The susceptibility of welded and unwelded samples of Al 5454 (UNS A95454) in the -O and -H34 tempers to pitting corrosion and stress corrosion cracking (SCC) in chloride solutions was studied. Welded samples were fabricated using the relatively new friction stir welding (FSW) process as well as a standard gas-tungsten arc welding process for comparison. Pitting corrosion was assessed through potentiodynamic polarization experiments. U-bend and slow strain rate tests were used to determine SCC resistance. The FSW samples exhibited superior resistance to pitting corrosion compared to the base metal and arc-welded samples. U-bend tests indicated adequate SCC resistance for the FSW samples. However, the FSW samples exhibited discontinuities that probably were associated with remnant boundaries of the original plates. These defects resulted in intermittent increased susceptibility to pitting and, particularly for Al 5454-H34 samples, poor mechanical properties in general.

Subject
Pits, Anode potential, Microstructure, Sodium chloride, Fracture surfaces, Gas tungsten arc welding, U bends, Electric potential, Pitting, Aluminum alloys, Alloys, Stress corrosion cracking, Potentiodynamic polarization
Keywords:
Al 5454, friction stir weld, gas-tungsten arc weld, heat-affected zone, potentiodynamic polarization, slow strain rate testing, sodium chloride, stress corrosion cracking, U-bend testing
NACE International
1999
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