scispace - formally typeset
Search or ask a question
Topic

Peening

About: Peening is a research topic. Over the lifetime, 5538 publications have been published within this topic receiving 73073 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the effects of various surface treatments on fatigue crack growth and residual stress distributions in friction stir welded 2195 aluminum alloy joints were investigated, and the degree to which residual stress treatments can reduce fatigue cracks, and enhance fatigue life of friction-stir welded components was investigated.
Abstract: The effects of various surface treatments on fatigue crack growth and residual stress distributions in friction stir welded 2195 aluminum alloy joints were investigated. The objective was to understand the degree to which residual stress treatments can reduce fatigue crack growth rates, and enhance fatigue life of friction stir welded components. Specimens were fabricated from 12.5 mm thick 2195-T8 aluminum plate, with a central friction stir weld along their length. Residual stresses were measured for three specimen conditions: as-welded (AW), welded then shot peened (SP), and welded then laser peened (LP). Crack growth rate tests were performed in middle-cracked tension specimens under constant amplitude load for each of the three conditions (AW, SP, LP) and at three temperatures (room, elevated, and cryogenic). At room and elevated temperature, crack growth rates were similar in the AW and SP conditions and were significantly lower for the LP condition. At cryogenic temperature, it was difficult to discern a trend between residual stress treatment and crack growth rate data. Laser peening over the friction stir welded material resulted in the fatigue crack growth rates being comparable to those for base material.

43 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the paint and foil coatings on the laser shock wave propagation into the aluminum specimen and the resulting change in mechanical properties versus depth was analyzed using nano-indentation.
Abstract: High power Q-switched laser systems are currently being developed for use in a process known as laser shock processing or “laser peening” which results in significantly improved fatigue properties in aluminum components. An ablative, sacrificial coating such as paint or metal foil is used to protect the aluminum component from surface melting by the laser pulse, which adversely affects fatigue life. This paper, using nano-indentation, analyzes the effect of the paint and foil coatings on the shock wave propagation into the aluminum specimen and the resulting change in mechanical properties versus depth. Near the surface, hardness was found to be increased by the laser peening, however this process decreased the measured elastic modulus. The laser pulse energy density and properties of the foil including its adhesion to the aluminum alloy were found to influence the change in surface mechanical properties.

43 citations

Journal ArticleDOI
TL;DR: In this article, the use of low transformation temperature electrodes for improving the fatigue strength of welded joints has been investigated for longitudinal welds containing high tensile residual stresses, and the results showed that the latter might be particularly suitable for transverse welds and longitudinal fillet welded gussets.
Abstract: The fatigue strengths of welded joints in welded structures are much lower than those of the base metal because there are stress concentrations and tensile residual stresses at weld toes. Ultrasonic peening treatment and the use of low transformation temperature electrodes are possible methods for improving the fatigue strengths of welded joints. It was thought that the latter might be particularly suitable for longitudinal welds containing high tensile residual stresses. Comparative fatigue tests carried out on treated transverse butt welded joints and on plate specimens with longitudinal fillet welded gussets confirmed this.

43 citations

Journal ArticleDOI
TL;DR: In this paper, a surface contamination layer was induced on AA 7150 surface during ultrasonic shot peening (USSP) treatment and its exfoliation evolution in solution containing HCl was investigated using immersion test, electrochemical impedance spectra (EIS), scanning kelvin probe force microscopy (SKPFM), SEM with energydispersive X-ray spectroscopy, XRD and TEM.
Abstract: Surface contamination layer mainly containing Fe, Ti and O with a thickness of ~ 20 μm was induced on AA 7150 surface during ultrasonic shot peening (USSP) treatment. The contaminated layer and its exfoliation evolution in solution containing HCl was investigated using immersion test, electrochemical impedance spectra (EIS), scanning kelvin probe force microscopy (SKPFM), SEM with energy-dispersive X-ray spectroscopy, XRD and TEM. USSPed AA 7150 with contamination layer showed ~ 3 times higher corrosion rate than that of controlled sample. However, after the exfoliation of the contamination layer, the corrosion rate of USSPed alloy actually is lower than that of its untreated counterpart. Additionally, as revealed by SKPFM, surface contamination layer is cathodic relative to the substrate, indicating that surface contamination layer is detrimental for the substrate alloy when galvanic corrosion occurs. Nonetheless, it should be noted that even in the presence of contamination layer, the localized corrosion resistance of peened alloy was greatly improved, which might be due to surface nanocrystallization, disappearance of rolled 〈220〉 texture and residual compressive stress effects caused by USSP.

43 citations

Journal ArticleDOI
TL;DR: In this article, the influence of laser shock peening on the microstructure and fatigue behavior of Ti-6Al-4V alloy manufactured via electron beam melting (EBM), a popular method of additive manufacturing, was investigated.
Abstract: Laser shock peening (LSP) is a post-treatment process that is widely used to modify the surface microstructure and mechanical properties of parts constructed by additive manufacturing (AM). In this study, the influence of LSP on the microstructure and fatigue behavior of Ti–6Al–4V alloy manufactured via electron beam melting (EBM), a popular method of AM, was investigated. The microstructure of the EBM sample consisted of the β phase (~6 vol%) and α lamellar phase. Grain refinement of the α phase occurred via both dislocation evolution and deformation twinning during LSP. A theoretical description of the microstructural evolution, particularly the distribution of deformation twins, was developed. The fatigue strength and micro-hardness of the EBM samples increased by approximately 17% and 11% after LSP treatment, respectively. The fatigue fracture morphologies at three defined damage stages (crack initiation, crack propagation, and instantaneous rupture) were examined for EBM samples before and after LSP. The dominant mechanism of fatigue strength enhancement by LSP was discussed. The effects of residual compressive stress assistant with adiabatic temperature increase and grain refinement of the α phase produced by LSP reduced the pre-existing crack size, suppressed crack initiation, and increased the required work for fatigue fracture.

42 citations


Network Information
Related Topics (5)
Alloy
171.8K papers, 1.7M citations
88% related
Microstructure
148.6K papers, 2.2M citations
87% related
Fracture mechanics
58.3K papers, 1.3M citations
84% related
Ultimate tensile strength
129.2K papers, 2.1M citations
83% related
Grain boundary
70.1K papers, 1.5M citations
81% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023256
2022500
2021282
2020303
2019340
2018305