nanoindentation

Functional regeneration of anisotropically aligned tissues such as ligaments, microvascular networks, myocardium, or skeletal muscle requires a temporal and spatial series of biochemical and biophysical cues to direct cell functions that promote native tissue regeneration. When these cues are lost during traumatic injuries such as volumetric muscle loss (VML), scar formation occurs, limiting the regenerative capacity of the tissue. Currently, autologous tissue transfer is the gold standard for treating injuries such as VML, but can result in adverse outcomes including graft failure, donor site morbidity, and excessive scarring...

Glucocorticoid-induced osteoporosis (GIOP) changes the microarchitecture of bones and often leads to the reduction of bone-mineral density (BMD) and increased fracture rates. Zebrafish has been used as an alternative model for GIOP, however, the interaction of GIOP, and its treatment, with zebrafish bone morphometrics and mechanical properties, remains a challenge. Thus, this study aimed to evaluate the effects of prednisolone and alendronate on the properties of zebrafish vertebrae. Adult 7-month-old zebrafish were distributed into four groups: control (CTRL), prednisolone-only (PN), alendronate-only (ALN), and the sequential use of both medicines (PN + ALN)...

Plasma electrolytic oxidation (PEO), applied to light metals such as titanium, aluminum, and magnesium, creates a two-layer coating and has become increasingly important in metal coatings. However, due to the high voltage and temperature of the process, no online instrument could monitor the underlying mechanism. This paper presents a new image proving that the surface of PEO-coated Mg3ZnCa boiled during the process and argues that three hypotheses are involved in the PEO mechanism based on boiling caused by tolerating high voltage during the PEO process, which could explain the current‒voltage diagram of the process...

The glass-glass interfaces (GGIs) are in a unique glass phase, while current knowledge on the interfacial phase has not completely established to explain the unprecedented improvements in the ductility of metallic nanoglasses (NGs). In this work, Co-P NGs prepared through the pulse electrodeposition are investigated, whose GGI regions clearly show elemental segregation with chemical composition dominated by element Co. Such compositional heterogeneity is further verified by molecular dynamics (MD) simulation on the formation of GGIs in Co-P NGs and atomic structures of GGIs with Co segregation are found to be less dense than those of glassy grains...

Extensive research has shown that nanolayered structures are capable of suppressing the shear banding in metallic glass in nanoindentation experiments. However, the specific mode and mechanism of the shear banding underneath the indenter remains unknown. Also, the quantification of shear banding-induced strain localization is still a challenge. Herein, the size-dependent shear banding behavior of a CuTiZrNb high-entropy alloy-based nanolayered glass with individual layer thicknesses ( h ) ranging from 5 to 80 nm was systematically investigated by nanoindentation tests...

Polyether-ether-2-ketone (PEKK) is a high-performance thermoplastic polymer used in various fields, from aerospace to medical applications, due to its exceptional mechanical and thermal properties. Nonetheless, the mechanical behavior of 3D-printed PEKK still deserves to be more thoroughly investigated, especially in view of its production by 3D printing, where mechanical properties measured at different scales are likely to be correlated to one another and to all play a major role in determining biomechanical properties, which include mechanical strength on one side and osteointegration ability on the other side...

The coal's mechanical properties have a significant influence on mining safety and the mine environment. Preparing a standard sample and conducting repeat mechanical testing are challenging because the coal is primarily soft, fragmented, and rich in developed fractures. This study used nanoindentation technology, combined with X-ray diffraction, small-angle X-ray, a high magnification microscope, and mechanical parameter scale-up analysis, to study the micromechanical of three coals being dominated by heterogeneous components and pores...

The mechanical properties of the jawbone play a critical role in determining the successful integration of dental prostheses. Chronic kidney disease (CKD) has been identified to abnormally accelerate bone turnover rates. However, the impact of CKD on the mechanical characteristics of the jawbone has not been extensively studied. This study sought to evaluate the time-dependent viscoelastic behaviors of rat jawbones, particularly in the scenarios both with and without CKD. We hypothesized that CKD might compromise the bone's innate toughening mechanisms, potentially owing to the time-dependent viscoelasticity of the bone matrix proteins...

We utilize room-temperature uniaxial pressing at applied loads achievable with low-cost, laboratory-scale presses to fabricate freestanding CH3 NH3 PbX3 (X- = Br- , Cl- ) polycrystalline ceramics with millimeter thicknesses and optical transparency up to ∼70% in the infrared. As-fabricated perovskite ceramics can be produced with desirable form factors (i.e., size, shape, and thickness) and high-quality surfaces without any postprocessing (e.g., cutting or polishing). This method should be broadly applicable to a large swath of metal halide perovskites, not just the compositions shown here...

Organic-inorganic organohalide hybrid solids have garnered significant attention due to their unique structural diversity, desirable electronic structures, and excellent optoelectronic properties. Here, we investigate the mechanical properties of a homologous series of 2D copper bromide hybrids (A2 CuBr4 , ACuBr4 ) through nanoindentation to analyze the contribution of organic interlayer interactions to bulk mechanical response. We identify a direct correlation between the identity of the organic spacer and the bulk mechanical response, where stronger bonding interactions in the organic interlayer resulted in increased hardness and elasticity...

Hepatocellular carcinoma (HCC) is a highly prevalent cancer with a significant impact on human health. Curcumin, a natural compound, induces cytoskeletal changes in liver cancer cells and modifies the distribution of lipids, proteins, and polysaccharides on plasma membranes, affecting their mechanical and electrical properties. In this study, we used nanomechanical indentation techniques and Kelvin probe force microscopy (KPFM) based on atomic force microscopy (AFM) to investigate the changes in surface nanomechanical and electrical properties of nuclear and cytoplasmic regions of HepG2 cells in response to increasing curcumin concentrations...

Ti6Al4V (Ti64) is a versatile material, finding applications in a wide range of industries due to its unique properties. However, hydrogen embrittlement (HE) poses a challenge in hydrogen-rich environments, leading to a notable reduction in strength and ductility. This study investigates the complex interplay of solute hydrogen (SH) and hydride phase (HP) formation in Ti64 by employing two different current densities during the charging process. Nanoindentation measurements reveal distinct micro-mechanical behavior in base metal, SH, and HP, providing crucial insights into HE mechanisms affecting macro-mechanical behavior...

Gas-atomization is extensively used to produce metallic feedstock powders for additive manufacturing processes, including gas dynamic cold spray processing. This work explores the potential utility of on-demand recycled titanium scrap feedstock powder as a viable substitute for virgin powder sources. Three recycled titanium powders were atomized from different battlefield scrap sources using a mobile foundry developed by MolyWorks Materials Corporation. Recycled titanium alloy powders were compared against virgin Ti-6Al-4V powder to verify there were no significant variations between the recycled and virgin materials...

The incorporation of energetic helium gaseous species into materials such as tungsten (W) imparts intrinsic surface fragility, yielding fuzzy tungsten. To enhance the robustness of the surface layers, aluminum oxide (AlO x ) was deposited by atomic layer deposition into the fuzzy W. The conformally deposited ceramic yields a new class of surface composites. Structural characterization of the fuzzy W-AlO x composites through nanoindentation testing indicated enhanced indentation modulus ( E ind ) and hardness ( H ind ) and was modeled through various rules of mixtures approaches...

The high occurrence of distal fibula fractures among older women suggests a potential link to impaired bone health. Here we used a multiscale imaging approach to investigate the microarchitecture, mineralization, and biomechanics of the human distal fibula in relation to age and sex. Microcomputed tomography was performed to analyze the local volumetric bone mineral density and various microstructural parameters of the trabecular and the cortical compartment. Bone mineral density distribution and osteocyte lacunar parameters were quantified using quantitative backscattered electron imaging in periosteal, endocortical and trabecular regions...

Nanoindentation cycles measured with an atomic force microscope on hydrated collagen fibrils exhibit a rate-independent hysteresis with return point memory. This previously unknown energy dissipation mechanism describes in unified form elastoplastic indentation, capillary adhesion, and surface leveling at indentation velocities smaller than 1 μm s-1 , where viscous friction is negligible. A generic hysteresis model, based on force-distance data measured during one large approach-retract cycle, predicts the force (output) and the dissipated energy for arbitrary indentation trajectories (input)...

Poly(methyl methacrylate) (PMMA) is commonly used for dental dentures, but it has the drawback of promoting oral health risks due to oral bacterial adhesion. Recently, various nanoparticles have been incorporated into PMMA to tackle these issues. This study aims to investigate the mechanophysical and antimicrobial adhesive properties of a denture resin by incorporating of nanoclay into PMMA. Specimens were prepared by adding 0, 1, 2, and 4 wt % surface-modified nanoclay (Sigma) to self-polymerizing PMMA denture resin...

Establishing low-resistance ohmic contact is critical for developing electronic devices based on traditional silicon and new low-dimensional materials. Due to unprecedented electronic and mechanical properties, the one-dimensional carbon nanotubes (CNTs) have been used as source/drain, gate, or tunnel to fabricate transistors. However, the mechanism causing low-resistance ohmic contact is not clear yet. Here, the hybrid atomic force microscopy-scanning electron microscopy (AFM-SEM) instrument was developed to establish lower-resistance ohmic contact between a radial compressed deformed multiwalled CNT bundle and high work function metal (platinum and gold)...

In this paper, the microstructure and mechanical properties (including nanoindentation, tensile test, and compression test) of Mongolian horse hooves were investigated. Many tubules and Intermediate Filaments (IF) were distributed longitudinally in the hoof of Mongolian horses, which could better help the hoof cushioning. The hardness and modulus of the hoof wall of Mongolian horses varied at different water contents. The hardness and modulus decreased with the increase in water content. The modulus of elasticity of the hoof wall decreased from 16...

Compositionally complex oxides (CCOs) or high-entropy oxides (HEOs) are new multielement oxides with unexplored physical and functional properties. In this work, we report fluorite structure-derived compositionally complex zirconia with composition Zr1- x (Gd1/5 Pr1/5 Nd1/5 Sm1/5 Y1/5 ) x O2-δ ( x = 0.1 and 0.2) synthesized in solid-state reaction route and sintered via hot pressing at 1350 °C. We explore the evolution of these oxides' structural, microstructural, mechanical, electrical, and electromechanical properties regarding phase separation and sintering mechanisms...