酸化物分散強化鋼の高温照射環境下における強度劣化とその機構の解明

研究了核用氧化物弥散强化钢（12 Cr-ODS）的组织演变和力学性能变化，系统研究了1473-1673 K高温退火对纳米颗粒粗化动力学和组织演变的影响。纳米颗粒非常稳定，在1473 K退火过程中继续沉淀，而在1673 K暴露过程中发生了显着的粗化。 在1573和1673 K下，随着保温时间的延长，孔洞尺寸明显增大。这可能是由于Ar-截留和预先存在的空隙的生长和/或聚集在所制造的条件。在1473 K时，织构没有明显变化，但强度有所降低.硬度略有下降，在1473 K至24 h，然而，观察到明显的减少后，在1573和1673 K退火超过6 h。氦注入实验在东北大学的回旋加速器进行。氦离子注入距离表面390 μm，浓度分别为35和70 appm。在873和973 K下测试了不同应力下的蠕变性能。氦使合金在973 K的蠕变断裂时间和断裂应变略有降低。而在873 K下几乎没有影响。结果表明，12 Cr-ODS钢具有良好的抗氦辐照性能，其原因在于高的数密度和弥散分布的纳米颗粒。

We studied microstructural evolution and mechanical properties change of an oxide dispersion strengthened steel (12Cr-ODS) for nuclear application.The effect of high-temperature annealing at 1473-1673 K on the coarsening kinetics of nanoparticles and microstructural evolution was systematically investigated. The nanoparticles were extremely stable and continued precipitating during annealing at 1473 K, whereas, significant coarsening took place during exposure at 1673 K. Furthermore, heterogeneously distributed voids were developed, sizes of which increased distinctly at 1573 and 1673 K for longer holding time. This is probably due to the growth and/or aggregation of Ar-entrapped and pre-existed voids in the as-fabricated condition. Additionally, no obvious changes were observed in texture at 1473 K, except that its intensity reduced. The hardness slightly decreased at 1473 K up to 24 h, however, obvious reduction was observed after annealing at 1573 and 1673 K for more than 6 h.The helium implantation experiments were carried out in cyclotron accelerator in Tohoku University. The implanted helium reached 390 μm from the surface, and concentration was 35 and 70 appm. The creep properties were tested at 873 and 973 K with different stresses. The helium leaded to slight reduction in creep time-to-rupture and strain-to-rupture at 973 K. While it shows almost no effects at 873 k. It indicates that 12Cr-ODS steel has the good resistance to helium irradiation, which was derived from the high number density and dispersed nano-particles.