Banca de DEFESA: MARIA MONIQUE DE BRITO LEITE

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA MONIQUE DE BRITO LEITE
DATE: 31/07/2023
TIME: 08:30
LOCAL: REMOTO
TITLE:

Induzed repair of electropulsing in AA5083 alloy in the oil industry.

 

KEY WORDS:

electropulsing. sefl-healing, AA5083 Alloy, oil industry

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia Física
SUMMARY:

The technique of emitting electrical pulses inside a material can be considered an effective alternative for promoting self-healing mechanisms. This technology can favor the prevention of nucleation, coalescence and propagation of microstructural defects in metallic materials used in several applications in the oil industry. This is because through microstructural regeneration promoted by the acceleration of atomic diffusion, movement of dislocations and, in some cases, nucleation and recrystallization mechanisms, the reduction and/or closure of defects in the microstructure are achieved. Thus, this research was based on carrying out analyzes of the influence of the application of electrical pulses on specimens (cp) of the AA5083-H112 alloy with a width of 3mm and a thickness of 5mm in cross section. These were submitted to tensile tests (speed of 1mm/min) to insert microstructural defects, which could later be repaired. In addition, this test was also used to verify the mechanical behavior. The cp in the state of origin showed a mean total deformation (εrupt) of 21.4%. New cp were pre-deformed to 80% of the εrupt and divided into: groups B (specimens 7 and 10) and C (specimens 8 and 19) were subjected to the emission of electrical pulses in cycles of 7s and 15s, respectively. In group A (specimens 18 and 21) EPE tests were not performed, so that a comparison between the material in the state of origin and the material with EPE could be made. The emission of the pulses was carried out in a closed circuit between the cp and a DigiPlus A7 600 model welding equipment in pulsed TIG mode. In the equipment software, the peak current was defined as 400A during a time of 0.1s and the base current as 0A during a time of 0.1s. The complete pulse emission time ranged from 7s to 15s. At the end, all cp were subjected to another tensile test until the material ruptured. With the use of SAP and SAT acquisition equipment, it was verified that there was current pulsation and that a thermal effect was obtained with the use of electrical pulses for 7s and 15s. The analysis of the results indicated that the electrical pulses performed with a current density of 26.67 A/mm² were effective in promoting the increase in ductility. Groups B and C showed an average of 9.13% and 10.98% of plastic deformation; while group C 7.62%. The microstructural characterization via scanning electron microscopy (SEM) in electron backscatter and secondary electron modes corroborated to prove the effectiveness of this technique to reduce the defects observed in the material.

COMMITTEE MEMBERS:
Presidente - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Interno - 2414250 - MEYSAM MASHHADIKARIMI
Externo ao Programa - 1652765 - MAURÍCIO MHIRDAUI PERES - UFRNExterno ao Programa - 1297264 - SERGIO RODRIGUES BARRA - UFRNExterno à Instituição - GUDSON NICOLAU DE MELO - UFPB