Microstructure, residual stress and tensile properties control of wire-arc additive manufactured 2319 aluminum alloy with laser shock peening

The strengthening effect and uniformity of residual stress and strain of 7075-T6 aviation aluminum after laser shock peening were investigated. The finite element simulation model of laser shot peening on 7075-T6 aviation aluminum alloy was established and verified. On this basis and combined with experiment, the microstructure, residual stress distribution and equivalent strain distribution of 7075-T6 aviation aluminum alloy after laser shock peening were studied. An index U for evaluating the strain uniformity in the peened area was proposed based on the statistical processing of the equivalent strain distribution in the peened area. The results show that the average grain size on the peened surface of the specimen was refined to 20–30 μm after LSP, and a residual compressive stress layer with thickness of about 0.5 mm was induced on the surface. Grain refinement and residual compressive stress can promote the strength and fatigue properties of 7075-T6 aviation aluminum alloy. The minimum value of U is obtained in the 6 × 6 spot array (the corresponding overlap ratio is 58%), which suggest that the most uniform deformation peened area can be obtained by using 58% overlap ratio in the laser shot peening process, which can avoid stress concentration and improve fatigue life.

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Effect of Laser Shock Peening on Microstructure and Residual Stress of Wire-Arc Additive Manufactured 2319 Aluminum Alloy

Laser & Optoelectronics Progress ◽

10.3788/lop55.011413 ◽

2018 ◽

Vol 55 (1) ◽

pp. 011413

Author(s):

孙汝剑 Sun Rujian ◽

朱颖 Zhu Ying ◽

李刘合 Li Liuhe ◽

郭伟 Guo Wei ◽

彭鹏 Peng Peng

Keyword(s):

Residual Stress ◽

Aluminum Alloy ◽

Laser Shock Peening ◽

Laser Shock ◽

Shock Peening

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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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