Mitigation of Active Corrosion Fatigue and Corrosion Pit Initiated in AA7075-T6 with Low Plasticity Burnishing

摘要

Corrosion related fatigue failures of aluminum structural alloys adversely impact the structural integrity of aging aircraft. A chemically active environment, susceptible material and alternating tensile stresses are all required for failure. Conventional mitigation strategies isolate the corrosive environment with coatings, change the alloy or heat treatment, or reduce the applied stress by redesign, all expensive solutions. This paper describes an alternate approach, employing surface enhancement by low plasticity burnishing (LPB) to introduce a deep, stable layer of compressive residual stress to eliminate the tensile stresses necessary for failure without altering environment, material or design.