Efeito do tratamento de envelhecimento na liga AA7075 para aplicações estruturais
Data
2023-06-28
Autores
Alves, Luis Gustavo Ferracioli 
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
As ligas de baixa massa específica têm sido prioritariamente utilizadas no setor automotivo devido a tendência de alta produção, demanda de clientes e o aumento de requisitos legais. Uma boa resistência mecânica e baixa massa específica fazem das ligas de alumínio fortes candidatas para aplicações mecânicas na indústria. Os principais elementos de liga da série 7XXX são o zinco e magnésio, que elevam as características de resistência mecânica do alumínio, porém a resistência à corrosão sob tensão permanece baixa e, por isso, é adicionado o cobre para melhorar o seu desempenho. Esta série está classificada dentre aquelas tratáveis termicamente e, assim, permite seu processamento através de tratamentos térmicos que aumentam sua resistência mecânica, dureza, resistência à fadiga e ductilidade, possibilitando sua utilização em peças sujeitas a grandes esforços. O objetivo principal deste trabalho foi analisar o efeito de diferentes tratamentos térmicos de envelhecimento nas propriedades mecânicas e microestruturais da liga AA7075. Neste estudo foram estudados os tratamentos de endurecimento por solubilização e têmpera (W) e envelhecimento artificial (T62) em corpos de prova de tração (CDPs) e amostras em chapas da liga AA7075 obtidos do processo aplicado à linha de produção das peças Sheet Metal da empresa Sonaca Brasil Ltda, instalada em São José dos Campos-SP, e comparadas com a condição da liga sem tratamento térmico (O). As etapas executadas para o desenvolvimento deste trabalho foram os tratamentos térmicos nos CDPs, análise das propriedades mecânicas por ensaio de dureza Rockwell superficial na escala 15T e por ensaio de tração, análise microestrutural, comparação dos resultados obtidos com a literatura e discussão dos fenômenos decorrentes do processamento que influenciaram os resultados obtidos. Como resultados, foram encontrados indícios da fase endurecedora MgZn2, típica nas ligas da série 7XXX. Houve um ganho de 170 % na resistência mecânica (σMAX) da liga na condição “W” em relação à condição inicial “O” e de 2,56 % quando comparada a condição T62 com a condição “W”. Quanto a dureza, teve-se um aumento de 130 % de “W” para “O” e de 30,4 % de T62 para “W”. Assim, foi possível concluir que o tratamento T62 foi o que alcançou melhores valores de resistência mecânica e dureza, propriedades essenciais em materiais para aplicação estrutural.
Low density alloys have been primarily used in the automotive sector due to the trend towards high production, customer demand and the increase in legal requirements. Good mechanical strength and low specific mass make aluminum alloys strong candidates for mechanical applications in industry. The main alloying elements of the 7XXX series are zinc and magnesium, which increase the mechanical resistance characteristics of aluminum, however, the stress corrosion resistance remains low and, therefore, copper is added to improve its performance. This series is classified among those heat treatable and, therefore, allows its processing through heat treatments that increase its mechanical resistance, hardness, resistance to fatigue and ductility, allowing its use in parts subject to great efforts. The main objective of this work will be to analyze the effect of different aging heat treatments on the AA7075 alloy. In this study, the treatments of hardening by solubilization and quenching (W) and artificial aging (T62) were studied in specimens (CDPs) of the AA7075 alloy obtained from the process applied to the production line of Sheet Metal parts of the company Sonaca Brasil Ltda, located in in São José dos Campos-SP, and compared with the condition of the alloy without heat treatment (O). The steps carried out for the development of this work were the heat treatments in the CDPs, analysis of the mechanical properties by superficial Rockwell hardness test on the 15T scale and by tensile test, microstructural analysis, comparison of the results obtained with the literature and discussion of the phenomena resulting from the processing that influenced the results obtained. As a result, evidence of the MgZn2 hardening phase, typical in 7XXX series alloys, was found. There was a gain of 170% in the mechanical resistance (σMAX) of the alloy in the “W” condition in relation to the initial condition “O” and of 2.56 % when comparing the T62 condition with the “W” condition. As for hardness, there was an increase of 130 % from “W” to “O” and 30.4 % from T62 to “W”. Thus, it was possible to conclude that the T62 treatment achieved the best mechanical strength and hardness values, essential properties in materials for structural application.
Low density alloys have been primarily used in the automotive sector due to the trend towards high production, customer demand and the increase in legal requirements. Good mechanical strength and low specific mass make aluminum alloys strong candidates for mechanical applications in industry. The main alloying elements of the 7XXX series are zinc and magnesium, which increase the mechanical resistance characteristics of aluminum, however, the stress corrosion resistance remains low and, therefore, copper is added to improve its performance. This series is classified among those heat treatable and, therefore, allows its processing through heat treatments that increase its mechanical resistance, hardness, resistance to fatigue and ductility, allowing its use in parts subject to great efforts. The main objective of this work will be to analyze the effect of different aging heat treatments on the AA7075 alloy. In this study, the treatments of hardening by solubilization and quenching (W) and artificial aging (T62) were studied in specimens (CDPs) of the AA7075 alloy obtained from the process applied to the production line of Sheet Metal parts of the company Sonaca Brasil Ltda, located in in São José dos Campos-SP, and compared with the condition of the alloy without heat treatment (O). The steps carried out for the development of this work were the heat treatments in the CDPs, analysis of the mechanical properties by superficial Rockwell hardness test on the 15T scale and by tensile test, microstructural analysis, comparison of the results obtained with the literature and discussion of the phenomena resulting from the processing that influenced the results obtained. As a result, evidence of the MgZn2 hardening phase, typical in 7XXX series alloys, was found. There was a gain of 170% in the mechanical resistance (σMAX) of the alloy in the “W” condition in relation to the initial condition “O” and of 2.56 % when comparing the T62 condition with the “W” condition. As for hardness, there was an increase of 130 % from “W” to “O” and 30.4 % from T62 to “W”. Thus, it was possible to conclude that the T62 treatment achieved the best mechanical strength and hardness values, essential properties in materials for structural application.
Descrição
Citação
Alves, L. G. F. Efeito do tratamento de envelhecimento na liga AA7075 para aplicações estruturais. Trabalho de conclusão de curso Engenharia de Materiais – Universidade Federal de São Paulo, Instituto de Ciência e Tecnologia, 2023.