Effect of niobium content on irradiation microstructure and hardening in FeCrAl-based alloys

• 作者: Xiong Zhou Hui Wang Liping Guo Yiheng Chen Fang Li Yunxiang Long Cheng Chen Ziyang Xie Hongtai Luo Shaobo Mo
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2021,（36）
• 页码范围: 181-192
• 页数: 12页
• 语种: 英文

摘要

Iron-chromium-aluminum (FeCrAl) alloys with different content of niobium (Nb)-0,0.4 wt％,0.8 wt％,and 1.2 wt％-were designed and prepared.All samples were then irradiated with 2A MeV Fe2+ ion to the dose of 1 and 15 displacements per atom (dpa) at 400 ℃ The formations of dislocation loops in-duced by self-ion irradiation in these alloys were investigated by transmission electron microscopy (TEM).Nano-indentation tests were used to assess the hardness and irradiation hardening of samples.For the samples before irradiation,the (Fe,Cr)2(Nb,Mo) Laves phases density and the nano-indentation hardness increased with increasing Nb content of the samples.After irradiation to 1 and 15 dpa,both of a/2<111>and a<100> dislocation loops were produced but no voids or α'phase were found in all samples.With increasing Nb content of the samples,the size of dislocation loops increased first and then decreased,while the total volume number density decreased and then increased.The fraction of a<100> disloca-tion loops increased first and then decreased with increasing Nb content,and increased with increasing irradiation dose.Dislocation networks and the amorphization of the Laves phases were observed in the samples with irradiation dose of 15 dpa.Irradiation hardening of Nb free samples was two to four times that of Nb containing samples,and the irradiation hardening increased with increasing Nb content of Nb containing samples.The experimental results indicate that the increase of Nb content in FeCrAl alloys can increase the density of Laves phases,leading to the decrease of Mo content and increase of Cr content in the matrix.The competition between the two types of solutes affects the nucleation and growth of the dislocation loops.