Banca de QUALIFICAÇÃO: NAILTON TORRES CAMARA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : NAILTON TORRES CAMARA
DATE: 27/05/2020
TIME: 14:00
LOCAL: Sala de vídeo conferência
TITLE:

Study of the effect of high energy grinding on the microstructure and properties of the sintered Cu-SiC composite in the solid state

KEY WORDS:

High energy milling, Cu-SiC Composites, Sintering, Powder Metallurgy

PAGES: 93
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Metalurgia de Pó
SUMMARY:

The Cu-SiC composite combines the high electrical conductivity and the good workability of copper with the good thermal conductivity, low density and abrasion resistance of SiC. Such characteristics allow it to be used as electrical contacts and heat sinks, however obtaining this composite is hampered by the mutual insolubility between its phases. Several studies use high energy milling (HEM) to prepare powders from immiscible systems with low wettability, as it produces greater refinement and homogenization of the phases, which increases the sinterability of the material. In this work, Cu-SiC composite powders with 2, 10 and 15% by weight of SiC were prepared by mechanical mixing and HEM in a planetary mill pulverissete 7 with container and hard metal milling bodies in liquid ethyl alcohol medium, 99,5 %, at 400 rpm for 2, 10, 20 and 30 hours. A mass ratio of powder to balls of 1:5 was used. Cu-2, 10 and 15% SiC powders were obtained at 200 MPa in a uniaxial cylindrical matrix. The green compacts were sintered in a tubular resistive oven with a dilatometric record at 1,000 ^oC for 1 h and 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 size of crystallites and the deformation of the crystalline network of the Cu and SiC phases of the Cu-SiC powders were determined from the most intense diffraction peak using the Scherrer equation. Particle distribution analysis by laser spectroscopy was used to measure the particle size of elemental powders and Cu-SiC composites. The density of green and sintered compacts was obtained using the geometric method (mass / volume). The density of the sintered compacts decreases with the increase of the SiC content from 2 to 15% and the milling time from zero to 30 h. The Vickers microhardness of the sintered compacts increases with an increase in the SiC content and the values are higher for the ground powder compacts.

BANKING MEMBERS:
Presidente - 2613355 - FRANCINE ALVES DA COSTA
Interno - 2414250 - MEYSAM MASHHADIKARIMI
Externo ao Programa - 345842 - UILAME UMBELINO GOMES
Externa à Instituição - ARIADNE DE SOUZA SILVA - UFRN