Electrochemical Testing of Aluminum-Lithium Alloys 2050, 2195, and the Current Aerospace Industry Standard 7075 to Measure the Galvanic Corrosion Behavior with Ti-6Al-4V

Author(s) Information

Trent Duncan, California Polytechnic State University - San Luis ObispoFollow
Kevin Knight, California Polytechnic State University - San Luis ObispoFollow

Department - Author 1

Materials Engineering Department

Degree Name - Author 1

BS in Materials Engineering

Date

6-2015

Primary Advisor

Blair London

Abstract/Summary

This project aimed to characterize the electrochemical behavior of four different aluminum alloys, and determine how much galvanic corrosion would occur when each alloy was coupled to Ti-6Al-4V. The particular alloys tested were 2050-T3, 2050-T852, 2195-T852, and 7075-T7352. These alloys were tested to determine the effects of aging, and adding lithium, to the corrosion behavior of aluminum alloys. Potentiodynamic polarization curves were generated using the Parstat 2273 potentiostat in accordance with ASTM standard G5, and corrosion analysis software was used to produce Tafel fit lines, which determined the open circuit potential (E_corr) of each sample. Nine tests were run on each alloy and proper statistical analysis was used to determine an E_corr value. These potential values were used to develop a galvanic series in accordance with ASTM standard G82 to characterize the corrosion behavior of the aluminum alloys when coupled to Ti-6Al-4V. The differences between average E_corr values of each aluminum alloy and Ti-6Al-4V were calculated to predict the extent of galvanic corrosion that would occur. The differences in E_corr values were found to be 281.21 mV for 2050-T3, 319.02 mV for 2050-T852, 300.72 mV for 2195-T852, and 439.45 mV for 7075-T7352.

URL: https://digitalcommons.calpoly.edu/matesp/125