Fatigue performance of laser shock peened Ti6Al4V and Al6061-T6 alloys
- Niroj Maharjan,
- Shi Ying Chan,
- Thivyaa Ramesh,
- Puay Nai,
- Dennise Ardi
Thivyaa Ramesh
Agency for Science Technology and Research
Author ProfileAbstract
Propagation of fatigue crack in laser shock peened metallic component is
retarded by introduction of deep compressive residual stresses during
the process. Apart from large compressive residual stress build-up near
the surface, surface topography is also significantly altered during
laser shock peening. However, a systematic evaluation of the individual
effects of residual stresses and surface topography as well as their
interaction effects on fatigue crack initiation and growth is still
lacking. This study investigates the effect of laser shock peening on
near surface properties of Ti6Al4V and Al6061-T6 alloys and how these
changes dictate their overall fatigue performance. The results show that
both surface residual stresses and surface topography influence the
fatigue life of a component. It is found that fatigue life of Ti6Al4V
alloy increased by at least 1.28 times after laser shock peening. In
contrast, the improvement is minimal for Al6061-T6 alloy due to the
surface roughening effect introduced by laser peening which results in
early crack initiation and negates the beneficial effect of compressive
residual stresses.