Banca de QUALIFICAÇÃO: LARISSA DE CARVALHO CIPRIANI

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LARISSA DE CARVALHO CIPRIANI
DATE: 18/06/2025
TIME: 09:00
LOCAL: https://meet.google.com/fww-qcor-onn
TITLE:

High-Temperature Isothermal Oxidation in Refractory High-Entropy Alloys in the Al-Cr-Mo-Ta-Ti System

KEY WORDS:

Refractory high-entropy alloys; High-temperature oxidation; Isothermal tests; Oxides.

PAGES: 11
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia Física
SPECIALTY: Corrosão
SUMMARY:

The present study aimed to analyze the oxidation behavior of refractory high-entropy alloys (RHEAs) in the Al-Cr-Ta-Ti-Mo system, with the goal of developing materials with greater resistance to high-temperature environments. Two compositions were investigated: an equiatomic alloy AlCrMoTaTi and an alloy 13Al19Cr20Mo31Ta17Ti, referred to as alloy A and alloy B, respectively, through isothermal tests at 1000 °C for 20, 100, and 300 hours. During the tests, the mass change of the samples was evaluated, and the oxide layers formed were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-Ray Diffraction (XRD). It was observed that elements with higher melting points, such as Ta and Mo, were concentrated in the dendritic regions, while Al and Ti, with lower melting points, accumulated in the interdendritic regions. Regarding oxidation results, alloy A gained less mass and formed a more uniform, thinner, and adherent oxide layer, while alloy B exhibited a thicker and apparently more irregular layer, which explains the greater mass gain observed in this composition. The analyses also indicated the probable predominant formation of TiO₂ and CrTaO₄ oxides, and possibly Al₂O₃ and Cr₂O₃. Overall, it was clear that the chemical composition and internal structure of the alloys are crucial factors in determining oxidation resistance. Alloy A, with its more stable oxide layer, proved to be more promising for applications in high-temperature environments. It is suggested to explore new alloy compositions, test even more severe conditions (such as temperatures above 1000 °C and longer exposure times), and evaluate the performance of these alloys in different atmospheres, more similar to those found in industrial settings.

BANKING MEMBERS:
Presidente - 1049564 - ARTUR MARIANO DE SOUSA MALAFAIA
Interna - 2029927 - ROSELI MARINS BALESTRA
Externo à Instituição - JOÃO GABRIEL DA CRUZ PASSOS