Influence Of Shot Peening On The Fatigue Behaviour Of Titanium Alloys

Author:  Wagner, L. and Lutjering, G.
Source:  Conf Proc: ICSP-1, (p.453-460)
Doc ID:  1981036
Year of Publication:  1981
Abstract:  
The effect of shot peening on the change of the surface layer properties and their influence on the fatigue behavior of Ti alloys in vacuum and aggressive environments was investigated. The influence of each of the important parameters (residual stresses, dislocation density and surface roughness) was evaluated separately for Ti--6A1--4V and Ti--8.6A1. If the residual stresses remained stable during fatigue their influence on fatigue strength was characteristically different for push--pull compared to rotating beam testing. The results showed that residual stresses could increase or decrease the fatige life. The stability of the residual stresses depended on the material cyclic hardening or softening behavior. Depending on many contributing factors crack nucleation occurred at the surface or inside the material. If crack nucleation occurred at the specimen surface the high dislocation density delayed nucleation whereas an increasing surface roughness had the opposite effect. Descriptors: Titanium base alloys-- Mechanical properties; Fatigue life; Shot Peening; Surface properties; Residual stress