Changes In Mechanical Properties Research Articles

Experimental Study on Bearing Capacity Reduction of the Steel Wire-Rings in Flexible Barriers Due to Corrosion

Flexible barriers mitigate geological hazards, relying crucially on wire-ring nets to intercept rockfalls and debris. However, constant exposure to natural environments renders their metal components susceptible to corrosion, affecting the protective efficacy. To investigate the changes in mechanical properties of wire-ring nets resulting from corrosion, the neutral salt spray tests followed by quasi-static tests on uncoated, Zinc-coated, and Galfan-coated high-strength steel wires and wire-rings were conducted. These tests established the correlation between the steel wire's breaking force and its weight loss rate, ultimately facilitating the creation of a pertinent mathematical model. The decline in the breaking force of various types of wire-rings due to corrosion was compared, indicating the influence of corrosion duration, number of winding turns, winding techniques, and coating types on the wire-ring's mechanical performance. Subsequently, the formula for calculating the breaking force of wire-rings in relation to the weight loss rate of the steel wire was derived. Finally, based on the linear relationship between the capacity of single wire-rings and wire-ring nets, a formula was established to estimate the puncturing force of wire-ring nets under different atmospheric corrosion periods. This predictive model provides a basis for the durability design of flexible barrier with different anti-corrosion measures under various atmospheric conditions, and also offers specific insights into maintenance strategy for the existing flexible barriers.

Nanoindentation Test of Ion-Irradiated Materials: Issues, Modeling and Challenges.

Exposure of metals to neutron irradiation results in an increase in the yield strength and a significant loss of ductility. Irradiation hardening is also closely related to the fracture toughness temperature shift or the ductile-to-brittle transition temperature (DBTT) shift in alloys with a body-centered cubic (bcc) crystal structure. Ion irradiation is an indispensable tool in the study of the radiation effects of materials for nuclear energy systems. Due to the shallow damage depth in ion-irradiated materials, the nanoindentation test is the most commonly used method for characterizing the changes in mechanical properties after ion irradiation. Issues that affect the analysis of irradiation hardening may arise due to changes in the surface morphology and mechanical properties, as well as the inherent complexities in nanoscale indentation. These issues, including changes in surface roughness, carbon contamination, the pile-up effect, and the indentation size effect, with corresponding measures, were reviewed. Modeling using the crystal plasticity finite element method of the nanoindentation of ion-irradiated materials was also reviewed. The challenges in extending the nanoindentation test to high temperatures and to multiscale simulation were addressed.

Exploring versatility: Investigating nanomaterials applications in relation to polymorphism

The crystal structure of a material holds immense power over its traits. In fact, both composition and structure form the bedrock of all physicochemical properties of materials. Given the pivotal role of crystal structures in shaping material attributes, the prevalence of nanoscale polymorphism is enabling the discovery and fabrication of novel materials endowed with distinctive characteristics. Polymorphism in nanomaterials had caused changes in thier mechanical, thermal, quantum and optical properties which finds applications in the fields of medicines, sensors, paints, dyes and pigments. In this connection, this review has been designed to explore the chemistry of a variety of nanomaterials and its significant applications in connection with polymorphism.

Impact of Standing and Sitting Postures on Spinal Curvature and Muscle Mechanical Properties in Young Women: A Photogrammetric and MyotonPro Analysis.

BACKGROUND This study aimed to evaluate the effect of standing and sitting positions on spinal curvatures evaluated using projection moire and muscle tone and stiffness using the MyotonPRO hand-held device in young women. MATERIAL AND METHODS Thirty-three healthy women, aged 21 to 23 years, volunteered in the study. We used the projection moire method to examine spinal curvatures in both positions and the MyotonPRO device to measure the tone and stiffness of muscles in 3 regions. We evaluated the effects of positions (standing vs sitting), regions (cervical, thoracic, and lumbar), and side factor (right vs left) using multivariate analysis. RESULTS The sitting position significantly decreased the lumbosacral and thoracolumbar angles (P<0.001), but had no effect on the superior thoracic angle. Muscle tension and stiffness were the highest (P<0.001) in the cervical region and did not differ between positions (P>0.05) in this region. We found significantly higher muscle tone and stiffness in the thoracic and lumbar regions during sitting than during standing (P<0.001). There was symmetry in the muscle tone and the stiffness between the right and left sides of the spine. CONCLUSIONS The sitting posture decreased lumbosacral and thoracolumbar angles but increased muscle tension and stiffness in the lumbar and thoracic regions only. The symmetry of muscle tone and transverse stiffness in both positions was the normative value. This study provides insight into the adaptive physiological changes in spinal curvature and muscle mechanical properties in young women and serves as an important reference point for clinical studies of women.

Analysis of changes in shale mechanical properties and fault instability activation caused by drilling fluid invasion into formations

During the drilling process, the issue of drilling fluid loss can lead to changes in the mechanical properties of the formation, thereby altering the stress environment of nearby faults. In order to assess the risk of fault activation during drilling operations, the Ordos M area shale was selected as the research object. Mechanical experiments were conducted on rock samples immersed in water-based drilling fluid with a pressure differential of 2 MPa and a temperature of 50 °C. The changes in the mechanical properties of the shale before and after immersion in drilling fluid were determined. Based on the experimental results, combined with the spring combination model and fault activation theory, a quantitative evaluation of fault activation risk was conducted. The findings revealed that the shale in this region has a high clay content, demonstrating a certain level of water sensitivity. The presence of micro-pores and micro-fractures is well-developed, increasing the interaction probability between drilling fluids and clay minerals. After immersion in drilling fluid, there was a varied decline in all mechanical strengths of the shale. The elastic modulus is positively correlated with the shear strength and Coulomb stress of the fault plane. The Poisson’s ratio is positively correlated with the shear strength and negatively correlated with the Coulomb stress. The greater the internal friction and cohesion, the higher the shear strength of the fault plane, and the larger the friction coefficient, the smaller the Coulomb stress, resulting in a more stable fault.

Tunneling nanotubes mediate KRas transport: Inducing tumor heterogeneity and altering cellular membrane mechanical properties

Mutation in oncogene KRas plays a crucial role in the occurrence and progression of numerous malignant tumors. Malignancy involves changes in cell mechanics for extensive cellular deformation during metastatic dissemination. We hypothesize that oncogene KRas mutations are intrinsic to alterations in cellular mechanics that promote malignant tumor generation and progression. Here, we demonstrate the use of optical tweezers coupled with a confocal fluorescence imaging system and gene interference technique to reveal that the mutant KRas protein can be transported between homogeneous and heterogeneous tumor cells by tunneling nanotubes (TNTs), resulting in a significant reduction of membrane tension and acceleration of membrane phospholipid flow in the recipient cells. Simultaneously, the changes in membrane mechanical properties of the tumor cells also enhance the metastatic and invasive ability of the tumors, which further contribute to the deterioration of the tumors. This finding helps to clarify the association between oncogene mutations and changes in the mechanical properties of tumor cells, which provides a theoretical basis for the development of cancer treatment strategies. Statement of significanceHere, we present a laser confocal fluorescence system integrated with optical tweezers to observe the transfer of mutant KRasG12D protein from mutant cells to wild-type cells through TNTs. Malignancy involves changes in cell mechanics for extensive cellular deformation during metastatic dissemination. Our results demonstrate a significant decrease in membrane tension and an increase in membrane phospholipid flow in recipient cells. These alterations in mechanical properties augment the migration and invasive capabilities of tumor cells, contributing to tumor malignancy. Our findings propose that cellular mechanical properties could serve as new markers for tumor development, and targeting membrane tension may hold potential as a therapeutic strategy.

Re-heat treatment effect on the microstructure and mechanical properties of the Inconel 706 alloy for repair

Although the understanding of microstructure and mechanical property changes in re-heat-treated Inconel alloys is important to evaluate the performance of repaired components, recent research has mainly focused on the heat treatment effect of as-fabricated products. Thus, in this work, the performance change of the used Inconel 706 rotor-disks under varying re-heat treatment conditions was investigated. Because of the heat exposure of the used rotor-disk component, a high fraction of plate-like η phase (6.36%) and compact γ'/γ" co-precipitate structure were initiated in the as-received sample. After re-heat treatment, η phase dissolution breakage and compact to non-compact γ'/γ" co-precipitate structure transition occur, resulting in mechanical properties changes of the Inconel 706 alloy. As a result, η phase fraction affects the tensile strength and ductility of Inconel 706 alloy, while the non-compact γ'/γ" co-precipitate structure in the matrix degrades the creep lifetime. These results indicate that re-heat treatment during the repair of operated components induces microstructural and mechanical properties changes. However, to investigate the detailed history of used Inconel 706 components, additional research on the microstructural degradation during operation of Inconel components is required.

Cumulative effect of molybdenum doping and nitrogen atmosphere on the properties of vanadium oxycarbide cermets with iron binder

The present study focuses on the effect of molybdenum and nitrogen on the microstructure and mechanical properties of VCxOy-Fe cermets. Samples with 0–23 at% Mo were fabricated using a wet synthesis route and heat treatment under Ar and N2 atmospheres. Phase transformations during heating were investigated by TGA-DSC in combination with XRD, and the resulting materials were analyzed by SEM/EDX. A doping level of 6–12 at% was found to be optimal, as it lowered the melting point of the metallic binder to 1320–1360 °C. Replacing argon with nitrogen further decreased the melting point to 1210–1240 °C and reduced the grain size. Depending on the sintering temperature, gas environment, and molybdenum content, the produced cermets were characterized by 92–97 % density, 17–29 vol% binder phase, 8–14 GPa hardness, and 6–9 MPa m0.5 fracture toughness. The average size of oxycarbide grains, their stoichiometry, and the amount of dissolved vanadium in the iron binder demonstrated a strong correlation with changes in mechanical properties.

Increasing Exploitation Durability of Two-Layer Cast Mill Rolls and Assessment of the Applicability of the XGBoost Machine Learning Method to Manage Their Quality.

The increase in exploitation durability of two-layer cast rolls with the working layer made of high chromium cast iron allows one to significantly improve the quality of rolled metal as well as to increase the economic efficiency of the manufacturing process. However, it is severely hindered due to the massiveness of castings, the impossibility of both evaluating mechanical properties along the depth of the working layer, and providing the structural uniformity of the working surface and the decrease in stresses. In our research, aiming to enhance the exploitation durability of sheet rolls, it is recommended to achieve structural uniformity by CuMg alloying, which increases the concentration of copper up to 2.78 wt.% in certain zones and, owing to the accelerated austenite decomposition at a high temperature during the cool-down of the castings, led to the reduction in excessive strength and the level of heat stresses in the castings. We propose the regimes of cyclic heat treatments which, due to the decomposition of retained austenite and the fragmentation of structure, control the level of hardness to reduce and uniformize the level of stresses along the length of a barrel. A further improvement in the predictions of exploitation durability using XGboost method, which was performed based on the chemical composition of the working layer of high-chromium cast iron and heat treatment parameters, requires taking into account the factors characterizing exploitation conditions of specific rolling mills and the transformations of structural-phase state of the surface obtained by a non-destructive control method. As the controlled parameter, the hardness measured on the roll's surface is recommended, while the gradient change in mechanical properties along the working layer depth can be feasibly analyzed by a magnetic method of coercive force measuring.

Microstructure induction of quaternary ammonium chitosan microcapsules based on magnetic field and study of their aroma release

Traditional pressure-sensitive microcapsules used in textiles face challenges of insufficient environmental friendliness in the production process and uncontrollable fragrance release. To address this issue, this study utilized quaternary ammonium chitosan and silica as wall materials to develop a magnetic aromatic microcapsule. The microstructure of the microcapsules was controlled by magnetic field induction, and its evolution pattern was investigated. After magnetic field induction, the microcapsules exhibited a trend of evolving from spherical to asymmetrical shapes, accompanied by significant changes in mechanical properties. Asymmetrical microcapsules showed higher adhesion and lower stiffness. When applied to cotton textiles, the cotton textiles treated with asymmetrical microcapsules released 63.40 % of lavender essential oil after 200 friction cycles, representing an 11.3 % improvement in release efficiency compared to regular microcapsules, indicating better mechanical stimulus responsiveness. Additionally, in antibacterial tests, aromatic cotton exhibited a 96.52 % inhibition ratio against Escherichia coli. In summary, this study explores methods to adjust the mechanical properties of microcapsules and the relationship between mechanical properties and microstructure, providing a new approach for functional textiles.

The fabrication of brass reinforced aluminum matrix composites by FSW

Brass sheet is added into the joining location in friction stir welding (FSW). Brass reinforced Al matrix composite is then formed in the FSW nugget zone with brass. A new microstructure based mechanical property model is proposed to predict both the microstructural evolutions and mechanical property changes in FSW with brass. The discrepancy between the numerical and experimental data is 0.77% for temperature, 2.2% for average grain size, and 6.4% for hardness. The change of temperature is very small in comparison of FSW and FSW with brass. However, compared to FSW, the hardness is obviously increased and the average grain size is decreased by 34.8% in FSW with brass in the nugget zone due to the pinning effect from the broken brass particles. The process parameters can be numerically tested to find the optimal design for experiment.

Grazer‐induced changes on mechanical properties of diatoms frustule: A new proof for a watery arms race

AbstractWe investigated changes in physiology and mechanical properties of diatoms exposed to chemical cues released by copepods Pseudodiaptomus annandalei. Our results showed that the diatoms Phaeodactylum tricornutum, Cylindrotheca closterium, Thalassiosira weissflogii, and Amphora coffeaeformis exhibited elevated growth rates and a substantial 2‐ to 50‐fold increase in biogenic silica (BSi) content increase when exposed to the chemical cues except for Cyclotella sp. Atomic force microscopy and X‐ray photoelectron spectroscopy analyses revealed that diatom frustules exhibited a remarkable 3‐ to 10‐fold increase in modulus and a substantial 2‐ to 5‐fold increase in hardness when they received grazing signals. The increase in the proportion of condensed silicon in the frustules could be the major reason for the more mechanically robust cells. Our results indicate that diatoms simultaneously increase their growth rate and robustness when exposed to copepod chemical cues. This study at the nanoscale enhanced our understanding of how diatoms respond to zooplankton predation in marine ecosystems.

Evaluation of Residual Structural Capacity in Corroded Reinforced Concrete Structures

Reinforcement corrosion is a critical issue that affects the durability and service life of reinforced concrete structures. This study focuses on evaluating the effectiveness of natural corrosion inhibitors in mitigating the corrosion attack on reinforced concrete beams in saline environments. The study utilizes extruded exudates/resins obtained from plants and characterizes their potential eco-friendly and non-hazardous properties. The corrosion resistance of uncoated and coated steel reinforcements is examined through exposure to a 5% sodium chloride solution for 360 days. The samples are subjected to flexural beam tests at regular intervals to assess changes in mechanical properties. The results indicate that natural corrosion inhibitors can effectively improve durability and maintain higher residual strength capacities, even under severe exposure conditions. Coated bars show higher residual capacities and yield strengths compared to uncoated bars, attributed to the protective effect of the coatings. The inhibitors also reduce corrosion rates and preserve mechanical properties like yield strength and ductility, enhancing the service life of reinforced concrete structures. The study emphasizes the use of locally available materials to counteract the negative effects of corrosion attack in marine environments.

Stretch-induced damage in endothelial monolayers

Endothelial cells are constantly exposed to mechanical stimuli, of which mechanical stretch has shown various beneficial or deleterious effects depending on whether loads are within physiological or pathological levels, respectively. Vascular properties change with age, and on a cell-scale, senescence elicits changes in endothelial cell mechanical properties that together can impair its response to stretch. Here, high-rate uniaxial stretch experiments were performed to quantify and compare the stretch-induced damage of monolayers consisting of young, senescent, and aged endothelial populations. The aged and senescent phenotypes were more fragile to stretch-induced damage. Prominent damage was detected by immunofluorescence and scanning electron microscopy as intercellular and intracellular void formation. Damage increased proportionally to the applied level of deformation and, for the aged and senescent phenotype, induced significant detachment of cells at lower levels of stretch compared to the young counterpart. Based on the phenotypic difference in cell-substrate adhesion of senescent cells indicating more mature focal adhesions, a discrete network model of endothelial cells being stretched was developed. The model showed that the more affine deformation of senescent cells increased their intracellular energy, thus enhancing the tendency for cellular damage and impending detachment. Next to quantifying for the first-time critical levels of endothelial stretch, the present results indicate that young cells are more resilient to deformation and that the fragility of senescent cells may be associated with their stronger adhesion to the substrate.

Effect of white mud on carbonation resistance of alkali activated slag

White mud (WM) is a solid waste produced in the process of papermaking and it remains to be effectively utilized. It contains a large amount of CaCO3 and residual alkali metal ions. This paper aims to explore the effect of WM on carbonation resistance of alkali activated slag. The changes in mechanical properties and microstructure of alkali activated white mud/slag (AAWS) after natural carbonation and accelerated carbonation were analyzed. The results indicate that the mechanisms of natural carbonation and accelerated carbonation are different. The carbonation depth achieved in 90 days of natural carbonation can be reached in just 14 days of accelerated carbonation. Samples with 15 wt% WM blended possesses the smallest carbonation depth and the highest compressive strength. WM can effectively mitigate the natural carbonation of AAWS by dissolving Mg2+ and Ca2+. Mg2+ can migrate to increase the solubility of calcite, promote the generation of hydrotalcite to absorb carbon dioxide, and reduce the carbonation degree. Ca2+ will migrate after the carbonation and decalcification of the gel product and reduce the decalcification sensitivity. This study offers a sustainable approach for improving the carbonation resistance of AAWS.

Molecular dynamics study of temperature and defects on mechanical properties of Gr(GO)/C-S-H composites

In this paper, the effects of temperature and different defect types on the interfacial properties, kinetic properties and mechanical properties of Gr(GO)/C-S-H composites were investigated by molecular dynamics. It is shown that the incorporation of graphene (Gr) and graphene oxide (GO) improves the mechanical properties of the calcium silicate hydrate (C-S-H) model to varying degrees. The presence of defects at different temperatures affects the ordering of oxygen (Ow) in water in the proximal range of interlayer Ca ions and can effectively influence the spatial correlation between interlayer Ca ions and oxygen (Oc) in functional groups. The bond lengths of some Caw-Oc at different temperatures can be modulated by defects, thus affecting the interaction between calcium ions and graphene oxide. Compared with Gr/GO and C-S-H composites in perfect state, the incorporation of defects slows down the rate of C atoms, which can effectively enhance the interfacial connection. At temperatures of 100K-300 K, the effect of defect type on Gr/GO and C-S-H composites is small and the mobility of H atoms did not change significantly. Whereas, at high temperatures 400 K and 500 K, the presence of defects gives higher mobility of H atoms, which affects the properties of the composites. The tensile strength (compressive strength) and Young's modulus of Gr(GO)/C-S-H composites at perfect and different defect types basically show a decreasing trend with increasing temperature. The system structure changes during the relaxation process because of the different defect types and Gr (GO), which make the initial structure different, and thus the mechanical properties change.

Assessment of structural defects and mechanical characteristics of IN718/St6 functionally graded material produced by direct laser deposition

Functionally graded materials (FGM) do not show special processing in the composite structure due to the combination of mechanical, thermal, magnetic and stress gradient properties. The aim of this study is to produce IN718/St6 FGM samples by direct laser deposition method. The product of this model should enable the development of mechanical products. Best of all, this can be done without significant reduction in texture and case to residual stress that are a consequence of rapid changes in mechanical and thermal properties in non-FGM samples. To fabricate part, direct laser deposition system equipped with a 1 kW continuous fiber laser is used, SEM/EDS analysis and microhardness testing to measure porosity, chemical composition, and quantify gradient mechanical properties is used. In this study, the cladding composition is selected from 100% IN718 to 100% St6 with a 25% change in St6 composition. To prevent the formation of defects, both single-parameter modes and individual layering are examined, considering the diverse nature of the combination. The result shows that using an individual layering structure, reduces 100% Lack of fusion defects in the IN718/St6 structure. EDS analysis confirmed that the St6 content gradually increased from the first to the fifth layer. The substrate hardness gradually increases from 200 Vickers hardness to 550 Vickers hardness, showing an almost linear trend. Moreover, by using individual layering, the coaxial structure is reduced by 55% and the relative orientation of the vertical line is reduced by 18° compared to using the St6 directly (non-FGM).

Surface Evaluation of Tricalcium Phosphate Bioceramic Coating on SS-316L by Electrophoretic Deposition

The development of orthopedic implant materials has become an important topic of discussion lately. The SS-316L alloy is widely used as an implant material due to its relatively low cost, corrosion resistance, and ease of production. However, metal alloys, especially SS-316L, are prone to ion release into the blood over time. Therefore, TCP or tricalcium phosphate [Ca3(PO4)2] is needed to coat the surface of SS-316L, preventing ion release into the blood and enhancing the biocompatibility of the implant material. In this study, TCP coating was applied to the SS-316L substrate using the electrophoretic deposition technique. The influence of deposition time on changes in microstructure and mechanical properties is the main focus of this study. The results of the coating technique indicate that the deposition yield increases with the deposition time. Morphological testing results show that increasing deposition time improves coating quality by increasing the thickness of the coating layer and preventing layer peeling. The coating process also reveals the accumulation of layers in certain areas and the formation of thin layers in other regions. A deposition time of 30 minutes results in a coating thickness ranging from 48.7 to 57.9 µm. Hardness testing, conducted with indentation loads of 50, 100, and 300 gf, indicates that longer deposition times and higher indentation loads during hardness testing result in reduced material hardness.

A two-step stress-annealing with stress-relaxation process for developing low-loss Fe-based nanocrystalline soft magnetic cores

Fe72.5Nb2Mo2Cu1Si15.5B7 at.% nanocrystalline soft magnetic ribbon was stress-annealed at several temperatures around its primary crystallization temperature and magnetic properties were characterized in strips to determine conditions that led to minimal magnetic coercivity, Hc. This optimal stress-annealing (SA) temperature, though yielding minimal Hc in strips, also produced non-linear or rounded BH loops in wound cores. The rounded loops could be changed to linear or flat B-H loops following a secondary static annealing process. Through X-ray diffraction, transmission electron microscopy, and indirect magnetostriction measurements, we determined that the change in loop shape was driven by additional crystallization and stress-relief from the static annealing process. A change in mechanical properties including fracture toughness, loss modulus, and Young’s modulus after SA, were shown to limit the processability of the ribbon. Tape-wound inductors subjected to the optimal 640 °C / 85 MPa / 4 s SA process followed by a static annealing treatment of 500 °C for 1 h resulted in flat loops, an Hc of 0.3 A/m, low magnetostriction of ∼ 2 ppm, and core losses of only 7 W/kg at an induction of 0.4 T when excited at 20 kHz.

Effect of the volume fraction of nanocrystals on the mechanical properties of (Fe0·9Ni0.1)86B14 amorphous/nanocrystalline alloy

The effect of the volume fraction of nanocrystals on the macroscopic mechanical properties and microscopic atomic structure of Fe-based nanocrystalline alloys, as well as the relationship between the two, is an urgent issue to be explored. Seven nanocrystalline alloys with different volume fractions of nanocrystals were formed by annealing treatment of (Fe0·9Ni0.1)86B14 amorphous precursor. Through hardness, flat plate bending, and nanoindentation experiments, it is found that when the volume fraction of nanocrystals reaches the range of 45–55 %, there is an abrupt change in the macroscopic mechanical properties. Specifically, when the volume fraction is less than this range, the properties inherit the amorphous matrix, however, larger than this range, the properties are dominated by precipitated nanocrystalline phases. Meanwhile, based on the molecular dynamics simulation method, seven Fe90Ni10 amorphous nanocrystalline models with different volume fractions of body-centered cubic nanocrystals are established, and the deformation mechanism of models and the evolution of their microstructures during the nanoindentation process are obtained intuitively. Moreover, it is further revealed that the significant changes in the Voronoi polyhedral index, which represents the microscopic atomic structure in this range of nanocrystal volume fractions, are the main reason for the abrupt changes in the mechanical properties at the macroscopic level.