Banca de QUALIFICAÇÃO: PAULO HENRIQUE CHIBÉRIO
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.STUDENT : PAULO HENRIQUE CHIBÉRIO
DATE: 25/06/2021
TIME: 09:00
LOCAL: meet.google.com/cvs-dxpn-akr
TITLE:
Fabrication and mechanical characterization of nano-sized alumina reinforced with NbC
KEY WORDS:
Niobium carbide, alumina, hot-presseed, mechanical properties, spark plasma sintering
PAGES: 13
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:
The incorporation of refractory hard particles in alumina-based composites may inhibit grain growth of the matrix, contributing significantly to improve the mechanical properties of the composite. Al2O3-NbC nanocomposites were uniaxially hot-pressed at 1500 C in an inert atmosphere and their mechanical properties and microstructures were analyzed. Sintered density, microhardness, crystalline phases and mechanical performance were evaluated. X-ray diffraction pattern revealed the presence of Alumina and NbC. No oxidation products were present after the sintering process. Nano-structured composite material showed mechanical properties comparable to other carbide systems. Alumina-NbC composite has showed a nano-structure with good potential to be used in cutting tool materials.
The addition of niobium carbide in hpot-pressed alumina-based composites has shown to improve the properties of the composite material. The main disadvantage to obtain a dense composite material is the necessary high sintering temperatures. Spark plasma sintering (SPS) process uses a high heating and cooling speed and lower sintering temperatures, making this sintering process a suitable method to produce a alumina-NbC composite material at lower temperatures. The sintering behavior of aluminaNbC composites fabricated by spark plasma sintering [SPS] was investigated at 1350, 1400 and 1450 ˚C. X-ray diffraction pattern of the sintered bodies revealed only the presence of alumina and NbC crystalline phases. No oxidation products or new crystalline phase were present after the sintering process. SPS process has produced dense alumina-NbC samples comparable to other alumina-hard particles systems. Microstructural observation revealed an inhibition of alumina grain growth in regions near the NbC particles. Fracture surfaces showed a mixture of intergranular and transgranular fracture mode. Keywords: Alumina. Niobium carbide. Spark plasma sintering
BANKING MEMBERS:
Interno - 1149564 - WILSON ACCHAR
Externo à Instituição - Antonio Carlos Silva da Costa - UFRN
Externo à Instituição - HUGO PLÍNIO DE ANDRADE ALVES