Effect of Zr on the microstructure of corrosion resistant ODS steels

抗辐射钢材对于下一代裂变和未来聚变能源系统的发展至关重要。通过粉末冶金工艺将纳米颗粒掺入金属基材中被广泛应用于抗辐射钢的开发，并一直是世界范围内密集研究的主题。在这些未来的反应堆设计中，这些材料的两个最关键的性能是在高于常规钢的软化点的温度下保持高强度，以及降低对辐射诱导的氦脆的敏感性。氧化物弥散强化(Ods)钢在这两种性能上都显示出相当大的前景。氧化物纳米颗粒的分布、化学和形状，以及它们对基质化学和辐射响应的影响，在许多性能的改善中起着至关重要的作用。然而，对于这些纳米粒子作为合金化学和制造工艺的功能的性质，以及它们对辐射损伤做出反应的确切机制，文献中存在相当大的分歧。还需要开发具有更好耐腐蚀性的新的消耗臭氧层物质钢，专门用于封闭燃料循环的燃料包层材料。近年来，添加Al的高铬ODS钢已被开发用于高腐蚀性环境，但其高温强度较差。其中一个合作者的第一性原理计算表明，在这些合金中添加Zr可以通过形成Y-Zr-O相来细化和增加氧化物颗粒的数密度。我们预测，这将提高高温强度，同时保持改善的耐腐蚀性和辐照性能。我们希望在这个新项目中检验这一预测。

Radiation-resistant steels are essential for the development of next-generation fission and future fusion energy systems. The incorporation of nano-particles in metallic matrices by powder metallurgy processing is widely employed for the development of radiation-resistant steels, and continues to be the subject of intense research worldwide. The two most critical properties of these materials for application in these future reactor designs are the maintenance of high strength at temperatures above the softening point of conventional steels and the reduction in sensitivity to radiation-induced He embrittlement. Oxide dispersion strengthened (ODS) steels show considerable promise in both properties. The distribution, chemistry and shape of the oxide nanoparticles, and their influence on the matrix chemistry and irradiation response, play a crucial role in many of the improved properties. However, there is considerable disagreement in the literature on the nature of these nanoparticles as a function of alloy chemistry and manufacturing process, and the precise mechanisms by which they respond to irradiation damage. There is also a requirement to develop new ODS steels with improved corrosion resistance specifically for fuel cladding materials for closed fuel cycles. Recently, high Cr ODS steels with Al additions have been developed for use in highly corrosive environments, but their high-temperature strength is poor. First principles calculations by one of the partners indicate that adding Zr to these alloys may refine and increase the number density of oxide particles by forming Y-Zr-O phases. We predict that this would improve the high temperature strength while maintaining the improved corrosion resistance and irradiation performance. It is this prediction that we wish to test in this new project.