Connection between shock wave induced indentations and hardness by means of neural networks

Czotscher, Tobias; Baguer, Daniel Otero; Vollertsen, Frank; Piotrowska-Kurczewski, Iwona; Maaß, Peter

doi:10.1063/1.5112634

Cited by 5 publications

(2 citation statements)

References 11 publications

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“…The descriptors were measured by means of a laser-scanning confocal microscope after the impact. Experiments revealed that the hardness can be predicted by means of neural networks when the descriptors' depth and diameter are considered, which shows that both descriptors contain relevant information [10].…”

Section: Results Of Indentation Measurement By Lisementioning

confidence: 95%

Descriptors for High Throughput in Structural Materials Development

et al. 2019

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The development of novel structural materials with increasing mechanical requirements is a very resource-intense process if conventional methods are used. While there are high-throughput methods for the development of functional materials, this is not the case for structural materials. Their mechanical properties are determined by their microstructure, so that increased sample volumes are needed. Furthermore, new short-time characterization techniques are required for individual samples which do not necessarily measure the desired material properties, but descriptors which can later be mapped on material properties. While universal micro-hardness testing is being commonly used, it is limited in its capability to measure sample volumes which contain a characteristic microstructure. We propose to use alternative and fast deformation techniques for spherical micro-samples in combination with classical characterization techniques such as XRD, DSC or micro magnetic methods, which deliver descriptors for the microstructural state.

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Section: Results Of Indentation Measurement By Lisementioning

confidence: 95%

Descriptors for High Throughput in Structural Materials Development

et al. 2019

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“…These values are correlated with mechanical material properties. So far, it has been shown that the measured characteristic values (indentation depth, indentation diameter and pile-up as well as sink-in behavior) with LiSE strongly correlate with the material hardness [8] and tensile strength [9]. Pre-treatment and ablation layers of the indenter are not necessary with the wavelength of the laser beam (λ = 10.6 µm) because a plasma is quasi-instantly formed on top of the irradiated surface, which absorbs nearly all the irradiation of the laser beam [10].…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Force Measurements to Determine Positioning Tolerances for Impulse-Based Indentations

Valentino

Höhmann

Schünemann

et al. 2021

Lasers Manuf. Mater. Process.

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High-throughput experimentation methods determine characteristic values, which are correlated with material properties by means of mathematical models. Here, an indentation method based on laser-induced shock waves is presented, which predicts the material properties, such as hardness and tensile strength, by the induced plastic deformation in the substrate material. The shock wave pushes a spherical indenter inside a substrate material. For reproducible indentations, the applied load is of importance. To compare different processes and process parameters, the measured plastic deformation is normalized by the applied load. However, eccentric irradiation leads to altered beam profiles on the surface of spherical indenters and the angle of incidence is changed. Thus, the influence of eccentric irradiation is studied with an adapted time-resolved force measurement setup to determine the required positioning tolerances. The spherical indenter is placed inside a cylindrical pressure cell to increase the laser-induced shock pressure. From the validated time-resolved force measurement method we derive that deviations from the indentation forces are acceptable, when the lateral deviation of the beam center, which depends only on the alignment of the setup, does not exceed ± 0.4 mm. A vertical displacement from the focus position between -3.0 mm and + 2.0 mm still leads to acceptable deviations from the indentation force.

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Identification of Characteristic Values in Impulse-Based Processes Using Small Specimens

Valentino

Radel

2022

Nanomanuf Metrol

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Suitable approaches are needed for rapid and cost-efficient materials development. High-throughput experimentation reduces the identification time of suitable material compositions. One approach is to use small specimen geometries to save additional production costs. Hence, research is continuously being conducted on a new hardness test based on laser-induced shock waves. Thus far, characteristic values from the induced indentations have been extracted, which correlate with hardness and tensile strength. However, the indentation result varies in dependence of the specimen size and mass. This condition hinders the correlation between characteristic values and material properties. Thus, the goal was to induce similar indentation results to minimum specimen size. Herein, different mounting materials and methods were investigated. The created indentations were compared with those induced in large specimens. Essential mounting parameters were derived from the findings. Consequently, small specimens can be used for material characterization by considering these mounting parameters.

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Connection between shock wave induced indentations and hardness by means of neural networks

Cited by 5 publications

References 11 publications

Descriptors for High Throughput in Structural Materials Development

Descriptors for High Throughput in Structural Materials Development

Time-Resolved Force Measurements to Determine Positioning Tolerances for Impulse-Based Indentations

Identification of Characteristic Values in Impulse-Based Processes Using Small Specimens

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