High Strain Rate Response of 7055 Aluminum Alloy Subject to Square-spot Laser Shock Peening

Laser shock peening (LSP) is a surface mitigation technique that can be applied to improve the life of a metallic component through the generation of a compressive surface stress field induced by high-power laser pulses. Numerical simulation of LSP (produced residual stresses) in presence of an initial stress field similar to those obtained under welding has been carried out in nonlinear dynamic by coupling an explicit code (Europlexus) and an implicit one (Code_Aster). In the first step, an axisymetrical model has been validated by comparison with an analytical solution considering an elastic-perfectly plastic behavior law. Then, comparisons with Abaqus calculations have been carried out in terms of displacements and residual stresses using the Johnson-Cook high strain rate constitutive law to validate multi-impact 3D modeling. High strain rate parameter of Johnson-Cook law has been identified using LSP on thin plates. Validations of the simulations are then performed by comparing with experimental determined deformations caused by LSP on thick plates. For 25 overlapped shots, LSP induced residual stresses calculated with and without initial residual stresses similar to those obtain under welding have been compared to adress the effect of initial stresses on final residual fields.

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Characterizations on Microscale Laser Dynamic Forming of Metal Foil

Manufacturing Science and Engineering, Parts A and B ◽

10.1115/msec2006-21003 ◽

2006 ◽

Cited By ~ 1

Author(s):

Gary J. Cheng ◽

Daniel Pirzada

Keyword(s):

High Strain Rate ◽

Strain Rate ◽

High Strain ◽

Electron Backscatter Diffraction ◽

Laser Forming ◽

Metal Foil ◽

Laser Shock ◽

Forming Process ◽

High Shock ◽

Shock Peening

Laser dynamic forming (LDF) is a unique hybrid forming process, combining the advantages of laser shock peening, laser forming and metal forming, with an ultra high strain rate forming utilizing laser shock waves. In this paper, a hybrid forming technique based on laser dynamic forming will be demonstrated. The feasibility of laser dynamic forming will be discussed through experiments. The mechanical and microstructure of the formed 3D structures will be characterized. The grain microstructure and misorientation will be investigated quantitatively with Electron backscatter diffraction (EBSD). The residual stress distributions are measured using X-ray diffraction. We will describe the important factors that lead to improved micro-formability at high strain rate induced by high shock pressure. It is concluded that with further development, this may be an important microforming technology for various materials. LDF has great potential for meso-, micro- and nano scale forming since the laser provides high precision, highly-localized heating intensity, high repeatability, fast setup and superb flexibility.

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Test for Dynamic Stress-strain of 2024 Aluminum Alloy Surface under High Strain Rate by Pulsed Laser Shock

Applied laser ◽

10.3788/al20153503.0324 ◽

2015 ◽

Vol 35 (3) ◽

pp. 324-329 ◽

Cited By ~ 1

Author(s):

曹宇鹏 Cao Yupeng ◽

冯爱新 Feng Aixin ◽

花国然 Hua Guoran

Keyword(s):

Aluminum Alloy ◽

High Strain Rate ◽

Strain Rate ◽

Dynamic Stress ◽

High Strain ◽

Pulsed Laser ◽

Laser Shock ◽

Stress Strain ◽

2024 Aluminum Alloy ◽

Aluminum Alloy Surface

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High Strain Rate Superplasticity in a Zr and Sc Modified 7075 Aluminum Alloy Produced by ECAP

Materials Science Forum ◽

10.4028/www.scientific.net/msf.584-586.164 ◽

2008 ◽

Vol 584-586 ◽

pp. 164-169 ◽

Cited By ~ 6

Author(s):

Krystof Turba ◽

Premysl Malek ◽

Edgar F. Rauch ◽

Miroslav Cieslar

Keyword(s):

Aluminum Alloy ◽

High Strain Rate ◽

Strain Rate ◽

High Strain ◽

Rate Sensitivity ◽

7075 Aluminum Alloy ◽

Fine Grained ◽

Angular Pressing ◽

Average Grain Size ◽

Elongation To Failure

Equal-channel angular pressing (ECAP) at 443 K was used to introduce an ultra-fine grained (UFG) microstructure to a Zr and Sc modified 7075 aluminum alloy. Using the methods of TEM and EBSD, an average grain size of 0.6 1m was recorded after the pressing. The UFG microstructure remained very stable up to the temperature of 723 K, where the material exhibited high strain rate superplasticity (HSRSP) with elongations to failure of 610 % and 410 % at initial strain rates of 6.4 x 10-2 s-1 and 1 x 10-1 s-1, respectively. A strain rate sensitivity parameter m in the vicinity of 0.45 was observed at temperatures as high as 773 K. At this temperature, the material still reached an elongation to failure of 430 % at 2 x 10-2 s-1. These results confirm the stabilizing effect of the Zr and Sc additions on the UFG microstructure in a 7XXX series aluminum alloy produced by severe plastic deformation.

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