1. Formation of FeMo2B2 phase in boron containing 9Cr-1.5Mo ferritic steels
- Author
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Suk-Woo Hong, Kwun SOOK-In, Sang-Min Song, Soon-Hyo Chung, and Woo-Sang Jung
- Subjects
Materials science ,Alloy ,Metallurgy ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,engineering.material ,Condensed Matter Physics ,chemistry ,Ultimate tensile strength ,Boron containing ,Materials Chemistry ,engineering ,Redistribution (chemistry) ,Tempering ,Physical and Theoretical Chemistry ,Boron ,Austenite grain - Abstract
The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo 2 B 2 formation was also studied. Finally, the effects of boron contents and FeMo 2 B 2 formation on the high temperature strength were studied. Boron atoms were segregated to prior austenite grain boundary during normalizing treatment. And these boron atoms were slowly diffused into the grain interior during tempering and aging at 700 °C. The FeMo 2 B 2 phase was only formed after 1,000 h aging at 700 °C in alloy containing 196 ppm boron. The formation of FeMo 2 B 2 phase is accelerated by the applied stress. It was expected that the formation of FeMo 2 B 2 is closely related to the redistribution of boron atoms. The tensile strengths at 700 °C are increased with the increase of boron contents. However, the formation of FeMo 2 B 2 phase results in lower tensile strength.
- Published
- 2006
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