Characterization of TC17 Titanium Alloy Treated by Square-Spot Laser Shock Peening

2013 ◽  
Vol 652-654 ◽  
pp. 2378-2383 ◽  
Author(s):  
Zi Wen Cao ◽  
Shui Li Gong ◽  
Yu Gao
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Stress Gradient ◽  
Laser Shock Peening ◽  
Fatigue Performance ◽  
Specimen Thickness ◽  
Laser Shock ◽  
Shock Peening ◽  
Square Spot

Laser shock peening (LSP) is widely known as a cold-worked surface treatment, and this technology has been to greatly improve the fatigue life of many metallic components. Our works focused on laser shock peening with Nd: glass laser system (pulse duration 30ns) and square laser spot size of 4mm×4mm for TC17 titanium alloy. Surface morphology, residual stresses and fatigue performance had been studied for TC17 alloy specimens and blades processed by LSP treatment. The results show that plastic strains in shocked dents become more homogeneous than ones produced by original circle spot with gaussian energy distribution. Surface residual stresses which measured using x-ray diffraction method showed different characteristic as varying specimen thickness, and LSP with overlapping ratio of 8% provided uniform residual stresses on peened surface. Low fluence peening which was implemented at borderline of peened surface was effective to diminish the stress gradient. Compared with mechanical shot peening, LSP attained smoother surface, lower microhardness and better fatigue performance. In a word, Square-spot LSP is an excellent way to improve fatigue life of titanium blade.

scholarly journals Effect of Laser Shock Peening on Fretting Fatigue Life of TC11 Titanium Alloy

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4711
Author(s):  
Xufeng Yang ◽  
Hongjian Zhang ◽  
Haitao Cui ◽  
Changlong Wen
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Power Density ◽  
Laser Power ◽  
Fretting Fatigue ◽  
Laser Power Density ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Shock Peening ◽  
Tc11 Titanium Alloy

The purpose of this paper is to investigate the performance of laser shock peening (LSP) subjected to fretting fatigue with TC11 titanium alloy specimens and pads. Three laser power densities (3.2 GW/cm2, 4.8 GW/cm2 and 6.4 GW/cm2) of LSP were chosen and tested using manufactured fretting fatigue apparatus. The experimental results show that the LSP surface treatment significantly improves the fretting fatigue lives of the fretting specimens, and the fretting fatigue life increases most when the laser power density is 4.8 GW/cm2. It is also found that with the increase of the laser power density, the fatigue crack initiation location tends to move from the surface to the interior of the specimen.

Experimental Study on Improving High-Cycle Fatigue Performance of TC11 Titanium alloy by Laser Shock Peening

2013 ◽  
Vol 40 (8) ◽  
pp. 0803006 ◽  
Author(s):  
聂祥樊 Nie Xiangfan ◽  
何卫锋 He Weifeng ◽  
臧顺来 Zang Shunlai ◽  
王学德 Wang Xuede ◽  
李玉琴 Li Yuqin
Keyword(s):  
Experimental Study ◽  
Titanium Alloy ◽  
High Cycle Fatigue ◽  
Laser Shock Peening ◽  
Fatigue Performance ◽  
Cycle Fatigue ◽  
Laser Shock ◽  
Shock Peening ◽  
Tc11 Titanium Alloy

scholarly journals Phase-field modelling for fatigue crack growth under laser shock peening-induced residual stresses

2021 ◽  
Author(s):  
Martha Seiler ◽  
Sören Keller ◽  
Nikolai Kashaev ◽  
Benjamin Klusemann ◽  
Markus Kästner
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Crack Growth ◽  
Phase Field ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Fatigue Model ◽  
Shock Peening

AbstractFor the fatigue life of thin-walled components, not only fatigue crack initiation, but also crack growth is decisive. The phase-field method for fracture is a powerful tool to simulate arbitrary crack phenomena. Recently, it has been applied to fatigue fracture. Those models pose an alternative to classical fracture-mechanical approaches for fatigue life estimation. In the first part of this paper, the parameters of a phase-field fatigue model are calibrated and its predictions are compared to results of fatigue crack growth experiments of aluminium sheet material. In the second part, compressive residual stresses are introduced into the components with the help of laser shock peening. It is shown that those residual stresses influence the crack growth rate by retarding and accelerating the crack. In order to study these fatigue mechanisms numerically, a simple strategy to incorporate residual stresses in the phase-field fatigue model is presented and tested with experiments. The study shows that the approach can reproduce the effects of the residual stresses on the crack growth rate.

scholarly journals Fatigue Life Extension of AA2024 Specimens and Integral Structures by Laser Shock Peening

2018 ◽  
Vol 165 ◽  
pp. 18001 ◽  
Author(s):  
Nikolai Kashaev ◽  
Sergey Chupakhin ◽  
Volker Ventzke ◽  
Manfred Horstmann ◽  
Stefan Riekehr ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Friction Stir Welding ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Laser Shock Peening ◽  
Specimen Thickness ◽  
Laser Shock ◽  
Friction Stir ◽  
Shock Peening

The goal of the present study is to understand the effects of laser shock peening (LSP)-induced residual stresses on the fatigue crack propagation (FCP) behaviour of the commonly used aircraft aluminium alloy AA2024 in T3 heat treatment condition. LSP treatment was performed using a pulsed Nd:YAG laser on compact tensile C(T)50-specimens with a thickness of 2.0 mm. LSP-treated specimens reveal a significant retardation of the fatigue crack propagation. The fatigue crack retardation effect can be correlated with the compressive residual stresses introduced by LSP throughout the entire specimen thickness. A possible application of the LSP process on a component like panel with three welded stringers representing a part of a fuselage structure was performed as well. The skin-stringer AA2024-AA7050 Tjoints were realised through stationary shoulder friction stir welding (SSFSW), a variant of the conventional friction stir welding process. In this relatively new process, the shoulder does not rotate and therefore does not contribute to the heat generation. Consequently, a reduced and more homogeneous heat input leads to a less affected microstructure and better mechanical properties. The efficiency of the LSP process has been demonstrated resulting in an increase of 200 – 400% in fatigue lifetime.

Dynamic Material Response of Aluminum Single Crystal Under Microscale Laser Shock Peening

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Sinisa Vukelic ◽  
Youneng Wang ◽  
Jeffrey W. Kysar ◽  
Y. Lawrence Yao
Keyword(s):  
Residual Stresses ◽  
Single Crystals ◽  
Electron Backscatter Diffraction ◽  
Target Material ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Laser Target ◽  
Aluminum Single Crystal ◽  
Anisotropic Mechanical Properties ◽  
Shock Peening

The process of laser shock peening induces compressive residual stresses in a material to improve material fatigue life. For micron sized laser beams, the size of the laser-target interaction zone is of the same order of magnitude as the target material grains, and thus the target material must be considered as being anisotropic and inhomogeneous. Single crystals are chosen to study the effects of the anisotropic mechanical properties. It is also of interest to investigate the response of symmetric and asymmetric slip systems with respect to the shocked surface. In the present study, numerical and experimental aspects of laser shock peening on two different crystal surfaces (110) and (11¯4) of aluminum single crystals are studied. Lattice rotations on the top surface and cross section are measured using electron backscatter diffraction, while residual stress is characterized using X-ray microdiffraction. A numerical model has been developed that takes into account anisotropy as well as inertial terms to predict the size and nature of the deformation and residual stresses. Obtained results were compared with the experimental finding for validation purpose.

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

2014 ◽  
Vol 891-892 ◽  
pp. 980-985 ◽  
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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