Microstructural and mechanical insights into 1.2709 maraging steel produced by direct energy deposition

Vol.:(0123456789) https://doi.org/10.1007/s10853-025-11439-8 J Mater Sci (2025) 60:17933–17952 Metals & corrosion Microstructural andmechanical insights into1.2709 maraging steel produced bydirect energy deposition AngelinaStrakošová1,2,* , DanielKvapil1 , FilipPrůša1 , MarekVronka2 , PetrSvora2,3 , PavelLejček2 ,and DaliborVojtěch1 1 Department ofMetals andCorrosion Engineering, University ofChemistry andTechnology, Prague 6, Technická 5, 16628Prague, CzechRepublic 2 Institute ofPhysics, Czech Academy ofScience, Na Slovance 1999/2, 18200Prague, CzechRepublic 3 Czech Technical University inPrague, University Centre forEnergy Efficient Buildings, Trinecka 1024, 27343Bustehrad, CzechRepublic ABSTRACT The present work focuses on the characterization of the ultra-high-strength 1.2709 maraging steel produced by the Direct Energy Deposition (DED) technique, either in its as-built or as-built + heat-treated state. Scanning electron microscope micrographs and X-ray diffraction patterns showed that the heat treatment (namely, solution annealing and aging) had minimal impact on the microstructure changes of the maraging steel. The material is characterized by fine cellular or dendritic microstructure containing several percent of the ductile γ-austenite phase in both as-built and as-built + heat-treated states. A small amount of the N i 3Mo0.5Ti0.5 intermetallic phase was observed even in the as-built state of the material. The heat treatment caused a substantial improvement of the mechanical properties through the homogeneous precipitation of nano-sized needle-shaped N i 3Mo0.5Ti0.5 intermetallic phase. Tensile yield strength increased from 753 to 1957 MPa, ultimate tensile strength—from 991 to 2024 MPa, and microhardness— from 350 to 700 HV0.1. The present results are also compared with those obtained for the same material produced by the more commonly used Laser Powder Bed Fusion (L-PBF) technique. Despite having a coarser microstructure with a presence of γ-phase than the LPBF-printed material, the DED-printed maraging steel exhibited greater precipitation hardening while maintaining 5% ductility after heat treatment. Received: 12 May 2025 Accepted: 25 August 2025 Published online: 6 September 2025 © The Author(s), 2025 Handling Editor: Sophie Primig. Address correspondence to E-mail: [email protected]; strakosov[email protected] J Mater Sci (2025) 60:17933–17952 Introduction Additive manufacturing (AM, also denoted as 3D printing) is a modern and currently very attractive production technology in the field of powder metallurgy [1–3]. AM allows printing parts of complex shapes, including small or even porous structures, which can be easily and relatively quickly reproduced. Likewise, it is possible to individually modify the shapes of individual parts without significant complications and thus produce unique parts [3]. As an advantage of this technique, there is also no need to make post-production machining of the additively manufactured parts. Often then, only the final surface treatment is sufficient [4, 5]. Due to the specific conditions that arise during printing, additively manufactured materials show different microstructures compared to conventionally produced equivalents [5, 6]. At the same time, their properties differ even when comparing products of different printing methods [7], which demonstrates the importance of thorough investigation of such prepared materials. Direct Energy Deposition (DED) and Laser Powder Bed Fusion (L-PBF) are the most commonly used additive manufacturing methods for metallic materials [8]. Both methods are based on the local melting of small material volumes using high-energy density sources (laser or electron beams). As a result of gradual but rapid solidification, characteristic dendritic/cell microstructures are formed [9–11]. The main differences influencing the microstructures between the two technologies are the cooling rates and the powder particle sizes [7]. DED is based on the localized melting of raw material supplied as either powder or wire at the point of deposition by a laser, electron beam, or electric arc. The deposition head then moves gradually across the surface, building up layers of the material [12]. In terms of usage, the DED method additionally enables, for example, the repairs and improvements of already installed parts and the modification of the chemical composition directly during printing [4, 5]. It is also possible to print the parts using both powder and wire feedstock material, unlike in the L-PBF method, where only powder can be used [2, 8]. Moreover, in 2019, the market shares of L-PBF systems were much higher compared to DED systems (85 and 8.3%, respectively) [6]. Therefore, DED-produced materials are still not as well researched as materials produced by the today’s most common alternative L-PBF method. Maraging steels rank among the strongest materials produced by AM. A significant group of these steels—based on the Fe–18Ni system—have generally little tendency for thermal shocks and cracking, while absorbing well the laser source energy, which makes them one of the excellent candidates for 3D printing [11, 13]. The 1.2709 (also denoted as X3NiCoMoTi 18-9-5, 18Ni300) maraging steel is the most widely used material of the Fe–18Ni group [2]. Apart from high strength and hardness, it also offers good toughness [14, 15]. This steel is characterized by good weldability [16], dimensional stability during aging heat treatment, as well as great machinability in the annealed state [14]. Its fundamental strengthening can be achieved through a simple heat treatment composed of aging that lasts for several hours [17–19]. The main strengthening mechanism is precipitation hardening with intermetallic phases such as Ni3(Mo, Ti) [20], Fe2Mo [21, 22], η-Ni3Ti [9], and Ni3Mo [23, 24]. The application of AM to produce parts of maraging steels thus forms a very potent and industrially usable resource. For this reason, it is crucial to investigate and compare the circumstances of both L-PBF and DED printing methods. Currently, a large number of research papers are focused on the characterization of the structure and properties of maraging steels produced by the L-PBF. Some of them [13, 25–31] relate to the examination of printing parameters for the successful production of high-quality products. Many research papers relate to the heat treatment of the L-PBF-produced maraging steel. Several works [26, 32–35] describe the impact of the combination of solution annealing and aging on the microstructure and changes in mechanical properties. Other works [36–38] focus on the impact of aging alone. Also, many researchers focus their studies on the types of precipitates that are formed during aging [9, 13, 16, 39, 40]. However, only a few studies [7, 20, 41–46] work with the maraging steel prepared by the direct energy deposition (DED) method. The work [20] describes changes in the structure and properties of DED-produced C250 maraging steel after heat treatment; the results were also compared to wrought counterparts. The response of DED process parameters and consequent heat treatment on the characteristics of 18%Ni M350 alloy is evaluated in the works [43, 45]. The effect of intrinsic heat treatment (IHT) during the DED process on MAR60HRC 17934 J Mater Sci (2025) 60:17933–17952 powder was studied in [41]. The investigation of the microstructure and mechanical properties of the DEDprinted MAR-60HRC maraging steel, as well as a composite based on the 18Ni300 core and MAR-60HRC coating, is described in Ref. [46]. Only two of the above-mentioned works [42, 44] deal with the DEDproduced 18Ni300 maraging steel. Detailed investigation of microstructure and mechanical properties of 18Ni300 maraging steel produced by DED using different types of printing strategies: single-trace-singlelayer, multi-trace-multi-layers, and single-trace-multilayers are reported in [42]. Authors of the study [44] investigated DED-produced 18Ni300 maraging steel in its as-built and aged states. However, there is a lack of studies where the standard mode of heat treatment (solution annealing + aging) was applied to the maraging steel. Therefore, in this work, the ultra-high-strength 1.2709 maraging steel produced by the DED technology is examined in terms of microstructure and mechanical properties changes depending on the twostep “solution annealing and aging” heat treatment. The results are compared to the equivalent steel produced by the common L-PBF method. Materials and methods The 1.2709 maraging steel powder was used to produce samples with the DED technology. The powder was commercially purchased from Praxair Surface Technologies. The particle size distribution (PSD, Fig. 1) was measured by Laser Scattering Particle Size Distribution Analyzer LA-960 (HORIBA, Ltd.). The chemical composition of the steel powder was measured using the inductively coupled plasma method by the supplier and is presented in Table 1. Samples in the shape of cylinders with a diameter of 10 mm and height of 50 mm were produced by the DED method on InssTek MX-600 (COMTES FHT a.s., Dobrany, Czech Republic). For this purpose, the SDM800 optical module was used. The process parameters are listed in Table 2. A Spiral CF (contour filling) strategy was used to build the samples from the maraging steel powder (Fig. 2). The building strategy consists of printing in spirals, always starting in the center of each layer. The “n” layers were printed clockwise while the “n + 1” layers were printed—the opposite way—counterclockwise. The average surface porosity of the samples produced by DED (namely, “as-built”) was measured by threshold method using ImageJ software both in the plane parallel to the printing direction (↑) and perpendicular to the printing direction (┴). Half of the as-built samples were heat-treated by solution annealing (820 °C/1 h, air cooling) and aging (490 °C/6 h, air cooling) according to the works of others [7, 33, 40]. For this purpose, a muffle furnace (Martinek MP05) was used. Heat-treated samples were named “as-built + SAT.” The relative density of the as-built + SAT heat-treated material was measured only in the (↑) direction. X-ray diffraction (XRD) analysis was used to determine the phase composition of the maraging steel in different conditions: powder, as-built, and as-built + SAT. For this purpose, diffractometer X´Pert PRO (PANalytical, Holland, Co Kα = 0.17929 nm) was used to scan the material, the range of 6–110° with a step size of 0.039°. The generator settings of the diffractometer were 40 mA and 35 kV. The metallographic cross-sections of the samples were prepared by grinding on SiC papers (P240–P4000), polishing on water-based polycrystalline diamond suspension with a particle size of 3 µm and final polishing on colloidal silicon suspension (Eposil F). Etching reagent Nital 2 (98 ml ethanol and 2 ml nitric acid) was used to visualize the microstructure. A light optical microscope (LOM, Zeiss Axio Observer D1m) and a scanning Figure1 Size distribution and cumulative curve of the 1.2709 maraging steel powder. 17935 J Mater Sci (2025) 60:17933–17952 electron microscope (SEM, Tescan Mira) were used to observe the microstructure of the 1.2709 maraging steel. SEM (Tescan Lyra 3) equipped with an energydispersive spectroscopy detector (EDS, Oxford Instruments, 80 mm2) was used to detect the chemical composition of the structural components of the steel. The LOM micrographs of the metallographic cross-sections of the samples were used to calculate the width and depth of the melt pools. The SEM micrographs were used to calculate the cell sizes using ImageJ. Detailed microstructure observation of the maraging steel in as-built and as-built + SAT conditions was performed using transmission electron microscopy (TEM). For this purpose, a thin foil of each material was prepared using a focused ion beam (FIB) in SEM (FEI Quanta 3D FEG). Conventional TEM, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), and selected-area diffraction (SAED) images were captured by Fei Tecnai F20 field emission gun TEM operated at 200 kV equipped with an EDS detector, which was used to identify individual phases. For STEM, Z-contrast imaging was performed using a high-angle annular dark field (STEM–HAADF) detector. FFT calculations of HRTEM images using the digital micrograph program were used to identify individual precipitates. The indexation of diffraction patterns was performed using the CrysTBox software [47]. To eliminate the potential influence of the anisotropic behavior of the maraging steel, porosity as well as microstructure and microhardness were evaluated both in (↑) and (┴) directions. Vickers microhardness (HV0.1) was measured on the FUTURE TECH FM-700 machine with a 100 g load and 10 s dwell time. In each case, ten measurements were made to achieve reliable statistics. Tensile tests were performed in the (↑) direction of the samples on the universal test machine Instron 5882. The tests (three for each material) were performed at room temperature with an initial strain rate of 0.001 s−1. The samples for the tensile stress–strain testing (Fig. 3) were prepared by machining from the DED-printed parts. Table 1 Chemical composition of the 1.2709 maraging steel (according to the supplier) Element Fe Ni Co Mo Ti Al Si Mn Cr [wt.%] Bal 18.1 9.0 5.0 1.1 0.1 0.1 0.02 0.09 Table 2 Parameters of the DED process * DMT—a mode, when the printer automatically adjusts the laser power so that the layer height is maintained while being controlled using built-in cameras Laser power* (W) Scanning speed (mm/min) Powder feeding speed (g/min) Flow rate of protective gas (l/ min) Hatch distance (µm) Layer height (µm) Laser beam diameter (µm) 300–600 850 2.5 15 500 250 800 Figure 2 Scheme of the DED printing strategy of the samples with the dimensions: diameter = 10 mm, height = 50 mm. (Arrows show the printing direction). 17936 J Mater Sci (2025) 60:17933–17952 Results and discussion Powder characterization Figure 4 shows the morphology and the microstructure of the 1.2709 maraging steel powder. It can be seen (Fig. 4) that the powder is characterized by different sizes and shapes. However, most particles are spherical and surrounded by small satellite particles on the surface (Fig. 4a, yellow arrows). This shape and presence of satellites are typical characteristics of powders produced by the gas atomization process. However, satellite particles have been found to be detrimental to additive manufacturing due to their potential negative impact on the powder spreading during the process. To prevent the formation of satellite particles, it is recommended to use the plasma atomization method [48, 49]. According to the results of the PSD measurement (Fig. 1), the particle sizes ranged from 60 to 110 µm with a median size of 80.6 µm. This size range is significantly higher than the size of powders that are used for the L-PBF method of additive manufacturing of metal materials [33, 50]. As shown in Fig. 4b, the microstructure of the 1.2709 maraging steel powder is characterized by dendritic or cell morphology showing the presence of a few occasionally found pores (Fig. 4b, red arrows). This type of microstructure occurs due to a high cooling rate (up to 1 0 5 K s−1) during the gas atomization process [51, 52]. EDS analysis was used to determine the chemical composition of the cross-section of the steel powder. One can see (Fig. 5, Table 3) that the alloying elements are distributed inhomogeneously in the powder microstructure. Iron (Fe) and cobalt (Co) are distributed mainly in the matrix of the cell structure. Conversely, areas between the cells (cell boundaries) are depleted of the above-mentioned elements but are enriched with nickel (Ni), molybdenum (Mo), titanium (Ti), and aluminum (Al) (Table 3, points 1–4). The rapid solidification process during the gas atomization of powder drives the segregation of heavier alloying elements (such as Mo and Ni) to the cell boundaries, resulting in solute partitioning in the liquid phase and constrained diffusion in the solid phase [53]. Although Mo and Ti are known as elements that stabilize the ferrite phase in steels, in the case of the maraging steel, their enrichment together with Ni enables the formation of the austenite phase [7]. Microstructure and phase composition Figure 6 (black spots) shows the presence of pores in the microstructure of the as-built maraging steel, which is typical for additive manufacturing [6, 54]. Due to the presence of pores of varying sizes, it was decided to classify them into two groups: small pores with a calculated diameter of 18.4 ± 3.2 µm and larger pores with a diameter of 66.1 ± 5.0 µm. Due to their regular circular shape, they can be considered as gas Figure3 The dimensions (in mm) of samples prepared for tensile strain–stress testing. Figure4 SEM micrographs of morphology (a) and crosssection microstructure (b) of the 1.2709 maraging steel powder. (Yellow arrows show the satellite on the powder surface; red arrows show pores). 17937 J Mater Sci (2025) 60:17933–17952 Figure5 SEM micrograph and EDS chemical composition maps of the 1.2709 maraging steel powder. Table 3 Chemical composition [wt.%] of the 1.2709 maraging steel powder according to the EDS analysis [wt.%] Fe Ni Co Mo Ti Al 1 61.60 19.52 9.71 6.60 2.33 0.23 2 64.39 17.93 9.40 5.95 2.14 0.19 3 63.97 18.05 9.42 6.61 1.84 0.12 4 63.36 18.33 9.94 6.19 1.93 0.24 5 67.81 17.56 9.42 4.30 0.71 0.20 6 67.45 17.17 9.35 5.17 0.72 0.14 7 68.76 17.08 9.32 4.16 0.66 0.03 8 68.28 17.39 9.59 3.85 0.71 0.18 Figure6 Representative LOM images of the DED-printed 1.2709 maraging steel porosity in the direction parallel to the printing direction: (a) upper part, (b) middle part; and (c) lower part of the as-built sample. 17938 J Mater Sci (2025) 60:17933–17952 pores [6, 54, 55]. This defect occurs due to the entrapment of gas bubbles formed during material melting and its rapid solidification. Also, the porosity of feedstock powder (as shown in Fig. 4b) can be another origin of the gas pore trapping in the molten material [54, 55]. Therefore, it is very important to use defect-free input material and find the optimal printing parameters. The relative density of the as-built material was calculated to be 99.89 ± 0.03 and 99.94 ± 0.02% in the (↑) printing direction and perpendicular (┴) to the printing direction, respectively. These results are in good agreement with the values of the relative density of the materials produced by L-PBF technology reported in Refs. [7, 30, 56]. Figure 7 shows the LOM micrographs of the 1.2709 maraging steel microstructure in the as-built state that is characterized by the presence of melt pools. The melt pool boundaries copy the laser movement according to the scanning strategy used during the manufacturing process. The measured depth of melt pools is equal to 590 ± 29 µm. This means that laser power was strong enough during DED to melt not only the newly deposited powder layer with a height of 250 µm (Table 2) but also at least one already solidified layer beneath it. The maraging steel produced by L-PBF exhibits smaller melt pools (60–130 µm, depending on the laser settings [7, 27]) compared to that produced by DED. The main reason for this trend is the difference between laser power, which is lower in the case of L-PBF technique [7, 8, 55], but also the powder particle size and the resulting thickness of the deposited powder [5]. Figure 8 shows that the microstructure of the DEDprinted material is characterized by fine dendritic or Figure7 LOM micrographs of the as-built 1.2709 maraging steel (a) parallel to the printing direction and (b) perpendicular to the printing direction. Figure8 SEM micrograph and EDS maps of the maraging steel in the as-built state. 17939 J Mater Sci (2025) 60:17933–17952 cellular morphology inside the melt pools. The average cell size was calculated to be 2.4 ± 0.2 µm, which is coarser than the approximately 1 µm cell size formed during the L-PBF method [9, 57]. Such a difference can be explained by the cooling rate which is several orders of magnitude higher during the L-PBF process (up to 108 K s−1), thus promoting faster cooling and heat dissipation within the material volume compared to the materials produced by the DED technique (cooling rate up to 105 K s−1) [2, 6, 9, 55, 58]. The EDS maps of the chemical composition and the weight percentage of each element in the microstructure of the DED as-built material are shown in Fig. 8 and Table 4, respectively. It can be seen that the difference in the alloying elements distribution in the cells matrix and cells boundaries has the same character as it was in the case of the powder (Fig. 5, Table 3). Significant segregation of Ni, Mo, Ti, and Al at the cell boundaries occurs, while substantial depletion of Fe and Co in these boundaries is evident. This phenomenon was also observed in Refs. [16, 44, 59]. Moreover, the authors in the Refs. [7, 20] found that not only Ni but also Mo and Ti promote the formation of retained austenite phase, which is located in the cell boundaries or even melt pools of additively manufactured maraging steels (as above-mentioned in the case of the powder). Figure 9a presents the bright-field TEM micrograph of the maraging steel microstructure in its asbuilt state. The SAED patterns of several grains were examined. All SAED patterns demonstrated the presence of the same body-centered cubic (BCC) structure of martensite. In Fig. 9a in the upper right corner, there is a selected diffraction pattern of the BCC martensite structure in the zone axis (ZA) [111] inserted in the picture. Moreover, some spherical particles were observed in the TEM micrograph (see Fig. 9b). According to the results of the EDS analysis, the particle depicted in Fig. 9b is enriched with Ti, Al, and C. It can be said that the particles are incoherent precipitates formed during the printing process due to the very fast precipitation kinetics of these elements. The presence of precipitates based on Ti and Al was also observed in Refs. [9, 40]. Moreover, the presence of TiN was described in Ref. [43], and TiO2 was found in the microstructure of the L-PBF-printed maraging steel in Ref. [17]. If there is nitrogen (N) present in the maraging steel, Ti reacts with C and N forming Ti(C, N) carbonitrides [60], which were not observed in our study. Figure 9c shows dislocation networks and a high amount of very fine precipitates. HRTEM micrograph shows several nanometers long needle-shaped coherent phases (Fig. 9d). In the HRTEM micrograph (Fig. 9d), there is a corresponding FFT image showing diffraction spots of a fine precipitate inserted in the upper right corner. It was found that the interplanar distances (d-spacing) of spots 1 and 2 correspond to the Ni3Mo0.5Ti0.5 phase. On the other hand, d-spacing for spot number 3 matched mainly with BCC martensite, but with the precipitate presence also. Precipitates with a size of about 5–20 nm were also observed in the matrix of the 1.2709 maraging steel produced by the L-PBF technique [9]. The formation of precipitates during the additive manufacturing of steels is caused by the cyclic reheating of already deposited layers during the deposition of new layers. This process is called IHT and was also reported in Refs. [17, 41, 61]. Figure 10 shows the representative image of the pore distribution in the as-built + SAT heat-treated 1.2709 maraging steel. It can be seen that the distribution and size of pores in the maraging steel have not Table 4 Chemical composition [wt.%] of the 1.2709 maraging steel powder according to the EDS analysis [wt.%] Fe Ni Co Mo Ti Al 1 65.70 18.78 10.20 3.15 1.80 0.36 2 62.64 19.64 9.96 4.27 3.37 0.12 3 64.46 19.75 9.56 3.72 2.34 0.16 4 63.59 19.34 9.46 4.38 2.93 0.29 5 65.24 19.40 9.66 3.52 1.95 0.24 6 70.05 18.02 9.71 1.28 0.71 0.24 7 70.05 17.91 9.68 1.62 0.59 0.15 8 70.39 17.37 10.02 1.36 0.62 0.24 9 70.15 17.83 9.65 1.49 0.64 0.23 17940 J Mater Sci (2025) 60:17933–17952 changed after SAT heat treatment (Fig. 10), compared to the as-built material (Fig. 6). Moreover, the measured relative density of the heat-treated material was calculated to be 99.9 ± 0.02%, which is equal to the relative density of the as-built sample, 99.89 ± 0.03%. It is recommended to employ hot isostatic pressing (HIP) as an effective method for removing pores from the material [62], but also as a step of heat treatment that helps to homogenize the microstructure of the maraging steel produced by AM [63]. Figure 11 shows the LOM micrograph of the as-built maraging steel after SAT heat treatment. It appears that the solution annealing + aging heat treatment has caused changes in the material microstructure. On the other hand, we can still observe the boundaries of the melt pools here (Fig. 11, yellow arrows). To fully homogenize the microstructure of AM-manufactured maraging steel, a homogenization treatment at 960 °C for 5 h was applied to the steel before a solution annealing step at 820 °C for 2 h [63–65]. Figure9 Bright-field TEM micrographs of the as-built maraging steel (a), (b), (c), and HRTEM micrograph of a very fine precipitate (d). Figure 10 Representative LOM image of the as-built + heattreated 1.2709 maraging steel porosity. 17941 J Mater Sci (2025) 60:17933–17952 the presence of structure defects, namely, pores. High magnification SEM micrographs (Fig. 17b, d) show that both as-built and as-built + SAT maraging steel fracture surfaces have a dimple-like morphology characteristic of ductile materials [18, 38]. Conclusions The detailed characterization of the ultra-highstrength 1.2709 maraging steel produced by additive manufacturing using the DED technique, either in its as-built or as-built + heat-treated state, is described and discussed in this work. The results are also compared to the same material produced by the L-PBF. The obtained results can be summarized as follows: • The DED technique allowed the production of almost fully dense 1.2709 maraging steel with an average relative density of approximately 99.9%. • The DED-printed maraging steel showed cellular or dendritic microstructure characteristics of additively manufactured steels. An average cell size of 2.4 ± 0.2 µm and an estimated melt pool depth of 590 ± 29 µm were measured to be several times larger compared to the steel produced by the L-PBF technique. • The first step of the chosen heat treatment, namely, solution annealing at 820 °C/1 h, was found insufficient to dissolve the characteristic fine cellular microstructure of the DED-printed maraging steel and transform it to a 100% martensitic as it was observed in the L-PBF-printed one. • The intermetallic phase of Ni3Mo0.5Ti0.5 was observed in the DED-printed steel in both as-built and as-built + SAT heat-treated conditions. • The DED-printed steel exhibited lower values of TYS, UTS, and HV0.1 compared to the L-PBF-produced equivalent due to the coarser microstructure. However, the SAT heat treatment caused extended Figure17 SEM micrographs of the fracture surfaces of the (a, b) as-built and (c, d) as-built + SAT maraging steel produced by DED. (Red arrows show pores). 17948 J Mater Sci (2025) 60:17933–17952 precipitation hardening of the DED-produced material with the Ni3Mo0.5Ti0.5 intermetallic phase compared to the L-PBF-produced material, which hardened with the Ni3Mo phase. Acknowledgements This publication was supported by the project “Mechanical Engineering of Biological and Bio-inspired Systems,” funded as Project No. CZ.02.01.01/00/22_008/0004634 by Programme Johannes Amos Commenius, call Excellent Research. It was also supported from the grant of Specific university research—Grant No. A1_FCHT_2024_007. We acknowledge CzechNanoLab Research Infrastructure supported by MEYS CR (LM2023051). Author contributions Angelina Strakošová helped in methodology, formal analysis, investigation, data curation, and writing— original draft. Daniel Kvapil helped in investigation, data curation, and writing—review and editing. Filip Průša helped in investigation and writing—review and editing. Marek Vronka helped in investigation and writing—review and editing. Petr Svora helped in investigation and writing—review and editing. Pavel Lejček helped in formal analysis and writing—review and editing. Dalibor Vojtěch helped in conceptualization, methodology, formal analysis, and writing— review and editing. Funding Open access publishing supported by the institutions participating in the CzechELib Transformative Agreement. Data availability The data used in this manuscript are available in the Zenodo repository at the following link: https:// doi. org/ 10. 5281/ zenodo. 14056 749. Declarations Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. 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