Banca de QUALIFICAÇÃO: MATHEUS DUARTE DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MATHEUS DUARTE DA SILVA
DATE: 05/01/2026
TIME: 15:00
LOCAL: PPGCEM
TITLE:

Study of the influence of Mn content on the microstructure and mechanical properties of the high-entropy CuCrFeNiMnx alloy produced by powder metallurgy

KEY WORDS:

High-entropy alloys; mechanical alloying; liquid-phase sintering; microhardness and CuCrFeNiMnx

PAGES: 68
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia Física
SPECIALTY: Propriedades Físicas dos Metais e Ligas
SUMMARY:

The high-entropy alloys (HEAs) of the CuCrFeNiMnx system were produced by high-energy ball milling followed by resistive furnace sintering under an H₂–Ar atmosphere, with the aim of investigating the influence of Mn content (x ={ 0; 0,05; 0,1; 0,15; 0,20}) on the microstructural evolution, densification, and mechanical properties. XRD analysis of the milled powders indicated the formation of FCC1, FCC2 and BCC solid-solution phases, while the sintered samples exhibited predominantly FCC1, FCC2 and σ-phase precipitation for all compositions. Increasing the Mn content promoted the stabilization of the FCC2 phase, intensified σ-phase precipitation, and reduced the fraction of the Cu-rich FCC1 phase, thereby decreasing the liquid volume during sintering. The microstructural study showed initial grain refinement (Mn0.05), followed by coalescence and growth at higher Mn levels, accompanied by increased solid contiguity and reduced densification for Mn0.20. The microhardness increased progressively from 201.6 HV (Mn0) to 277.8 HV (Mn0.20), attributed to the higher σ-phase fraction and solid-solution strengthening associated with Mn. The estimated tensile strength ranged from 542 MPa to 744 MPa, demonstrating that the Mn additions significantly enhance the mechanical performance of the alloy. Overall, the results show that Mn plays a decisive role in phase stability, sintering kinetics, and the mechanical behavior of CuCrFeNiMnx HEAs.

COMMITTEE MEMBERS:
Presidente - 1674707 - MARCO ANTONIO MORALES TORRES
Interno - 2414250 - MEYSAM MASHHADIKARIMI
Externo à Instituição - CLEBER DA SILVA LOURENÇO