Investigation of laser shock peening effects on residual stress state and fatigue performance of titanium alloys

Laser shock peening is a very effective mechanical surface treatment to enhance the fatigue behaviour of highly stressed components. In this work the effect of different laser shock peening conditions on the residual stress depth profile and fatigue behaviour without any sacrificial coating layer is investigated for two high strength titanium alloys, Ti-6Al-4V and Timetal LCB. The results show that the optimization of peening conditions is crucial to obtain excellent fatigue properties. Especially, power density, spot size and coverage severely influence the residual stress profile of laser shock peened Ti-6Al-4V and Timetal LCB specimens. For both alloys, subsurface as well as surface compressive residual stress peaks can be obtained by varying the peening conditions. In general, Timetal LCB exhibits steeper stress gradients than Ti-6Al-4V for identical peening conditions. The main parameters affecting the fatigue life are near-surface cold work and compressive residual stresses.

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Regularity of Residual Stress Distribution in Titanium Alloys Induced by Laser Shock Peening with Different Energy Spatial Distributions

Laser & Optoelectronics Progress ◽

10.3788/lop55.061402 ◽

2018 ◽

Vol 55 (6) ◽

pp. 061402

Author(s):

李翔 Li Xiang ◽

何卫锋 He Weifeng ◽

聂祥樊 Nie Xiangfan ◽

杨竹芳 Yang Zhufang ◽

罗思海 Luo Sihai ◽

...

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Titanium Alloys ◽

Residual Stress Distribution ◽

Laser Shock Peening ◽

Spatial Distributions ◽

Laser Shock ◽

Shock Peening

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Residual Stress and Deformation Induced by Laser Shock Peening on Titanium Alloys

Experimental Analysis of Nano and Engineering Materials and Structures ◽

10.1007/978-1-4020-6239-1_33 ◽

2007 ◽

pp. 69-70

Author(s):

Christophe Cellard ◽

Pierre Osmond ◽

Delphine Retraint ◽

Emmanuelle Rouhaud ◽

Sébastien Remy ◽

...

Keyword(s):

Residual Stress ◽

Titanium Alloys ◽

Laser Shock Peening ◽

Laser Shock ◽

Shock Peening ◽

Stress And Deformation ◽

Residual Stress And Deformation

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Fatigue Life Recovery via Laser Shock Peening in Mechanically Damaged Aluminium Sheet; Experiments and Prediction Models

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.980 ◽

2014 ◽

Vol 891-892 ◽

pp. 980-985 ◽

Cited By ~ 2

Author(s):

Niall Smyth ◽

Philip E. Irving

Keyword(s):

Residual Stress ◽

Fatigue Life ◽

Prediction Models ◽

Load Cycle ◽

Laser Shock Peening ◽

Stress Fields ◽

Hole Drilling ◽

Laser Shock ◽

Aluminium Sheet ◽

Shock Peening

This paper reports the effectiveness of residual stress fields induced by laser shock peening (LSP) to recover pristine fatigue life. Scratches 50 and 150 μm deep with 5 μm root radii were introduced into samples of 2024-T351 aluminium sheet 2 mm thick using a diamond tipped tool. LSP was applied along the scratch in a band 5 mm wide. Residual stress fields induced were measured using incremental hole drilling. Compressive residual stress at the surface was-78 MPa increasing to-204 MPa at a depth of 220 μm. Fatigue tests were performed on peened, unpeened, pristine and scribed samples. Scratches reduced fatigue lives by factors up to 22 and LSP restored 74% of pristine life. Unpeened samples fractured at the scratches however peened samples did not fracture at the scratches but instead on the untreated rear face of the samples. Crack initiation still occurred at the root of the scribes on or close to the first load cycle in both peened and unpeened samples. In peened samples the crack at the root of the scribe did not progress to failure, suggesting that residual stress did not affect initiation behaviour but instead FCGR. A residual stress model is presented to predict crack behaviour in peened samples.

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