Microstructure and properties in the weld surface of friction stir welded 7050-T7451 aluminium alloys by laser shock peening

Laser shock peening (LSP) was used to treat the weld surface of friction stir welded joints of 7050-T7451 alloys. After the LSP, a large number of micro-holes were formed in the shock region. The hardness of thermo-mechanically affected zone (TMAZ) and heat-affected zone (HAZ) at a distance from the...

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Bibliographic Details
Published in:Vacuum 2018-06, Vol.152, p.25-29
Main Authors: Liu, Peng, Sun, Siyu, Xu, Shubo, Li, Yang, Ren, Guocheng
Format: Article
Language:English
Subjects:
Aluminium alloys
Friction stir welding
Laser shock peening
Microstructure
Residual stress
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Summary:Laser shock peening (LSP) was used to treat the weld surface of friction stir welded joints of 7050-T7451 alloys. After the LSP, a large number of micro-holes were formed in the shock region. The hardness of thermo-mechanically affected zone (TMAZ) and heat-affected zone (HAZ) at a distance from the upper surface of 0.5 mm increased obviously. The average hardness increased 9HV. The fatigue life after the LSP increases 30%, 27% and 5% when the loading stress is 200 MPa, 250 MPa and 300 MPa. The residual stress in weld nugget zone, TMAZ and HAZ generated a compressive residual stress, and the biggest value is 100 MPa after the LSP. •Microstructure changes were analyzed by LSP, and a large number of micro-holes were formed in the shock region.•ESPI is used here to analyze the stress relief of surface zone of friction stir welded aluminium alloys.•Relation among the hardness, fatigue properties and microstructure in the shock region were analyzed and discussed.
ISSN:0042-207X
1879-2715
DOI:10.1016/j.vacuum.2018.03.002