検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年

低放射化フェライト鋼の介在物形成に及ぼすTiの影響

Influence of Ti on inclusion formation of reduced activation ferritic/martensitic steels

澤畠 篤司; 谷川 博康; 芝 清之; 榎本 正人*

Sawahata, Atsushi; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Enomoto, Masato*

核融合炉用構造材料の第一候補材料である低放射化フェライト鋼F82Hの重要な課題の一つとして照射脆化の問題がある。現在、脱酸剤として添加したAlがTaと介在物を形成すること、介在物が靱性低下の原因となっていること、またTiが靭性低下を招くことが明らかになりつつある。そこでTiの靭性低下の原因と介在物形成との関係を調べるために、Tiをなるべく含んでいない高純度材と一般純度材のF82鋼を用いてシャルピー衝撃試験,微細組織観察・分析(FE-SEM)を行った。高純度材,低純度材ともにAl$$_{2}$$O$$_{3}$$とTa$$_{2}$$O$$_{5}$$の複合介在物, Al$$_{2}$$O$$_{3}$$を含まないTa$$_{2}$$O$$_{5}$$介在物が観察された。また、複合介在物のTa$$_{2}$$O$$_{5}$$部分にはTi, Vが含まれており、一般純度材の介在物は全体的にTiのEDSピークが高かった。また、高純度材には1$$mu$$m以下のTa$$_{2}$$O$$_{5}$$介在物が多く、一般純度材で多く見られた複合介在物はほとんどなかった。シャルピー衝撃特性は高純度(-64$$^{circ}$$C)が一般純度材(-16$$^{circ}$$C)よりも低いDBTTを示すことから、不純物元素であるTiの低減は複合介在物を減少と、良好な衝撃特性を得るには有効な手段であると考えられる。

Reduced activation ferritic/martensitic steels (RAFs), such as F82H (Fe-8Cr-2W-0.2V-0.04Ta-0.1C), are one of the leading candidates for structural materials of fusion reactors, and it is essential for RAFs R&D to assure its good toughness property for fusion application. In this study, the influence of Ti on impact property was studied based on microstructural analyses and charpy impact tests which were performed against general-purity F82H (0.004Ti-0.0060N) and high-purity F82H ($$<$$0.001Ti- 0.0014N). In general-purity F82H, its impact property around DBTT showed both 100% brittle fracture and brittle-ductile, and this tendency is not appeared in high-purity F82H. SEM observation on those brittle fracture surfaces of general-purity F82H revealed the presence of Al$$_{2}$$O$$_{3}$$-Ta(V,Ti)O complex oxides at the fracture initiation point. The size distribution analyses of oxides suggest that the complex oxide in general-purity F82H showed a higher number density than in high-purity F82H. In addition to this, EDS analyses showed the complex oxides in general-purity F82H had a strong peak of Ti, but they were not detected in the oxide in high-purity F82H. These results suggest the influence of Ti on complex oxide formation which affects impact property.

Access

:

- Accesses

InCites™

:

パーセンタイル:84.18

分野:Metallurgy & Metallurgical Engineering

Altmetrics

:

[CLARIVATE ANALYTICS], [WEB OF SCIENCE], [HIGHLY CITED PAPER & CUP LOGO] and [HOT PAPER & FIRE LOGO] are trademarks of Clarivate Analytics, and/or its affiliated company or companies, and used herein by permission and/or license.