Residual Stress-induced Subsurface Fatigue Crack Nucleation In Shot Peened Titanium Alloys

Author:  Maawad, Yi, Brokmeier, Wollmann, Wagner
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008117
Year of Publication:  2008
Abstract:  
ABSTRACT High-cycle fatigue performance of shot peened titanium alloys is associated with subsurface fatigue crack nucleation. This phenomenon may be related to the presence of process-induced residual tensile stresses necessarily present below the mechanically treated surface and required to balance the outer compressive stress field. Although an analysis of these deeply located residual tensile stresses is quite difficult, there is evidence to what extent the HCF strength of the various titanium alloy classes can be affected by residual tensile stresses. Most important are tensile mean stress and environmental sensitivities of the materials HCF strengths. Anomalous mean stress sensitivities as observed in (