Methods for the suppression of “residual stress holes” in laser shock treatment

2021 ◽  
pp. 102486
Author(s):  
Guoxin Lu ◽  
Lu Wang ◽  
Heng Li ◽  
Zhong Ji ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Shock Treatment ◽  
Laser Shock ◽  
Laser Shock Treatment

Response of silicon nitride ceramics subject to laser shock treatment

2021 ◽  
Author(s):  
P. Shukla ◽  
X. Shen ◽  
Ric Allott ◽  
Klaus Ertel ◽  
S. Robertson ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Shock Treatment ◽  
Laser Shock ◽  
Nitride Ceramics ◽  
Laser Shock Treatment

Outlooks in laser work hardening for characteristics increase of parts obtained by selective laser melting

2018 ◽  
Vol 2018 (7) ◽  
pp. 32-37
Author(s):  
Д. Мельников ◽  
D. Melnikov ◽  
Е. Калёнова ◽  
E. Kalyonova ◽  
Зо Зо Йе Мьят ◽  
...  
Keyword(s):  
Surface Layer ◽  
Selective Laser Melting ◽  
Work Hardening ◽  
Shock Treatment ◽  
Fatigue Properties ◽  
Laser Shock ◽  
Laser Melting ◽  
Near Surface ◽  
Hybrid Technology ◽  
Laser Shock Treatment

The paper deals with the development of a new hybrid technology – 3D laser work hardening which consists in the integration of laser shock treatment (laser work hardening) into the process of selective laser melting. The technology offered will allow obtaining an area of compressing residual stresses in a near surface layer and achieving the improvement of mechanical and fatigue properties of parts manufactured. In this paper the aluminum alloy samples were processed with laser work hardening with the use of uncommon absorbing and transparent layers (foil and glass) which are necessary for the introduction selective laser melting in a plant. Modes of laser work hardening were also investigated which may be used in the hybrid technology offered.

Influence of Laser Shock Processing on the Weld Line and Finite Element Simulation

2011 ◽  
Vol 464 ◽  
pp. 627-631
Author(s):  
Jie Zhang ◽  
Ai Hua Sun ◽  
Le Zhu ◽  
Xiang Gu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Residual Stress ◽  
Laser Shock ◽  
Analysis Software ◽  
Laser Shock Processing ◽  
Element Analysis ◽  
Welding Line ◽  
Simulation Results ◽  
Shock Processing

Welding residual stress is one of the main factors that affect the strength and life of components. In order to explore the effect on residual stress of welding line by laser shock processing, finite element analysis software ANSYS is used to simulate the welding process, to calculate the distribution of welding residual stress field. On this basis, then AYSYS/LS-DYNA is used to simulate the laser shock processing on welding line. Simulation results show that residual stress distributions of weld region, heat-affected region and matrix by laser shock processing are clearly improved, and the tensile stress of weld region effectively reduce or eliminate. The simulation results and experimental results are generally consistent, it offer reasons for parameter optimization of welding and laser shock processing by finite element analysis software.

High Dense Compressive Residual Stress Produced in Laser Shock Processing on Ti6Al4V Alloys

2007 ◽  
Vol 353-358 ◽  
pp. 1617-1620 ◽  
Author(s):  
Xu Dong Ren ◽  
Yong Kang Zhang ◽  
Jian Zhong Zhou ◽  
Yong Yu Gu ◽  
Y.Y. Xu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Surface Stress ◽  
Compressive Residual Stress ◽  
High Energy ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Large Spot ◽  
Small Spot ◽  
Shock Processing

Laser shock processing (LSP) employs high-energy laser pulses from a solid-state laser system to create intense shock waves into a material, which can induce compressive residual stresses in the target surface and improve its mechanical property efficiency. Residual stress of Ti6Al4V alloy both before and after LSP with multishocks was analysised. The depth of compressive residual stress was found to have a dependence on the number of shocking layers and a slight dependence on the level of irradiance. Surface stress improvements of more than 50% increases are possible after laser shock processing with either large spot or small spot patterns. The large spot gave a surface stress of 432MPa and a depth of over 1mm. The low intensity small spot gave a surface stress of 285MPa with a depth comparable to the large spot. Laser shock processing induces a compressive residual stress field, which increases fatigue crack initiation life and reduces fatigue crack growth rate.

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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