Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.20191634
Tecnologia em Metalurgia, Materiais e Mineração
ABM Week 2018

EFEITO DA SOLUBILIZAÇÃO E ENVELHECIMENTO NA MICROESTRUTURA E RESISTÊNCIA A CORROSÃO DA LIGA DE MAGNÉSIO AZ31

COMPARATIVE BEHAVIOR OF MAGNESIUM ALLOY AZ31 BY CYCLIC POLARIZATION TEST

Camila Queiroz Correia Fernandes, José Adilson de Castro, Elivelton Alves Ferreira, Darlene Souza da Silva Almeida, Leonardo Martins da Silva

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Resumo

Este trabalho apresenta um estudo comparativo da resistência a corrosão da liga de magnésio AZ31 tratada termicamente por solubilização e diferentes tempos de envelhecimento, submetida ao teste de polarização cíclica em solução de 3,5% de NaCl. Amostras da liga foram solubilizadas a 440 °C por 24 horas. Após a solubilização três amostras foram envelhecidas a 220 °C; por 2, 6 e 12 horas, respectivamente. Foram realizadas análises microestruturais com a finalidade de compreender as alterações microestruturais advindas dos tratamentos térmicos realizados. As amostras foram submetidas ao ensaio de polarização cíclica com a finalidade de correlacionar o efeito das mudanças alcançadas pelos tratamentos térmicos na resistência à corrosão da liga de magnésio AZ31. O comportamento das curvas de polarização cíclica foi semelhante para todas as amostras, sugerindo tendência a corrosão por pite. Não houve variação significativa nos valores de potencial de corrosão, sugerindo que os tratamentos térmicos aplicados não influenciaram a resistência a corrosão da liga.

Palavras-chave

Liga de magnésio; AZ31; Corrosão; Polarização cíclica.

Abstract

This work presents a comparative study between the corrosion resistance of the magnesium alloy AZ31 treated by solubilization and aging at different times, submitted to the cyclic polarization test in 3.5% NaCl solution. Four samples were solubilized at 440 °C for 24 hours. After solubilization, three samples were aged at 220 °C; one for 2 hours, another for 6 hours and a third for 12 hours. Microstructural analysis were carried out to identify microstructural changes obtained. The samples were submitted to the cyclic polarization test in order to correlate the effect of the changes achieved by heat treatments on the corrosion resistance of the magnesium alloy AZ31. The cyclic polarization presents curves with similar behavior for the samples, indicating propensity to pitting corrosion. There were no significant variation in the values of corrosion potential, suggesting that the heat treatments applied did not influenced the corrosion resistance of the alloy.

Keywords

Magnesium Alloy; AZ31; Corrosion resistance; Cyclic polarization.

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