Banca de QUALIFICAÇÃO: REGINA BERTÍLIA DANTAS DE MEDEIROS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : REGINA BERTÍLIA DANTAS DE MEDEIROS
DATE: 16/06/2021
TIME: 08:00
LOCAL: SALA VIRTUAL
TITLE:

Tantalum as a novel binder of polycrystalline diamond


KEY WORDS:

PCD, Tantalum, Binder, High Pressure-High Temperature sintering, Powder Technology, Cutting too


PAGES: 100
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia Física
SPECIALTY: Transformação de Fases
SUMMARY:
Polycrystalline diamond (PCD) is widely applied in the cutting and drilling industry due to its excellent mechanical properties. Currently, several researchers have been studying the use of different binders in its manufacturing, seeking to improve their properties and reduce the use of traditional metals that are harmful to human health and the environment. This work aimed to study the viability of tantalum as an alternative binding agent for PCD. The products developed here were processed using powder metallurgy and High Pressure-High Temperature (HPHT) sintering. The effect of different tantalum concentrations (2.5, 5.0, 7.5, and 10.0 wt. %) was investigated using X-ray diffraction (XRD), Confocal Microscopy, Density measurement, Particle Size Analysis, and Scanning electron microscopy (SEM). Mechanical properties and failure behavior were employed to evaluate the products. The PCD-Ta system was also tribologically tested against ferrous and ceramic materials, in order to simulate industrial machining conditions. The results suggest that increasing Ta quantity on PCD mixtures promoted reduction of milling contaminations and enhanced the mechanical properties of the as-sintered bodies by modifying the fracture mechanism predominance. No occurrence of chemical reactions between the two compounds was observed on the milling, but the formation of TaC resulting from a reaction between the free carbon and the metallic Ta was identified on all as-sintered compositions. The PCD-Ta ratio directly influences the tribological behavior of the present system with ceramic and ferrous materials, and severest wear was provoked by samples with the lowest binder content. Furthermore, abrasive and adhesive were the predominant wear mechanisms detected in all studied compositions. Finally, the overall microstructural, mechanical, and tribological outcomes demonstrated that all studied composites presented satisfactory performance, which may indicate that tantalum can be a viable alternative to act as a PCD BINDER


BANKING MEMBERS:
Presidente - 345842 - UILAME UMBELINO GOMES
Interno - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Externo ao Programa - 2414250 - MEYSAM MASHHADIKARIMI
Externa à Instituição - ALESSANDRA AGNA ARAÚJO DOS SANTOS - UENF
Externo à Instituição - MARCELLO FILGUEIRA - UENF
Notícia cadastrada em: 01/06/2021 14:20
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