Multi- industry applications
Laser peening is a solution awaiting to solve industrial problems. Many applications suffer from fatigue, corrosion, wear, microstructural defects as well as onset of tensile residual stresses. These applications tend to be treated by shot peening in general, but could benefit from applying laser peening because it is possible to penetrate deeper within the material, as well as applying a cleaner, greener technology. Laser peening can be applied in various industrial sectors and are presented below but are not limited to:
transmission gears, pistons, connecting rods; big-end bearings; brake discs; crank shaft, torsion bars
ship hull, propellers
turbine blisk, fir tree.
die tools, cutting
fuselage; Pressure vessel, pressure tubes
Components of various size, (large to miniature) made from conventional or additive manufacturing processes also suffer from tensile stresses, inhomogeneous microstructure. These parts could also be subject to laser shock peening for enhancing the aforementioned aspects within the aforementioned materials and components.
Laser Shock peening, often known as laser shock processing or just laser peening, imparts beneficial residual stresses into metals and alloys. Laser shock Peening is an advance surface modification technique which can be widely applied to metallic parts in various industrials sectors to improve mechanical properties, namely: fatigue; wear, corrosion resistance just to name a few. Laser peening generally utilises a short-pulse (nanosecond), laser pulse of high peak power density (GW/cm2), to rapidly vaporise the absorbing layer to generate high-pressure plasma in presence of a confinement layer. If the shock-waves are high enough that the peak pressure exceeds the Hugoniot Elastic Limit (HEL), of the metallic material, undergoing plastic deformation, even a nanocrystalline layer. After the shock-wave are transported within the material - plastically deformed metal surface is generated in a layer of compressive residual stress, extending from the surface to depths up to 2mm. This can greatly improve the mechanical properties, part quality as well as the performance, safety and longevity (functional life) of these parts and engineering systems and structures.
Laser shock processing ceramics
Laser Shock Peening has been widely used for the treatment of metals and alloys with many studies elucidating its effect on these (traditional engineering) materials. However, the effect of LSP on engineering ceramics is not well understood with only a few published studies available in the literature. The main rationale behind this preference for metallic alloys esteems from the brittleness, low fracture toughness and inability to induce plastic deformation inherent to ceramics, inhibits their more wide-scale use in many high performance applications that their otherwise desirable mechanical and thermal properties would enable, thus, preventing a more widespread use of ceramics in high-performance applications. Upon using a controlled laser shock based technique could provide a practical technique to address the inherent (vulnerability) of ceramics to brittle fractures, by enhancing their local surface fracture toughness and reduce their crack sensitivity to expand diverse range of commercial applications.
Shukla, P.P, Swanson, T.P., Page J.C., (2014) ‘Laser Shock Peening and Mechanical Shot Peening Processes Applicable for the Surface Treatment of Technical Grade Ceramics: A Review’. Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 228 (5), 639 – 652.
Shukla P., Smith G.C., Waugh, D.G., Lawrence. J. (2015), ‘Development in Laser Peening of Advanced Ceramics’, Proceedings of the SPIE, 9657, 77-85.
Shukla, P., Nath, S., Wang, W., Shen, X., Lawrence, J. (2017), ‘Surface property modifications of silicon carbide ceramic following laser shock peening’. Journal of European Ceramic Society, 37(9), 1728 - 1739. DOI: 10.1016/j.jeurceramsoc.2017.03.005
Shukla, P., Robertson, S., Wu, H., Telang, A., Kattoura, M., Nath, S., Mannava, S.R., Vasudevan, V.K., and J. Lawrence, (2017), ‘Surface Engineering Alumina Armour Ceramics with Laser Shock Peening’, Materials and Design, 134, 523 - 538.
Shukla, P., Crooks, R., Wu. H., (2019), Shock-wave induced Compressive Stress in Alumina ceramics by Laser Peening, Material and Design, 167, 107626, 1-8.
Shukla, P., X. Shen, Ric Allott, Klaus Ertel, S. Robertson, R. Crookes, H. Wu, A. Zammit, P. Swanson, and M. E Fitzpatrick, (2021), Response of Silicon Nitride Subject to Laser Shock Treatment, Ceramics International, Volume 47, Issue 24, Pages 34538-34553.
Shukla, P., Zhang, V., Shen, X., and Swanson, P., Laser Shock Treatment of Zirconia Ceramics, Recent Progress in Materials, Lidsen Publishing Inc. (Open Access). Accepted in Oct 2022. In Press.
Shukla P. (February 2018 (winter Issue)), Laser Shock Peening of Metals and Advanced ceramics, The Laser User, Issue 87, Winter, 24 – 25.