scholarly journals Improvement of Fatigue Life of GH3039 Superalloy by Laser Shock Peening

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3849
Author(s):  
Yang Tang ◽  
MaoZhong Ge ◽  
Yongkang Zhang ◽  
Taiming Wang ◽  
Wen Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Surface Profile ◽  
Optical Microscope ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Transmission Electron ◽  
Before And After ◽  
Shock Peening ◽  
Improve Fatigue

In order to improve fatigue life of GH3039 superalloy, GH3039 superalloy sheets were treated by laser shock peening (LSP). The microstructure of GH3039 superalloy before and after LSP was characterized using an optical microscope, transmission electron microscope (TEM), and X-ray diffractometer. The fatigue life of the samples with and without LSP was investigated by fatigue experiments. Moreover, surface profile and residual stress were also examined. Experimental results indicated that the grains in the surface layer of the LSP sample were remarkably refined and reached the nanometer scale. The average surface roughness increased from 0.024 μm to 0.19 μm after LSP. The average fatigue life of the laser treated samples was 2.01 times larger than that of the untreated specimens. Additionally, mathematical statistical analysis confirms that LSP has a significant influence on the fatigue life of GH3039 superalloy. The improvement of fatigue life for the laser processed GH3039 superalloy was mainly attributed to compressive residual stress and grain refinement generated by LSP.

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.

scholarly journals Effect of laser shock peening on residual stress and fatigue life of clad 2024 aluminium sheet containing scribe defects

2012 ◽  
Vol 548 ◽  
pp. 142-151 ◽  
Author(s):  
M. Dorman ◽  
M.B. Toparli ◽  
N. Smyth ◽  
A. Cini ◽  
M.E. Fitzpatrick ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Aluminium Sheet ◽  
Shock Peening

scholarly journals Influence of Laser Shock Peening on Residual stress and Fatigue life of stainless steels

2019 ◽  
Author(s):  
Zbyněk ŠPIRIT ◽  
Jan KAUFMAN ◽  
Josef STREJCIUS ◽  
Michal CHOCHOLOUŠEK ◽  
Josef KOTT
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Shock Peening

Plastic Deformation in Silicon Crystal Induced by Heat-Assisted Laser Shock Peening

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Gary J. Cheng ◽  
M. Cai ◽  
Daniel Pirzada ◽  
Maxime J.-F. Guinel ◽  
M. Grant Norton
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Compressive Residual Stress ◽  
Silicon Crystal ◽  
Brittle Materials ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Electron Backscattered Diffraction ◽  
Transmission Electron ◽  
Shock Peening

The response of solid to shock compression has been an interesting topic for more than a century. The present work is the first attempt to experimentally show that plastic deformation can be generated in brittle materials by a heat-assisted laser shock peening process, using silicon crystal as a sample material. Strong dislocation activity and large compressive residual stress are induced by this process. The dislocation structure is characterized with transmission electron microscopy and electron backscattered diffraction. The residual stress is measured using Raman scattering. This work presents a fundamental base for the application of laser shock peening in brittle materials to generate large compressive residual stress and plastic deformation for better mechanical properties, such as fatigue life and fracture toughness.

scholarly journals Effect of Residual Stress on S–N Curves and Fracture Morphology of Ti6Al4V Titanium Alloy after Laser Shock Peening without Protective Coating

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3799 ◽  
Author(s):  
Xinlei Pan ◽  
Xiang Li ◽  
Liucheng Zhou ◽  
Xiaotai Feng ◽  
Sihai Luo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Compressive Residual Stress ◽  
Fracture Morphology ◽  
High Amplitude ◽  
Laser Shock ◽  
Ti6al4v Titanium Alloy ◽  
Before And After ◽  
Shock Peening

In this paper, the effect of residual stress on the stress–life (S–N) curve and fracture morphology characteristics of Ti6Al4V titanium alloy after laser shock peening (LSP) without protective coating was experimentally investigated. The fatigue test and residual stress measurement were conducted on specimens before and after the LSP process. It was shown that LSP produced a high-amplitude compressive residual stress field on the surface of the specimen. After the LSP process, the fatigue life limit was increased by 16%, and the S–N curve shifted upward. Then, based on the theory of mean stress, the mechanism whereby the compressive residual stress improves the fatigue life of Ti6Al4V titanium alloy was analyzed. It indicated the improvement in fatigue life was because of the high-amplitude compressive residual stress on the surface and in depth induced by LSP to reduce the tensile stress produced by external loading. In addition, the scanning electron microscope (SEM) pattern of fatigue fracture demonstrated distinct differences in the fracture morphology before and after LSP. After LSP, the crack initiation sites of the samples moved to the subsurface where it was difficult for fatigue cracks initiating here. Moreover, after the LSP process, there were high density of fatigue striations and many secondary cracks on the fracture of the treated specimen.

Comparison of warm laser shock peening and laser shock peening techniques in lengthening the fatigue life of welded joints made of aluminum alloy

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744045 ◽  
Author(s):  
Chun Su ◽  
Jianzhong Zhou ◽  
Xiankai Meng ◽  
Jie Sheng
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Welded Joints ◽  
Laser Shock Peening ◽  
Fracture Mechanisms ◽  
Al Alloy ◽  
Laser Shock ◽  
Estimation Model ◽  
Surface Residual Stress ◽  
Shock Peening

Welded joints made of 6061-T6 Al alloy were studied to evaluate warm laser shock peening (WLSP) and laser shock peening (LSP) processes. The estimation model of laser-induced surface residual stress was examined by means of experiments and numerical analysis. The high-cycle fatigue lives of welded joint specimens treated with WLSP and LSP were estimated by conducting tensile fatigue tests. The fatigue fracture mechanisms of these specimens are studied by surface integrity and fracture surface tests. Experimental results and analysis indicated that the fatigue life of the specimens processed by WLSP was higher than that with LSP. The large increase in fatigue life appeared to be the result of the larger residual stress, more uniform microstructure refinement and the lower surface roughness of the WLSP specimens.

The Effects of Laser Shock Peening on Fatigue Life in Ni-Based Superalloy

2010 ◽  
Vol 135 ◽  
pp. 209-214 ◽  
Author(s):  
Wei Feng He ◽  
Ying Hong Li ◽  
Qi Peng Li ◽  
Hai Lei Liu ◽  
Yu Qin Li ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Compressive Stress ◽  
Structure Design ◽  
High Density ◽  
Residual Compressive Stress ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Vibration Fatigue ◽  
Shock Peening

The goal of this work was to determine effects of laser shock peening (LSP) on the fatigue life of the nickel-based superalloy, as well as the mechanism including the residual stress-depth profile (both depth of compression and magnitude) and the microstructure. The vibration fatigue performance of the standard test coupons made by Ni-based superalloy K417 with and without laser shock peening is researched. The residual stress distribution and microscopic structure after LSP are tested and analyzed by X-ray diffraction, SEM and TEM. The results indicated that the compress residual stress is up to 1.0mm in the test coupons after LSP, and the maximum residual compressive stress is about 660MPa under the surface. At the same time, the high pressure shock wave caused by laser propagate into the material which formed high density dislocation in the surface of the samples, and the γ' is divided leading to increase the sub-grain. Because of the deep residual compressive stress, high density dislocation and much more sub-grains, the vibration fatigue strength is improved about 180MPa by LSP. It is very instructive in the structure design and applying LSP to Ni-based superalloy.

Effects of Laser Shock Peening on TC11 Titanium Alloy with Different Impacts

2013 ◽  
Vol 681 ◽  
pp. 266-270 ◽  
Author(s):  
Xiang Fan Nie ◽  
Wei Feng He ◽  
Liu Cheng Zhou ◽  
Yu Qin Li ◽  
Yan Chai
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Shock Peening ◽  
Tc11 Titanium Alloy ◽  
The Impact ◽  
Test Result

The blade, made of TC11 titanium alloy, is prone to result in fatigue failure in the formidable environment in aero-engine. So a higher performance request of the material is brought forward. In this paper, laser shock peening(LSP) as a solution is applied to TC11 titanium alloy and microstructure, residual stress and microhardness with and without LSP were examined and compared via transmission electron microscope(TEM), X ray diffraction(XRD)and microhardness tester. The TEM results indicate that a great high density of dislocations are generated and evolve into the dislocation wall, sub-boundary and grain boundary. The nanocrystallites are formed and become smaller and more uniform with greater impacts. A high compressive residual stress above -540MPa is introduced with an increasing plastically affected layer with different impacts. The microhardness test result shows that LSP can obviously increase the hardness by 20 percent or so, and the affected depth increases with the impact from 600μm to 1200μm.

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