Influence Of Ball-burnishing On Stress Corrosion Cracking, Fatigue And Corrosion Fatigue Of Ai 2024 And Ai 6082

Author:  M. Mhaede, M. Wollmann and L. Wagner
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008118
Year of Publication:  2008
Abstract:  
ABSTRACT Ball-burnishing (BB) was done on the age-hardenable alloys Al 2024 and Al 6082. The main process parameter rolling force was varied to a wide extent. The processinduced changes in near-surface properties were determined by microhardnessdepth profiles and residual stress-depth profiles measured by the incremental hole drilling method. The influences of these surface layer properties on stress corrosion cracking (SCC) and corrosion fatigue (CF) in aqueous 3.5% NaCl solutions were studied. Results were compared with electrolytically polished references. Stress corrosion cracking (SCC) tests were performed on standard tensile specimens under stress control using stress levels ranging from 60 to 100% of the yield stress. The time to failure was recorded. Corrosion fatigue (CF) tests were performed on hour-glass shaped specimens in rotating beam loading (R = -1) at frequencies of 50 s-1. Results of these corrosion fatigue (CF) tests were compared with results obtained in fatigue tests in air. It was found that the time to failure (TTF) in the SCC tests as well as the fatigue life in the CF tests were markedly improved by ball-burnishing. KEY WORDS Ball-burnishing, stress corrosion, fatigue, corrosion fatigue