Relationship between Electrical Conductivity and the Stage of the Heat Treatments of Aging and Overaging of the Aluminum Alloy AA2024

Abstract:

The aluminum alloys of the 2xxx series have been widely used in structural applications because the interesting combination of their good mechanical properties and their low weight. This interesting combination of properties is only possible because of the heat treatments and the control of these properties deserves special attention because these alloys "age" over time as a function of the temperature to which they are submitted. The studies of the respective thermal treatments and the behavior of these properties in function of these treatments can lead to the development and the validation of a simple, fast and nondestructive test to control the useful life of the components. The objective of this work is to evaluate the possibility of the use of eddy currents to evaluate the mechanical properties of the AA2024 alloy in different conditions: annealed, solubilized, aged and over-aged, that is, through the electrical conductivity and hardness obtained in the respective heat treatments in other words, through the electrical conductivity and hardness obtained in the respective heat treatments, be able to obtain a relation between them, in such a way that, with the measured conductivity value, it is possible to predict the aging stage in which the alloy is found, without having to resort to a destructive test. Samples of the alloy, as received, were submitted to over-aging treatment, using temperatures between 250°C and 415°C for times of 8 min to 24h. In a second step, samples of this alloy were submitted to solubilization and artificial aging treatments, and measurements were made of hardness and electrical conductivity and the behavior of electrical conductivity and hardness was also studied. The results indicate good a correlation between hardness and conductivity and this investigation suggests a way to obtain the nondestructive test.

• Periodical: Materials Science Forum (Volume 930)
• Pages: 400-404
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.930.400
• Online since: September 2018
• Authors: Paulo Oliveira*, Mirian Lourdes Noronha Melo, Renato Sergio Mello Silva, Daniel Oliveira Caixeta
• Keywords: Aging, Alloy AA2024, Electrical Conductivity, Hardness, Overaging, Solubilization

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