Banca de DEFESA: MARIA GERLÂNIA DE OLIVEIRA QUEIROZ

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA GERLÂNIA DE OLIVEIRA QUEIROZ
DATE: 25/07/2025
TIME: 14:00
LOCAL: Google meet
TITLE:

Synthesis and Characterization of the High-Entropy Alloy AlCuCrFeMnZn Produced by CCyPD.

 

KEY WORDS:

 

High entropy alloys, CCyPD, AlCuCrMnZn, Corrosion, Civil construction.

PAGES: 85
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

This study presents the synthesis and characterization of a high-entropy alloy (HEA) with equiatomic composition AlCuCrFeMnZn, produced via plasma deposition using the cathodic cage cylinder technique (CCyPD). This represents the first documented application of CCyPD for HEA fabrication, demonstrating its viability in producing multielemental coatings. The alloys were deposited onto CA-60 steel substrates under controlled temperatures ranging from 350 °C to 500 °C in an Ar and H2 atmosphere. The samples were characterized by X-ray diffraction (XRD) with Rietveld refinement, Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Vickers and Rockwell C hardness tests. The XRD patterns revealed the predominant formation of body- centered cubic (BCC) and face-centered cubic (FCC) phases, with the crystalline orientation evolving with increasing temperature. Raman spectroscopy confirmed the formation of metal oxides, whose intensity decreased at higher temperatures, indicating partial oxide reduction. SEM analysis revealed surfaces with dense granular morphology and particle coalescence, while EDS mapping showed relatively homogeneous elemental distribution, despite selective volatilization of Cu and Zn. The chemical composition indicated aluminum enrichment and a decrease in oxygen content, reflecting the interaction with the plasma and the chemical affinity of the elements. Mechanical tests showed a significant improvement in Vickers hardness compared to the substrate, associated with compact structure and low porosity. Rockwell C tests revealed progressive structural failures with increasing temperature, including cracks, cavities, and delamination, corroborating the degradation observed in the micrographs. The results demonstrate that the CCyPD technique is effective for producing HEAs with high hardness and mechanical resistance, representing a promising alternative for applications in civil engineering, aerospace, and advanced materials industries.

COMMITTEE MEMBERS:
Externo à Instituição - LUIZ HENRIQUE PORTELA DE ABREU - IFAM
Externo ao Programa - 3820855 - MAXWELL SANTANA LIBÓRIO - nullPresidente - ***.133.814-** - IGOR OLIVEIRA NASCIMENTO - UFRN
Interno - 2550377 - THERCIO HENRIQUE DE CARVALHO COSTA