Banca de QUALIFICAÇÃO: GERLÂNEA SILVA DE OLIVEIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : GERLÂNEA SILVA DE OLIVEIRA
DATE: 31/01/2023
TIME: 13:30
LOCAL: Remoto
TITLE:

Influence of Nickel (Ni) Addition on the Microstructure and Mechanical Properties of W-Cu Composite Sintered by SPS.

KEY WORDS:

tungsten-copper, nickel, high energy milling, SPS sintering.

PAGES: 79
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Metalurgia de Pó
SUMMARY:

Tungsten and its composites, such as the tungsten-copper (W-Cu) and tungsten-copper-nickel (W-Cu-Ni) system, have attracted increasing attention to studies, due to their excellent mechanical, physical and chemical properties, for applications in the field of electroelectronics, in addition, they do not present toxicity or environmental risks. In view of this, the present work studied the influence of the addition of Nickel on the microstructure and mechanical and physical properties of the W-Cu composite, obtained by high-energy milling and sintered by Spark plasma sintering (SPS). The effects of Ni percentage variation and sintering temperature on the properties of W-Cu composites were studied. To obtain the powders, tungsten (W) and copper (Cu) were mixed with 2%w and 5%w. of Nickel (Ni), were subsequently ground in a high-energy planetary mill for 10 hours. Sintering was performed by SPS at temperatures of 900 ºC and 1000 ºC. The starting powders (W, Cu and Ni) and those ground in the proportions mentioned above were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS); Particlemetry and FRX. After sintering, the samples were characterized by SEM, EDS, optical microscopy (OM), density and microhardness measurements. The results of scanning electron microscopy and EDS revealed that high energy milling for 10 hours was enough to obtain the composite with good homogeneity and free of impurities. XRD diffractograms showed the peaks of the characteristic phases of the composite. The sintered compacts had densities ranging from 10.71 g/cm³ to 12.35 g/cm³ and microhardness from 258 HV to 371 HV. The W-30%p.Cu sample sintered at 900 ºC showed a higher density value (12.35 g/cm³) and consequently lower porosity. The sample with the addition of nickel (W-28%Cu-2%Ni) sintered at 1000ºC showed the highest density and highest hardness value. Thus, nickel positively influences the mechanical properties of the composite under study, when added in small amounts.

COMMITTEE MEMBERS:
Presidente - 345842 - UILAME UMBELINO GOMES
Interno - 2414250 - MEYSAM MASHHADIKARIMI
Externa à Instituição - MARIA JOSÉ SANTOS LIMA
Externo à Instituição - RAFAEL ALEXANDRE RAIMUNDO