Costa, Franciné Alves daCâmara, Nailton Torres2022-03-212022-03-212021-02-05CÂMARA, Nailton Torres. Estudo do efeito do teor de SiC e da moagem de alta energia na microestrutura e nas propriedades mecânicas e físicas do compósito Cu-SiC. 2021. 121f. Tese (Doutorado em Engenharia Mecânica) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2021.https://repositorio.ufrn.br/handle/123456789/46643The Cu-SiC composite combines high thermal and electrical conductivity and good copper ductility with good thermal conductivity, low density and high abrasion resistance of SiC. Such characteristics allow this composite to be applied as electrical contacts and heat sinks, however, the mutual insolubility of both phases difficulty to obtain by sintering. Several studies use high energy milling (HEM) to prepare powders from immiscible systems with low wettability, as it produces greater sinterability of the material through the reduction of tehe particle size and homogenization of the phases. In this work, Cu-SiC composite powders with 2, 10 and 15% of SiC were prepared by mechanical mixing and MAE. The mechanical mixing was carried out to manually mix the powders in a plastic package. The WEM of the powders was carried out in a planetary mill pulverisette 7 with pool and metal grinding hard in liquid medium of alcohol - 99.5% at 400 rpm for 2, 10, 20 and 30 hours. The mass ratio of poder/ball used was 1: 5. Cu-SiC powder compacts were pressed at 500 MPa in a uniaxial cylindrical matrix. The green compacts were sintered in a tubular resistive oven and with a dilatometric record at 1000 oC for 1 h under an argon atmosphere. The heating rate used was 10 oC / min. Analyzes of FRX, DRX, MEV and EDS were used to characterize both powders and sintered compacts. The crystallite size and the microdeformation of the Cu and SiC phases of the Cu-SiC powders were determined using the TOPAS software. Particle size distribution measurements of elementary powders (Cu and SiC) and Cu-SiC composite were performed by laser diffraction. The density of green and sintered compacts was obtained using the geometric method, and the Archimedes principle. Eletrolytic corrosion measurements were performed on the sintered compacts of mixed powders and milled for 30 h. The corrosion resistance of the Cu-SiC composite decreases significantly to a contente above 2% by mass of SiC. The density values of the sintered compacts decrease with the increase in the SiC content (0, 2, 10 and 15% w) and the grinding time (2, 10, 20 and 30 h). The sintered compacts of mixed powders Cu-2% SiC reached 77.2% relative density, while the compacts of Cu-2% SiC powders milled for 2 and 30 h obtained a relative density of 72.7 and 65.4%. The compacts of Cu-SiC powders with 10 and 15% by weight of SiC milled for 2 h obtained a density of 64.9 and 58.2%, respectively. The HV values of the sintered compacts increase with an increase in the SiC content and the highest values were obtained by compacts of Cu-SiC powder ground for 10 h. The microhardness values of these compacts of powders milled for 10 h with 2, 10 and 15% by mass of SiC reached 50.9, 83.7 and 115.6 HV, respectively. The microstructures of the sintered compacts of milled Cu-SiC powders are more homogeneous than that of mixed powders.Acesso AbertoMoagem de alta energiaCompósitos Cu-SiCSinterizaçãoMetalurgia do pódoctoralThesis