Ion-irradiation hardening accompanied by irradiation-induced dissolution of oxides in FeCr(Y, Ti)-ODS ferritic steel
Ion-irradiation hardening accompanied by irradiation-induced dissolution of oxides in FeCr(Y, Ti)-ODS ferritic steel
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DOI：
10.1016/j.jnucmat.2018.09.007
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发表时间：
2018-12
影响因子：
3.1
通讯作者：
P. Song;Jinzhu Gao;K. Yabuuchi;A. Kimura
中科院分区：
文献类型：
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作者：
P. Song;Jinzhu Gao;K. Yabuuchi;A. Kimura
研究了 Y-Ti-O 纳米粒子强化的 FeCr(Y, Ti)-ODS 铁素体钢在室温 (RT) 下经 6.4MeV Fe3+ 辐照至 2、10 和 50 dpa 的标称损伤后，辐照对硬度和相稳定性的影响。随着局部位移损伤增加到~20 dpa，纳米尺寸的氧化物颗粒略有收缩，而相应的数密度与辐照前相比急剧下降了近两个数量级。据认为，弹道溶解应是颗粒尺寸和数量密度减小的原因。在弱束暗场（WBDF）成像条件下，在50 dpa标称损伤辐照的样品中观察到由1/2<111>型（>80%）和<100>型位错环组成的位错环。在~72 dpa的局部损伤下，所有位错环的平均尺寸和数量密度分别为2.8±0.7nm和(4.1±0.7)×1022m−3。尽管氧化物颗粒几乎完全溶解，但纳米压痕硬度测量表明，硬化随着位移损伤的增加而持续增加，并且根据 Nix-Gao 模型在 50 dpa 的标称损伤下估计为 1.63±0.39GPa。伴随氧化物颗粒溶解的辐射硬化被解释为氧化物颗粒的损失、固溶硬化和精细位错环的形成。通过透射电子显微镜（TEM）观察到的位错环对硬化的贡献不足以克服溶解造成的强化损失，这表明固溶硬化的重要性以及位错环作为硬化贡献者的较大强度因子。
Irradiation effects on hardness and phase stability were investigated for an FeCr(Y, Ti)-ODS ferritic steel strengthened by Y-Ti-O nano-particles after irradiation with 6.4 MeV Fe3+at room temperature (RT) up to nominal damages of 2, 10 and 50 dpa. With increasing local displacement damage up to ∼20 dpa, nano-sized oxide particles slightly shrank, while the corresponding number density drastically decreased by almost two orders of magnitude compared to that of before irradiation. It is considered that ballistic dissolution should be responsible for such reductions in the particle size and number density. Dislocation loops consisting of 1/2<111> type (>80%) and <100> type were observed under weak beam dark field (WBDF) imaging condition in the specimen irradiated to the nominal damage of 50 dpa. The average size and number density of all the dislocation loops were 2.8 ± 0.7 nm and (4.1 ± 0.7) × 1022m−3, respectively, at the local damage of ∼72 dpa. Although the oxide particles were almost completely dissolved, nanoindentation hardness measurements revealed that the hardening went up continuously with increasing displacement damage and was estimated to be 1.63 ± 0.39 GPa by the Nix-Gao model at the nominal damage of 50 dpa. The irradiation hardening accompanied by the dissolution of oxide particles was interpreted in terms of loss of oxide particles, solid solution hardening and formation of fine dislocation loops. The contribution of dislocation loops observed by transmission electron microscopy (TEM) to the hardening was insufficient to overcome the loss of strengthening by dissolution, suggesting the importance of solid solution hardening and the larger strength factor of dislocation loops as a hardening contributor.