Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing

0369890 - ÚFM 2012 RIV NL eng J - Journal Article
Stratil, Luděk - Hadraba, Hynek - Buršík, Jiří - Dlouhý, Ivo
Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing.
Journal of Nuclear Materials. Roč. 416, č. 3 (2011), s. 311-317. ISSN 0022-3115. E-ISSN 1873-4820
R&D Projects: GA ČR(CZ) GAP108/10/0466; GA ČR GA106/08/1397
Institutional research plan: CEZ:AV0Z20410507
Keywords : Eurofer´97 * DBTT * impact behaviour * fracture behaviour * carbide coarsening * hardness
Subject RIV: JG - Metallurgy
Impact factor: 2.052, year: 2011

The microstructure and fracture properties of the Eurofer97 steel plates of thickness 14 mm and 25 mm were investigated in as-received state and in state after long-term thermal ageing (550 °C/5000 h). Detailed microstructure studies were carried out by means of optical light, electron and quantitative electron microscopy. Mechanical properties were evaluated by means of Charpy impact testing and hardness testing and fracture surfaces were fractographically analysed in macro and microscales. The microstructure of the Eurofer97 consisted of tempered martensite with M23C6 and MX precipitates. Microstructure of 14 mm plate was more homogenous and fine grained than 25 mm plate. Due to different microstructure the tDBTT of thicker plate was on +10 °C higher than for 14 mm plate for which reached −60 °C. Slight microstructural changes on the level of subgrain consisting of their partial recrystallization and slight carbide coarsening were observed after applied ageing. The isothermal ageing caused evident shift in tDBTT about +5 °C, which was most likely caused by recrystallization of subgrains.
Permanent Link: http://hdl.handle.net/11104/0203851