resumo
Hardmetal wear tools industry has observed a consistent increase in new applications and market interest for submicrometer carbides, despite the fabrication issues related with powder processing and sintering that subsist on these new materials. New technologies with lower temperature exposure and high heating rates or optimizing the current sintering process are imperative to improve their quality and consistency. As the new sintering technologies in study are costly for industrial use and still limited in terms of flexibility, we studied and developed in this work a combined sintering approach to maximize the densification of submicrometer grades (WC 0.6 mu m and WC 0.4 mu m) with 3.5 and 12 wt% Co while controlling the deleterious grain growth. Sintering at solid and liquid phase was performed with vacuum sintering and post-sintering performed using Hot-Isostatic-Pressing. Thermal cycles were designed based on thermal analyses experiments performed to the powders allowing to design a densification process at lower temperatures to maximize microstructural homogeneity, densification, and reduce grain growth using current industrial technologies, reflected in high hardness and mechanical strength obtained.
palavras-chave
CEMENTED CARBIDES; WC-CO; HARDMETALS; POWDER
categoria
Materials Science
autores
Soares, E; Malheiros, LF; Sacramento, J; Valente, MA; Oliveira, FJ
nossos autores
Filipe José Alves de Oliveira
Investigador Principalagradecimentos
Work supported by DURIT and Portuguese Science Foundation (FCT) under grant BDE15663.