TY - JOUR
T1 - Mechanical properties of a thermally-aged cast duplex stainless steel by nanoindentation and micropillar compression
AU - Zhang, Qingdong
AU - Singaravelu, Arun Sundar S.
AU - Zhao, Yongfeng
AU - Jing, Tao
AU - Chawla, Nikhilesh
N1 - Funding Information:
The authors acknowledge use of facilities at the Center for 4D Materials Science at Arizona State University (ASU). Qingdong Zhang is grateful to the China Scholarship Council for financial support during his stay at ASU. Helpful discussions with Dr. Enyu Guo from Dalian University of Technology on micropillar compression are appreciated.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/1/16
Y1 - 2019/1/16
N2 - Cast duplex stainless steels (CDSS) were investigated in order to understand the mechanical properties of their individual constituents, ferrite and austenite, after thermal aging at 475 °C for up to 2000 h, using nanoindentation and micropillar compression. Nanoindentation experiments indicate that the hardness of ferrite continuously increases with increasing aging time, while after annealing heat treatment the hardness drops to slightly higher than that of the as-received condition. The hardness in austenite did not change significantly with different aging conditions. The results of micropillar compression on both ferrite and austenite, with [1 1 1] orientation, reveal similar trends to the results from nanoindentation. After the long-term thermal aging process, spinodal decomposition takes place, as well as G-phase precipitates forming in the ferrite phase. Then, after annealing, the spinodal decomposition products were reduced and only the G-phases were left in the ferrite phase. Hardening in ferrite is mostly caused by the spinodal decomposition but also related to G-phase precipitates. The role of the G-phase can be explained via precipitation hardening theory, i.e., the small G-phases block the movement of dislocations throughout the ferrite lattice.
AB - Cast duplex stainless steels (CDSS) were investigated in order to understand the mechanical properties of their individual constituents, ferrite and austenite, after thermal aging at 475 °C for up to 2000 h, using nanoindentation and micropillar compression. Nanoindentation experiments indicate that the hardness of ferrite continuously increases with increasing aging time, while after annealing heat treatment the hardness drops to slightly higher than that of the as-received condition. The hardness in austenite did not change significantly with different aging conditions. The results of micropillar compression on both ferrite and austenite, with [1 1 1] orientation, reveal similar trends to the results from nanoindentation. After the long-term thermal aging process, spinodal decomposition takes place, as well as G-phase precipitates forming in the ferrite phase. Then, after annealing, the spinodal decomposition products were reduced and only the G-phases were left in the ferrite phase. Hardening in ferrite is mostly caused by the spinodal decomposition but also related to G-phase precipitates. The role of the G-phase can be explained via precipitation hardening theory, i.e., the small G-phases block the movement of dislocations throughout the ferrite lattice.
KW - Cast duplex stainless steel
KW - Micropillar compression
KW - Nanoindentation
KW - Thermal aging
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U2 - 10.1016/j.msea.2018.11.112
DO - 10.1016/j.msea.2018.11.112
M3 - Article
AN - SCOPUS:85057329400
VL - 743
SP - 520
EP - 528
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -