Surface strengthening of single-crystal alumina by high-temperature laser shock peening

Wang, Fei; Yan, Xueliang; Liu, Lei; Nastasi, M.; Lu, Yongfeng; Cui, Bai

doi:10.1080/21663831.2020.1862933

Cited by 12 publications

(11 citation statements)

References 28 publications

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“…The temperature increase caused by the laser irradiation is thus negligible, which has been verified by the comparison of LSP of sapphire with and without the furnace heating in our previous work. 27 The temperature of the SiC sample is solely controlled by the furnace temperature (1,000 • C).…”

Section: Methodsmentioning

confidence: 99%

“…HT-LSP applied to single crystal Al 2 O 3 (sapphire) enabled LSP at temperatures higher than 1000 • C for the first time. 27 The experimental results suggest that HT-LSP at 1200 • C can minimize the shock wave damage in sapphire while improving the hardness and fracture toughness by 9% and 29%, respectively. 27 This study investigates the influence and fundamental mechanisms of HT-LSP on polycrystalline ceramics using α-SiC as a model material.…”

Section: Introductionmentioning

confidence: 91%

“…27 The experimental results suggest that HT-LSP at 1200 • C can minimize the shock wave damage in sapphire while improving the hardness and fracture toughness by 9% and 29%, respectively. 27 This study investigates the influence and fundamental mechanisms of HT-LSP on polycrystalline ceramics using α-SiC as a model material. The microstructural changes caused by HT-LSP were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).…”

Section: Introductionmentioning

confidence: 91%

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Microstructures and mechanical properties of α‐SiC ceramics after high‐temperature laser shock peening

et al. 2021

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A novel high-temperature laser shock peening (HT-LSP) process was applied to polycrystalline α-SiC to improve the mechanical performance. HT-LSP prevents microcrack formation on the surface while induces plastic deformation in the form of dislocation slip on the basal planes, which may be caused by the combination of high shock pressure and a lower critical resolved shear stress at 1000°C. A maximum compressive residual stress of 650 MPa, measured with Raman spectroscopy, was introduced into the surface of α-SiC by HT-LSP, which can increase the nanohardness and in-plane fracture toughness of α-SiC by 8% and 36%, respectively. This work presents a fundamental base for the promising applications of HT-LSP to brittle ceramics to increase their plasticity and mechanical properties.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 91%

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Microstructures and mechanical properties of α‐SiC ceramics after high‐temperature laser shock peening

et al. 2021

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“…However, in previous studies, change in bending strength of ceramics after LP application had not been investigated, except by Akita et al [ 11 ]. Surface damage can be prevented by applying a coating called a sacrificial layer during LP construction and, in previous studies, laser peening with coating has been widely used for ceramics [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. However, the changes in residual stress and bending strength with and without coating are also not clear.…”

Section: Introductionmentioning

confidence: 99%

Improvement in Bending Strength of Silicon Nitride through Laser Peening

et al. 2022

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This study aimed to improve the bending strength and reliability of ceramics using laser peening (LP). In the experiment, LP without coating (LPwC) and with coating (LPC) were applied to silicon nitride (Si3N4) under various conditions. The surface roughness, residual stress, and bending strength were then measured for the non-LP, LPwC, and LPC specimens. The results show that the LPwC specimen had a greater surface roughness but introduced larger and deeper compressive residual stress when compared with the non-LP and LPC specimens. In addition, the bending strength of the LPwC specimen was higher and scatter in bending strength was less compared with the non-LP and LPC specimens. This may be attributed to the transition of the fracture initiation point from the surface to the interior of the LPwC specimen because of the compressive residual stress introduced near the surface. Thus, it was demonstrated that the application of LP is effective in improving the strength and reliability of ceramics.

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“…The mechanical properties are enhanced upon the introduction of compressive residual stress below the peened surface. [1,2] Compressive residual stress improves the total safety and reliability of components by preventing the formation and propagation of surface defects. [3,4] Therefore, a deeper compressive residual stress, together with a corresponding higher magnitude for it, alters the tensile stress distributions under external loading conditions.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Laser Shock Peening Depth Through Regulation of Surface Optical Absorption

Yan

Zhu

et al. 2021

Adv Materials Inter

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Higher depths at the millimeter scale (1-2 mm), along with greater magnitudes, have been reported after the NLSP of Ti6Al4V titanium alloy, [2,10] 2024, [11] 6061, [12] and 7075 [13] aluminum alloys. Elaborated laser systems with large power densities are currently required to increase the peak pressure to enable a high input of energy (slightly over 10 GW cm -2 ) during the interaction between the incident laser and metals. [14] The critical power density threshold for the confinement layer breakdown is validated to limit the possible peak pressure. [15][16][17] Changing the wavelength of the incident laser from 1064 to 532 nm decreases the breakdown threshold of the confining water layers from 10 to 6 GW cm -2 , and the maximum peak pressure from ≈5.5 to 4.5 GPa. [18,19] Compressive residual stresses can also be generated deep below the peened surface by multiple or overlapping laser pulses. [20,21] The reduced attenuation of the shock wave indicates an increased depth for the plastic-deformed layer during subsequent peening, while the affected depths usually reach saturated border values within three to five impacts. [22,23] Additionally, femtosecond laser shock peening is applied to induce a shallower affected depth and a limited compressive layer owing to the high instantaneous power density. [24] It is necessary to increase the surface optical absorption and associated energy conversion at higher affected depths in NLSP. The surface optical absorption property determines the thermal energy fraction, [25,26] with a value of ≈0.2 utilized in investigations. [27,28] In this case, optical absorption is defined by the surface morphology of the metal rather than its intrinsic absorptance. [29] Various absorption mechanisms with different optical behaviors are found in the structures induced using lithographic and chemical techniques. [30,31] These essentially originate from selective absorption responses such as the surface plasmon resonance, magnetic-polariton, geometric optical response, and metamaterial resonances. [29,[32][33][34] A nanoscale structure and laser-induced periodic surface structure can enhance the absorption of laser energy by the reconstruction of surface electromagnetic distributions. [35] The absorption of light is enhanced on structured surfaces by multiple reflections based on the angular dependence of Fresnel absorption. [35] The absorption spectrum of femtosecond laser treated surfaces increased sharply over a wide range of wavelengths of incident Laser shock peening is conducted to enhance the mechanical properties of metals. Efficient optical absorption of metal surface is desirable to increase the laser shock peening depth. In this work, a method is proposed to regulate the absorption behavior by surface colorizing to increase the affected depth and magnitude of nanosecond laser shock peening (NLSP). Colorized samples are fabricated with high absorption of 400-1500 nm, which is 89% higher than that of un-colorized samples. This regulated optical response is attributed to the multi-ref...

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Surface strengthening of single-crystal alumina by high-temperature laser shock peening

Cited by 12 publications

References 28 publications

Microstructures and mechanical properties of α‐SiC ceramics after high‐temperature laser shock peening

Microstructures and mechanical properties of α‐SiC ceramics after high‐temperature laser shock peening

Improvement in Bending Strength of Silicon Nitride through Laser Peening

Improvement of Laser Shock Peening Depth Through Regulation of Surface Optical Absorption

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