Fabricação, caracterização e avaliação de desempenho em usinagem de metal duro com adição de grafeno sinterizado por plasma pulsado
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Data
2025-09-30
Autores
Rosa, Jhonatan Dantas dos Santos
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Universidade Federal do Espírito Santo
Resumo
Cemented carbide, primarily composed of tungsten carbide (WC) and cobalt (Co), is the most widely used cutting tool material in the metalworking industry. Even with its excellent hardness and toughness properties, cemented carbide continues to be the focus of constant development, such as the addition of graphene. This nanoadditive promises to increase the performance of conventional materials by improving mechanical and lubrication properties. In this regard, this work aims to fabricate, characterise and evaluate the machining performance of cemented carbide with fewlayer graphene (FLG) addition. For this purpose, WC-10Co+0.1FLG and WC-10Co samples were sintered by spark plasma (SPS) at 1400°C, with uniaxial pressure of 40MPa in vacuum. Some of these samples were used for microstructural, hardness, fracture toughness, and density characterisation. Others were ground to produce cutting tools. The SPS-sintered tools with and without graphene addition were compared with a commercial insert (WC-Co - Commercial). Dry turning tests on grey cast iron FC250 were carried out under constant cutting conditions (Vc=150 m/min, f=0.15 mm/rev and ap=1.5 mm). Machining force, apparent coefficient of friction, cutting temperature, surface roughness parameter and tool wear were evaluated. The results showed that the addition of 0.1%wt of FLG has little influence on densification, with no effect on hardness; however, it promoted an average increase of 13.82% in fracture toughness. Graphene addition also promoted a overall gain in cutting tool performance, significantly reducing the machining force, the apparent coefficient of friction, and cutting temperature by 40.17%, 46.13% and 15.65%, respectively, compared to commercial insert. Furthermore, the nanoadditive improving the surface finish, reducing Ra by 68.75% compared to the commercial cutting tool. Regarding SPS-sintered tools, the graphene contributed to a 19.56% reduction in FU and a 29.22% reduction in the apparent friction coefficient. The WC10Co+0.1FLG tool showed crater wear (KB) of 448 µm and flank wear (VBB) of 218.3 µm. The last one was approximately three times smaller than the other inserts evaluated, with attrition as the dominant mechanism. Therefore, 0.1%wt of few-layer graphene (<10) added to cemented carbide (WC-10Co), which provides self lubrication and increased thermal conductivity, as well as fracture toughness; together with SPS sintering technique, which promotes high physical-mechanical characteristics; are shown as promising, innovative and efficient alternatives in the machining process sustainability.
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Palavras-chave
Metal duro , Ferramentas de corte , Usinagem