| Texto completo | |
| Autor(es): |
Freitas, Brenda Juliet Martins
;
Koga, Guilherme Yuuki
;
Amancio-Filho, Sergio de Traglia
;
Bolfarini, Claudemiro
Número total de Autores: 4
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T; v. 36, p. 14-pg., 2025-03-24. |
| Resumo | |
Cracking, anisotropy, texture, brittleness, coarse-reinforcing particles, and columnar grains often characterize ultrahigh small-radii-containing alloys processed via additive manufacturing. In this study, we demonstrate how Laser Powder Bed Fusion (L-PBF) processing, combined with massive boron addition (>1000 ppm), enables the formation of a refined and complex microstructure composed of an ultrafine stainless steel matrix and nanoborides decorating grain boundaries (GBs). Boron in L-PBF-produced stainless steel effectively transforms coarse columnar grains (similar to 200 mu m) into equiaxed ultrafine grains (similar to 1 mu m). Beyond exceptional grain refinement, colossal boron content promotes the formation of nanometric Cr2B particles along GBs. Such surprising grain refinement arises from the extended thermal undercooling caused by a lag between the real and theoretical grain growth rate caused by the segregation of boron, forming a boundary layer ahead of the solid-liquid interface. This extended undercooling increases the nucleation rate on the underlying layer, suppressing the columnar-like grain growth of the primary phase. These findings provide a mechanistic understanding of grain refinement in boron-modified alloys, offering insights that are transferable to other materials and additive manufacturing conditions. (AU) | |
| Processo FAPESP: | 19/05885-7 - Microestrutura, propriedades mecânicas e resistência a corrosão de aços inoxidáveis modificados com boro processados por manufatura aditiva |
| Beneficiário: | Brenda Juliet Martins Freitas |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 21/10735-4 - Microestrutura, propriedades mecânicas e resistência a corrosão de aços inoxidáveis modificados com boro processados por manufatura aditiva |
| Beneficiário: | Brenda Juliet Martins Freitas |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado |