resumo
Alternative binders to cobalt, based on stainless steel (SS, AISI304) and copper were investigated for tungsten carbide (WC) based cemented carbides. The binder content was fixed at 12 wt%, and the Cu:SS ratio varied in proportions of 0:1, 1:5, 1:2, 1:1, 1:0. High energy ball milling was applied to ensure high homogenization, nanometric particle size and mechanical alloying of binder elements in the powders' mixtures. To assess an adequate sintering route, wettability testing and constant heating rate dilatometry in vacuum were performed. The composites were analyzed in terms of their structural, microstructural and mechanical characteristics. The poor wettability of melted Cu on WC surfaces was increased by alloying it with SS and highly dense compacts could be successfully attained at reduced vacuum sintering temperatures with binders having a Cu:SS ratio equal to or lower than 1:2. The microstructures show secondary phases and significant grain coarsening during sintering, whereas the average grain size was kept in the nanometric range. The composites that attained almost full densification present high hardness, comparable to that of nanometric WC-12Co cemented carbides processed by similar routes, but lower toughness values.
palavras-chave
TUNGSTEN CARBIDE; CEMENTED CARBIDES; MICROSTRUCTURE
categoria
Materials Science; Metallurgy & Metallurgical Engineering
autores
Cardoso, JP; Puga, J; Rocha, AMF; Fernandes, CM; Senos, AMR
nossos autores
Alexandre Manuel Ferro Rocha
Estudante de doutoramento
Ana Maria de Oliveira e Rocha Senos
Colaborador
Cristina Maria da Silva Fernandes
Colaborador
João Pedro Veleirinho Cardoso
Estudante de doutoramentoGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
Projectos
HARDCorr - Desenvolvimento de metal duro com elevada resistência ao desgaste e à corrosão (HardCorr)
agradecimentos
C.M. Fernandes gratefully acknowledges the financial support from the program COMPETE and by national funds through FCT under the grant SFRH/BPD/43402/2008. This work was financed by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of Operational Competitiveness and Internationalization Programme (POCI) and in the scope of the project HardCorr (POCI-01-0247-FEDER-003382). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID /CTM /50011 /2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. We thank R. C. Pullar for assistance with the English editing of this article.