冷轧和退火对V-5Cr-5Ti合金组织结构和抗辐照硬化性能的影响

钒合金(V-5Cr-5Ti)是聚变堆第一壁以及包层的重要候选结构材料。不同加工工艺会对钒合金在聚变堆中的服役性能产生影响。本文利用兰州重离子研究装置(HIRFL)提供的337 MeV的高能Fe离子对不同程度冷轧(冷变形量分别为40%、60%和80%)以及冷轧后退火(1 273 K退火1 h)的V-5Cr-5Ti合金样品进行了辐照，研究了不同的冷轧和退火处理过程对材料抗辐照硬化性能的影响。电子背散射衍射技术(EBSD)测试结果显示，随着冷变形量的增加，样品中细小破碎晶粒比例增大，晶粒平均尺寸减小。退火处理后，细小破碎晶粒出现一定程度的长大，大晶粒几乎全部消失，晶粒尺寸分布更加均匀。维氏硬度结果表明随着冷变形量的增加，硬度随之增加，退火后硬度降低。辐照之后，材料硬度升高，出现了辐照硬化效应。在冷轧样品和退火样品中都观察到了辐照硬化效应随冷变形量的增加显著减弱的现象，这表明冷变形可以显著提高材料的抗辐照硬化能力。结合EBSD和硬度数据，对冷变形和退火处理引起钒合金抗辐照硬化性能变化的机理进行了讨论。讨论结果显示，冷轧使材料总的吸收尾闾增大，引起辐照硬化程度降低，退火处理使材料中晶界密度和位错密度降低，材料的总吸收尾闾降低，辐照硬化效应增加。

The Effect of Cold Rolling and Annealing on the Microstructure and Irradiation Hardening Resistance of V-5Cr-5Ti Alloys

Vanadium alloys (V-5Cr-5Ti) have been considered as the candidate materials for the first wall and the blanket of fusion reactors. Different fabrication process will affect the performance of vanadium alloy in fusion reactors. In this study, the response of hardening of V-5Cr-5Ti vanadium alloys with different cold deformation (40%, 60% and 80%) followed by annealing treatment (1 273 K for 1 h) under irradiation with 337 MeV Fe ions was investigated. The irradiation experiment was performed at a terminal of the Sector-Focused Cyclotron(SFC) at HIRFL(Heavy Ion Research Facility in Lanzhou). The results of electron backscattering diffraction(EBSD) indicated that the proportion of fine broken grains in the sample increased and the average grain size decreased with the increase of cold deformation amount. After annealing, the distribution of grains become more uniform with the fine broken grains growing up and the large grains almost disappeared. The results of the Vickers hardness test show that the hardness increases with the increase of cold deformation amount and decreases after annealing treatment. After irradiation, the hardness of all samples increased significantly, which suggested the occurrence of irradiation hardening. In both cold rolling samples and annealing samples, the irradiation hardening effect decreased with the increase of cold deformation amount, which indicated that cold rolling can significantly improve the irradiation hardening resistance property. Based on the EBSD and hardness results, the mechanism of the effect of cold rolling and annealing on irradiation hardening resistance property of V-5Cr-5Ti was discussed. The increase of the cold deformation amount results in the increase of the sink strength, which suppressed the occurrence of irradiation hardening. The annealing treatment results in the decrease of the density of grain boundary and dislocation and the decrease of the total sink strength, which caused more significant irradiation hardening in the sample with annealing treatment.