On the influence of laser peening with different coverage areas on fatigue response and fracture behavior of Ti–6Al–4V alloy

• Published in: Engineering fracture mechanics 2015-10, Vol.147, p.72-82
• Main Authors: Huang, S., Sheng, J., Zhou, J.Z., Lu, J.Z., Meng, X.K., Xu, S.Q., Zhang, H.F.
• Format: Article
• Language: English
• Subjects: Compressive properties; Coverage area; Crack propagation; Fatigue crack growth; Fatigue failure; Fatigue life; Fracture mechanics; Fracture morphology; Laser peening; Lasers; Peening; Residual stress; Titanium base alloys
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2015.08.026

The laser peening coverage areas over the central-hole of Ti–6Al–4V alloy specimens can significantly affect the final rupture morphologies, including the FCI location, crack front, and even the fatigue striation spacing (FSS). [Display omitted] •Residual stress trends induced by LP with different coverage areas were revealed.•Fatigue fracture microstructures induced by LP with different coverage areas was studied.•Evolution of FCI and FCG as well as dislocations was systematically demonstrated.•Strengthening mechanism of residual stress and surface nanocrystallization was investigated. Laser peening (LP) with different coverage areas was carried out on Ti–6Al–4V titanium alloy specimens. Residual stresses, fatigue lives and fracture morphologies of specimens subjected to LP were analyzed. The LP-induced compressive residual stresses under different coverage areas were revealed in the superficial layer. The results show that LP coverage area has significant effect on fatigue response and fracture behavior. The decreased fatigue striation spacing and increased dislocations observed in the treated specimens further confirmed the effect of LP on decelerating fatigue crack growth (FCG). In addition, the strengthening mechanism of LP-induced compressive residual stress and surface nanocrystallization was theoretically investigated.