Corrosion Fatigue Crack Propagation Behavior of Friction Stirred Dissimilar Metal Welds in 3.5% NaCl Solution by Chromate and Molybdate Inhibition

摘要

The purpose of this investigation is to study the effects of molybdate and chromate inhibitors on the fatigue crack propagation behavior of friction stirred dissimilar metal welds between AA5083 and AA6061 in 3.5% NaCl solution. The chromate and molybdate inhibitors were added to 3.5% NaCl solution at various concentrations of 0.1, 0.3 and 0.5%. A corrosion test was conducted using electrochemical polarization technique to study the effectiveness of the inhibitors. Fatigue crack propagation test was conducted using a sinusoidal load with constant load amplitude and stress Ratio (R) of 0.1. To allow corrosion and fatigue to occur a low load frequency typically of 11 Hz was used. Results of this obsevation showed that the addition of chromate and molybdate inhibitors improved both resistance to corrosion and fatigue crack propagation performance, especially in the initial stages of propagation.