Micro-mechanisms of corrosion fatigue using atomic force microscopy at active microstructural sites on 2024-T3 aluminum. Final report, May 1995-May 1996

Technical Report · Tue Oct 22 04:00:00 EDT 1996

OSTI ID:468412

Laird, C; DeLuccia, J J

This is a final report summarizing a one-year effort to define the micro-mechanisms of corrosion fatigue of 2024-T3 sheet aluminum alloy in low pH environments using in-situ and ex-situ instrumentation, e. g., atomic force microscopy (AFM), scanning electron microscopy, and Auger spectroscopy. Constant stress, flexure fatigue specimens cycled in a unique mechanically driven, environmentally controlled, deformation stage, are electrochemically polished to exhibit uniform quality metallographic surfaces. Pertinent surface microstructural features of crack nucleation were determined by AFM on specimens fatigued in air, .01 M and 0.1 M HCl. Imposed cathodic polarization potentials during corrosion fatigue indicate a hydrogen embrittlement contribution to the fatigue process at potentials not affording sufficient cathodic protection. Enhanced embrittlement (approx. 40% decreased in cycles to failure) was observed when 1.5 mg/ml of NaAsO2 was added to 0.1M HCl solution at open circuit voltages (freely corroding). Other results from the subject program previously reported in the open literature are referenced here, but not reported again.

• Research Organization: Pennsylvania Univ., Philadelphia, PA (United States)
• OSTI ID: 468412
• Report Number(s): AD-A--320602/6/XAB; CNN: Contract F49620-95-1-0334
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CORROSION FATIGUE
PROGRESS REPORT