Corrosion-Fatigue Testing of High-Strength Aluminum

Alloys

Melanie Chatham

Advisor: Dr. David Lanning

Problem Overview• Corrosion typically combines with other

modes of failure

• Stress-corrosion cracking (SCC) compromises fatigue life– Many high-strength aluminum alloys are

susceptible to SCC in saline environments

• SCC is not well understood

Objectives• Understand how SCC affects fatigue life

of high-strength aluminums

• Process:– Build environmental chamber for saline

environment– Test under varied fatigue conditions– Analyze S-N data– Observe fracture surfaces

Corrosion Chamber

• Simulates a wet environment

• In-situ testing• Leak-free during

testing• Reusable

Testing

• Saline solution circulated around specimen

• Environment refreshed from reservoir

• Salt concentration similar to sea water

Current Progress• Leak-free chamber

• Three preliminary fatigue tests completed– Evaluating low-fatigue life failures– Possible misalignment issue with chamber

• Observing fracture surfaces of failed specimens

Future Progress• Possible chamber improvements

• Perform fatigue tests under varied conditions– Baseline laboratory air– Saline solution environment– Loading, stress ratio, frequency

• Inspect fracture surfaces for SCC damage

Questions?