Banca de DEFESA: DAVID DOMINGOS SOARES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: DAVID DOMINGOS SOARES DA SILVA
DATA: 14/04/2020
HORA: 09:00
LOCAL: AUDITÓRIO DO PPGEM
TÍTULO: Effects of Sigma Phase Precipitation in Duplex Stainless Steel with Nondestructive Testing Evaluation
PALAVRAS-CHAVES: Duplex stainless steel; Sigma phase embrittlement; Nondestructive testing.
PÁGINAS: 108
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Mecânica
RESUMO: Duplex stainless steels (DSS) have a structure composed of α-Fe and γ-Fe in approximately equal volume fractions. Which provides an excellent integration between mechanical properties and corrosion resistance. However, the precipitation of sigma phase (σ) may cause a severe deterioration of these properties, phenomenon known as sigma phase embrittlement. In the present work, the effect of the isothermal aging treatment at 800 °C (temperature in which σ phase can be formed) on metallurgical, corrosion, magnetic and mechanical properties on DSS UNS S31803 was investigated. In addition, two new nondestructive methods for monitoring of sigma phase embrittlement in DSS were proposed and evaluated. The first method is based on the lead zirconate titanate (PZT) using electromechanical impedance (EMI). The basic idea of this method is that the increase mechanical stiffness, due to sigma phase embrittlement, will leads to the variation in the EMI signatures. The second method, designated as low-fields magnetic analysis (LFMA) is based on the measurement of magnetic flux density. Once the precipitation of σ phase cause a change in the volume fraction of α-Fe/γ-Fe phases due to α-Fe (ferromagnetic phase) decomposition to precipitate σ (paramagnetic phase). The developed techniques present accurate results with high sensitivity and reliability.
MEMBROS DA BANCA:
Interno - 2454645 - MARCELO CAVALCANTI RODRIGUES
Externo ao Programa - 2890742 - RAMON ALVES TORQUATO
Presidente - 1367468 - RODINEI MEDEIROS GOMES
Interno - 3581068 - SANDRO MARDEN TORRES
Externo à Instituição - THIAGO ARAUJO SIMOES