Experimental and thermodynamic investigation of the microstructural evolution of a boron-rich Fe-Cr-Nb-B alloy

Autor(es)

Guo, Y. ; Moreira Jorge, Jr., A. ; Costa e Silva, A. ; Kiminami, C. S. ; Bolfarini, C. ; Botta, W. J.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 713, p. 119-124, AUG 5 2017.
• Citações Web of Science: 0

Resumo

Wear and corrosion resistant amorphous/nanocrystalline Fe-Cr-Nb-B coatings have been successfully synthesized by high velocity oxygen fuel in previous works. These coatings show excellent wear resistance and superior corrosion resistance. However, the phase evolution during cooling of the new alloys in the Fe-Cr-Nb-B system is not well understood. In addition, commercial thermodynamic databases for Fe-based alloys do not fully describe the system at the composition ranges of interest. In the present work, the phase evolution of as-melted Fe51Cr10Nb20B19 alloy was investigated by combining detailed microstructural characterization with thermodynamic evaluation using a database developed for the Fe-Nb-B system. The solidification path starts with the formation of (Fe, Cr, Nb)(3)B-2 diboride phase, followed by the formation of austenite at lower temperature. On further cooling, the remaining liquid transforms eutectically to (Fe, Cr) NbB boride and austenite. In the solid-state region, the austenite transform allo-tropically to ferrite. At even lower temperature, there exists a peritectoid-like transformation, where the (Fe, Cr)NbB boride nucleates both at ferrite grain boundaries and around the existing (Fe, Cr, Nb)(3)B-2 diboride. Thermodynamic calculations showed good agreement with experimental observations, opening new possibilities to guide future alloy development in the Fe-Cr-Nb-B quaternary system. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 14/22112-8 - Produção e caracterização estrutural, mecânica e eletroquímica de recobrimentos metálicos produzidos por aspersão térmica utilizando ligas amorfizáveis do sistema Fe-Cr-Nb-B.
• Beneficiário: Yaofeng Guo
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/05987-8 - Processamento e caracterização de ligas metálicas amorfas, metaestáveis e nano-estruturadas
• Beneficiário: Claudio Shyinti Kiminami
• Modalidade de apoio: Auxílio à Pesquisa - Temático