Estudo do comportamento da liga Al-Mg-Si 6005 A solubilizada e envelhecida

• Ano de defesa: 2016
• Autor(a) principal: Bonfitto, Guilherme Bruno Barroso
• Orientador(a): Couto, Antonio Augusto
• Banca de defesa: Vatavuk, Jan , Lima, Nelson Batista de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Presbiteriana Mackenzie
• Programa de Pós-Graduação: Engenharia de Materiais
• Departamento: Escola de Engenharia Mackenzie (EE)
• País: Brasil
• Palavras-chave em Português: materiais metálicos; micrografia; metalografia; análise de falhas; tratamento térmico; solubilização; envelhecimento artificial
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA MECANICA::PROJETOS DE MAQUINAS
• Link de acesso: http://dspace.mackenzie.br/handle/10899/24229

The possibility of increase use of aluminum in place of ferrous materials and wood in automotive industry, mainly in manufacturing of bus and truck structure, corrosion resistance, high ratio resistance and weight due low density and cost are the main reasons for this study. The alloy 6005A without any heat treatment appears disadvantageous compared to other alloys of aluminum and ferrous materials, however, with appropriate heat treatment, the mechanical properties are improved considerably, which is the case of this study. After comparisons in 36 different conditions of temperature of solubilization and temperature and time of artificial aging, the temperatures of 545ºC (30 minutes followed by water cooling) and 185°C (4 hours) solubilizing and artificial aging, respectively, showed the best growth of hardness alloy 63HRF to 85HRF. The metallography alloy after quenching was performed by optical microscopy showed in the microstructure equiaxed grains with homogeneous distribution. When compared the microstructures with different oven time and temperature, it was not showed the difference that relates the difference in hardness. It was realized the tensile test and the tensile strength limit values (σt) 279,21MPa and yield strength (σe) 257,33 MPa are among the average values for the alloy 6005A T6. The study of fatigue alloy was realized in a rotating bending testing machine (R=-1) at ambient temperature and the data was analyzed in a S-N curve. When applied stress less than 117,42 MPa, the specimen supported more than 1,0x107 cycles before breaking down. The fracture surfaces of the specimens with many tensile were analyzed by optical microscopy and by SEM and indicated the presence of ratchet marks, stretch marks, and integranular and transgranular cracks.