Formation of Cu-rich Nanoprecipitates in Cu Containing Pearlitic SGI

• Autor(a) principal: GARCÍA, LAURA N.
• Data de Publicação: 2020
• Outros Autores: Rodrigo Magnabosco, BOERI, ROBERTO E., TOLLEY, ALFREDO J., SAAVEDRA, MARCELA E.
• Tipo de documento: Artigo
• Título da fonte: Biblioteca Digital de Teses e Dissertações da FEI
• Texto Completo: https://repositorio.fei.edu.br/handle/FEI/3418
• topic: spheroidal graphite cast irons; Cu-rich nanoprecipitates; nanostructured materials; Thermo-Calc; microsegregations; transmission electron microscopy

The presence of Cu-rich nanoprecipitates in a pearlitic spheroidal graphite (ductile) cast iron alloyed with 0.82 wt%Cu was studied. The size and distribution of the precipitates were examined by transmission electron microscopy at different locations of the pearlitic matrix. Some areas were nearly free from precipitates, while other regions showed precipitates at the cementite and ferrite lamellae and at the ferrite/cementite interface. Calculation of the thermodynamic equilibrium under stable and metastable conditions using Thermo-Calc led to the identification of the conditions controlling the formation of Cu-rich nanoprecipitates along three different stages depending on the Cu concentration. Together with a differential scanning calorimetry test and elemental diffusional calculations, thermodynamic predictions supported the observation of Cu-rich precipitates despite the low concentration of Cu of the alloy investigated and allowed the authors to explain the observed heterogeneity in the distribution of precipitates as resulting from the heterogeneous distribution of Cu in the alloy caused by microsegregation during solidification. The knowledge gained is relevant for the design of strengthening strategies in SGI based on the dispersion of Cu-rich nanoprecipitates.