Modulus Mapping Research Articles

Region- and degeneration dependent stiffness distribution in intervertebral discs derived by shear wave elastography

Information on the local stiffness characteristics of the intervertebral disc (IVD) is crucial for the understanding of its structure-function properties in health and disease and may improve numerical modeling. Previous studies have attempted to map local tissue stiffness by sectioning the disc and performing mechanical testing on these discrete tissue units, which is technically challenging and may bias the results. Shear wave elastography (SWE) represents a nondestructive alternative that can provide spatially continuous elasticity estimates. We investigated the feasibility of SWE for human intervertebral disc elasticity mapping in a laboratory setting.To this end, global spinal segment mechanical behavior was determined in 6 loading directions and served as ground truth data for the validation of the approach. Subsequently, the cranial spinal vertebra was removed and shear wave elastographic scans of the IVD were acquired. SWE-measurements were reconstructed into three-dimensional elastographic maps, discretized into distinct IVD regions and correlated with global segment mechanical parameters. SWE-derived Young’s modulus estimates were compared among different regions and as a function of their state of degeneration.We found annulus shear wave speed to be moderately correlated with segment mechanical behavior irrespective of the loading direction whereas shear wave speed in the nucleus pulposus showed a very weak association (mean (SD) absolute Pearson correlation coefficients: 0.51 (0.14) and 0.17 (0.12), respectively). Young’s modulus mapping of the intervertebral disc revealed stiffness to be highest in the ventral annulus with a stiffness decrease both circumferentially towards the dorsal aspect as well as towards the center of the disc. SWE hence provides a valid alternative to disc sectioning and piecewise mechanical testing.

High-resolution mechanical mapping of the adhesive–dentin interface: The effect of co-monomers in 10-methacryloyloxydecyl dihydrogen phosphate

The presence of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) at the adhesive–dentin interface enables ionic binding to calcium salts, which results in rigid nano-layering within the submicron scale resin–dentin interdiffusion zone. MDP has been used with additional co-monomers, such as hydroxyethyl methacrylate (HEMA) and/or 4-methacryloyloxyethyl-trimellitic acid (4-MET), mainly to enhance the chemical bonding properties. However, the use of co-monomers may compromise the rigidity of the adhesive–dentin interface. In this study, we use high-resolution mechanical mapping across the interface to discern the in situ mechanical properties of each target region at the nanoscale. Visualization by modulus mapping demonstrated that HEMA increases the diffusion properties of MDP into dentin structures. However, the rigidity of the adhesive–dentin interface indicated by the storage modulus was markedly lower in MDP containing HEMA than in MDP containing 4-MET. Dynamic indentation testing revealed that the bonding layer was more deformable in the presence of HEMA. Moreover, the presence of MDP in the bonding layer might also increase the deformability because the polymerization linearity allows a large degree of viscoelasticity. These factors also diminish the rigidity of the adhesive–dentin interface. Within the limitations of this study, our findings demonstrated that 4-MET is a better co-monomer than HEMA in MDP-based dental adhesives. Modulus mapping and nanoindentation are introduced as new tests for the adhesive–dentin interface to address queries about the effectiveness of dental adhesives.

Dynamic X-ray elastography: A new tool for characterizing soft materials

Dynamic X-ray elastography using propagating shear waves is a novel technique to visualize the spatial distribution of elasticity in soft materials. We demonstrate that it can be applied to a gel sample with a fine structure. We prepared a viscoelastic gel sample with a two-dimensional lattice structure filled with ZrO2 particles, and applied the technique to map storage and loss moduli. The obtained storage modulus map successfully distinguished the harder lattice structure from the soft gel matrix with a spatial resolution much higher than those of other conventional elastography techniques using magnetic resonance and ultrasound.

Effect of phase transformation on mechanical properties of Al16.80Co20.74Cr20.49Fe21.28Ni20.70 high entropy alloy coatings processed by laser cladding

Eight Al16.80Co20.74Cr20.49Fe21.28Ni20.70 high entropy alloy (HEA) coatings were fabricated by laser cladding with different laser scanning speed. The mechanical properties caused by phase transformation and microstructure evolution of Al16.80Co20.74Cr20.49Fe21.28Ni20.70 HEA coatings were investigated. The experimental results showed that the volume fraction of the FCC phase and the BCC phase in each coating were different depending on laser scanning speed. High laser scanning speed will increase the number of BCC phase. BCC phase was composed of alternate A2 and B2 structure formed by spinodal decomposition. All coatings exhibited a polycrystalline structure composed of uniform equiaxed grains. The grain size of equiaxed grains reduced from 185 to 42 µm with increased laser scanning speed. The phase-mechanical properties connection at nano-scale were established by nano-hardness mapping and elastic modulus mapping. Furthermore, the micromechanical properties of individual FCC phase and BCC phase were studied by analyzing nanoindentation data statistically. The BCC phases were found to have a higher nano-hardness and elastic modulus than the FCC phases. Therefore, the increment of the BCC phase could significantly enhance the strength and wear resistance of coatings. The optimum wear resistance was obtained in V17, owning a higher volume fraction of BCC (>90%) and finer grains (75 µm). In addition, the strengthening mechanism has been discussed. Grain boundary strengthening makes a great contribution to the excellent performance of coatings.

Development and evaluation of polyvinyl alcohol films reinforced with carbon nanotubes and alumina for manufacturing hybrid metal matrix composites by the sandwich technique

<abstract> Metal matrix composites (MMCs) have been a fundamental element in the development of technologies related to the aerospace and automotive industries. This is because they have an excellent weight-to-strength ratio, i.e., they are light materials with a high mechanical resistance. In the manufacturing of MMCs, the incorporation and homogeneous dispersion of reinforcements in the matrix has been one of the biggest challenges. The issue has expanded to the manufacturing of materials reinforced with nano-scaled particles. This study is aimed at the manufacturing, optimization, and characterization of the polymeric matrix reinforced with carbon nanotubes and alumina (hybrid composites), in order to use the polymeric matrix as an inclusion vehicle of the nano-reinforcements in a metallic matrix. The synthesis of the polymeric matrix composites was carried out by a solution mixing technique using polyvinyl alcohol as a matrix. For the reinforcement's dispersion, a magnetic stirring and sonication were used. Finally, the solution was put into a petri dish to allow its polymerization. The nano-reinforcement dispersion qualification and the quantification of the polymer matrix composite were carried out through the tension, nanoindentation, dynamical mechanical analysis test, elastic modulus mapping, and statistical model for dispersion. In addition, a preliminary study of the metallic composite was carried out and was fabricated by the sandwich technique. The initial characterization of the composites was performed through the nanoindentation test. </abstract>

Application of aberration-corrected scanning transmission electron microscopy in conjunction with valence electron energy loss spectroscopy for the nanoscale mapping of the elastic properties of Al-Li-Cu alloys.

The stress and strain play an important role in strengthening of the precipitation-hardened Aluminum (Al) alloys. Despite the determination of relationship between the mechanical properties and the precipitation existing in the microstructure of these alloys, a quantitative analysis of the local stress and the strain fields at the hardening-precipitates level has been seldom reported. In this paper, the microstructure of a T8 temper AA2195 Al alloy is investigated using aberration corrected scanning transmission electron microscopy (AC-STEM). The strain fields in Al matrix in the vicinity of observed precipitates, namely T1 and β' , are determined using geometric phase analysis (GPA). Young's modulus (Ym ) mapping of the corresponding areas is determined from the valence electron energy loss spectroscopy (VEELS) measured bulk Plasmon energy (Ep ) of the alloys. The GPA-determined strains were then combined with VEELS-determined Ym under the linear theory of elasticity to give rise the local stresses in the alloy. The obtained results show that the local stresses in Al matrix having no precipitates were in the range of 138 ± 2 MPa. Whereas, in the vicinity of thin and thick T1 platelet shape precipitates, the stresses were found to be about 202 ± 3 MPa and 195 ±3 MPa, respectively. The stresses measured in the vicinity of β' spherical shape precipitates found out to be 140 ± 3 MPa which was near to the local stress value in Al matrix. Our findings suggest that the precipitate hardening in T8 temper AA2195 Al alloy predominantly stems from thin T1 precipitates.

Repeatability of Linear and Nonlinear Elastic Modulus Maps From Repeat Scans in the Breast.

Compression elastography allows the precise measurement of large deformations of soft tissue in vivo. From an image sequence showing tissue undergoing large deformation, an inverse problem for both the linear and nonlinear elastic moduli distributions can be solved. As part of a larger clinical study to evaluate nonlinear elastic modulus maps (NEMs) in breast cancer, we evaluate the repeatability of linear and nonlinear modulus maps from repeat measurements. Within the cohort of subjects scanned to date, 20 had repeat scans. These repeated scans were processed to evaluate NEM repeatability. In vivo data were acquired by a custom-built, digitally controlled, uniaxial compression device with force feedback from the pressure-plate. RF-data were acquired using plane-wave imaging, at a frame-rate of 200 Hz, with a ramp-and-hold compressive force of 8N, applied at 8N/sec. A 2D block-matching algorithm was used to obtain sample-level displacement fields which were then tracked at subsample resolution using 2D cross correlation. Linear and nonlinear elasticity parameters in a modified Veronda-Westmann model of tissue elasticity were estimated using an iterative optimization method. For the repeated scans, B-mode images, strain images, and linear and nonlinear elastic modulus maps are measured and compared. Results indicate that when images are acquired in the same region of tissue and sufficiently high strain is used to recover nonlinearity parameters, then the reconstructed modulus maps are consistent.

AMB2018-03: Benchmark Physical Property Measurements for Material Extrusion Additive Manufacturing of Polycarbonate.

Material extrusion (MatEx) is finding increasing applications in additive manufacturing of thermoplastics due to the ease of use and the ability to process disparate polymers. Since part strength is anisotropic and frequently deviates negatively with respect to parts produced by injection molding, an urgent challenge is to predict final properties of parts made through this method. A nascent effort is underway to develop theoretical and computational models of MatEx part properties, but these efforts require comprehensive experimental data for guidance and validation. As part of the AM-Bench framework, we provide here a thorough set of measurements on a model system: polycarbonate printed in a simple rectangular shape. For the precursor material (as-received filament), we perform rheology, gel permeation chromatography, and dynamical mechanical analysis, to ascertain critical material parameters such as molar mass distribution, glass transition, and shear thinning. Following processing, we conduct X-ray computed tomography, scanning electron microscopy, depth sensing indentation, and atomic force microscopy modulus mapping. These measurements provide information related to pores, method of failure, and local modulus variations. Finally, we conduct tensile testing to assess strength and degree of anisotropy of mechanical properties. We find several effects that lead to degradation of tensile properties including the presence of pore networks, poor interfacial bonding, variations in interfacial mechanical behavior between rasters, and variable interaction of the neighboring builds within the melt state. The results provide insight into the processing-structure-property relationships and should serve as benchmarks for the development of mechanical models.

Elastic modulus mapping for bovine cortical bone from submillimeter- to submicron-scales using PeakForce Tapping atomic force microscopy

Bone is a composite material consisting of organic and inorganic components that are organized into hierarchical structures to provide load-bearing functions. This paper presents the results of PeakForce Tapping atomic force microscopy (AFM) scans on cut and polished bovine cortical bone specimens that were submerged in water. The elastic modulus map and surface morphology were obtained for various bone hierarchical structures from submillimeter- to submicron-scales. The elastic modulus of osteons (20.51 ± 6.85 GPa) was slightly lower than the interstitial bone (21.87 ± 5.48 GPa); they were both much greater than that of the cement lines (7.49 ± 4.23 GPa). The elastic modulus in the lamella structures varied periodically from higher values in thick sub-lamellae (21.49 ± 6.58 GPa) to the lower values in thin sub-lamellae (9.67 ± 2.69 GPa). The results also show relatively softer mineralized collagen fibril bundle arrays (12.94 ± 2.71 GPa) embedded in harder matrix materials (28.39 ± 5.75 GPa). The variations in the elastic modulus suggest different degrees of mineralization or different fibril orientations. The histograms of elastic modulus indicate the dominating compositions or dominating fibril orientations.

Macroscopic and microscopic analysis of the mechanical properties and adhesion force of cells using a single cell tensile test and atomic force microscopy: Remarkable differences in cell types

Many experimental techniques have been reported to provide knowledge of the mechanical behavior of cells from biomechanical viewpoints, however, it is unclear how the intercellular structural differences influence macroscopic and microscopic mechanical properties of cells. The aim of our study is to clarify the comprehensive mechanical properties and cell-substrate adhesion strength of cells, and the correlation with intracellular structure in different cell types. We developed an originally designed micro tensile tester, and performed a single cell tensile test to estimate whole cell tensile stiffness and adhesion strength of normal vascular smooth muscle cells (VSMCs) and cervical cancer HeLa cells: one half side of the specimen cell was lifted up by a glass microneedle, then stretched until the cell detached from the substrate, while force was simultaneously measured. The tensile stiffness and adhesion strength were 49 ± 10 nN/% and 870 ± 430 nN, respectively, in VSMCs (mean ± SD, n = 8), and 19 ± 17 nN/% and 320 ± 160 nN, respectively, in HeLa cells (n = 9). The difference was more definite in the surface elastic modulus map obtained by atomic force microscopy, indicating that the internal tension of the actin cytoskeleton was significantly higher in VSMCs than in HeLa cells. Structural analysis with confocal microscopy revealed that VSMCs had a significant alignment of F-actin cytoskeleton with mature focal adhesion, contrary to the randomly oriented F-actin with smaller focal adhesion of HeLa cells, indicating that structural arrangement of the actin cytoskeleton and their mechanical tension generated the differences in cell mechanical properties and adhesion forces. The finding strongly suggests that the mechanical and structural differences in each cell type are deeply involved with their physiological functions.

Nanoscale effects of beverages on enamel surface of human teeth: An atomic force microscopy study

Dental erosion has become a prevalence disease and attracted increasing attention worldwide. In this research, we quantitatively evaluate the mechanical and morphological changes in the very early stages of softening and weakening of human enamel surfaces induced by soft drinks using atomic force microscopy (AFM). With an increase of the immersion time in soft drinks, we found a significant increase of surface roughness (Rq) of the enamel surface. The prismatic structure of enamel was clearly observed after a 1-h immersion in Coca-Cola®, which shows its strong erosion effect. According to the elastic modulus mapping images obtained by AFM, a considerable decrease of elastic modulus (E) of enamel surface has been found as the enamel surface structures are etched away by soft drinks. A high surface roughness of enamel will result in a high chance of cavities due to easier bacterial adhesion on rougher surface, while a drastic deterioration of the mechanical properties of the enamel will weaken its protection property. Our findings show the serious influence of acidic drinks on enamel surface at the very beginning stage of etching process, which is quite meaningful for people to prevent dental erosion and keep dental health.

Bacterial vs. thermal degradation of algal matter: Analysis from a physicochemical perspective

Bacteria are ubiquitous in all depositional environments, especially in marine environments where anoxic/euxinic conditions prevail. In such environments, sulfate-reducing bacteria play a critical role to supply sulfur as a biogenic source for H2S through biomass degradation. In the biodegradation process, chemical and mechanical properties of the organic matter alter. In order to document these variations in-situ, selected samples from a deeply buried mudrock (Bakken Formation), were examined through microscopy analysis. Two separate but adjacent telalginite particles were selected; An unaltered telalginite and a bacterially degraded telalginite, which still contains relicts of the parent Tasmanites. A combination of AFM-based IR spectroscopy with high-resolution amplitude-frequency modulation was used to evaluate and compare the physicochemical variations across these two particles at the nanoscale. Results indicate that all aromaticity indexes increase for both particles but at a higher rate as a result of bacterial degradation. Furthermore, it was found that bacterial degradation imposes a major mechanical heterogeneity to the organic matter under study, which was detected through phase imaging and modulus mapping captured from submicron to micron-scale level, which exposed the remnants of the parent Tasmanites. This study reveals that bacterial degradation can accelerate the maturation process, thus the generation of hydrocarbons from the kerogen to happen at the earlier stages of thermal adavance.

X-ray elastography by visualizing propagating shear waves

Elastography, an imaging modality for mapping elastic modulus in soft viscoelastic materials, has been developed using magnetic resonance imaging and ultrasound imaging, but few studies were reported on using X-ray imaging. We report on dynamic X-ray elastography, which relies on shear-wave propagation. We pneumatically vibrated polyacrylamide gel phantoms and obtained two-dimensional maps of storage and loss moduli, which were determined from temporal variation in displacement vectors of the vibrating particles in the phantoms. Our experiment provided storage moduli with a precision of 30% and a spatial resolution was one order of magnitude higher than other imaging modalities.

Compositionally modulated microstructure in nano-layered Ni-P metallic glass composite coating prepared by electrodeposition

Nano-domain metallic glass (or also termed as nanoglass) is a different modality of amorphous solid. Here we present a NiP metallic glass coating with periodic glassy/nanocomposite layered construction by multi-phase pulsed electrodeposition. The multilayered structure was identified by transmission electron microscopy and atom probe tomography. There is a periodic layered structure, ~30 nm intervals with close dependence of elements distribution and crystallinity. The modulus mapping reveals ~95 GPa for loosely glassy interfacial regions and ~115 GPa for metallic glassy core regions. The NiP composite implies superior resistance to corrosion and wear. An interesting insight into architecture control is demonstrated, opening a new design for various nanoglasses coatings with potential industrial applications, such as a strong coating on electrocatalytic electrodes.

Technical Note: Radiotherapy dose characterization of gel dosimetry using shear wave elasticity imaging.

Radiotherapy is an effective treatment for many types of cancer in clinical settings. Gel dosimetry has the potential to record three-dimensional (3D) dose distribution compared to a conventional ion chamber. As the elasticity of the gel is altered after irradiation due to gel polymerization, we aim to measure the dose recorded in gel dosimetry with ultrasonic shear wave elasticity imaging (SWEI), a nondestructive and quantitative elasticity imaging tool. In this study, a cylindrical N-isopropylacrylamide (NIPAM) polymer gel with a diameter of 10cm and a height of 10cm and with cellulose as an ultrasonic scatterer was irradiated by a linear accelerator with the irradiation parameters of 6MV x-ray, dose rate of 100cGy/min and field size of 10 20mm2 . The six gel phantoms were irradiated with the dose of 0, 1, 3, 5, 8, or 10Gy. The gel phantoms were measured with SWEI at 24, 36, and 48h after x-ray irradiation. The two-dimensional (2D) shear wave velocity and Young's modulus maps corresponding to x-ray dose distribution were reconstructed following a time-of-flight reconstruction from a set of time-series displacement maps. The spatial resolution of the reconstructed SWEI image is ~1mm. Our results show that the elastic modulus increases linearly as irradiation dose increases (R2 =0.94 at 24h, R2 =0.98 at 36h, R2 =0.98 at 48h), suggesting that the gel elasticity is highly associated with x-ray irradiation dose at 36h post irradiation, and the dose resolution was 0.66kPa/Gy. From the 3D elastic modulus maps, the dose distribution along the depth and lateral direction can be reflected in the NIPAM gel dosimetry using SWEI as well. In this study, the irradiated NIPAM gel phantom was quantitatively measured with SWEI for the first time to read the dose distribution recorded in the gel dosimetry. The results suggest that the gel elasticity is highly associated with x-ray irradiation dose. In the future, 2D/or 3D dose distribution from intensity modulated radiotherapy (IMRT) or other potential particle radiotherapy will be measured and reconstructed with SWEI and compared with the dose map from a treatment planning system (TPS) in the clinic.

Nanopore structure and nanomechanical properties of organic-rich terrestrial shale: An insight into technical issues for hydrocarbon production

Hydrocarbons in terrestrial shale are prospective unconventional resources, which have not yet been successfully produced worldwide despite strong interest. The unique microscopic characteristics of terrestrial shale and their implications for oil and gas development are demonstrated. Ultra-high-resolution imaging is performed based on a state-of-the-art focused ion beam and helium ion microscope (FIB/HIM) system. The results reveal that the nanopore structure and connectivity in terrestrial shale possess significant anisotropy and heterogeneity. Terrestrial shale presents much less micro- and mesopores than does successfully developed marine shale, which is the primary reason for the extremely low permeability in the former. Quasi-static indentation and modulus mapping based on a nanoindenter find significant modulus reduction due to water imbibition, which provides direct microscopic evidence for the ineffectiveness of hydraulic fracturing in terrestrial shale. The resources in terrestrial shale have the potential to be profitably developed. However, unfavorable factors, including high clay content, extremely low permeability, significant heterogeneity, strong anisotropy, and high water sensitivity, can lead to technical challenges for reservoir stimulation, which may be solved promisingly by waterless or water-free fracturing.

High-Resolution Ex Vivo Elastography to Characterize Tumor Stromal Heterogeneity In Situ in Pancreatic Adenocarcinoma.

Tumor stiffening in pancreatic adenocarcinoma (PDAC) has been linked to cancer progression and lack of therapy response, yet current elastography tools cannot map stiffness in a whole tumor field-of-view with biologically relevant spatial resolution. Therefore, this study was developed to assess stiffness heterogeneity and geometrical patterns across whole PDAC xenograft ex vivo tumors. The ex vivo elastography (EVE) mapping system was capable of creating stiffness map at 300-micron spatial resolution under a 5-20 mm field of view relevant to whole tumor assessment. The stiffness value at each location was determined by compression testing and an absolute tumor Young's modulus map was calculated based on the calibration between the system and ultrasound elastography (R2 = 0.95). Two PDAC tumor lines AsPC-1 and BxPC-3 implanted in xenograft models were assessed to show tumor stiffness and its linear relationship to collagen content (R2 = 0.59). EVE was able to capture stiffness heterogeneity ranging between 5 and 100kPa in pancreatic tumors with collagen content up to 25%. More importantly, data shows the inverse relationship of local stiffness to local drug distribution (R2 = 0.66) and vessel patency (R2 = 0.61) in both PDAC tumor lines. The results suggested that elastography could be utilized to predict drug penetration in PDAC tumors or assess response to biological modifying adjunct therapies. This study presents the first attempt to map out stiffness on a biologically relevant spatial scale across whole PDAC tumor slices with spatial resolution in the hundreds of microns.

Исследование влияния колхицина на нативные фибробласты методами атомно-силовой и конфокальной микроскопии

Using atomic force and confocal laser scanning microscopy, we studied the effect of colchicine, 1 µg/ml, which is known to cause the depolymerization of tubulin microtubules, on the primary rat fibroblast culture. When analyzing atomic force microscopy data, the sliding type of probe–cell contact was revealed by observing a clear increase of deformation signal at the sample inclined areas. For an unambiguous interpretation of the observed variations in the mechanical characteristics of fibroblasts, it is necessary to prove the sliding of the probe over the cell surface. It was found that some fibroblasts are soft and are characterized by a quite uniform distribution of the apparent Young's modulus over their surface, while others, much harder cells have rigid fibrous structures on the Young's modulus map. Colchicine has been shown to cause significant cell hardening in both groups. Confocal microscopy data show that the observed effect is associated with an increase in the intracellular content of F-actin in fibroblasts.

Nanomechanical characterization of a metal matrix composite reinforced with carbon nanotubes

A new technique for the manufacture metal matrix composites has recently been developed. This technique produces a structure of a metallic matrix banded structured-layers of multiwall carbon nanotubes by a diffusive processes. To understand the increase in the volumetric mechanical properties of the composite and the dispersion of the nano-reinforcement, a nanomechanical characterization was performed by nanoindentation and atomic force microscopy. From the mechanical tests performed, a stiffness and elastic modulus maps were made near the reinforced areas, then the dispersion of the nano-reinforcements and the homogeneity of the mechanical properties were accessed. The results showed an increase in the modulus of elasticity of up to 150%; and a good dispersion of the nano-reinforcements in the reinforced zone, which demonstrates the feasibility of the alternative manufacturing process for increasing the mechanical properties of the composite.

High-speed mechanical mapping of blended cement pastes and its comparison with standard modes of nanoindentation

The paper presents a new nanoindentation mode of accelerated property mapping (XPM) which is designed to access local mechanical property maps in the order of minutes, i.e. much faster than with standard modes of grid nanoindentation or modulus mapping. XPM is tested on three typical cementitious samples: cement paste, fly-ash and slag blended cement pastes. The results from the techniques were found quantitatively comparable in terms of local mechanical properties. The methods are characterized by different spatial resolution, different property fluctuations and acquisition times. High-speed loading in XPM brings strain rate effects that are not present in standard modes. The paper summarizes advantages and disadvantages of each technique and shows mutual comparisons for the tested composites. It is concluded that the new XPM mode brings an advantage of very fast characterization of heterogeneous composites with reasonably high spatial resolution. The quantitativeness of the method is disturbed by strain rate effects causing artificial shift of the properties towards higher values compared to static loading cases. Some parameters associated with longer acquisition times such as creep properties are not captured with XPM. XPM is especially suited for fast sensing of local differences between composite phases on smaller areas (≈103μm2). Statistical data from larger sample areas (104‐105μm2) are still easier obtainable from classical grid nanoindentation.