Banca de DEFESA: MARIANA CHIANCA LÚCIO DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MARIANA CHIANCA LÚCIO DA SILVA
DATA : 16/02/2017
HORA: 13:30
LOCAL: Sala de reunião DEMAT
TÍTULO:

STUDY THE EFFECT OF ALUMINA IN THE WC-Al₂O₃ SYSTEM BY POWDER METALLURGY

PALAVRAS-CHAVES:

Tungsten Carbide, Aluminia, High Energy Milling, Sintering.

PÁGINAS: 80
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Cerâmicos
RESUMO:

Tungsten Carbide (WC) is best known for its excellent physical and mechanical properties. However, it has limitations, mainly when the tougher and lighter material is requested. An alternative to minimize these problems is a composite of WC and alumina (Al₂O₃) to reducing density and promoting toughness at certain temperatures. Thus, in this work, the effects of the different amount of alumina and powder metallurgy processing parameters on microstructure of particulate and sintered composite (WC-Al2O3) were studied and the mechanical properties, particularly the microhardness, of the product were analyzed to find an alternative cutting tool material. In the study, the particulate materials production route was applied. The composite powders have the following compositions: WC with 5, 10 and 15wt% of Al₂O₃ processed by high energy milling in a planetary milling for 1, 4 and 10 hours. Compacting of mixed powders was done using a uniaxial press in a cylindrical die of 5 mm diameter under a pressure of 400 MPa. Solid phase sintering was performed in a resistance furnace at 1450 and 1550 °C with 1 hour of holding time and heating rate of 10°C/min in argon atmosphere. The raw materials were characterized by particulometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The milled powders and sintered samples were subjected to the same tests and microhardness test was also done for sintered samples as well. The results showed that high energy milling met the targets for particle size and dispersion of composite components. However, due to partial sintering or consolidation of green compact, the microhardness did not achieve to significant results and microstructures with high porosity were observed.

MEMBROS DA BANCA:
Externo à Instituição - ARIADNE DE SOUZA SILVA - UFRN
Externo à Instituição - LEILIANE ALVES DE OLIVEIRA - UFRN
Presidente - 345842 - UILAME UMBELINO GOMES