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

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 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.

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

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.

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