The reflection of light from the surface of an elastic solid gives rise to various types of elastic waves that propagate inside the solid. The weakest waves are generally those that are generated by the radiation pressure acting during the reflection of the light. Here, we present the first quantitative measurement of such light-pressure-induced elastic waves inside an ultrahigh-reflectivity mirror. Amplitudes of a few picometers were observed at the rear side of the mirror with a displacement-measuring conical piezoelectric sensor when laser pulses with a fluence of 1 J=cm2 were reflected from the front side of the mirror.
COBISS.SI-ID: 13195035
Laser shock peening (LSP) without ablative coating at various power densities was applied to AA6082 aluminium alloy to investigate corrosion behaviour in a 0.6 M NaCl solution. Cyclic polarisation results showed enhanced passivity with corrosion current reduction by as much as a factor of 12, compared to the untreated specimen. Additionally, EIS after 24 h confirmed almost seven times higher polarisation resistance after LSP, compared to the untreated specimen (45 and 6.7 k cm2). XPS analysis indicated Al2O3 enrichment, which contributed to higher corrosion resistance with reduced anodic dissolution of the LSP-treated surface due to plasma ablation and shock waves.
COBISS.SI-ID: 12293915
Complexity has been identified as a ubiquitous and ever increasing property of manufacturing systems. Conventional theories of management lack the tools to describe, analyzse, and manage complexity, and can, in turn, no longer cope with the issues it gives rise to. New approaches are offered by complexity science, namely by computational mechanics. In the paper, a method for complexity assessment is proposed and illustrated on real industrial data. The results of the presented case study suggest a distinct relationship between complexity and throughput, and indicate that the tool used has a major impact on complexity.
COBISS.SI-ID: 11870235
This study examines the effect of laser shock peening without coating (LSPwC) on the corrosion behaviour of AA6082-T651 alloy in a near natural chloride environment. The results confirmed LSPwC as an effective method, yielding lower anodic dissolution (EswEcorr), improve drepassivation (EcorrErp) as well as corrosion current reduction. Characterization of the corrosionattack was performed by SEM/SEI/BEI and EDS analysis, where results confirmed crystallographic pitting as the predominant effect due to local dissolution of the Al matrix around Fe rich precipitates. Moreover, it was found that LSPwC reduces crystallographic and surface hemispherical pitting, as well as intergranular attack.
COBISS.SI-ID: 13336091
This paper systematically investigates the effect of laser shock peening without coating parameters on the microstructural evolution, and dislocation configurations induced by ultra-high plastic strains and strain rates. Based on an analysis of optical microscopy, polarized light microscopy, transmission electron microscopy observations and residual stress analysis, the significant influence laser shock peening parameters due to the effect of plasma generation and shock waves propagation has been confirmed. Although the optical microscopy results revealed no significant microstructural changes after laser shock peening, i.e. no heat effect zone, differences in the distribution of second-phase particles, etc., expressive influence of laser treatment parameters on the laser shock induced craters was confirmed. Moreover, polarized light microscopy results have confirmed the existence of well-defined longish grains up to 455 nm in length in the centre of the plate due to the rolling effect, and randomly oriented smaller grains (20 nm - 50 nm) in the surface due to the static recrystallization effect. Laser shock peening is reflected in an exceptional increase in dislocation density with various configurations, i.e. dislocation lines, dislocation cells, dislocation tangles, and the formation of dense dislocation walls. More importantly, the microstructure is considerably refined due to the effect of strain deformations induced by laser shock peening process. The results have confirmed that dense dislocation structures during ultra-high plastic deformation with the addition of shear bands producing ultra-fine (60-200 nm) and nano-grains (20-50 nm). Furthermore, dislocation density was increased by a factor of 2.5 compared to the untreated material.
COBISS.SI-ID: 13648155