The Impact of Aging Time on Structure and Corrosion Resistance of Aluminum 2091 Lithium Alloy for Aerospace Application

Abstract

In need of aerospace and automotive industries, the aluminum lithium alloy becomes a worldwide topic because of its corrosion resistance, hardness, and categorized as a lightweight material. This alloy has high resistance to corrosion due to doped alloying element, such as copper. Addition of lithium to aluminum alloys lowers its density. This paper was meant to study the impact of aging time at 190°C for 24 hours, 42 hours, and 72 hours on aluminum alloy crystal. The materials had solutionized at 525°C for 5 hours and had quenched at water before it was artificially aged. Besides corrosion resistance, the structure of this alloy are change as the aging times rise that caused by Al2Cu precipitation. To examine the electrochemical response of this material, potentiodynamic curves were obtained for aluminium lithium alloy 2091 during standard test in natural deaerated 3.5% wt and 7.0% wt NaCl solution after heat treatment. The structure after heat treatment were characterized by using X-ray diffraction. The results showed that aging time modified the structure and lead to change the electrochemical behaviour.