Banca de DEFESA: ELISÂNGELA BARROS DANTAS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ELISÂNGELA BARROS DANTAS
DATE: 17/06/2022
TIME: 09:00
LOCAL: Remota
TITLE:

MICROSTRUCTURAL EVOLUTION OF SINTERIZED NICKEL AND NI-SiC AFTER UNIAXIAL COMPACTION OR THERMOPLATIC PROCESSING

KEY WORDS:

Nickel, Ni-SiC, uniaxial pressing, thermoplastic processing, microstructure

PAGES: 130
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Metalurgia de Pó
SUMMARY:

Mixtures of Ni and SiC powders can be sintered resulting in materials with superior properties, especially at high service temperatures, such as corrosion resistance, mechanical and wear resistance, allied to low production costs. This set of properties is important, for example, for the automotive and aerospace industries. This work aimed to study mixtures of sintered Ni and SiC powders shaped by uniaxial pressure or thermoplastic processing. The nickel powder and the mixture Ni + 3 wt.% SiC were drum granulated with 2.5 wt.% of paraffin, uniaxially pressed at 600 MPa and sintered in a conventional oven at 1200 °C for 1 h (heating rate of 10 ºC/min). The samples obtained by thermoplastic processing were produced from Ni and a mixture of Ni + 1 wt.% SiC with 50% polymeric binders, homogenized in a co-rotating conical mixer with double screw and molded in a capillary rheometer. After thermal extraction of the binders, they were sintered at a heating rate of 5 °C/min up to 1200 °C. The sintering time was for 4 h. XRD, FTIR, microstructural characterization by MO and SEM/EDS analyses were carried out, as well as measurements of green and sintered density and Vickers microhardness tests. The nickel samples, produced by thermoplastic processing, showed larger pores concentrated in certain areas, greater diametral shrinkage and lower Vickers microhardness, with a higher standard deviation than the compacted samples. However, there was no interference of the production techniques in the densities of the sintered nickel samples. The addition of 3 wt% of SiC influenced the densification and also increased the microhardness of the sintered samples after compaction. Microscopic and XRD analyzes suggested that uniaxial compaction under 600 MPa and thermoplastic processing produced Ni-Si-type materials with carbon precipitates.

BANKING MEMBERS:
Presidente - 1298936 - ANTONIO EDUARDO MARTINELLI
Interno - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Externo ao Programa - 083.983.414-40 - ARMANDO MONTE MENDES - UFRN
Externo à Instituição - ANTONIO AUGUSTO COUTO - UPM
Externo à Instituição - FRANK JORG CLEMENS - EMPA