伽马辐照诱导Ti35合金中Ta元素偏析及其对力学性能的影响

Gamma Irradiation Influence on Ta Element Segregation and Mechanical Properties of Ti35 Alloy

摘要:

基于乏燃料后处理高放射性服役环境，通过施加不同辐照剂量伽马射线，研究了伽马辐照对于Ti35合金组织结构演变规律，建立了辐照诱导组织-性能间构效关系。结果表明，伽马辐照诱导Ti35合金产生大量缺陷，且随辐照剂量升高，缺陷密度也随之增加。辐照致使Ti35合金基体中Ti原子快速迁移，导致晶内产生体心立方富Ta相，且此相中Ta含量及尺寸变化与辐照剂量呈高度依赖关系。伽马辐照降低了Ti35合金的延伸率，通过界面分析确定其与富Ta相主导的变形及界面失效机制有关。辐照前后Ti35合金均呈现韧性断裂模式，通过观察断口形貌发现伽马辐照显著增大了断口微孔尺寸及密度。

Abstract:

Based on the highly radioactive service environment of spent fuel reprocessing, the influence of gamma irradiation on the structure of Ti35 alloy was studied by applying gamma rays at different irradiation doses, and the structure-activity relationship between irradiation-induced structure and performance was established. The results show that gamma irradiation induces a large number of defects in Ti35 alloy, and the defect density increases with the increase in irradiation dose. The rapid migration of Ti atoms in the Ti35 alloy matrix caused by irradiation results in the formation of a body-centered cubic Ta-rich second phase in the granules, and the Ta content and size of this phase further increase with the increase in irradiation dose. Gamma irradiation significantly reduces the elongation of Ti35 alloy, which is related to the deformation and interface failure mechanism dominated by Ta-rich soft phase according interface analysis. The Ti35 alloy shows ductile fracture mode before and after irradiation, and it is found that gamma irradiation significantly increases the size and density of fracture micropores by observing the fracture morphology.