Cyclic Nanoindentation Research Articles

Evaluation of plasma process-induced mechanical property change in SiN films using a cyclic nanoindentation technique

Evaluation of plasma process-induced mechanical property change in SiN films using a cyclic nanoindentation technique

Strain softening observed during nanoindentation of equimolar-ratio Co–Mn– Fe–Cr–Ni high entropy alloy

This research article presents an atomistic study on the cyclic nanoindentation of an equimolar-ratio Co–Mn–Fe–Cr–Ni high-entropy alloy (HEA) using molecular dynamics simulation. The study investigated the effects of indentation depth on the cyclic load versus the indentation depth of the HEA. The results showed that the cyclic response exhibits a pronounced shift towards plasticity with pile-up formation instead of sinking behavior at higher indentation depths. Within the realm of molecular dynamics simulations, the simulated hardness value reached up to 16 GPa for the initial indentation cycle. A steep drop in the load–displacement curve was observed during the elastic–plastic transition, signifying substantial strain softening of the substrate. It was found that the densely clustered stacking faults undergo a reverse transition during cyclic loading, contributing to the backpropagation phase responsible for elastic recovery despite subsequent strain hardening. The study provides important insights into the underlying mechanisms governing the cyclic mechanical behavior of HEAs to guide their improved micromanufacturing.

Cyclic degradation mechanisms of Al0.3CoCrFeNi high-entropy alloy under different loading rates

The effect of loading rate on the cyclic degradation behavior of Al0.3CoCrFeNi high-entropy alloy (HEA) was investigated through nanoindentation experiments and molecular dynamics simulations. The evolution of mechanical properties and microstructure characteristics under different loading rates, as well as the mechanisms of cyclic degradation, were revealed. It is found that the increase of the loading rate induces higher hardness and smaller nanoindentation depth of the Al0.3CoCrFeNi HEA, which gradually increases with the cyclic loading of nanoindentation, resulting in a larger difference in characteristic nanoindentation depth among different loading rates. What’s more, a larger loading rate is inclined for nanoindentation depth to reach a steady state. Slip lines and pile-ups are formed around the nanoindentation region at higher loading rates indicating the occurrence of a more localized plastic deformation, while an amorphous transformation occurs at different loading rates after cyclic nanoindentation. Cyclic loading results in the gradual accumulation of residual stress, nanoindentation depth and amorphous structures within the material, and a localized plastic deformation. In summary, cyclic degradation of the Al0.3CoCrFeNi HEA is featured by cyclic softening due to dislocation slipping and the accumulation of amorphous phases.

Influence of α‐Precipitate Orientation and Distribution on the Deformation Behavior of the Additively Manufactured Metastable β‐Titanium Alloy Ti‐5553 Assessed by Cyclic Nanoindentation

The metastable β‐titanium alloy Ti–5Al–5V–5Mo–3Cr (Ti‐5553) has recently found growing interest as medical implant material due to its advantageous mechanical properties when compared to the up‐to‐date standard alloys. Besides biocompatibility, implant materials need to exhibit sufficient fatigue resistance. Herein, cyclic nanoindentation is applied up to a maximum cycle number of 105 to elucidate the influence of the local phase distribution on the cyclic deformation behavior of Ti‐5553, made by laser powder bed fusion of metals (LPBF‐M), in the (α + β)‐solution annealed state. By combining the localized cyclic mechanical loading and high‐resolution transmission electron microscopy, the influence of the presence and orientation of αp‐precipitates within the β‐grains on the cyclic deformation behavior and mechanisms is unraveled. αp‐phase orientation and distribution significantly contribute to the effectiveness of the precipitates as barriers to dislocation motion. A high density and trapping of dislocations are observed at α/β interfaces. The occurrence and size of the pile‐up surrounding the indents are correlated with the cyclic deformation behavior, and, thus, with the presence of αp‐precipitates. The gained improved knowledge of the phase‐dependent deformation behavior helps to better understand the fatigue performance of this alloy also on the macroscale.

Elastic-plastic properties of Li2B4O7 determined by nanoindentation

Relevance. Crystalline and amorphous lithium tetraborate (Li2B4O7) has a wide range of practical applications due to its physical properties. The knowledge of the mechanical characteristics of the surface layers of these materials, which are studied by nanoindentation, is necessary for optimising the technological processes for obtaining “optically perfect” samples. Aim. A comparative study of the mechanical properties and deformation mechanisms of glassy and crystalline Li2B4O7 samples in a wide range of applied loads. Methodology. The elastic-plastic properties of crystalline and glassy lithium tetraborate were investigated using the multiple-loading cyclic nanoindentation method. The samples were measured at maximum loading forces of 50, 100, 150, 200, 250, 300, 350, 400, 450, and 500 mN. Four measurements (in the form of a 2x2 matrix) were made at a distance of 50 µm from each other on each sample and at each load. Young’s modulus, hardness, and Poisson’s ratio of Li2B4O7 glass were also calculated using the Makishima-Mackenzie theory. Results. The load-displacement curves and graphs of the dependence of the average contact pressure on the displacement of the diamond Berkovich indenter were obtained, which have a “smooth” shape and no anomalies associated with “pop-in” or “pop-out” effects. The indentation modulus (Young’s modulus E) and hardness H of the studied samples were obtained from the experimental P-h load-displacement diagrams. The measured values mainly depend on the applied load or the contact depth of the indenter penetration into the crystalline and vitreous lithium tetraborate. Conclusions. Both the hardness and Young’s modulus of Li2B4O7 glass are lower than those of the single crystal, indicating a lower resistance of amorphous lithium tetraborate to elastic and plastic deformations. The obtained experimental values of hardness and Young’s modulus of Li2B4O7 glass correlate well with the results of the calculation within the framework of the Makishima-Mackenzie theory. Multiple-loading cyclic nanoindentation leads to deformation densification of glassy Li2B4O7 due to changes in the angles and lengths of chemical bonds, which leads to a decrease in the free volume in the medium-order structure of glass, as well as a change in the coordination of Boron atoms relative to Oxygen, i.e., the transformation of three-coordinated Boron into four-coordinated Boron

Effects of coals microscale structural features on their mechanical properties, propensity to crushing and fine dust formation

The work is dedicated to revealing the structural features of coals with different ranks, such as anthracites, metaanthracite and graphite, that determine their ability to crush and form fine dust. For this purpose, a combination of various nanoindentation techniques and Raman spectroscopy was used. The mechanical behavior of the selected coals was investigated by cyclic nanoindentation with increasing peak load and quasi-static loading. The alteration of the mechanical properties was studied by analysis of elastic moduli and damage indices Rw. Three groups of coals were identified based on their propensity to crushing during cyclic nanoindentation. Coals assigned to the first and second groups are characterized by local destruction in the contact zone with the indenter and the formation of a core of crushed material. Coals assigned to the third group are characterized by bulk destruction (outside the zone of contact with the indenter). In general, the ability of coals to fracture under mechanical loading decreases in the series of metamorphism due to microscale compaction of vitrinite matter. In the series of anthracite, metaanthracite and graphite, it is established that the coal matter compaction takes place for the anthracite and metaanthracite, whereas graphite reveals rather different behavior due to abrupt change of its structure. The ratios between the amorphous and crystalline phases of carbon (S) were determined by deconvolution of coals Raman spectra. The propensity of coals to crushing (a damage index Rw) increases with growth of the proportion of amorphous carbon in the coal matter. For the considered coals and metaanthracite, it is established that the proneness to destruction outside the contact zone with the indenter is determined by the ratio of amorphous and crystalline carbon of 1 and higher. When S parameter is lower than 1, the coals are being crushed only in the zone of contact with the indenter.

Cyclic Nanoindentation for Local High Cycle Fatigue Investigations: A Methodological Approach Accounting for Thermal Drift

Cyclic nanoindentation allows characterizing the influence of single phases and their interactions on fatigue mechanisms. Herein, a method for high cycle fatigue testing by nanoindentation is presented. By combining high‐ and low‐frequency indentation modes, high cycle numbers are achieved while obtaining sufficient data points to reconstruct force–displacement hysteresis loops. A challenge is the stochastic course of thermal drift which is addressed by measuring drift rate in regular low‐force holding segments. Drift rates are used to correct the displacement values, yielding reproducible cyclic deformation data as it is shown for two very different materials, a ductile metal and a brittle ceramic.

Towards understanding the mechanism of vibration-assisted cutting of monocrystalline silicon by cyclic nanoindentation

Ultrasonic vibration cutting (UVC) is a promising technology that can promote the processing of hard-brittle materials in ductile mode. The feature of intermittent cutting in UVC is considered to promote the ductile responses of brittle materials. However, the effect of cyclic loading/impact on microscopic deformation behavior of the workpiece material in UVC is not clearly understood. This study used cyclic nanoindentation to reveal the UVC mechanism in monocrystalline silicon (Si). The surface morphology and subsurface microstructure of the residual indents were characterized and compared with those of the UVC-machined grooves. This work attempted to correlate the tool-workpiece contacts for cyclic nanoindentation and vibration cutting. Cyclic nanoindentation results show that cyclic loading promotes the extent of silicon amorphization and decreases the threshold for transitioning the β–Sn phase to the bc8 and r8 phases. As the number of indentation cycles increases, the subsurface microstructure changes from the amorphous phase to the bc8 and r8 phases. In UVC, both the critical cutting depth for brittle-to-ductile transition and the degree of amorphization in cutting chips increase in comparison to conventional cutting, which matches the trend of cyclic nanoindentation results. The findings inform the chip formation and subsurface deformation mechanisms of brittle materials during UVC.

Effect of structural heterogeneity on work-hardening behavior of metallic glass thin film

In this study, three kinds of atomic disordered Cu50Zr50 metallic glass thin films (MGTFs) with different structural heterogeneities are prepared by controlling the substrate temperature in magnetron sputtering, i.e., controlling the thermal history. A work-hardening behavior is observed in the MGTFs by cyclic nanoindentation. The spatial distribution of structural heterogeneities, and the correlation length of the viscoelasticity of heterogeneity in three MGTFs with different thermal histories demonstrate the effect of thermal history on the viscoelasticity of three MGTFs. The activation volume of heterogeneity controlling the initiation of shear band during local deformation correlates the correlation length of viscoelastic heterogeneity, which is used to elucidate the relationship between the structural heterogeneity and the work-hardening behavior. The results show that the increase of the substrate temperature causes the viscosity of structural heterogeneity to be increased, which means the reduction of viscoelastic heterogeneity correlation length. In this case, the activation volume of heterogeneity in the MGTF is decreased, which leads the formation of shear band to be difficult.

Crack Propagation Behavior of Fused Silica during Cyclic Indentation under Incremental Loads

Fused silica is an important optical material with important applications, where the surface must be precisely machined without subsurface damage. In this study, multi-cyclic indentations under incremental loads were performed on fused silica using two kinds of indenters to clarify the mechanisms of crack generation and propagation induced by precision grinding. It was found that incremental loading cyclic nanoindentation induced various patterns of subsurface cracking and surface spalling. Four kinds of surface spalling were identified at different locations around an indent, the temporal formation mechanisms of which were clarified by microscopic observation and topographical measurement. Load–displacement curve analysis demonstrated that incremental propagation of lateral cracks during early indentation cycles caused large-scale brittle fractures during later cycles. Compared with a Berkovich indenter, a cube-corner indenter caused more significant brittle fractures and surface spalling. The findings in this study will deepen the understanding of subsurface damaging mechanism of fused silica and other brittle solids caused by cyclic tool-workpiece interactions in grinding and other mechanical machining processes.

Effects of low-temperature treatment on the coals mechanical properties microscale and airborne dust formation

The effect of freezing-thawing on the mechanical properties of coals at the microscale, the character of their destruction during cyclic nanoindentation, and the release of airborne dust have been studied. For these purposes, three hard coals from the Apsatsky deposit, two hard coals from the Pechora coal basin, and two lignites from the Kangalassky deposit were studied. It has been established that low-temperature impacts lead to a decrease in the content of airborne dust for all the coals. It was revealed that after freezingthawing of coals, their strength decreases, however, the character of destruction under mechanical impacts do not change. The exception is the coal of the middle stage of metamorphism of the Pechora basin, selected from a pack potentially prone to coal and gas outbursts. For this coal, low-temperature effects lead to a change in the character of its destruction during cyclic nanoindentation. Namely, there was a switch from the local (in the zone of contact with the indenter) character of destruction of the initial coal to the bulk one (outside the zone of contact with the indenter) for coal after low-temperature treatment. To assess the coals propensity to form fine dust particles, an index characterizing the degree of compaction of coal matter during cyclic nanoindentation with increasing load was introduced. It has been established that this index is proportionally connected with the content of airborne dust in coals (with sizes of less than 10 microns). It is shown that the coals proneness to form airborne dust under low-temperature impacts does not depend on the stage of coal metamorphism. For bituminous coals of the Apsatsky deposit with similar metamorphism degree the propensity to form dust is different. Variations in the propensity to form dust in coals of the Pechora basin, which also have a similar metamorphism degree, are apparently due to the peculiarities of the vitrinite structure of these coals.This work was carried out with the financial support of the Russian Science Foundation (Grant No. 18-77-10052).

Cyclic nanoindentation of ITO/Ag/ITO multilayer films: Hysteresis behavior and cyclic deformation response

The poor evaluation of the cyclic deformation response has been a main challenge for extensive applications and developments of ITO/Ag/ITO (IAI) multilayer films. In this paper, the effects of tri-layer film structure on hysteresis behavior and cyclic deformation response were investigated for IAI multilayer films via nanoindentation. The results indicate that the decreased density of picture-frame cracks and the enhanced mechanical performances for 300°C-IAI multilayer films are compared with those of ITO single-layer films under cyclic nanoindentation. Additionally, according to the energy-based method, the values of fracture toughness for 300°C-IAI multilayer films and ITO single-layer films are 3.49–4.17 MPa m0.5 and 3.04–3.18 MPa m0.5, respectively. Consequently, the structural design of ceramic/metal/ceramic tri-layer films are expected to be a potential method to enhance the resistance of cyclic deformation damage for transparent conducting films.

Damage Accumulation Phenomena in Multilayer (TiAlCrSiY)N/(TiAlCr)N, Monolayer (TiAlCrSiY)N Coatings and Silicon upon Deformation by Cyclic Nanoindentation.

The micromechanism of the low-cycle fatigue of mono- and multilayer PVD coatings on cutting tools was investigated. Multilayer nanolaminate (TiAlCrSiY)N/(TiAlCr)N and monolayer (TiAlCrSiY)N PVD coatings were deposited on the cemented carbide ball nose end mills. Low-cycle fatigue resistance was studied using the cyclic nanoindentation technique. The obtained results were compared with the behaviour of the polycrystalline silicon reference sample. The fractal analysis of time-resolved curves for indenter penetration depth demonstrated regularities of damage accumulation in the coatings at the early stage of wear. The difference in low-cycle fatigue of the brittle silicon and nitride wear-resistant coatings is shown. It is demonstrated that when distinguished from the single layer (TiAlCrSiY)N coating, the nucleation and growth of microcracks in the multilayer (TiAlCrSiY)N/(TiAlCr)N coating is accompanied by acts of microplastic deformation providing a higher fracture toughness of the multilayer nanolaminate (TiAlCrSiY)N/(TiAlCr)N.

Surface topography affects the nanoindentation data

The near-surface mechanical properties of thin films as well as bulk materials are amongst the key parameters important for their application, and instrumented nanoindentation is a standard technique for determining these mechanical properties. However, it is known that the surface topography of the characterized materials may affect the nanoindentation data when a sharp indenter for small penetration depths (displacements) is used. A thin film of hydrogenated amorphous silicon carbide with a thickness of 1.0 μm was deposited on a silicon wafer by plasma-enhanced chemical vapour deposition. The cyclic nanoindentation was used to construct a depth profile of mechanical properties for the flat surface (0.5 nm roughness) of the thin film, which made it possible to determine its modulus of elasticity of 83 GPa and hardness of 8.6 GPa unaffected by the silicon substrate. Grains with a spherical cap geometry with a typical radius of 0.5 µm and a height of 60 nm are distributed along the flat surface of the film. The grains have the same mechanical properties as the deposited film. Depth profiles of mechanical properties were determined for different types of contact between the Berkovich indenter with a radius of 50 nm and the selected grain (grain top, grain foot, two or three grains); i.e. for these measurements the following applied - the radius of the tip curvature was less than grain radii (RBerkovich < Rgrain). Residual imprints after nanoindentation measurements were carefully observed by atomic force microscopy and scanning electron microscopy. The near-surface mechanical properties were significantly affected by the surface topography, and the determined modulus of elasticity and hardness were crucially under- or overestimated in the range of 50% to 100% compared to the real values. The nature of these deviations was discussed. The solution is to use cyclic nanoindentation performed on the flat surfaces or on the top of grains, followed by extrapolation of the depth profiles to the zero-contact depth (film surface).

In-situ SEM cyclic nanoindentation of pre-sintered and sintered zirconia materials

Efficient diamond machining of zirconia requires a comprehensive understanding of repetitive diamond indentation mechanics. This paper reports on in-situ cyclic nanoindentations of pre-sintered and sintered zirconia materials performed inside a scanning electron microscope (SEM). In-situ SEM imaging of cyclic indentation processes and high-magnification SEM mapping of indentation imprints were conducted. The elastic and plastic behaviors of pre-sintered and sintered zirconia materials were investigated as a function of the cyclic nanoindentation number using the Sakai and Sakai-Nowak models. For pre-sintered zirconia, cyclic nanoindentation induced quasi-plastic deformation, causing localized agglomeration of zirconia crystals with microcracks and large cracking along the indentation edge. Severely compressed, fragmented, and pulverized zirconia crystals and smeared surfaces were also observed. For sintered zirconia, shear bands dominated quasi-plastic deformation with the formation of edge pile-ups and localized microfractures occurred at indentation apex and diagonals. All elastic and plastic behaviors for pre-sintered and sintered zirconia materials revealed significantly microstructure-dependent. Pre-sintered zirconia yielded significantly lower contact hardness, Young's moduli, resistance to plasticity, elastic deformation components, and resistance to machining-induced cracking, and higher elastic and plastic displacements than sintered state. Meanwhile, all the behaviors for the two materials were independent from the cyclic nanoindentation number. A model was proposed for cyclic nanoindentation mechanics, revealing their cyclic indentation-induced microstructural changes in the two zirconia materials. This study advances the fundamental understanding of nanoindentation mechanics of zirconia materials.

Mechanical response of silver/polyvinyl alcohol thin film: From one-step and cyclic nanoindentation

Polymer nanocomposite and its mechanical properties are the area of immense interest for material developers in academia and industry. Present study investigates mechanical behavior of novel hexagonal bipyramidal Silver-Poly (vinyl alcohol) nanocomposites (Ag/PVA NCs) thin film fabricated using aqua-mediated in-situ reduction at room temperature. Specimen was characterized through UV-Visible (λmax = 417 nm), PL (λ(em) = 482 nm), XRD (average crystallite size 29.7 nm and preferential growth of thin film along [111] plane), TEM (hexagonal bipyramidal morphology, size ∼26.25 nm), TGA (increased thermal stability), FTIR (peaks at 945, 604 cm-1 confirms coordination of Ag and PVA matrix) and SAED. Depth sensing single-step and multi-step nanoindentation was employed to extract material’s sensitive mechanical property. Hardness (H: 0.352 to 0.192 GPa) and elastic modulus (Er: 8.718 to 6.72GPa) decreased with increasing single-step loads (from 50 μN to 10 mN), which can be attributed to indentation size effect (ISE). Cyclic nanoindentation (p∼5 mN, 23 cycles) was performed to deeply understand material sensitive degree of dislocation-structure interaction for fatigue analysis. The reduction in % elastic recovery was found at higher loads. On account of smooth surface, elastic unloading (stiffness) values linearly (y = 1.3944x + 3.8676 with R2 = 0.9835) increased from cycle 1 to 23 and contact depth increases linearly (y = 0.0329x + 1.5697, R2 = 0.9901) with the number of cycles. Interpretation of p-h profile indicated H and Er decreases with increasing load, along with proceeding cycles and no fracture or breakage/ weakening of NCs / progressive and localized structural damage was observed which evidenced that surface was completely uniform and defect free.

Cyclic deformation behavior of Mg–SiC nanocomposites on the macroscale and nanoscale

AbstractMetal‐ceramic nanocomposites are promising candidates for applications necessitating light weight and excellent fatigue resistance. We produced Mg–SiC nanocomposites from mechanically milled powders, yielding a homogeneous nanocrystalline structure and excellent quasistatic strength values. Little is known, however, about the fatigue behavior of such composites. Here, we used load increase tests on the macroscale to yield estimation values of the fatigue endurance limit. Fatigue strength increased significantly for the materials processed by the powder metallurgical route. We further investigated the cyclic deformation behavior under stress‐controlled conditions on the macroscale and nanoscale. Cyclic nanoindentation showed that indentation depth and cyclic plastic deformation decreased with increasing reinforcement content, hinting to a higher cyclic strength and corroborating the results from the macroscopic load increase tests. Our results therefore show that cyclic nanoindentation reliably determines the plastic deformation behavior of Mg nanocomposites offering the possibility of fast material analysis.

Deformation response of gradient low-temperature gaseous carburized case in austenitic stainless steel during cyclic nanoindentation

Low-temperature gaseous carburizing is an effective strengthening technology for austenitic stainless steel which could generate a gradient carburized hardening case on the surface. Cyclic nanoindentation tests with different loadings were carried out to investigate micro deformation response along the depth in the gradient carburized case. The results shows that the properties of carburized case appear a gradient distribution and the elastoplastic property of carburized case is different from that of substrate. Moreover, cyclic hardening occurs during the cyclic nanoindentation tests. The cyclic hardening rate of the carburized case changes along depth and it is significantly higher than that of substrate. The micro morphologies have been scanned and it appears different micro deformation responses along depth in the carburized case during cyclic nanoindentation. Pile-up was found in carburized case but it is not obvious in substrate. Finally, the micro deformation mechanisms of carburized case and substrate during cyclic nanoindentation were analyzed. Backward deviation of hysteresis curve was found in carburized case during cyclic nanoindentation and it is believed that the extremely high compressive residual stress plays a key role in the backward deviation of hysteresis curves for carburized case.

Development of micro- and nanoindentation methods for assessing the mechanical properties of coals and their propensity to destruction

The destruction of coals in the processes of mining, storage, transportation and processing is associated, among other, with their mechanical properties. As a rule, the mechanical properties of coals are evaluated by the resul ts of measurements of such characteristics as tensile and compressive strength, stiffness (elastic modulus) and Poisson’s ratio, etc. For this, experiments are carried out on specially prepared samples in tensile testing machines and mechanical presses. Such integral indicators characterize the mechanical behavior of coals at the macro scale and do not allow assessing the influence of structural features on the initiation of defects leading to destruction. In this regard, the characteristics of the mechanical properties of coals, obtained in areas comparable to the levels of microcracks initiation, are of interest. Micro- and nanoindentation techniques are quite simple to implement for obtaining the reliable information on various mechanical properties of materials at the appropriate scale levels. This paper is dedicated to an overview of the current state of research on the use of these methods to assess the mechanical properties of coals and their individual macerals, as well as their ability to crush with the formation of dust particles. The use of micro- and nanoindentation techniques made it possible to establish the differences in the mechanical properties of individual macerals of coals, as well as to characterize the heterogeneity of the distribution of various indicators characterizing mechanical properties within the individual macerals. Based on experimental data on nanoindentation and Raman spectroscopy, it was shown that the change in the mechanical properties (values of the modulus of elasticity and hardness) of vitrinite in the series of coal metamorphism is associated with an increase in the proportion of graphitized components in organic matter. Nanoindentation methods, combined with an analytical mathematical apparatus, made it possible to obtain data on the ability of coals to crush under mechanical effects with the formation of particles with sizes comparable to those of hazardous aerosol dust (class PM 2.5). The method of cyclic nanoindentation with an increasing maximum load was proposed as a method for determining the degree of coal tendency to fracture with the formation of dust. Its application made it possible to reveal the characteristics of irreversible changes occurring in the structure of coals during destruction. They are expressed in a change in their mechanical properties (stiffness and fracturing ability) with an increase in the applied load. The use of the cyclic nanoindentation method is a promising method for the qualitative and quantitative analysis of the degree of coal propensity to crushing with the formation of dust. This work was carried out with the financial support of the Russian Science Foundation (Grant No. 18-77-10052).

Evaluation of the surface fatigue behavior of amorphous carbon coatings through cyclic nanoindentation

Diamond-like carbon (DLC) coatings, frequently used to reduce wear and friction in machine components as well as on forming tools, are often subjected to cyclic loading. Doping of DLC coatings with metals or metal carbides as well as the usage of multilayer architectures represent promising approaches to enhance toughness, which is beneficial for the coatings' behavior under cyclic loading. In this study, we utilized cyclic nanoindentation to characterize the tribologically induced surface fatigue behavior of single-layer tungsten-doped (a-C:H:W) and multilayer silicon oxide containing (a-C:H:Si:O/a-C:H)25 amorphous carbon coatings under cyclic loading. Columnar growth was observed for both coatings by focused ion beam microscopy and scanning electron microscopy, while the multilayer architecture of the (a-C:H:Si:O/a-C:H)25 coating was verified by the silicon content using glow-discharge optical emission spectroscopy. In cyclic nanoindentation of the (a-C:H:Si:O/a-C:H)25 multilayer coating, stepwise small changes in indentation depth were observed over several indentation cycles. The surface fatigue process of the single-layer a-C:H:W covered a smaller number of indentation cycles and was characterized by an early steep increase of the static displacement signal. Microscopical analyses hint at grain deformation, sliding at columnar boundaries, and grain detachment as underlying fatigue mechanisms of the a-C:H:W coating, while the (a-C:H:Si:O/a-C:H)25 multilayer coating showed transgranular crack propagation and gradual fracturing. In case of the (a-C:H:Si:O/a-C:H)25 multilayer coating, superior indentation hardness (HIT) and indentation modulus (EIT) as well as a higher HIT3/EIT2 ratio suggest a higher resistance to plastic deformation. A high HIT3/EIT2 ratio, being an indicator for hindered crack initiation, combined with the capability of stress relaxation in soft layers contributed to the favorable surface fatigue behavior of the (a-C:H:Si:O/a-C:H)25 multilayer coating observed in this cyclic nanoindentation studies.