Properties Of Wires Research Articles

Exceptional grain refinement induced by dispersed MgO particles in TIG-welded AZ31 alloy

Due to the low content of alloying elements and the lack of effective nucleation sites, the fusion zone (FZ) of tungsten inert gas (TIG) welded AZ31 alloy typically exhibits undesirable coarse columnar grains, which can result in solidification defects and reduced mechanical properties. In this work, a novel welding wire containing MgO particles has been developed to promote columnar-to-equiaxed transition (CET) in the FZ of TIG-welded AZ31 alloy. The results show the achievement of a fully equiaxed grain structure in the FZ, with a significant 71.9% reduction in grain size to 41 µm from the original coarse columnar dendrites. Furthermore, the combination of using MgO-containing welding wire and pulse current can further refine the grain size to 25.6 µm. Microstructural analyses reveal the homogeneous distribution of MgO particles in the FZ. The application of pulse current results in an increase in the number density of MgO (1-2 µm) from 5.16 × 104 m−3 to 6.18 × 104 m−3. The good crystallographic matching relationship between MgO and α-Mg matrix, characterized by the orientation relationship of [112‾0]α−Mg//[01‾1]MgO and (0002)α−Mg//(111)MgO, indicates that the MgO particles can act as effective nucleation sites for α-Mg to reduce nucleation undercooling. According to the Hunt criteria, the critical temperature gradient for CET is greatly enhanced due to the significantly increased number density of MgO nucleation sites. In addition, the correlation with the thermal simulation results reveals a transition in the solidification conditions within the welding pool from the columnar grain zone to the equiaxed grain zone in the CET map, leading to the realization of CET. The exceptional grain refinement has contributed to a simultaneous improvement in the strength and plasticity of welded joints. This study presents a novel strategy for controlling equiaxed microstructure and optimizing mechanical properties in fusion welding or wire and arc additive manufacturing of Mg alloy components.

Fatigue Behavior and Fracture Surface Analysis of Corroded High-Strength Bridge Cable Wires.

Bridge cable wires suffer from alternating stress and environmental erosion, leading to premature failure prior to its design life. This paper investigates the fatigue and mechanical behaviors of corroded bridge cable wires with a zinc-aluminum (Zn-Al) alloy coating. Based on the salt spray corrosion test and microstructure analysis, the anti-corrosion resistance and corrosion appearance characteristics of the Zn-Al alloy coating and galvanized coating were investigated. The Zn-Al alloy coating was superior in resistance to corrosion fatigue for the improvement in toughness and the generation of anti-corrosion Zn-Al and Fe-Zn-Al phases. Equations of the accelerated corrosion depth of the steel wires had been regressed to roughly estimate the corrosion life of the Zn-Al alloy coating, which can reach 29.1 years with a thickness of 70 μm. The fatigue and mechanical properties of the bare wires after the salt spray test were further studied based on tensile tests and fatigue tests. The fatigue properties of the bridge cable wire would decrease with the corrosion degree due to the deterioration and embrittlement of materials, where ductility characterized by the elongation rate was the most affected. Fracture surfaces of the wires were captured and analyzed based on a method for recognizing graphical contours. Insufficient fatigue life may occur in the steel wires after corrosion and increase with the degree of corrosion. The pit depth logarithmically weakened the fatigue life of steel wires for the weakening of fatigue toughness and the bearing area. The flat fracture was more common with a single fatigue source, while multiple fatigue sources led to step-like fractures for the generation of multiple dispersed crack propagation regions. Corrosion fatigue was more sensitive to the existence of fatigue sources than the reduction. Multiple initiation sources significantly reduced the fatigue life due to the cracking facilitation of the joint effect of multiple pits. The electrochemical reactions of corrosion can lead to material embrittlement and a reducing effect on the fracture toughness of the steel wires.

Development of persistent joints for superconducting Bi-2212 coils

Bi2Sr2CaCu2O8+x (Bi-2212) multifilamentary wire is the only high-temperature superconductor manufactured in the form of an isotropic round wire, and so offers a number of advantages for the designers of high field magnets. However, for high-field (>25 T), high-stability magnet applications, ultra-low resistance superconducting joints (R < 10−12 Ω) will be needed to take advantage of the excellent properties of the Bi-2212 wire. This study focuses on the fabrication of compact melt processed joints in small coils of Bi-2212/Ag multifilamentary round wires and the testing of their superconducting performance by inductive resistance measurements. Microstructural analysis is carried out to correlate the microstructure to the superconducting performance of the joints. Our optimized technique led to a reliable process for the preparation of small coils with melt processed joints that occupy very small volumes but can still carry the highest persistent currents reported so far for Bi-2212.

Model-based closed-loop process control for the manufacturing of hairpin coils

As a consequence of the increasing market share of hybrid and all-electric mobility solutions, there is a need for robust manufacturing technologies that enable the efficient production of powerful electric traction motors in automotive industry. In the context of high-quality distributed stator windings, the so-called hairpin technology already meets the automotive demand regarding productivity – but process reliability is still limited by variations in the mechanical and geometric properties of the enameled rectangular copper wire leading to different springback effects within the forming processes. Against this background, a model-based closed-loop process control for the sequential tool-bound bending of hairpin coils is introduced and validated in this paper.

Comparative investigation on fire resistance of different fire prevention schemes for 1670 MPa steel wires used in bridge cables

This paper mainly investigated the fire resistance of different fire prevention schemes for 1670 MPa steel wires used in bridge cables. The fire resistance tests on bridge cables under different fire protection schemes were carried out. The failure modes and the varied patterns of temperature at different positions of the cables was studied, and the optimal design scheme of fire protection for bridge cables was also obtained. Furthermore, the tensile test of steel wire after fire was carried out to study the degradation law of mechanical properties of steel wire. The results showed that the cables undergo varying degrees of bending deformation after the fire, mainly due to the poor fire protection effect. The wrapping process of the fire protection scheme was a key factor affecting the protective effect. When the premature invalidation of the wrapping mode failed to occur, the aerogel material would have better thermal insulation behavior than the basalt fiber. The temperature rising rate of Schemes D (6 mm ceramic fiber aerogel tape), E (10 mm high silica glass aerogel tape) and F (10 mm nano thermal isolation felt-ceramic fiber aerogel) was relatively gentle, and the temperature of most measuring points within 4500s was not more than 300 °C. Based on the failure mode and the temperature of the cables, it could be judged that Schemes E and F were better than Schemes C (4 mm composite fiber fire-resistant isolation tape) and D while schemes A (4 mm basalt fiber needled felt) and B (4 mm aerogel tape) had the worst fire protection effect. Due to the surface temperature, the fracture morphology of steel wires after fire varied greatly, mainly divided into brittle fracture and ductile fracture. With the increase of temperature, the yield and ultimate strength of steel wire of Schemes A, B, C, D and E decreased greatly after fire, and along with a maximum decrease of 73.78% and 69.02% respectively.

Test Rig for Investigating the Functional and Structural Fatigue of Shape Memory Alloy Wires Based on Different Activation Profiles.

This work presents a test rig developed for testing the lifetime of electrically and cyclically activated shape memory alloy wires. This test rig is developed to provide information on the functional and structural fatigue of the wires. Therefore, electrical activation on the test rig can be carried out using different activation profiles, because it is of great research interest to determine whether those profiles have a significant influence on the wire's lifetime and functional behavior. The test rig monitors the process parameters such as stroke, current, voltage, and force. After presenting the electrical and mechanical design of the test rig, this publication evaluates an initial series of tests to demonstrate its functionality. Three different activation profiles are run in parallel on four identical test rig setups and are then evaluated. The functionality of the test rig is verified by a detailed evaluation of the process data on the one hand, and by comparing the results with existing literature on the other. The functionality of the test rig can thus be verified. At the same time, the strong influence of the different activation profiles on both the lifetime and the functional properties of the shape memory alloy wires becomes clear.

Study on thermal fatigue stability in microstructure and mechanical property of Fe35Ni35Cr20Mn10 high-entropy alloy wire and pearlite wire at high/medium temperature environment

Thermal fatigue stability in microstructure and strength of Fe35Ni35Cr20Mn10 high-entropy alloy (HEA) wire and pearlite wire at 400–700 °C with low cycles was studied. The pearlite wire has a poor stability in microstructure and strength, significantly changing with the temperature. HEA wire has an excellent thermal fatigue stability. After the thermal fatigue at 400 °C and 500 °C, the microstructure and strength does not change at all. Only after the thermal fatigue at 600°C and 700 °C, the microstructure and strength change considerably. Both the values of UTS and YS of the HEA wires after the thermal fatigue at 500 °C and 600 °C are higher than that of the pearlite wires, even both the values of HEA wire in as-drawn state are much lower than that of pearlite wire. Both the thermal fatigue and isothermal annealing at 500 °C and 600 °C resulted in an obvious tempering brittleness in pearlite wire.

Impact of Prophylactic Fluoride Agents On the Surface Roughness of Newer orthodontic arch wires

Fluorides serve an important part in orthodontic therapy as a prophylactic strategy. However, the harmful effects of fluoride are typically disregarded due to its widespread use as an anti-cariogenic agent in a variety of dental materials. The effects of these fluoride agents on conventional arch wires have been studied extensively but not on newer wires such as coated wires or braided wires. Hence this study was undertaken to assess the effects of prophylactic fluoride agents on the surface properties of non-coated Nickel-Titanium orthodontic wires and compare it with coated esthetic Ni-Ti wires and braided Ni-Ti wire. Materials and methods: In this study, we compared three packages of 270 orthodontic arch wires made of nickel titanium. For the control, the third set of 30 wires was stored in plastic vials containing 5ml of artificial saliva for two months. Subgroup a did not make use of any fluoride treatments. Samples from subgroup b were treated with Phos-flur gel for one minute every day for 2 months, while those from subgroup c were treated with Prevident 5000. An optic profilometer was used to measure the wires roughness. Results: The investigation found that both the acidulated fluoride agent (Phos-flur gel) and neutral fluoride agent (Prevident 5000) had an effect on the surface attributes of all three sets of wires. Coated esthetic Ni-Ti wires showed highest surface roughness followed by braided Ni-Ti wire. Conclusion: The findings of the research showed that using fluoride preventive treatments (such as mouthwash or gels) during orthodontic treatment decreases the arch wires characteristics. Bangladesh Journal of Medical Science Vol.23 (Special Issue) 2024 p.S107-S114

Experimental Analyses and Predictive Modelling of Ultrasonic Welding Parameters for Enhancing Smart Textile Fabrication.

This study aims to illustrate the design, fabrication, and optimisation of an ultrasonic welding (UW) machine to join copper wires with non-woven PVC textiles as smart textiles. The study explicitly evaluates UW parameters' impact on heat generation, joint strength, and electrical properties, with a comprehensive understanding of the process dynamics and developing a predictive model applicable to smart textiles. The methodological approach involved designing and manufacturing an ultrasonic piezoelectric transducer using ABAQUS finite element analyses (FEA) software and constructing a UW machine for the current purpose. The full factorial design (FFD) approach was employed in experiments to systematically assess the influence of welding time, welding pressure, and copper wire diameter on the produced joints. Experimental data were meticulously collected, and a backpropagation neural network (BPNN) model was constructed based on the analysis of these results. The results of the experimental investigation provided valuable insights into the UW process, elucidating the intricate relationship between welding parameters and heat generation, joint strength, and post-welding electrical properties of the copper wires. This dataset served as the basis for developing a neural network model, showcasing a high level of accuracy in predicting welding outcomes compared to the FFD model. The neural network model provides a valuable tool for controlling and optimising the UW process in the realm of smart textile production.

Effect of large deformation on microstructure and properties of copper alloy wire

Cu–Ag alloy wire with different deformations and Ag contents of 1%, 2%, and 4% are prepared using vacuum continuous casting technology combined with cold drawing and intermediate annealing processes. The evolution of microstructure, electrical properties, and mechanical properties of the Cu–Ag alloy wire is investigated, and a relationship model between wire diameter, Ag content, and alloy wire properties is established. The results showed that the directionally solidified billets exhibited good elongation and are suitable for drawing fine wire. As the Ag content increased, the twinning content inside the Cu–Ag alloy wire also increased significantly. It is found through Strain++ characterization that there is non-uniform deformation within the wire, and the tensile and compressive strains that exist interactively tend to aggregate within the twins. The properties of the Cu–Ag alloy wire with different diameters varied significantly at different stages of deformation, showing a pronounced size effect below 1 mm. With decreasing wire diameter or increasing Ag content, the DC resistance, resistivity, and tensile strength of the Cu–Ag alloy wire gradually increased, while the conductivity decreased. The effect of Ag content on elongation is not significant. Statistical analysis revealed that the established performance model had high predictive accuracy and could provide references for the optimization of production processes for Cu–Ag alloy wire.

The Effect of Electroless Nickel–Polytetrafluoroethylene Coating on the Frictional Properties of Orthodontic Wires

In orthodontic treatment, to achieve efficient tooth movement, it is important to reduce the frictional force between the wire and the bracket, especially the binding friction that occurs when the angle between the wire and the bracket is large. Electroless nickel–polytetrafluoroethylene (Ni-PTFE) coating is a coating technology used to deposit PTFE particles with a low coefficient of friction on the coating surface to provide a low-friction surface for metallic materials. The purpose of this study was to investigate the effect of Ni-PTFE-coated orthodontic wires on the frictional force between brackets. The surface morphology, surface roughness, and frictional properties of Ni-PTFE-coated stainless steel wires and Ni-Ti wires were evaluated. The results demonstrate that the Ni-PTFE coating reduced the frictional force between the orthodontic wires and brackets, despite the increased surface roughness. Even when the angle between the wire and bracket was increased, assuming binding friction, the frictional force was reduced by the Ni-PTFE coating. This suggests that the friction between the wire and the bracket was suppressed by the PTFE particles deposited on the wire surface in contact with the bracket.

Development and research of technology for obtaining and properties of welding wire from Al–Mg–Sc alloys using combined methods of thermal deformation treatment

The results of studies technological processes for obtaining welding wire from alloys of the Al–Mg system with a scandium content of 0.12 (alloy 1580) and 0.25 wt % (alloy 01570) presented. A feature of the technology is the production of a billet for further cold deformation by an energy-efficient method of ingotless rolling-extrusion (IRE). It was found that hot-extruded rods from the investigated alloys obtained by the IRE method have the required level of plastic and strength properties necessary for further cold deformation up to 80%. Thermomechanical processing of hot-extruded rods manufactured by IRE have been developed and experimentally tested, which made it possible to obtain a billet with a square side of 5 × 5 mm by sectional rolling and wire with a diameter of 3 mm by drawing. Studies of the structure and mechanical properties of deformed semi-finished products have shown that the developed modes make it possible to obtain a welding wire from the investigated alloys that meets the requirements of current standards. Studies of the operational properties of the obtained welding wire were carried out. It was found that alloy 1580 with a minimum content of scandium (0.12 wt %) is not inferior to alloy 01570 in terms of corrosion resistance and weld quality. Developed technology for the production of welding wire from alloys of the Al–Mg system with different scandium content can be recommended for industrial use. It is advisable to implement alloy 1580, which has a lower cost compared to alloy 01570.

Selected properties of aluminum ultrasonic wire bonded joints with nickel-plated steel substrate for 18650 cylindrical cells

Ultrasonic wire bonding is a process of connecting two or more surfaces using a metal wire. In battery manufacturing heavy wire bonding is used to connect battery cells with each other or more commonly with printed circuit board or metal (aluminum, plated or bare copper) busbar by means of metal (aluminum, copper) wire with diameters ranging 100–500 µm. Single sided battery cell bonding means that connections are made from one side on both positive (cap) and negative (crimp) battery terminals. The main advantages of this method are easy process automation, low production time, easier recyclability, self-fusing properties of the wire and high process flexibility allowing for more space efficient battery holder design and different material thermal expansions (in comparison with direct busbar to cell joining using resistance or laser welding). This study is focused on analysis of selected properties of 400 µm aluminum wire ultrasonic wedge heavy wire bonding on 18,650 Lithium-Ion cylindrical battery cells. Bonding process was conducted using a RBK03 bond head equipped on a Hesse Bondjet BJ985 CNC wire bonder. As part of the work, the transversal and the longitudinal cross-section profile of the weld, the microstructure of the weld and the heat-affected zones of the dissimilar joint were described using electron and optical microscopy, the microhardness distribution in the joint was characterized and the joint sheer tests were performed according to DVS-2811. Materials of the aluminum bonding wire and the battery cell cylinder used for joining were also characterized. Bonding process on the machine used in this study is controlled by its duration, wire deformation or both of these parameters and consist of wire touch down and several (usually 2 or 3) bonding phases. Parameters of each bonding phase consist of bonding force, bonding force ramp, ultrasonic generator current/voltage, ultrasonic generator current/voltage ramp and bonding time. Each wire has at least 2 bonds connected by wire loop and is ended with wire pre-cut and tear off.

Mechanical Manipulation of Quantum Interference in Single-Molecule Junctions.

Mechanosensitive molecular junctions, where conductance is sensitive to an applied stress such as force or displacement, are a class of nanoelectromechanical systems unique for their ability to exploit quantum mechanical phenomena. Most studies so far relied on reconfiguration of the molecule-electrode interface to impart mechanosensitivity, but this approach is limited and, generally, poorly reproducible. Alternatively, devices that exploit conformational flexibility of molecular wires have been recently proposed. The mechanosensitive properties of molecular wires containing the 1,1'-dinaphthyl moiety are presented here. Rotation along the chemical bond between the two naphthyl units is possible, giving rise to two conformers (transoid and cisoid) that have distinctive transport properties. When assembled as single-molecule junctions, it is possible to mechanically trigger the transoid to cisoid transition, resulting in an exquisitely sensitive mechanical switch with high switching ratio (> 102). Theoretical modeling shows that charge reconfiguration upon transoid to cisoid transition is responsible for the observed behavior, with generation and subsequent lifting of quantum interference features. These findings expand the experimental toolbox of molecular electronics with a novel chemical structure with outstanding electromechanical properties, further demonstrating the importance of subtle changes in charge delocalization on the transport properties of single-molecule devices.

Effects of Different Heating and Cooling Rates during Solution Treatment on Microstructure and Properties of AA7050 Alloy Wires.

In the present study, the effects of varying heating and cooling rates during the solution treatment process on the microstructure and properties of AA7050 alloy wires were investigated using tensile tests, metallographic microscopy, electron backscattered diffraction, and transmission electron microscopy. It was found that the recrystallized grain size of the alloy, subjected to method of rapid heating, exhibited a smaller and more uniform distribution in comparison to method of slow heating. The low density of η' strengthening phases after the artificial aging treatment was formed using air cooling method. Meanwhile, by using the water quenching method sufficient solute atoms and more nucleation sites were provided resulting in a large number of η' strengthening phases being formed. In addition, the alloy processed using the water quenching method displayed higher strength than that treated using the air cooling method for the T6 and T73 states. Furthermore, coarse precipitates formed and less clusters were observed in the matrix, while high density nanoscale clusters and no continuous precipitation are formed when using the water quenching method.

Fabrication of a novel aesthetic orthodontic bracket and evaluation of friction properties between PEEK and stainless steel wires.

Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical and lubrication properties favorable for biomedical applications. Despite of its aesthetic appearance, ceramic brackets are unsatisfactory in brittleness and thickness, while PEEK is a potential material for aesthetic orthodontic brackets. To fabricate a novel aesthetic orthodontic bracket and evaluate friction properties of PEEK and stainless steel wires. All polyether ether ketone (PEEK) and ceramic samples disks were made into disks (diameter, 5 mm; thickness, 2mm). The tested surfaces of PEEK were ground with #600, #800 and #1200 SiC papers, followed by polishing with Sof-Lex kit (3M ESPE, USA). The surface roughness was tested using a laser profilometer device (VK-X200, Keyence, Japan). The COFs of the specimens and stainless steel (SS) archwires were tested using a Universal Micro-Tribotester (UMT-3, Bruker, USA). The wear scratches on the materials' surfaces were examined by using a scanning electron microscope (SEM) (Hitachi SU8010). The elastic modulus and hardness of samples were examined with a nano-indenter (XP, Keysight Technologies, USA). The mean surface roughness of PEEK and Ceramic are 0.320 ± 0.028 μm and 0.343 ± 0.044 μm, respectively. PEEK has a lower Friction coefficient than Ceramic and the difference between the two groups was statistically significant (P< 0.05). The abrasive wear of Ceramic was the main wear style and was characterized by the observation of chipping fractures, while PEEK surface looked smooth without obvious scale-like desquamations and granular debris, indicating adhesive wear. Within the limitations of the present study, PEEK shows lower coefficient of friction than ceramic. PEEK has excellent properties such as low friction coefficient, smooth surface and good mechanical properties, and thus meets the requirements for orthodontic brackets. It is considered as a potential bracket material with both low friction and aesthetic performance.

Long-range electron transfer mediated by G-quadruplex wires attached to gold electrodes via phosphorothioated dA tags

G-quadruplex (G4) DNA wires are perspective highly-conductive building blocks for self-assembling bioelectronic nanocircuits. Here, we interrogated electrochemically G4-mediated electron transfer (ET) reaction between the gold electrodes and redox indicator methylene blue (MB) intercalated into ten-tetrade G4 DNA tethered to the gold electrode via four phosphorothioated adenosine tags. The efficiency of DNA-mediated ET evaluated by kinetic analysis of MB redox transformations was characterized by the ks of 155 s−1. This value was well below 108 s−1 per ten tetrades determined by the current-voltage measurements in the absence of any redox active species, primarily. Due to the complex 2e−/1H+ electrochemistry of MB that apparently gated the overall ET reaction. However, it was superior to 74 s−1 found for MB intercalated into (dGdC)20 duplexes and close to 184 s−1 estimated for MB groove-bound to (dAdT)25. The ET-mediating efficiency of highly hydrated G4 wires was thus superior to the electronically-corrupted and water-poor dGdC duplexes and approaching that of dAdT-rich DNA. We show that the electrical properties of G4 DNA wires assessed electrochemically with MB as a redox probe differ essentially from those measured in the absence of redox indicators, indicating that the electrochemical reaction of the redox probe intercalating/interacting with the G4 DNA wires limits the overall kinetics of ET through the wire.

Structure and vibrational properties of 1D molecular wires: from graphene to graphdiyne.

Graphyne- and graphdiyne-like model systems have attracted much attention from many structural, theoretical, and synthetic scientists because of their promising electronic, optical, and mechanical properties, which are crucially affected by the presence, abundance and distribution of triple bonds within the nanostructures. In this work, we performed the two-step bottom-up on-surface synthesis of graphyne- and graphdiyne-based molecular wires on the Au(111). We characterized their structural and chemical properties both in situ (UHV conditions) through STM and XPS and ex situ (in air) through Raman spectroscopy. By comparing the results with the well-known growth of poly(p-phenylene) wires (namely the narrowest armchair graphene nanoribbon), we were able to show how to discriminate different numbers of triple bonds within a molecule or a nanowire also containing phenyl rings. Even if the number of triple bonds can be effectively determined from the main features of STM images and confirmed by fitting the C1s peak in XPS spectra, we obtained the most relevant results from ex situ Raman spectroscopy, despite the sub-monolayer amount of molecular wires. The detailed analysis of Raman spectra, combined with density functional theory (DFT) simulations, allowed us to identify the main features related to the presence of isolated (graphyne-like systems) or at least two conjugated triple bonds (graphdiyne-like systems). Moreover, other spectral features can be exploited to understand if the chemical structure of graphyne- and graphdiyne-based nanostructures suffered unwanted reactions. As in the case of sub-monolayer graphene nanoribbons obtained by on-surface synthesis, we demonstrate that Raman spectroscopy can be used for a fast, highly sensitive and non-destructive determination of the properties, the quality and the stability of the graphyine- and graphdiyne-based nanostructures obtained by this highly promising approach.

Study of Effect of Grain Size on Tensile Properties of Pure Titanium Thin Wire

Study of Effect of Grain Size on Tensile Properties of Pure Titanium Thin Wire

Effect of artificial defect on tensile properties of thin titanium alloy wire

Effect of artificial defect on tensile properties of thin titanium alloy wire