TY - JOUR
T1 - Crystallography of ausformed upper bainite structure in Fe-9Ni-C alloys
AU - Kawata, H.
AU - Sakamoto, K.
AU - Moritani, T.
AU - Morito, S.
AU - Furuhara, T.
AU - Maki, T.
N1 - Funding Information:
The financial supports by the Ministry of Education, Culture, Sports, Science and Technology through Grain-in-aids for Scientific Research (A) No.14205104 (2002-2004) and for Encouragement of Young Scientists No.11750569 (1999-2000) are appreciated.
PY - 2006/11/25
Y1 - 2006/11/25
N2 - The effect of ausforming on formation of upper bainite structure was investigated in Fe-9Ni-(0.15-0.5)C (mass%) alloys, focusing on the crystallographic feature of bainitic ferrite. The specimens were ausformed at 1073 or 873 K by 50% compressive reduction after austenitizing, and transformed at 623 K. Lath-shaped upper bainite structures similar to lath martensite are formed at 623 K. A bainite packet is partitioned into blocks of all the six variants of the K-S orientation relationship satisfying the same parallel close-packed plane relationship. In both of the non-ausformed and ausformed specimens, bainite blocks are coarsened with increasing carbon content. In the Fe-9Ni-0.15C alloy, the effect of ausforming on the bainite block width is small. For higher carbon alloys (Fe-9Ni-0.3C and 0.5C), bainite blocks are remarkably coarsened by the ausforming. In contrast, the ausforming refines lath martensite blocks in the Fe-9Ni-0.15C alloy but has a small effect in higher carbon alloys.
AB - The effect of ausforming on formation of upper bainite structure was investigated in Fe-9Ni-(0.15-0.5)C (mass%) alloys, focusing on the crystallographic feature of bainitic ferrite. The specimens were ausformed at 1073 or 873 K by 50% compressive reduction after austenitizing, and transformed at 623 K. Lath-shaped upper bainite structures similar to lath martensite are formed at 623 K. A bainite packet is partitioned into blocks of all the six variants of the K-S orientation relationship satisfying the same parallel close-packed plane relationship. In both of the non-ausformed and ausformed specimens, bainite blocks are coarsened with increasing carbon content. In the Fe-9Ni-0.15C alloy, the effect of ausforming on the bainite block width is small. For higher carbon alloys (Fe-9Ni-0.3C and 0.5C), bainite blocks are remarkably coarsened by the ausforming. In contrast, the ausforming refines lath martensite blocks in the Fe-9Ni-0.15C alloy but has a small effect in higher carbon alloys.
KW - Ausforming
KW - Crystallography
KW - Lath martensite
KW - Phase transformation
KW - Steel
KW - Upper bainite
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U2 - 10.1016/j.msea.2006.02.175
DO - 10.1016/j.msea.2006.02.175
M3 - Article
AN - SCOPUS:33750477001
VL - 438-440
SP - 140
EP - 144
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
IS - SPEC. ISS.
ER -