Abstract
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.
Original language | English |
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Pages (from-to) | 140-144 |
Number of pages | 5 |
Journal | Materials Science and Engineering A |
Volume | 438-440 |
Issue number | SPEC. ISS. |
DOIs | |
Publication status | Published - 2006 Nov 25 |
Externally published | Yes |
Keywords
- Ausforming
- Crystallography
- Lath martensite
- Phase transformation
- Steel
- Upper bainite
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering