India - UK Civil Nuclear Collaboration: Development of Radiation Damage Resistant High Entropy Alloys for Advanced Nuclear Systems

高熵合金(HEAs)是近年来发展起来的一类不含单一主导元素的新型材料。相反，四个或更多元素以相等或接近相等的度量组合在一起，每个元素随机排列。据报道，它们具有许多理想的性能，包括在高温下的高强度，良好的耐腐蚀性和抵抗辐射损伤的能力。这些特性使HEAs成为未来核裂变和聚变反应堆中用作结构材料的强有力的候选材料。这些反应堆的设计是为了在更高的温度下运行，消耗更少的燃料，并且可以使其比目前的反应堆更安全和更高效。要想在这种极端恶劣和苛刻的环境中使用HEA，必须解决三个关键需求。首先，我们必须确定有希望的合金，小规模地制造它们，并表征它们的机械行为和微观结构的稳定性。这将使用先进的显微镜进行，能够在原子水平上研究这些合金的化学和结构。第二，需要充分了解提供优异抗辐射损伤能力的HEAs的潜在材料物理。为了评估抗辐射损伤能力，我们将进行离子注入，而不是使用中子。这使得我们可以进行大量的实验，而且样品没有放射性，所以可以很容易地在实验室里处理。将使用能够探测这些重离子产生的小损伤区域的机械测试方法来研究造成的损伤。实验的结果，结合对这些新型合金的损伤效应的计算模拟，将使我们能够描述这些材料中的辐射损伤累积和恢复机制，这可以用于设计更先进的合金。最后，我们必须通过评估材料在高温下长时间处于负载下时的反应来确定材料在使用中的性能。我们将与印度合作伙伴合作，利用他们独特的设施，对我们最有希望的成分进行这些测试。这些组合物将被大规模生产、测试并返回英国进行进一步研究。

High entropy alloys (HEAs) are a novel and recently developed class of materials that do not contain one dominant element. Rather, four or more elements are combined together in equal or near equal measures with each element being randomly arranged. They have been reported to have a large number of desirable properties, including high strengths at high temperatures, good corrosion resistance and ability to withstand irradiation damage. These properties make HEAs strong candidate materials for use as structural materials in future nuclear fission and fusion reactors. These reactors are being designed to operate at higher temperatures, use less fuel and can be made safer and more efficient than current reactors.For HEAs to be utilised in this highly harsh and demanding environment there are three key needs that must be addressed. First, we must identify promising alloys, have them manufactured on a small scale, and characterise their mechanical behaviour and the stabilities of their microstructures. This will be carried out using advanced microscopes capable of studying the chemistry and structure of these alloys at the atomic level.Second, the underlying materials physics of HEAs that provide the excellent resistance to irradiation damage need to be fully understood. To assess radiation damage resistance, we will perform ion implantations rather than using neutrons. This allows us to perform a large number of experiments and the samples are not radioactive so can be easily handled in a laboratory. The damage caused will be studied using mechanical testing methods capable of probing the small damage regions produced by these heavy ions. Results from experiments, combined with computational modelling of damage effects in these novel alloys, will allow us to describe radiation damage accumulation and recovery mechanisms in these materials, which can be used to design even more advanced alloys. Finally, we must determine how well the materials will behave in service by assessing how they react when placed under load at high temperatures for long periods of time. We will work with Indian partners, utilising their unique facilities, to perform these tests on our most promising compositions. These compositions will be manufactured in large-scale quantities, tested, and returned to the UK for further study.