The Influence Of Surface Enhancement By Low Plasticity Burnishing On The Corrosion Fatigue Performance Of 7475-T7351 And 2024

Author:  D. Hornbach, P. Prev
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008098
Year of Publication:  2008
Abstract:  
ABSTRACT Corrosion fatigue and stress corrosion cracking (SCC) are primary failure mechanisms that reduce the structural integrity of aircraft. Conventional corrosion mitigation in aircraft involves coatings, alloy substitution, or modifications in design to reduce stresses. All are expensive solutions. This paper describes the use of low plasticity burnishing (LPB) to enhance the corrosion fatigue strength in 7475-T7351 and 2024-T351, without alteration of environment, material or component design. The fatigue performance of LPB processing and shot peening of both 7475-T7351 and 2024-T351 were compared. Various processing and exposure conditions, typical of aircraft structures, were investigated including shot peening, anodization, thermal exposure and salt spray exposure. X-ray diffraction residual stress measurements revealed that LPB produced twice the depth of compression as shot peening. LPB produced a 10X improvement in life over shot peening for 7475-T7351 and a 50% improvement in life over shot peening in 2024-T351. KEYWORDS Low Plasticity Burnishing, shot peening, corrosion fatigue, residual stress, surface enhancement