本和工作难度，因此需要开发用于在微观尺度上表征辐照材料的稳健方法。这样做有两个好处。首先，它允许从小体积的中子辐照材料返回最大的数据。其次，它允许使用重离子辐照来模拟中子损伤。在这种情况下，虽然损害类似于中子的损害，并且可以在更短的时间内建立，但损害仅超过几十微米。这就排除了使用传统的机械测试方法。虽然理解微观尺度塑性变形所需的方法已经发展得很好，但微观断裂测试却落后了。该项目将建立在MFFP和微观力学小组在微米和纳米尺度上的高温frcature测试的专业知识基础上。设备包括两个高温纳米压痕仪（-50 ° C至950 ° C）、高温显微硬度仪（RT至1500 ° C）、专用的FIB-SEM和带EBSD的FEG-SEM以及高性能建模站。纳米压痕、微压缩和微弯曲实验将用于研究钨和钨合金的弹塑性断裂。了解这些合金的脆性破坏是关键的聚变反应堆部件，如偏滤器的安全设计的关键。目前的分流器设计假设钨作为面向等离子体的组件。然而，有最小的理解（只有两个以前的研究，都缺乏完整的实验细节，在发表的形式）的影响，辐照损伤的脆韧性转变温度在tungs.HR-EBSD和TKD将被用来研究周围的裂纹尖端在测试过程中产生的位错变形结构，并通知晶体塑性有限元和离散位错动力学模型。新的科学将关注强大的弹塑性断裂测试方法的发展，以及对钨和钨合金在重辐照或气体注入之前和之后的变形的基本物理学的更全面的理解。这项工作将包括通过聚变CDT与CCFE-UKAEA合作。EPSRC的主题和研究领域是能源