Analysis of damage in 5083 aluminum alloy deformed at different strain rates

This paper presents a study on damage evolution in 5083 marine-grade Aluminum alloy while deformed under different strain rates. The concept of continuum damage mechanics (CDM) was utilized to evaluate the evolution of damage throughout the deformation process of 5083 Aluminum alloy. Tensile tests with several unloading and reloading stages were conducted at room temperature to generate true stress-true strain curves at three different strain rates of 0.001 s(-1), 0.01 s(-1), and 0.1 s(-1). A scanning electron microscope (SEM) was utilized to characterize the damage at several strain levels for each strain rate. SEM results showed that void area fraction increases with strain rate and with accumulation of plastic strain. Reduction in stiffness with accumulation of plastic strain was also evaluated. Isotropic damage values were predicted using the hypotheses of strain equivalence and strain energy equivalence, as well as a recently developed energy-based model. The predicted damage values were verified via comparisons with the present SEM results. The energy-based model showed good comparisons, while the other two hypotheses overestimated the damage, especially at higher strain rates. (C) 2013 Elsevier B.V. All rights reserved.