Elastic Ratio Research Articles

Establishing a benchmark for comparative analysis of thin and thick plate modal frequencies: A non-dimensional paradigm

This study presents a methodological framework to establish a standardised baseline for comparing the vibrational characteristics of thin and thick rectangular orthotropic plates in acoustics. The research addresses the inherent difficulties associated with varying plate parameters by proposing the use of non-dimensional frequencies for comparative assessments. It will be shown that, under the thin-plate approximation, plates with identical aspect ratios, boundary conditions, and elastic constant ratios exhibit identical non-dimensional modal frequencies and shapes. The proposed methodology involves generating baseline non-dimensional frequencies and modal shapes via numerical simulations for a reference plate with specified parameters. Subsequent analysis entails systematically varying plate thickness and determining the number of modes that yield the same non-dimensional frequencies within a predefined deviation of the baseline. Notably, the comparison is conducted on an eigenshape basis, thereby circumventing the consideration of dimensional frequencies. This approach offers a structured framework for comparative analysis, centred on identifying modes exhibiting thin behaviour regardless of dimensional frequency, thus enhancing the objectivity of modal characterisation.

Damage characteristics and constitutive model of magnesium slag-based cemented backfill based on energy dissipation

Uniaxial compression tests were conducted on magnesium slag-based backfill with different curing ages (3, 7, and 28 d) and different magnesium slag grinding time (0, 40, 60, and 80 min) to investigate the energy damage characteristics and the constitutive model of ground magnesium slag-based cemented backfill in depth. The effects of curing age and magnesium slag grinding time on the energy evolution and distribution characteristics, as well as energy indexes at characteristic points of magnesium slag-based backfills, were examined. From the perspective of energy dissipation, damage variables and modified damage constitutive models were proposed to address the shortcomings of existing damage constitutive studies. The results of the study show that extending the curing age can effectively increase the energy storage limit of backfill and exhibit higher linear elastic deformation capacity. The elastic energy ratio curves of the backfill show an upward and then a downward trend, while the dissipated energy ratio curves show the opposite trend. The relationship between the total energy at the peak stress and the curing age and magnesium slag grinding time can be characterized by linear and quadratic polynomial functions, respectively. The pre-peak energy consumption, post-peak energy consumption, total energy consumption, and energy storage limit of magnesium slag-based backfill all show a linear increase with increasing curing age. The modified energy damage constitutive of magnesium slag-based backfill considering the compaction stage and residual strength shows higher consistency with the test constitutive, which can more realistically reflect the deformation process of the backfill. These results can provide a theoretical basis for investigating the stability of magnesium slag-based backfills in mine filling applications.

Study on visualization of impact damage characteristics of honey peaches based on finite element method.

The study of visualization of impact damage of fruit under different thicknesses of buffer materials can provide more efficient transportation and packaging solutions, and thus the economic losses caused by fruit damage can be reduced. Pearl cotton (EPE) is commonly used as a buffer material in the market, and the impact damage behavior of honey peaches under different thicknesses of EPE buffer material was studied by using the finite element method. Firstly, the damage area, maximum contact force and damage volume during the collision of honey peaches with EPE materials of different thicknesses (2, 4, and 6mm) were obtained by the single pendulum device, and then the Modulus of elasticity and Poisson's ratio of peach flesh were obtained by compression test. Finally, the finite element model of honey peach was built and the collision simulations were performed. The results of the study showed that the values of mechanical parameters of honey peach decreased with the increase of the thickness of the buffer material. When the collision angle was below 60°, the honey peaches were not damaged in the collision with the EPE material with a thickness of 4mm or more. By comparing the tested values with the simulated values, it was found that the errors of the damage area, damage volume and maximum contact force were less than 19.71%, 26.82%, and 25.88%, respectively. The study not only proves the possibility of the finite element method in the quantitative prediction of honey peaches damage but also provides rational support for the packaging design of honey peaches.

Experimental study on energy and damage evolution of dry and water-saturated dolomite from a deep mine

The deformation and failure of a rock is closely related to the strain energy consumption during the load process of rock. To investigate the effect of water on energy evolution and damage characteristics of dolomite samples from a deep mine, the uniaxial compression tests were carried out on dry and water-saturated dolomite samples at different burial depths (900 m–1200 m). The effects of water on the evolution characteristics of elastic and dissipative energy ratios ( Ue/ U and Ud/ U) during rock deformation and failure was analyzed. Based on the variation rate of damage factor ( Df), a new brittleness index is proposed, which can effectively characterize the brittleness characteristics of water-bearing dolomite. The results show that the uniaxial compressive strength and elastic modulus of the water-saturated dolomite are significantly reduced compared to dry sample. The energy and damage evolution process of dolomite can be divided into four stages: initial damage stage, stable damage stage, pre-peak accelerated damage stage and post-damage stage. The variation rate of damage factor of the rock samples in the stable damage stage and the pre-peak accelerated damage stage appeared to increase significantly after water saturation treatment. Compared with water-saturated samples, more pronounced energy hardening characteristics and brittleness characteristics were observed in dry samples. In addition, the possible impact on the stability of deep rock engineering after the deterioration of rock mechanical properties and energy storage properties caused by water was analyzed. Groundwater can somewhat reduce rock burst proneness. However, it also has the potential to lead to greater rock engineering destabilization and failure hazards.

Energy dissipation damage constitutive relation of CFRP passively confined coal sample

In view of the stability problem of coal pillars left over during coal resource mining, (Carbon Fiber Reinforced Polymer) CFRP sheet is applied in coal pillar reinforcement. Uniaxial compression tests of CFRP passively confined coal samples are carried out to explore the mechanical response mechanism of passively confined coal samples under different layers, and the energy dissipation damage constitutive relationship of CFRP passively confined coal samples is established based on the energy dissipation principle. The conclusions are: As CFRP layers increased, the local damage of coal samples before the peak evolved from a 'cliff-like jagged' to a 'capillary jagged', with post-peak instability marked by a shift to more 'cliff-like' characteristics. The tests revealed improvements in peak strength and elastic modulus, with a defined functional relationship between these properties and CFRP layers. The energy storage capacity of passively confined coal samples improved with CFRP layers, requiring less axial deformation to achieve equivalent energy levels. The energy dissipation rate showed an initial decrease followed by an increase, with a minimum inflection point, the elastic energy consumption ratio tends to decrease slowly and then rapidly during post-peak instability. A damage constitutive relationship and evolution equation were developed, highlighting that the CFRP sheet significantly inhibits damage, with diminishing effectiveness beyond two layers. The study concludes that three-layer CFRP sheets provide optimal confinement, offering a novel strategy for the reinforcement of coal pillars and the prevention and control of rock burst, without considering the actual coal pillar dimensions and shape. To sum up, the use of CFRP sheet to strengthen coal pillar has considerable potential research value in strengthening coal pillar and improving the recovery rate of coal resources.

Parametric analysis of vibration characteristics of laminated composite plate structures

Abstract In order to conduct the vibration performance of laminated composite structures, the relationship between the vibration frequency and the parameters such as aspect ratio, width-thickness ratio, elastic modulus ratio and lay-up angle of the plate structure under different boundary conditions was investigated and the variation law of its vibration characteristics was obtained. The conclusions are as follows: 1. The vibration frequency tends to be smaller and smaller as the value of length increases. 2. The vibration frequency tends to be larger and larger as the value of thickness increases. 3. The vibration frequency increases with the increase of the value of elastic modulus.4. The symmetrical lay-up structure with the lay-up angle of the middle ply at 45 degrees has the lowest vibration frequency.

Static and Dynamic Characteristics of 3D-Printed Orthogonal Hybrid Honeycomb Panels with Tunable Poisson’s Ratio

By adjusting the two wall angles of the orthogonal hybrid honeycomb (OHH), the tunable Poisson’s ratio change from negative to positive values and the variation in stiffness can be achieved. To effectively analyze its static and dynamic characteristics, a two-dimensional equivalent Kirchhoff–Love model (2D-EKM) is established based on the variational asymptotic method (VAM).This model aids in effectively addressing the complexity arising from anisotropy. The obtained equivalent orthotropic properties are validated through unit-cell uniaxial compression tests and three-point bending experiments on 3D-printed specimens. The numerical simulation results suggest that the VAM-based 2D-EKM can predict the in-plane and out-of-plane static behaviors of OHH panels, with a maximum error below 10%. Particularly in the dynamic analysis of a four-sided fixed OHH panel, the analysis time required by 2D-EKM is only 0.37% of that needed for the 3D FE model. The OHH-ZPR panel exhibits exceptional resistance to deformation, with a maximum deformation under in-plane tension reaching only 27% of that in the OHH-PPR panel. Moreover, each 1% increase in the height–length ratio results in a respective increase of 275.62% and 281.93% in equivalent bending stiffness along both directions. This highlights that enhancing this ratio effectively boosts the fundamental frequency compared to the elastic modulus ratio, effectively prevents low-frequency resonance occurrences, and offers vital insights for the design and optimization of OHH panels.

Time-domain expression and mechanical response of the viscoelastic Poisson's ratio in asphalt pavement

Poisson's ratio (PR) is a fundamental mechanical parameter for materials. Unlike the constant Elastic Poisson's Ratio (EPR), the Viscoelastic Poisson's Ratio (VEPR) is significantly influenced by external factors such as environmental temperature, stress level, and loading frequency. Using the VEPR to characterize the stress state of asphalt pavements provides a more accurate reflection of their actual service conditions. Moreover, the VEPR plays a more critical role than the EPR in predicting fatigue life, analyzing temperature sensitivity, and optimizing pavement structure design. In this study, the Elastic-Viscoelastic Correspondence Principle (EVCP) and the Zener mechanical model were combined to derive a time-domain expression for the VEPR of asphalt pavement. Fiber Bragg Grating (FBG) sensors were embedded within various structural layers of an in-service road to collect mechanical response and temperature data under traffic loads. Based on the measured temperature data, Finite Element Models (FEMs) were developed for both the VEPR and EPR conditions. The mechanical responses were validated using these FEMs, and the results were compared with the strain data collected by the FBG sensors. The results indicated that both VEPR and EPR increase most rapidly between 20°C and 35°C, with VEPR resulting in higher transverse and longitudinal strains and stresses than EPR, while vertical strain remained constant. Furthermore, the VEPR was better suited to actual driving conditions, with a peak error of only 3.97 % and an average error of 10.04 %.

Design and additive manufacturing of novel hybrid lattice metamaterial for enhanced energy absorption and structural stability

In this work, a novel dual-phase metamaterial, named as “hybrid lattice metamaterial (HLM),” are designed and fabricated by combining reentrant and sea-urchin (SU) based surface-lattice (SL) structure with polyamide12 (PA12) material via material extrusion (MEX) process. Four different designs with varying reentrant truss thicknesses of 0.8 mm (H1), 1.0 mm (H2), 1.2 mm (H3), and 1.5 mm (H4) have been modified to assemble seamlessly with the empty spaces within the SL structure. Quasistatic compression tests were conducted to evaluate the deformation modes and compression characteristics. The findings from quasistatic experiments were subsequently validated using numerical simulations. The H4 metamaterial exhibited superior structural properties, with 42 % increase in stiffness and 35 % enhancement in specific energy absorption compared to only SL structure. Additionally, dynamic sinusoidal compression tests were conducted to evaluate the dynamic elastic ratio (DER), hysteresis work and viscoelastic properties using the tan δ. The H4 metamaterial outperformed the SL in all dynamic properties, with a 50 % increase in elastic modulus and 36 % increase in hysteresis work. This study shows metamaterial properties can be tailored for specific requirements. SL structure facilitate elastic recovery, while H4 metamaterials offer superior energy absorption and stability, making it well-suited for protective equipment and impact-resistant components.

Evaluating fetal lung development at various gestational weeks using two-dimensional shear wave elastography.

Noninvasive evaluation of fetal lung development is a critical area of study. Two-dimensional shear-wave elastography (2D-SWE) provides valuable insights into tissue stiffness, potentially correlating with different stages of lung development. This study aims to explore the potential of the 2D-SWE technique for assessing the maturity of fetal lung development. This prospective cohort study included pregnant women undergoing routine antenatal ultrasound examinations at the Second Affiliated Hospital of Fujian Medical University and Quanzhou Women's and Children's Hospital from September 2022 to September 2023. The study consecutively recruited 300 pregnant women with normal pregnancies and 15 who opted for induced labor. Among those with normal pregnancies, the study assessed the differences in fetal pulmonary and hepatic elasticity measurements across different gestational weeks (GW) using one-way analysis of variance (ANOVA). Furthermore, regression analyses using linear, quadratic, and cubic equations were conducted to investigate the relationship between fetal parameters and GW. For those who opted for induced labor, elasticity measurements were taken before induction, and fetal lung tissue specimens were collected for post-induction observation. Fetal lung and liver elasticity values, along with the lung-to-liver elasticity ratio (LLE ratio), showed significant variations across different GW (P<0.05). Specifically, fetal lung elasticity values initially increased and then decreased as GW advanced (R2=0.41). Liver elasticity values continuously increased throughout GW, though the rate of increase diminished during the prenatal period (R2=0.37). The LLE ratio values increased and then decreased over GW, fluctuating overall between 0.8 and 0.9 (R2=0.14). A 71.4% concordance was observed between the predicted stage of lung development, based on lung elasticity values, and the histological stage of lung development in the induced fetuses. 2D-SWE can depict the maturation of fetal lung development at various stages.

Effects of Boric Acid on Laminated Composites: An Experimental Study.

In this study, the effect of boric acid (H3BO3) on fiber-reinforced layered composites was investigated. Glass fiber-reinforced epoxy composites were used, and the effects of boric acid on thermal and mechanical properties were investigated. For this purpose, composite plates were manufactured by adding boric acid (BA) to the epoxy in different ratios (0, 0.5, 1, and 1.5% by weight). Tensile tests, compression tests, and shear tests were performed to determine the mechanical properties of these plates, and DSC, TGA, and DMA analyses were performed to determine their thermal properties. SEM and EDS analyses were performed on the specimens to examine their morphologies. Furthermore, examinations were conducted on how BA affected the specimens' failure behavior. In the study, it was found that, except for the compressive strength, the mechanical properties were improved by the added BA. The highest tensile strength, shear strength, modulus of elasticity, shear modulus, and Poisson's ratio were obtained from 0.5% BA-added specimens and were 24.78%, 8.75%, 25.13%, 11.24%, and 12.5% higher than the values obtained from 0% BA-added specimens, respectively. The highest loss and storage modulus were obtained from 0% and 0.5% BA-added specimens, respectively. The specimens' glass transition temperatures were decreased by the addition of BA; the specimen with a 1% addition of BA had the lowest value. Furthermore, interlayer delamination and fiber/matrix failure were observed in all BA-added specimens.

Atomic-scale investigation of the synergistic impact of Mo and Nb addition on enhancing the performance of laser cladding FeCoCrNi-based high entropy alloy coatings

Utilizing synchronous powder feeding laser cladding technology, two high entropy alloy coatings, FeCoCrNiMo and FeCoCrNiMoNb, were deposited on the surface of low-carbon steel. An in-depth investigation into the synergistic interplay of Mo and Nb on FeCoCrNi-based high entropy alloy coatings was conducted. The findings reveal that FeCoCrNiMo comprises an FCC stable solid solution, Mo3Co3C, and Ni3Mo3C. Conversely, FeCoCrNiMoNb exhibits a composition comprising an FCC stable solid solution phase, NbC, and (Mo, Nb)C. This is attributed to the robust interaction between Mo and Nb, wherein Mo infiltrates the NbC lattice, substituting for a portion of Nb atoms. Notably, the synergistic influence of Mo diminishes the formation energy of NbC, thereby lessening the energy barrier encountered during the nucleation of (Mo, Nb)C. Consequently, the incorporation of Mo facilitates the precipitation of Nb. The refined microstructure and solid solution strengthening effect of (Nb, Mo)C and NbC, coupled with their elevated Vickers hardness and hard elastic ratio, contribute significantly to the notable enhancement in surface hardness and wear resistance observed in the FeCoCrNiMoNb high entropy alloy coating.

Prospective Evaluation of Normal Supraspinatus Muscle Using Shear Wave Elastography: Comparison With Symptomatic Tendon Tears.

This study aimed to evaluate normal supraspinatus (SS) muscle elasticity using shear wave elastography (SWE) in an asymptomatic group, analyze its correlation with demographic factors and ultrasound (US) grayscale grade, and compare the elasticity between normal SS muscles and symptomatic SS muscles with tendon tears. A prospective study was conducted with 101 adult patients with normal SS muscle scheduled for surgery due to a contralateral shoulder with SS tendon tear. Both shoulders underwent US examinations, including SWE. The SWE values, including mean and median elasticity, as well as the elasticity ratio, were analyzed for their correlation with demographic characteristics and grayscale grades. A comparison of SWE values was performed between the normal and symptomatic SS muscle groups. The mean SWE modulus of the normal SS muscle was 27.87 kPa (±49.04), with an elasticity ratio of approximately 1.52 (±0.03). Males exhibited slightly higher elasticity ratios compared with females (1.61 vs 1.45, P = .016). The interobserver agreement for all SWE measurements was excellent (>0.8). Grayscale grade increased with age, showing a similar pattern in females (P < .001). However, no significant correlation was observed between SWE values and grayscale grade in the normal SS muscle group. SWE values in normal SS muscles were significantly lower than those with tendon tears (P < .001). SWE provides objective measurements of normal SS muscle elasticity. Gender-based variations were observed, with males exhibiting slightly higher elastography ratios. SWE values were significantly lower in asymptomatic SS muscles compared with those with tendon tears.

Experimental Study on the Damage of Bridge Concrete in a Fire Environment Based on the Impact Echo Method

Abstract To accurately assess the damage degree of bridge structures in a fire environment, fire damage test studies were conducted on the C30 and C50 concrete specimens at different temperatures (room temperature, 100°C∼700°C) based on the impact echo method. In addition, the variation rules of mass, impact echo signal, dynamic modulus of elasticity Ed, and static and dynamic modulus of elasticity ratios (Ec/Ed) with overfire temperature were obtained. The results show the following: (1) at ablation temperature ≤ 300°C, the main frequency of the impact echo signal is single, the peak value is obvious, the signal attenuation is fast, and the change is uniform; at ablation temperature &amp;gt; 300°C, the main frequency is frequent, there is more than one peak, and the vibration duration of the phenomenon is longer. (2) After fire damage, the specimen’s dynamic modulus of elasticity Ed is in a cubic relationship with the overfire temperature. (3) In engineering practice, the static and dynamic modulus of elasticity (Ec/Ed) ratio is classically based on Lydon and Balendran’s formula, which is usually used for derivation at room temperature. This article found that the formula can be extended to the rough estimation at lower temperatures (≤200°C), and the model proposed in this article can be used for the derivation of the static modulus of elasticity Ec and the dynamic modulus of elasticity Ed at high temperatures. In summary, the impact echo method can be used to quantitatively assess the damage state of bridges after fire. After the signal time-frequency domain conversion, a qualitative assessment of the degree of concrete damage can be made. Furthermore, a quantitative assessment of bridge concrete after fire damage can be made using the model proposed in this article.

Investigate the effect of elastic yarn ratios and cotton spinning techniques using different structures on functional and mechanical properties of compression bandages

Investigate the effect of elastic yarn ratios and cotton spinning techniques using different structures on functional and mechanical properties of compression bandages

Deep Learning in Rockburst Intensity Level Prediction: Performance Evaluation and Comparison of the NGO-CNN-BiGRU-Attention Model

Rockburst is an extremely hazardous geological disaster. In order to accurately predict the hazardous degree of rockbursts, this paper proposes eight new classification models for predicting the intensity level of rockbursts based on intelligent optimisation algorithms and deep learning techniques and collects 287 sets of real rockburst data to form a sample database, in which six quantitative indicators are selected as feature parameters. In order to validate the effectiveness of the constructed eight machine learning prediction models, the study selected Accuracy, Precision, Recall and F1 Score to evaluate the prediction performance of each model. The results show that the NGO-CNN-BiGRU-Attention model has the best prediction performance, with an accuracy of 0.98. Subsequently, engineering validation of the model is carried out using eight sets of real rockburst data from Daxiangling Tunnel, and the results show that the model has a strong generalisation ability and can satisfy the relevant engineering applications. In addition, this paper also uses SHAP technology to quantify the impact of different factors on the rockburst intensity level and found that the elastic strain energy index and stress ratio have the greatest impact on the rockburst intensity level.

Ultrasonic Study of Longitudinal Critically Refracted and Bulk Waves of the Heat-Affected Zone of a Low-Carbon Steel Welded Joint under Fatigue

Currently, ultrasonic methods for assessing the fatigue lifetime of various structural materials are being actively developed. Many steel constructions are made by welding. The weld heat-affected zone is the weak point of the construction, as it is most susceptible to destruction. Therefore, it is actually important to search for acoustic parameters that uniquely characterize the structural damage accumulation in the heat-affected zone of a welded joint in order to predict failure. In this work, the specimens were made from the base metal and the welded joint’s heat-affected zone. The specimens were subjected to uniaxial tension–compression under a symmetrical cycle in the region of low-cycle fatigue with control of the strain amplitude. The propagation bulk velocities of longitudinal, shear waves and subsurface longitudinal critically refracted (LCR) waves during cyclic loading were studied. The acoustic birefringence of shear waves was calculated, and a similar parameter was proposed for longitudinal and LCR waves. The dependence of the elastic modulus ratio on the cycle ratio was obtained. It was shown that the acoustic parameters change most intensively in the heat-affected zone. According to the data of the C33/C55 ratio changes measured through the ultrasonic method, a formula for calculating the remaining fatigue life in the heat-affected zone was proposed.

Ultrasound elastography predicts anticoagulation in lower extremity deep vein thrombosis.

To investigate predictors of anticoagulation efficacy in deep venous thrombosis (DVT) by ultrasound elastography (UE). The basic clinical, laboratory and ultrasound treatment data of fifty-eight patients with DVT were collected and analyzed. Then the results of ultrasound after 3-month anticoagulation treatment were compared among different groups. Multiple logistic regression analysis was used to identify independent risk factors that affected anticoagulation efficacy. The predictive efficacy of each independent risk factor was accessed by drawing operating characteristic (ROC) curves. According to the regression analysis, the elastic modulus (OR = 0.631, P = 0.001) and strain rate ratio (OR = 0.332, P = 0.006) were identified as independent risk factors for the effectiveness of anticoagulation therapy in patients with DVT. According to the ROC curves, elastic modulus and strain rate ratio could predict effective anticoagulation therapy for DVT, and the optimal threshold values were 22.10 kPa and 1.80 respectively. The corresponding AUC values were 0.879 and 0.854, with a sensitivity of 71.4% and 59.5%, a specificity of 93.7%, and a Youden index of 65.1% and 62.7%, respectively. The elastic modulus (≤22.10 kPa) or strain rate ratio (≤1.80) of the thrombus were independent predictors for the effectiveness of anticoagulation therapy.

Unloading Model of Elastic-Plastic Half-Space Contacted by an Elastic Spherical Indenter.

A new unloading contact model of an elastic-perfectly plastic half-space indented by an elastic spherical indenter is presented analytically. The recovered deformation of the elastic indenter and the indented half-space has been found to be dependent on the elastic modulus ratio after fully unloading. The recovered deformation of the indented half-space can be calculated based on the deformation of the purely elastic indenter. The unloading process is assumed to be entirely elastic, and then the relationship of contact force and indentation can be determined based on the solved recovered deformation and conforms to Hertzian-type. The model can accurately predict the residual indentation and residual curvature radius after fully unloading. Numerical simulations are performed to demonstrate the assumptions and the unloading model. The proposed unloading model can cover a wide range of indentations and material properties and is compared with existing unloading models. The cyclic behavior including loading and unloading can be predicted by combining the proposed unloading law with the existing contact loading model. The combined model can be employed for low-velocity impact and nanoindentation tests and the comparison results are in good agreement.

Fabrication of amorphous AlMo0.5NbTa0.5TiZr RHEA coatings and the impact of deposition temperature on microstructure and properties

In this study, protective AlMo0.5NbTa0.5TiZr refractory high-entropy alloy coatings were prepared by DC magnetron sputtering, and the influence of deposition temperature on the microstructure, deposition rate, mechanical properties, and adhesion force was investigated in detail. All coatings are in a nearly amorphous state. Their elastic recovery ratio (ηw), microhardness (H), elastic strain failure strength (H/E), plastic deformation strength (H3/E2), and adhesion force (Lc2) are positively correlated with deposition temperature mainly attributing to the synergy of increased thickness and the generation of the nanocrystal. The coating reaches its maximum ηw, H, H/E, H3/E2, and Lc2 of 43.87 ± 0.94 %, 12.74 ± 0.37 GPa, 0.073 ± 0.002, and 0.067 ± 0.005 GPa at the deposition temperature of 500 °C and exhibits superior wear resistance and resistance to plastic deformation, compared with reported refractory Cr and α-Ta coatings.