1. Synergism between B and Nb improves fire resistance in microalloyed steels
- Author
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Ferreira, Pedro P., Carvalho, Felipe M., Ariza-Echeverri, Edwan A., Delfino, Pedro M., Bauri, Luiz F., Ferreira, Andrei M., Braga, Ana P. V., Eleno, Luiz T. F., Goldenstein, Hélio, and Tschiptschin, André P.
- Subjects
Condensed Matter - Materials Science - Abstract
The development of new fire-resistant steels represents a challenge in materials science and engineering of utmost importance. Alloying elements such as Nb and Mo are generally used to improve the strength at both room- and high-temperatures due to, for example, the formation of precipitates and harder microconstituents. In this study we show alternatively that the addition of small amounts of boron in Nb-microalloyed steels may play a crucial role in maintaining the mechanical properties at high temperatures. The 66\,\% yield-strength criteria for fire resistance is achieved at $\approx 574$\,{\deg}C for a boron steel, whereas without boron this value reaches $\approx 460$\,{\deg}C, a remarkable boron-induced mechanical strengthening enhancement. DFT calculations show that boron additions can lower the vacancy formation energy when compared to pure ferrite and, for Nb-B steels, there is a further 24\,\% reduction, suggesting that the boron-niobium combination acts as an effective pinning-based strengthening agent., Comment: 7 pages, 4 figures
- Published
- 2022