Response of thin films and substrate to micro scale laser shock peening

2004 ◽  
Author(s):  
Youneng Wang ◽  
Hongqiang Chen ◽  
Jeffrey W. Kysar ◽  
Y. Lawrence Yao
Keyword(s):  
Thin Films ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Shock Peening

Response of Thin Films and Substrate to Micro-Scale Laser Shock Peening

2006 ◽  
Vol 129 (3) ◽  
pp. 485-496 ◽  
Author(s):  
Youneng Wang ◽  
Hongqiang Chen ◽  
Jeffrey W. Kysar ◽  
Y. Lawrence Yao
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Single Crystal Silicon ◽  
Laser Shock Peening ◽  
Experimental Result ◽  
Subgrain Structure ◽  
Laser Shock ◽  
Crystal Silicon ◽  
Micro Scale ◽  
Shock Peening

Micro-scale laser shock peening (μLSP) can potentially be applied to metallic structures in microdevices to improve fatigue and reliability performance. Copper thin films on a single-crystal silicon substrate are treated by using μLSP and characterized using techniques of X-ray microdiffraction and electron backscatter diffraction (EBSD). Strain field, dislocation density, and microstructure changes including crystallographic texture, grain size and subgrain structure are determined and analyzed. Further, shock peened single crystal silicon was experimentally characterized to better understand its effects on thin films response to μLSP. The experimental result is favorably compared with finite element method simulation based on single-crystal plasticity.

Numerical Investigation of Opposing Dual Sided Micro Scale Laser Shock Peening

2006 ◽  
Author(s):  
Yajun Fan ◽  
Youneng Wang ◽  
Sinisa Vukelic ◽  
Y. Lawrence Yao
Keyword(s):  
Residual Stress ◽  
Shock Waves ◽  
Laser Shock Peening ◽  
Time Lags ◽  
Laser Shock ◽  
Surface Residual Stress ◽  
Strain Rate Effects ◽  
Micro Scale ◽  
Stress Profiles ◽  
Shock Peening

Laser shock peening (LSP) is an innovative process which imparts compressive residual stresses in the processed surface of metallic parts to significantly improve fatigue life and fatigue strength of this part. In opposing dual sided LSP, the workpiece can be simultaneously irradiated or irradiated with different time lags to create different surface residual stress patterns by virtue of the interaction between the opposing shock waves. In this work, a finite element model, in which the hydrodynamic behavior of the material and the deviatoric behavior including work hardening and strain rate effects were considered was applied to predict residual stress distributions in the processed surface induced under various conditions of the opposing dual sided micro scale laser shock peening. Thus the shock waves from each surface will interact in different ways through the thickness resulting in more complex residual stress profiles. Additionally, when treating a thin section, opposing dual sided peening is expected to avoid harmful effects such as spalling and fracture because the pressures on the opposite surfaces of the target balance one another and prohibit excessive deformation of the target. In order to better understand the wave-wave interactions under different conditions, the residual stress profiles corresponding to various workpiece thicknesses and various irradiation times were evaluated.

scholarly journals Grain boundary response of aluminum bicrystal under micro scale laser shock peening

2009 ◽  
Vol 46 (18-19) ◽  
pp. 3323-3335 ◽  
Author(s):  
Siniša Vukelić ◽  
Jeffrey W. Kysar ◽  
Y. Lawrence Yao
Keyword(s):  
Grain Boundary ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Shock Peening

scholarly journals A Novel Micro-Scale Plastic Deformation Feature on a Bulk Metallic Glass Surface under Laser Shock Peening

2013 ◽  
Vol 30 (3) ◽  
pp. 036201 ◽  
Author(s):  
Yan-Peng Wei ◽  
Bing-Chen Wei ◽  
Xi Wang ◽  
Guang-Yue Xu ◽  
Lei Li ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glass Surface ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Deformation Feature ◽  
Shock Peening

Spatially Resolved Characterization of Residual Stress Induced by Micro Scale Laser Shock Peening

2004 ◽  
Vol 126 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Hongqiang Chen ◽  
Y. Lawrence Yao ◽  
Jeffrey W. Kysar
Keyword(s):  
Residual Stress ◽  
Cell Structure ◽  
Fem Analysis ◽  
Dislocation Cell ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
X Ray ◽  
Micro Scale ◽  
Spatially Resolved ◽  
Shock Peening

Single crystal aluminum and copper of (001) and (110) orientation were shock peened using laser beam of 12 micron diameter and observed with X-ray micro-diffraction techniques based on a synchrotron light source. The X-ray micro-diffraction affords micron level resolution as compared with conventional X-ray diffraction which has only mm level resolution. The asymmetric and broadened diffraction profiles registered at each location were analyzed by sub-profiling and explained in terms of the heterogeneous dislocation cell structure. For the first time, the spatial distribution of residual stress induced in micro-scale laser shock peening was experimentally quantified and compared with the simulation result obtained from FEM analysis. Difference in material response and microstructure evolution under shock peening were explained in terms of material property difference in stack fault energy and its relationship with cross slip under plastic deformation. Difference in response caused by different orientations (110 and 001) and active slip systems was also investigated.

Experimental Study of Micro-Scale Laser Shock Peening on Copper Foils

2011 ◽  
Vol 464 ◽  
pp. 506-509 ◽  
Author(s):  
W. Zhu ◽  
Jian Zhong Zhou ◽  
M Wang ◽  
Shu Huang ◽  
Deng Hui Wei ◽  
...  
Keyword(s):  
Laser Energy ◽  
Mechanical Test ◽  
Test System ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Copper Foils ◽  
Typical Experiment ◽  
Shock Peening ◽  
Reliability Performance

Micro-scale laser shock peening (μLSP) is a flexible and precise process that can potentially be applied to metallic structures in micro devices to improve strength and reliability performance. In order to understand the mechanism of μLSP process, a typical experiment was carried out for copper foils specimen with various process parameters. Surface morphology, deformation and hardness of the specimens were observed and characterized by 3D microscope system and situ nano-mechanical test system respectively. It was found that overlapping rate of laser spot has a little effect on microscopic deformation depth which increases slowly with the increasing of laser energy, and micro-hardness of the laser treated specimens was improved significantly.

Microscale Laser Shock Peening of Thin Films, Part 1: Experiment, Modeling and Simulation

2004 ◽  
Vol 126 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Wenwu Zhang ◽  
Y. Lawrence Yao ◽  
I. C. Noyan
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Silicon Substrate ◽  
Metal Film ◽  
Shock Pressure ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Stress Strain ◽  
Laser Shock Processing ◽  
Shock Peening

Microscale Laser Shock Peening (LSP), also known as Laser Shock Processing, is a technique that can be potentially applied to manipulate residual stress distributions in metal film structures and thus improve the fatigue performances of micro-devices made of such films. In this study, microscale LSP of copper films on single crystal silicon substrate is investigated. Before and after-process curvature measurement verifies that sizable compressive residual stress can be induced in copper thin films using microscale LSP. Improved modeling work of shock pressure is summarized and the computed shock pressure is used as loading in 3D stress/strain analysis of the layered film structure. Simulation shows that the stress/strain distribution in the metal film is close to equi-biaxial and is coupled into the silicon substrate.

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