Maximum Elongation Research Articles

Tensile and Crystallization Behavior of Melt‐Spun Fibers Derived From Poly(Butylene Terephthalate‐Co‐2,6‐Naphthalate) Copolyester

ABSTRACTIn this study, a series of poly(butylene terephthalate‐co‐2,6‐naphthalate) (PBTN) copolymers was synthesized via a one‐step polycondensation process. These PBTN copolymers demonstrate excellent thermal stability and semi‐crystalline behavior, with the enthalpy of melting values exceeding 17 J g−1. Crystallization kinetics analysis revealed that the copolymers exhibit significantly higher crystallization rates than neat poly(butylene terephthalate) (PBT) and poly(butylene naphthalate) (PBN), making them well‐suited for fiber production. The copolymers were melt‐spun, followed by a post‐drawing process at a ratio of 2.0, to enhance fiber strength. By adjusting the 2,6‐naphthalene dicarboxylate (NDC) content, the mechanical properties and crystallinity of the PBTN fibers were fine‐tuned. Tensile testing revealed that the copolymer fiber containing 50 mol% NDC, post‐drawn at a ratio of 2.0, exhibits superior toughness, with maximum tenacity and elongation values of 3.13 g den−1 and 69.3%, respectively.

Environmental Conservation by Using Recycled Aggregates: Enhancing Sustainability in Road Construction

Every day, construction and demolition waste is generated worldwide. As the road business and traffic grow, construction materials have evolved to include more unorthodox features. Road construction and maintenance rely significantly on quarried aggregates, resulting in high resource extraction demands. There is a trend toward employing secondary (recycled) materials rather than primary (virgin) ones to address this. This transformation requires the use of a variety of secondary and tertiary components, including waste byproducts. Numerous studies have been conducted to study and analyze the suitability and practical application of recycled materials in the field. Some recycled materials have better qualities than others, proving satisfactory performance in real-world circumstances. However, concerns about their incorporation persist, based on laboratory research and field observations. These concerns emphasize the necessity for more in-depth research to address potential difficulties. It is claimed that using recycled and tertiary materials in road construction can greatly help to save natural resources. This study predicts the attributes of selected materials, such as gradation, water absorption, maximum dry density, impact value, flakiness, and elongation, to establish their appropriateness for the production of Granular Sub-base (GSB) and Wet Mix Macadam (WMM).

Analysis of Gravel Migration Patterns During Vibration Rolling and Their Impact on GCL Performance Based on DEM

In this study, a multilayer composite rolling model consisting of a rolling wheel, a protective layer, a GCL, and a support layer was constructed by the discrete element method (DEM). Soil compaction and gravel migration, and their effects on the GCL, were analyzed from a fine viewpoint, and three key indexes for the safety assessment of the GCL were proposed: local elongation, gravel embedment value, and bentonite allotment number. The results show that the soil porosity and cumulative settlement do not decrease all the time with the number of rolling passes, and there exists an optimal number of rolling passes during the rolling process; the protective layer of gravel soil moves more frequently than the support layer; and the nearly rectangular and nearly elliptical gravels are more likely to rotate. The maximum local elongation of the GCL was 3.79% during the lapping process, and all gravels in contact with the upper boundary of the GCL extruded the GCL to varying degrees during the lapping process. The distribution of bentonite particles is closely related to the contact mode between gravel and GCL.

Preparation and Antibacterial Properties of Poly (l-Lactic Acid)-Oriented Microporous Materials.

In this manuscript, an efficient self-reinforcing technology-solid hot drawing (SHD) technology-was combined with green processing supercritical carbon dioxide (SC-CO2) foaming technology to promote poly (l-lactic acid) (PLLA) to form an oriented micropore structure. In addition, Polydimethylsiloxane (PDMS), with a high affinity of CO2 and biological safety, was introduced to enhance the nucleation effect in SC-CO2 foaming and co-regulate the uniformity of oriented micropores' structure. The results showed that orientation induced PLLA crystallization, so the tensile strength was improved; the maximum tensile strength of the oriented micropores' PLLA reached 151.2 MPa. Furthermore, the micropores mainly improved the toughness; the maximum elongation at break reached 148.3%. It is worth mentioning that PDMS can form an antibacterial film on the surface of the material, so that the material has a continuous antibacterial effect.

Effect of pinless friction stir processing on microstructure and properties of surface modification layer of 2024 aluminum alloy

Friction stir processing (FSP) is an advanced material surface modification technology that is both green and energy-efficient. This technology plays a crucial role in regulating the surface microstructure of alloys and improving alloys’ surface properties. It reaches this through the synergistic effect of non-equilibrium thermodynamic and surface mechanical deformation. In this work, the surface modification of an aluminum alloy was performed using pin-less FSP. Then, the modified surface was analyzed using stress–strain curves, optical microscopy (OM), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical tests to investigate the impact of spindle velocity on the properties of the modified layer. Results of the study show that after undergoing pinless FSP modification treatment, the surface of the alloy appears bright and flat. The modified layer displays refined grains and numerous dispersed second-phase particles. Furthermore, the grains in the modified layer exhibit a gradient distribution from the surface to the matrix. Regarding the properties, compared to the base material (BM), the yield strength (σ 0.2) and tensile strength (σ b ) of the alloy-modified layer were increased by 34.8% and 29.4%, respectively. The maximum elongation (δ) of the modified coating reached 22.3%. The modified layer exhibits a tough-brittle mixed fracture pattern. Additionally, the modified layer’s corrosion resistance significantly improves. The performance of the modified coating shows the most significant improvement when the spindle speed reaches 1000 rpm.

The Peculiarities of Acoustic Normal Waves Propagation in Thin Porous Sheets of Thermally Expanded Graphite

Thermally expanded graphite belongs to a new class of graphite materials with unique physical, chemical and mechanical properties. Acoustic wave velocity is one of the most important characteristics for study of porous materials including thin porous sheets of thermally expanded graphite. In this paper peculiarities of symmetric mode S0 Lamb wave propagation and SH-wave with horizontal polarization in sheets of thermally expanded graphite are experimentally investigated. To determine their velocities a differential measurement scheme on the base of a low-frequency acoustic flaw detector DIO1000 LF and specialized piezoelectric transducers with dry point contact was used. Additionally the longitudinal wave velocity in direction of sheet thickness was determined using piezoelectric transducers based on polyvinylidene fluoride. Indicatrices of normal wave velocities in the rolling plane were plotted and it was shown that the maximum acoustic anisotropy is characteristic for the S0-mode. The velocity minimum corresponds to the longitudinal direction of the rolling plane in which the maximum elongation of gas pores was observed. Influence of thickness and density of thermally expanded graphite sheets on the velocities of normal waves was investigated and presence of the thickness range where the minimum velocity values were observed due to the maximum inhomogeneity of layers formed in the rolling process. Method for determination of dynamic elastic moduli of porous thermally expanded graphite sheets using experimentally measured velocities of normal waves was proposed. It was shown that in the longitudinal direction of the rolling plane the Poisson's ratio took negative values which allow to attribute the specified material to auxetics ones.

Evaluation and Prediction of Mechanical Properties According to Welding Methods of Ni 825/A516-70N Clad Plates

In this study, the microstructures and mechanical properties of different methods of FCAW (Flux-cored arc welding) + FCAW or FCAW + GTAW (Gas tungsten arc welding) welding on Ni825/A516-70N clad plate were investigated, using a double U groove angle on a laboratory scale. The amount of specimen deformation with FCAW + FCAW welding was ~1.5 mm, and that with FCAW + GTAW welding was ~3.6 mm. In the Vickers hardness tests, the average hardness value of the FCAW + GTAW welding specimens tended to be higher, and the hardness of the steel showed the same value. Also, in the tensile tests, the maximum strength and elongation of the FCAW + GTAW specimens were found to be higher. The SEM analysis of the welding boundaries of each specimen revealed the phenomenon of grain refinement in the specimens with FCAW + GTAW welding. This was due to the slow welding speed of this welding process and the rapid cooling rate caused by the relatively low layer thickness despite the relatively high number of weld passes. The computer simulation of the amounts of deformation were similar, with a value of 1.5 mm for FCAW + FCAW and 3.6 mm for the computer simulation, indicating the credibility of the simulation. In the computational simulation of butt welding, FCAW + GTAW showed high values for both residual stress and angular strain. The L-seam and C-seam of the demo vessel size were welded under the same conditions as the actual welding. The residual stress and angular deformation in the L-seam were 849 MPa and 2.3 mm for the FCAW + FCAW and 852 MPa and 2.9 mm for FCAW + GTAW. The residual stress and angular deformation in the C-seam were 920 MPa and 0.7 mm for FCAW + FCAW and 930 MPa and 0.9 mm for FCAW + GTAW, respectively.

Enhancing the viscoelastic properties of bacterial cellulose hydrogels through ultrasonic and enzymatic modification of xyloglucan

Bacterial cellulose (BC) hydrogels exhibit nanofibril porous network with good viscoelasticity for use as food ingredients and medical materials. Xyloglucan (XG), a hemicellulose with branching residues, can hybridize with BC to improve the hydrogel's extensibility. Thus, modifying the molecular structure of XG can fine-tune the viscoelastic properties of BC hydrogels. In this study, tamarind seed XG subjected to ultrasonic and enzymatic treatment was hybridized with BC to form composite materials. The results indicated that incorporating modified XG reduced the modulus and enhanced the viscous behaviour of BC to varying degrees. XG modified via ultrasonic treatment demonstrated a higher binding efficiency (19–22 %) with cellulose compared to enzymatically treated XG (11–13 %). The enzymatically treated XG improved the maximum elongation ratio to 57 %, but reduced the storage modulus to 30 kPa. Although ultrasonic-treated XG had a similar effect on the shear modulus, it had less impact on the extensibility of BC, with an elongation ratio of 38 %. Additionally, the incorporation of modified XG also regulated the nonlinear viscoelasticity of BC. These findings advance our understanding of the application of XG as a regulator of mechanical and rheological properties, broadening its utility in BC hydrogel formulations for the food industry and medical material development.

Characterization of CL-20/HMX cocrystallization and its effects on GAP-based propellants during thermal aging process

The incorporation of HMX and CL-20 as component particles can greatly improve the energy efficiency of composite propellants. Nevertheless, the occurrence of cocrystallization arises when HMX and CL-20 exists together. Further investigation is needed to determine the effects of the CL-20/HMX cocrystallization on the aging features of the propellants. The present study examines the evolutionary trends and effects of the CL-20/HMX cocrystal on the process of solid propellant aging. Experimental thermal aging studies were carried out on GAP-based composite propellants at temperatures of 60 °C/180-day and 70 °C/90-day. An investigation of density bottle, differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, and uniaxial tensile testing were performed on the samples. The results indicate that the cocrystallization behaviours of CL-20/HMX undergo three distinct stages during propellant aging. The reaction rate accelerates most during the middle aging stage. As the GAP-based propellant ages, the recently developed cocrystal structure deteriorates the interfacial characteristics between the propellant particles and the matrix, leading to the formation of cavities inside the material. This will further enhance the decrease in elastic modulus, ultimate strength, and maximum elongation of the propellants. Among them, the most notable distinction from the aging behaviours of propellants without the addition of particles is the increase of the elastic modulus. Furthermore, a strong linear correlation was observed between variation of the elastic modulus and the cocrystal content of CL-20/HMX. This correlation offers a reliable indicator for monitoring the extent of cocrystallization phenomena.

Cavity formation in silica‐filled rubber compounds observed during deformation by ultra small‐angle x‐ray scattering

AbstractWhen silica‐filled rubber compounds are deformed, structural modifications in the material's bulk lead to irreversible damage, the most significant of which is cavitation appearing within the interfaces of interconnected polymer and filler networks. This work introduces a new method to analyze cavitation in industrial‐grade rubbers based on ultra small‐angle x‐ray scattering. This method employs a specially designed multi‐sample stretching device for high‐throughput measurements with statistical relevance. The proposed data reduction approach allows for early detection and quantification of cavitation while providing at the same time information on the hierarchical filler structures at length scales ranging from the primary particle size to large silica agglomerates over four orders of magnitude. To validate the method, the scattering of SSBR rubber compounds filled with highly dispersible silica at different ratios was measured under quasi‐static strain. The strain was applied in incremental steps up to a maximum achievable elongation or breakage of the sample. From the measurements performed in multiple repetitions, it was found that the minimum strain necessary for cavity formation and the size evolution of the cavities with increasing strain are comparable between these samples. The sample with the highest polymer content showed the lowest rate of cavity formation and higher durability of silica structures. The structural stability of the compounds was determined by the evolution of the filler hierarchical structures, obtained by fitting data across the available strain range.

Effect of friction stir processing on grain refinement and superplastic properties of binary Al-8 wt.% Si to Al-30 wt.% Si alloys

ABSTRACT As-cast binary Al–Si alloys containing ∼8, 12, 20, and 30 wt.% Si, representing the hypoeutectic, eutectic (12 wt.% Si), and hypereutectic compositions, were subjected to severe plastic deformation by friction stir processing (FSP) for grain refinement to 2.3–2.7 μm by dynamic recrystallization. Tensile tests conducted by differential strain rate test technique over the strain rates of 10−4 – 10−2 s−1 and test temperatures in the range of ∼840–530 K led to strain rate sensitivity index (m) varying from ∼0.04 to 0.40 depending on temperature, strain rate, and alloy composition. The constant initial strain rate tests conducted at 10−4 s−1 and 840 K exhibited a maximum elongation of 250% in the hypereutectic Al–20Si alloy, but the same increased linearly with m irrespective of alloy composition. Generally, with increasing Si content, the activation energy for deformation increased from 104.7 ± 14.4 kJ/mol for eutectic Al–12Si to 310.4 ± 32.3 kJ/mol for hypereutectic Al–30Si, which increased further to 572 ± 148 kJ/mol over the higher temperature range of 840–800 K. Analysis of observed deformation and microstructure behaviour supports the occurrence of superplasticity, whereby the accommodation of grain boundary sliding by grain boundary migration led to enhanced grain growth or else the local high-stress concentration at the particle-matrix interface led to cavity formation. There was no evidence of dynamic recrystallization during high-temperature tensile deformation but the flow softening observed is ascribed to the occurrence of concurrent cavitation.

Plastic recovery and strength enhancement of pre-deformed AZ31B magnesium alloy using transient strong pulse current

Magnesium alloy components are mainly used in aerospace and automotive fields, but poor deformation ability at room temperature restricts their application in other industries. To address this issue, electrically-assisted technology is employed to enhance plasticity of alloys. However, conventional method weaken strength and intensify surface oxidation of such alloys because of prolonged action of current. In view of the above, pre-deformation (PF) treatment in combination with transient induced pulse current treatment (TIPCT) is proposed in the present work so as to balance between plasticity recovery and strength of AZ31B alloy. The results show that the total elongation of PF sample and the corresponding TIPCT specimen first increases and then decreases with the increase in PF percentage under the same voltage. At the same PF percentage, the total elongation of PF and TIPCT specimens also presents the same trend as the voltage increases. At the same time, the total elongation in PF and TIPCT specimens is greater than that of the as-received sample. The maximum total elongation is achieved at the PF percentage of 16 % and the voltage of 6 kV, being 35 % higher than that in the as-received sample. The improvement in total elongation is due to activation of more non-basal dislocations induced by TIPCT and the appropriate amount of microcracks generated by PF. In addition, the TIPCT process also improves the yield strength even if the PF percentage and voltage are changed. Besides that, the work hardening induced by PF treatment and instantaneous action of TIPCT process are the key factors enhancing yield strength. Moreover, comprehensive mechanical properties of TIPCT sample are found to outperform those after direct pulse current treatment (DPCT) under the same PF percentage. Therefore, the proposed composite process provides a feasible scheme to enhance strength and elongation of Mg sheets.

Examination of the Effects of Chemical Treatments on the Mechanical, Chemical, and Physical Characteristics of <i>Hibiscus rosa-sinensis</i> Plant Fiber

Natural fibres in recent years have been found to contribute a great share in making composites. Hibiscus rosa-sinensis plant fibres which are natural were used in this work and have not yet been tried to make the composites so far and easily available thus making this study very necessary it aims to perform various chemical treatments and to study the physical and chemical properties of them. The methodology adopted was that literature review, problem identification, extraction of fibres, treatment of fibres, chemical and mechanical testing of fibres, results and discussions and conclusion. Fibre chemical composition tests were also done to determine the constituents of the fibres. Two chemical treatment methods (alkalinization and benzoylation) were proposed in this work. Chemical treatments were found to improve surface roughness. Using Scanning Electron Microscopy (SEM), researchers examined the fibres' structural and morphological alterations and discovered that components like pectin were largely eliminated. The structural properties of fibres were known from X-ray diffractograms, and crystallinity percentages were found for the cellulosic fibres. Fourier Transform Infrared (FTIR) spectroscopy presented the spectra of the fibres which revealed the structure of organic compounds and the presence or the absence of functional groups. It showed the partial removal of hemicellulose and lignin. Axial tensile tests were performed for the fibres to know the maximum tensile force and percentage elongation. Chemical treatments partially removed impurities in the fibres and made morphological changes. The improvements in mean tensile values and percentage elongation were found in 5% alkali-treated and benzoylation-treated fibres, 56% and 63% higher than the untreated fibres respectively.

Analyzing the Influence of Titanium Content in 5087 Aluminum Filler Wires on Metal Inert Gas Welding Joints of AA5083 Alloy

As the demand for lightweight structures in the transportation industry continues to rise, AA5083 aluminum alloy has become increasingly prominent due to its superior corrosion resistance and weldability. To facilitate the production of high-quality, intricate AA5083 components, 5087 aluminum filler wire is commonly utilized in metal inert gas (MIG) welding processes for industrial applications. The optimization of filler wire composition is critical to enhancing the mechanical properties of AA5083 MIG-welded joints. This study investigates the effects of modifying 5087 aluminum filler wires with different titanium (Ti) contents on the microstructure and weldability of AA5083 alloy plates using MIG welding. The influence of Ti contents was systematically analyzed through comprehensive characterization techniques. The findings reveal that the constitutional supercooling induced by the Ti element and the formation of Al3Ti facilitate the heterogeneous nucleation of α(Al), thereby promoting grain refinement. When the Ti content of 5087 filler wire is 0.1 wt.%, the grain size of the weld center was 78.48 μm. This microstructural enhancement results in the improved ductility of the AA5083 MIG-welded joints, with a maximum elongation of 16.64% achieved at 0.1 wt.% Ti addition. The hardness of the joints was the lowest in the weld center zone. This study provides critical insights into the role of Ti content in MIG welding and contributes to the advancement of high-performance filler wire formulations.

Preparation and Characterization of Ni-Mn-Ga-Cu Shape Memory Alloy with Micron-Scale Pores

Porous Ni-Mn-Ga shape memory alloys (SMAs) were prepared by powder metallurgy using NaCl as a pore-forming agent with an average pore size of 20–30 μm. The microstructure, phase transformation, superelasticity, and elastocaloric properties of the porous alloys were investigated. The prepared porous alloy had a uniform pore distribution and interconnected microchannels were formed. Cu doping can effectively improve the toughness of a porous alloy, thus improving the superelasticity. It was found that porous Ni-Mn-Ga-Cu SMAs have a flat stress plateau, which exhibits a maximum elongation of 5% with partially recoverable strain and a critical stress for martensite transformation as low as about 160 MPa. In addition, an adiabatic temperature change of 0.6 K was obtained for the prepared porous alloy at a strain of 1.2% at about 150 MPa. This work confirms that the introduction of porous structures into polycrystalline Ni-Mn-Ga SMAs is an effective way to reduce costs and improve performance, and provides opportunities for engineering applications.

Mathematical and Statistical Analysis of Fused Filament Fabrication Parameters for Thermoplastic Polyurethane Parts via Response Surface Methodology

This work aims to analyze the effects of the main process parameters of fused filament fabrication (FFF) on the mechanical properties and part weight of 3D-printed thermoplastic polyurethane (TPU). Raster angle (RA), infill percentage (IP), and extruder temperature (FFF) in the ranges of 0–90°, 15–55%, and 220–260 °C, respectively, were considered as the FFF input parameters, and output variables part weight (PW), elongation at break (E), maximum failure load (MFL), ratio of the maximum failure load to part weight (Ratio), and build time (BT) were considered as responses. The Response Surface Methodology (RSM) and Design of Experiments (DOE) were applied in the analysis. Subsequently, the RSM approach was performed through multi-response optimizations with the help of Design-Expert software. The experimental results indicated a higher maximum failure load is achieved with an increased raster angle and decreased extruder temperature. ANOVA results show that ET has the most significant effect on elongation at break, with elongation at break decreasing as ET increases. The raster angle does not significantly affect the part weight of the TPU samples. The ratio of the maximum failure load to part weight of samples decreases with an increase in IP and ET. The results also indicated that the part weight and build time of FFF-printed TPU samples increase with an increase in IP. An ET of 220 °C, RA of 0°, and IP of 15% are the optimal combination of input variables for achieving the minimal part weight; minimal build time; and maximum elongation at break, maximum failure load, and ratio of the maximum failure load to part weight.

Superplastic Deformation Behavior of 2 mm Ti60 Rolled Sheet in Air Environment

The superplastic deformation behavior of 2 mm Ti60 sheet is studied, and the constitutive equation of superplastic deformation is established. The results show that when the strain rate is 5.00 × 10−3 s−1 and the temperature is 950 °C, the maximum superplastic elongation reaches 400%. Through the analysis of the true strain–true stress curve, it is found that the average apparent activation energy (Q) is 490.783 kJ mol−1 and the average strain rate sensitivity (m) is 0.49. Dynamic spheroidization (DG) promotes the transformation of lath α phase to equiaxed α phase. Dynamic recrystallization (DRX) promotes the generation of high‐angle grain boundaries (θ > 15°). After deformation, the strength of R‐type textures changes significantly. From the grip to the tip, the strength of R‐type texture gradually weakens, which is mainly caused by the rotation of grains during deformation. The deformation mechanism of Ti60 sheet is dominated by grain boundary sliding, and is coordinated by grain growth, DG, DRX, dislocation motion, and grain rotation.

The Effects of an Oral Supplementation of a Natural Keratin Hydrolysate on Skin Aging: A Randomized, Double-Blind, Placebo-Controlled Clinical Study in Healthy Women.

Keratin hydrolysates are active components used in food supplements to alleviate aging signs on skin, hair, and nails. This randomized, double-blind, placebo-controlled study evaluates a novel keratin hydrolysate obtained from poultry feathers. This feather keratin hydrolysate (FKH) results in a characteristic mix of free L-amino acids (≥ 83.5%). FKH was administered as a food supplement to a panel of adult women showing aging physiological signs. Participants were randomly assigned in three groups to receive daily dosages of 500 or 1000 mg of FKH or placebo for 90 days. Parameters of skin roughness, wrinkle features, deep skin moisturization, skin maximum elongation and elasticity, skin thickness, skin anisotropy, skin density, gloss of skin, hair and nails, and nail hardness were evaluated. Subjects also answered a questionnaire related to the treatment efficacy perception. Both FKH treatments showed a significant improvement of all parameters compared to day 0 and to placebo, with an exception for fiber anisotropy and fiber density which showed a significant improvement compared to day 0 and a tendency to improve compared to placebo. These measurements were bolstered by the results of a self-assessment questionnaire, showing an overall set of positive answers for both treatments compared to placebo. Oral supplementation of FKH for 90 days is associated with an improvement in the appearance of facial skin, hair, and nails. This study highlights the benefits of free L-amino acids mix as potential aminobiotics and not just as building blocks of proteins, suggesting a new perspective of nutricosmetic food.

Effect of order-disorder transition and lattice distortion on the mechanical properties of W-X (X = V, Nb, Ta) solid solutions

With the prosperity of high entropy alloys, short-range ordering is getting more and more attentions and regarded as the deciding role in the hardening or softening of solid solutions. In this work, the phase stability and mechanical properties of short-range ordered and disordered body-centered cubic (BCC) structures of W-X solid solutions (X = V, Nb, and Ta) are systematically investigated through a combination of first-principles calculation, cluster expansion and quasi-harmonic Debye formula. Based on the calculated heat of formation (ΔHf), W-X solid solutions show a strong short-range ordering tendency, as those ordered structures have a lower ΔHf than the disordered ones. Generally, short-range ordering results in the decrease of the shear modulus to bulk modulus ratio (G/B) and hardness for W-V and W-Ta systems, while an increase for W-Nb system, manifesting solid-solution softening and hardening effect, respectively. The short-ranged ordered C11b W2X phase exhibits a singularity in mechanical properties characterized by a higher G/B than solid solution phases compared to other ordered phases. The lattice distortion breaks the symmetric W-W bonds and leads to partial covalency in the W2X phases. Besides the increased brittleness, this distortion also causes the increase of ideal strength and the reduction of maximum tensile elongation of W2X. The effect of short-range ordering and lattice distortion on the hardening or softening of the W-X systems disappears after the order-disorder transition. The W-V and W-Ta phases have higher order-disorder transition temperature than W-Nb phase. Nevertheless, the transition temperature is relatively low in comparison to their melting points, signifying the important role in controlling the solute concentration at lower temperature.

Numerical study of two equal-sized miscible drops undergoing head-on collision

The numerical analysis focuses on investigating head-on collisions between two miscible drops composed of distinct fluids, specifically ethanol and water. The simulations are performed using a coupled level set and volume of fluid approach with different Weber numbers to study the effect of drop inertia. The code is validated against experimental and numerical results from earlier investigations. Additionally, a comparative study involving both water drops and ethanol–water drops is conducted to explore the impact of varying surface tension ratios on collision outcomes. Results show that when miscible drops collide, the merged liquid drop exhibits asymmetric behavior, such as an asymmetric combined drop shape in cases of permanent coalescence or an asymmetric end droplet breakup in cases of reflexive separation. The collision outcome undergoes significant variation as the Weber number changes. At lower Weber numbers, permanent coalescence is observed, while at medium Weber numbers, reflexive separation occurs without the formation of a secondary drop. For medium to large Weber numbers, reflexive separation with the generation of one secondary drop becomes prominent, and in the case of very large Weber numbers, multiple satellite drops form. The maximum vertical elongation of the merged drop and corresponding surface energy increase as the surface tension ratio rises, irrespective of the Weber number. However, for a fixed surface tension ratio, the maximum vertical elongation and associated surface energy vary with an increase in the Weber number. The findings also shed light on the enhanced internal mixing arising from the mismatched surface tension of the colliding drops as the Weber number increases. Furthermore, the study explores the effect of drop inertia on various aspects, including asymmetric collision behavior, energy budget, and mixing index.