<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>Mechanical surface treatments such as shot peening or ball-burnishing induce high dislocation densities and residual compressive stresses in near-surface regions. In addition, the surface roughness is changed. Micro-hardness and residual stress-depth profiles are evaluated in Ti-6Al-4V as a function of the Almen intensity being the main process parameter in shot peening. In the finite life regime, residual compressive stresses are shown to drastically increase the fatigue life by retarding crack growth from the surface into the interior. However, in the HCF regime a shift in crack nucleation site occurs from the surface to subsurface regions where residual tensile stresses balance the outer compressive stress field. Therefore, the tensile mean stress sensitivity of the fatigue strength which can largely vary in Ti-6Al-4V needs to be taken into account in order to understand the observed differences in HCF responds to shot peening.</p></abstract>

Mechanical surface treatments such as shot peening or ball-burnishing induce high dislocation densities and residual compressive stresses in near-surface regions. In addition, the surface roughness is changed. Micro-hardness and residual stress-depth profiles are evaluated in Ti-6Al-4V as a function of the Almen intensity being the main process parameter in shot peening. In the finite life regime, residual compressive stresses are shown to drastically increase the fatigue life by retarding crack growth from the surface into the interior. However, in the HCF regime a shift in crack nucleation site occurs from the surface to subsurface regions where residual tensile stresses balance the outer compressive stress field. Therefore, the tensile mean stress sensitivity of the fatigue strength which can largely vary in Ti-6Al-4V needs to be taken into account in order to understand the observed differences in HCF responds to shot peening.

Mechanical Surface Treatments for Improving Fatigue Behavior in Titanium Alloys

Institute of Materials Science and Engineering, Clausthal University of Technology, Agricolastr.6, 39768 Clausthal-Zellerfeld, Germany

Advances in Materials Science

{"article-title":"Mechanical Surface Treatments for Improving Fatigue Behavior in Titanium Alloys"}

Mechanical surface treatments such as shot peening or ball-burnishing induce high dislocation densities and residual compressive stresses in near-surface...

Mechanical Surface Treatments for Improving Fatigue Behavior in Titanium Alloys

Published Online: Oct 17, 2008

Page range: 44 - 52

DOI: https://doi.org/10.2478/v10077-008-0030-5

Keywords
shot peening, residual stresses, crack nucleation, micro-crack propagation

This content is open access.

Mechanical Surface Treatments for Improving Fatigue Behavior in Titanium Alloys

Published Online: Oct 17, 2008

Page range: 44 - 52

DOI: https://doi.org/10.2478/v10077-008-0030-5

Keywordsshot peening, residual stresses, crack nucleation, micro-crack propagation

This content is open access.

Keywords
shot peening, residual stresses, crack nucleation, micro-crack propagation