Strength Of Wire Research Articles

Enhancing mechanical property and corrosion resistance of Mg–Zn-Nd alloy wire by a combination of SPD techniques, extrusion and hot drawing

Poor formability and corrosion resistance are the limitations that restrict the widespread applications of biodegradable magnesium alloys as surgical staples. In this study fine-grained Mg–2Zn-0.5Nd (ZN20) alloy wire with a diameter of 0.23 mm was fabricated by a combination of equal-channel angular pressing (ECAP), friction stir processing (FSP), extrusion and hot drawing. ECAP could be beneficial to the subsequent deformation by texture weakening, and FSP could improve the corrosion resistance by decreasing the number of second phases. A typical microstructure with similar diameter of matrix grains and second phase particles was observed in ZN20 alloy wire after combined processing of ECAP, extrusion and hot drawing. The strength of ZN20 alloy wire after combined processing of FSP, extrusion and hot drawing was increased from 292 MPa to 392 MPa due to the grain boundary strengthening, precipitates strengthening and texture strengthening. It was beneficial to the ductility by promoting shear band nucleation and inhibiting its prolongation when the diameter of matrix grains and second phase particles was similar, and the ductility was increased by 3.5 times. The immersion test showed that the corrosion rate could be decreased by nearly 31% after combined processing of FSP, extrusion and hot drawing. Grain refinement could improve the corrosion resistance by stabilizing the corrosion product layer, and the smaller amount of second phase also had a positive influence on the corrosion resistance by avoiding the galvanic corrosion.

Corrosion characteristics and damage constitutive model of galvanized steel wires for bridge cables

The characteristic parameters of corrosion pits on the surface of steel wires in service bridges are discussed. The degradation of mechanical properties of corroded steel wires and its relationship with different corrosion evaluation parameters are studied through tensile test. Finally, the damage constitutive model of corroded steel wires is established by introducing the damage variable D. The results show that there are four types of corrosion pits on the surface of steel wires, including the deep ellipsoid, shallow ellipsoid, groove and saddle shape. The higher the corrosion degree of steel wires, the less the number of deep ellipsoidal pits, the more the number of groove and saddle pits. The average corrosion depth of steel wires is positively correlated with the maximum pit depth, width and length. The strength of corroded steel wires mainly depends on the maximum pit depth. In addition, compared with the new steel wire, the average yield strength and ultimate strength of old steel wires decrease due to the influence of corrosion and the discreteness increases. The similarity of probability density function of new and old steel wires is high, and the corrosion has little effect on the elastic modulus of steel wires. Finally, the model curve is in good agreement with the experimental curve, and the proposed damage model of corroded steel wires is basically accurate.

High strength and conductivity copper/graphene composites prepared by severe plastic deformation of graphene coated copper powder

In order to uniformly disperse graphene in the copper matrix, the complete coating of few-layers high-quality graphene on the surface of the copper powder was realized by chemical vapor deposition, and the graphene coated copper powder is sequentially formed through vacuum hot pressing, hot extrusion, and cold drawing processes. The results show that during the vacuum hot pressing, the metallurgical bonding between original copper powders is hindered by the graphene with a relatively complete structure. And the copper grains are recrystallized and refined in the hot extrusion process, and then stretched into a long and thin fibrous structure during the cold drawing process. Besides, the graphene is partially agglomerated during the hot extrusion process, and is dispersed again during the cold drawing process and gradually oriented along the drawing direction. Finally, the graphene and the copper matrix form a network interpenetrating structure, which improves the mechanical and electrical properties of the composite synergistically. The tensile strength and conductivity of the composite wire drawn to 1 mm reached 573.3 MPa and 5.79 × 107 S/m, respectively, achieving a breakthrough in the performance of copper-based materials.

EXPERIMENTAL INVESTIGATION ON THE CREEP RESPONSE AND THERMAL EXPANSION OF PARALLEL STEEL WIRES AT ELEVATED TEMPERATURES

The thermal expansion at 15 different temperatures and the high temperature creep at multiple stress levels of 1670 MPa parallel steel wires, which are widely used in practical engineering, were experimentally investigated by a charge-coupled device camera (CCDC) system. The tensile strength of the specimens which experienced 2-hour’s high temperature creep investigation was measured at the ambient temperature. The curves of thermal expansion strain and high temperature creep strain of the parallel steel wires were obtained. The test results show that the thermal expansion strain of the parallel steel wires increased nonlinearly with the increase of the temperature and the microstructure changed at 750 ℃. Both the heating temperature and the stress level significantly affected the high temperature creep strain. At a higher temperature, the effect of the stress level on the residual tensile strength of the parallel steel wires was more significant. Compared with the 1860 MPa pre-stressed twisted steel wires, the 1670 MPa parallel steel wires had a lower creep strain at a high temperature. Based on the test data, the function of the thermal expansion coefficient of parallel steel wires with respect to the temperature and the high temperature creep model are proposed. The thermal expansion coefficient and the high temperature creep model proposed in this paper can benefit the mechanical response analysis of pre-stressed steel structures at elevated temperatures.

Study on bonding mechanism of hot-cast anchorage of Galfan-coated steel cables

As a common anchoring method of prestressed cable, hot cast anchor is lack of relevant research and complete design method. In engineering, safety is usually ensured by safety factor, resulting in material waste. In this paper, the bonding properties and failure mechanism between Galfan-coated steel wire and hot casting material at room temperature and high temperature were deeply studied. The following conclusions are obtained: 1) Based on the elastic shear lag model and the debonding theory, the stress transfer of the Galfan-coated steel wire–hot-cast material interface during the steel wire-drawing process was investigated, and a partial-debonding model and the calculation method of critical embedded length Lc were proposed; 2) The failure load and mechanism of steel wire with different anchorage length and insertion angle are obtained by pull-out test at room temperature. It is found that the bond strength of steel wire with Galfan-coated inserted vertically is 16 MPa, which is less than that of ordinary galvanized steel wire. 3) Carry out the pull-out test of steel wire at high temperature to obtain the failure mechanism of steel wire hot cast anchor under fire, and put forward the prediction formula of bond strength of hot cast anchor under fire, which provides theoretical basis for the design of hot cast anchor.

Ultrasonic Bonding Interface Degradation Characteristics of Gold-Coated Silver Wire for Semiconductor Packaging

Gold-coated silver wire was developed to alleviate the high cost of Au wire used in semiconductor packaging. Ball-bonding and stitch-bonding techniques were used to fabricate the dummy packaging material, comprising 97.3 % Ag, 97.3% Au-Coated Ag, and 99.99 %Au wires. The wire ball shear test (BST), the wire ball pull test (BPT), and the microstructural attributes of the ultrasonic bonding interfaces were compared with the initial properties, both before and after the highly accelerated stress test (HAST), conducted at 130 ℃ and 85% relative humidity (RH). The initial bonding strength for all the wire variants was ?23~24 gf. Following the HAST, the bonding strength of the Ag wire, the Au-coated Ag wire, and the Au wire decreased by approximately 75 %, 47 %, and 17 %, respectively. The microstructure analysis revealed that cracks developed and propagated at the ends of the interface and that the Au-rich Au-Al intermetallic compound (IMC) inhibited the propagation of the crack at the ACA/Au wire interface. Additionally, it was discovered that the presence of the Ag-Au-Al IMC at the interface of the ACA wire reduced Kirkendall voids, which act as a barrier to Au-Al interdiffusion.

Anatomical changes in vertebra in dystrophic scoliosis due to neurofibromatosis and its implications on surgical safety.

Detailed radiological analysis by multimodality imaging. To document anatomical changes jeopardizing instrumentation safety in Neurofibromatosis deformity correction surgeries. The apical and 3 adjacent vertebral segments above and below amounting to 70 segments in 10 NF scoliosis were studied by radiographs, CT and MRI. The changes in lamina, pedicle and vertebral body that could jeopardize pedicle screw and sublaminar wire placement were documented and changes were appropriately classified. Extensive anatomical changes were noted. These changes were more severe at the apex and independent of the curve severity. Both laminae were normal in only 36 (Type 1), rest had either gross asymmetry in length and shape (Type 2; 21) or also in sloping (Type 3; 13). Of the 140 pedicles, normal pedicles were found only in 48 (Type 1); while they were divergent (Type 2; 4) or abnormally elongated with only thinning (Type 3a; 26); or with sclerosis (3b; 34); or very curved and wavy (3c; 23) and even fractured or indistinct (Type 4; 5). It was notable that 92 of the 140 pedicles were unsuitable for pedicle screws. A unique phenomenon of body drift was identified in 29 segments which could jeopardize screw placement and rib dislocation into the canal was found in 18 segments. Gross anatomical changes jeopardizing both sublaminar wire strength and trajectory of pedicle screws were common in NF and independent of curve severity. Therefore, detailed preoperative assessment and planning by a 3D CT are essential.

Mechanical and thermoelectric properties of iridium-ruthenium alloy grown by the micro-pulling-down method

Iridium, ruthenium, and iridium-ruthenium alloy wires were fabricated by the dewetting micro-pulling-down method, a type of unidirectional solidification method. The length of the grown Ir-20Ru reached 47 m. Furthermore, their mechanical and thermoelectric properties were investigated. The as-grown Ir-17.9Ru wire exhibited a tensile strength of approximately 765 MPa and a nominal fracture elongation of 21% at room temperature. After work-hardening by three cycles of winding and rewinding for a bending radius of 10 mm and annealing at 2273 K for 3 h, the tensile strength and fracture elongation of the Ir-Ru wire were 1061 MPa and 25%, respectively. From the electromotive force (EMF) characteristics of platinum obtained by integrating the Seebeck coefficient, the EMF characteristics from room temperature to ~ 2000 K of iridium, ruthenium, and Ir-17.9Ru were investigated. The EMF characteristics for several thermocouples using iridium, ruthenium, or Ir-17.9Ru as one of the pairs were estimated from the combination of the obtained EMF characteristics. Ir/Ir-17.9Ru showed similar EMF characteristics to Ir-40Rh/Ir.

Microstructure and Mechanical Properties of ER70-Ti Steel for Gas Shielded Welding Wire

In this paper, ER70-Ti welding wire steel produced by an enterprise was used as the test material. The final rolling temperature was set at 960 °C, 930 °C and 900 °C, and the spinning temperature was set at 880 °C, 860 °C and 840 °C. The results showed that the microhardness of the steel decreased from 303HV to 248HV and from 317HV to 276HV as the spinning temperature decreased from 880 °C to 840 °C. The microstructure and mechanical properties of the wires with the diameters of 5.5mm, 4mm, 2.5mm, 1.4 mm and 1.2mm were examined. It was observed that the microstructure of each sample had bainite and ferrite dual phase structure. With the decrease of wire diameter, the strength gradually increased and the ductility decreased. The experimental results show that the existence of bainite structure in the welding wire is the main reason for the high strength of the welding wire and easy fracture in drawing. Based on this, the final rolling temperature of 900 °C and the spinning temperature of 840 °C should be adopted in the production of ER70-Ti welding wire steel.

A Study of the Occurrence of Resonance under the Influence of Dynamic Forces on the Structural Elements of Electrical Installations

The increase in the levels of short-circuit currents in the power system of the Republic of Belarus requires the study of the parameters of the electrodynamic stability of the main structural elements of electrical installations with flexible conductors. In case of a short circuit in the network, currents tenfold exceeding the rated one hundreds of times can flow through the current-carrying part of the device. When the magnetic fields formed by these currents interact, significant electromagnetic forces arise, which have a destructive effect both on the current-carrying parts themselves and on the structural elements of electrical installations, viz. support insulators, switching devices, measuring equipment. The movement of the wires in a short-circuit mode leads to the appearance of significant dynamic loads in them, which, in turn, are transmitted to the portals, support insulators and electrical devices. A topical problem is the occurrence of unacceptable mechanical forces in the main structural elements that can cause their destruction. Thus, the analysis of the physical and mechanical parameters and geometric dimensions of the flexible busbar of switchgear shows that a violation of the condition of electrodynamic resistance to tension is unlikely due to the high mechanical strength of the large-section steel-aluminum wires used. At the same time, span-limiting portals, support insulators and other electrical devices have significantly lower permissible bending loads. When exposed to dynamic forces, the conductors bend and transfer the load to the structural elements which have certain elasticity. Thus, a reliable determination of dynamic loads, taking into account the current-carrying parts acting on the supporting structures, is possible only if a dynamic task is set. The article describes the methods of mathematical modeling and computational experiment for analyzing the parameters of the electro-dynamic stability of the main structural elements which are determined using coefficients that depend on the natural frequencies of oscillations and the nature of changes in dynamic forces over time. To solve these problems, mathematical models are compiled and boundary value problems are formulated for calculating the electrodynamic stability of structural elements, taking into account the possible coincidence of the frequencies of natural and forced oscillations of structural elements taking into account the probable coincidence of the frequencies of forced and natural vibrations of structural elements.

Enabling effective electrochemical healing of structural steel

Low-carbon steel is a widely used structural metal that, when fractured, can be repaired with high temperature processes. There are many applications, however, that would benefit from a room-temperature repair process which maintains the steel microstructure and prevents nearby materials and electronics from overheating. This work seeks to enable effective room-temperature healing of steel by understanding how ion transport and electrolyte chemistry influence growth morphology and strength in fractured steel struts repaired with nickel electrodeposition. Experiments and simulations show that pulsed electroplating mitigates diffusion-limited growth to enable smooth and dense nickel deposits that have 4× higher adhesion to steel than nickel deposited by potentiostatic electroplating. By combining pulsed electroplating and electrolyte chemistry selection, fully fractured steel wires could be repaired to achieve up to 69% of their pristine wire strength. Finally, a simple geometric model highlights the advantageous energy and time requirements of electrochemical healing across length scales.

Failure analysis of high-strength steel wire under random corrosion

Given the randomness of corrosion and the variability of the constitutive model under corrosion conditions, the high-strength steel wire is selected as the basic component, and the constitutive model of steel wire is obtained through the tensile test of high-strength steel wire under different corrosion degrees. The innovation of this paper is the generation of random corrosion pits in numerical simulations. The random corrosion model of steel wire is developed by python, and the constitutive model of steel wire under different corrosion degrees is developed by FORTRAN, which is embedded in ABAQUS. The failure modes of high-strength steel wire under different random corrosion were analyzed. The results show that corrosion has little effect on elastic modulus and yield strength of steel wire. The ultimate strength and fracture strain of steel wire are decreased due to corrosion. The steel wire becomes brittle, and the breaking force is greatly reduced.

Effect of cold drawing strain on the microstructure, mechanical properties and electrical conductivity of low-oxygen copper wires

The effects of cold drawing process on the microstructure, mechanical properties and electrical conductivity of low-oxygen copper wires were studied. The results show that at low drawing strains (ε ≤ 1.23), the plastic deformation is dominated by planar slip, some of grains are rotated along the drawing direction, giving rise to a <111> texture. At medium strains (1.23 < ε ≤ 1.91), most of grains have re-oriented and laid parallel to the drawing direction, and the <111> and <100> textures are highly developed. At high strains (ε > 1.91), a fibrous structure is formed, with a staggered distribution of <111> and <100> textures. With the increase of drawing strain, the volume fraction of the <111> texture first increases and then decreases, while the volume fraction of the <100> texture increases monotonously. The yield strength first increases and then decreases, yielding the maximum value of 427.5 MPa at the strain of 1.91. Interestingly, the electrical conductivity of the copper wires changes with cold drawing strain and moves in the opposite way to the yield strength. The electrical conductivity first decreases and then increases with the minimum value at a strain of 1.91 (~87.5% IACS). At strains higher than 2.74, dynamic recrystallization occurs, resulting in a decrease in dislocation density and an increase in grain size. In addition to the dislocation density and grain size, the yield strength of the copper wires is further impacted by the texture development. The electrical conductivity is less influenced by dislocations and vacancies. Instead, it is dominated by those grain boundaries perpendicular to the drawing direction. An excellent strength-conductivity combination was achieved by tailoring the microstructure of copper wires. For example, a wire with the yield strength (YS) of 400.5 MPa and electrical conductivity (EC) of 94.3% IACS was acquired when the drawing strain reaches 2.74.

Evaluating the Mechanical Properties of Zinc-Coated Stainless Steel Orthodontic Wires Using Physical Vapor Deposition.

The aim of this study was to evaluate the mechanical properties of stainless steel (SS) orthodontic wires coated with zinc (Zn), using a Physical Vapored Deposition (PVD) machine. A total of 100 straight SS orthodontic wires were cut into pieces of 5 centimeters in length and were divided into two groups. Half of the wires were coated with Zn using a PVD machine, and the others remained uncoated. Tensile strength (n = 15), three-point bending (n = 15), and frictional resistance at 0° (n = 10) and 10° (n = 10) were measured to compare the mechanical properties of the Zn-coated and uncoated orthodontic wires using the universal testing machine. The surface of the coated wires was observed by SEM and AFM. An independent t-test, multivariate ANOVA, and measurement ANOVA were used for data analysis. SEM and AFM showed a homogenous Zn layer of 0.28 ± 0.006 µm on the SS wires. The tensile strength and three-point bending strength significantly increased after Zn coating of wires with the PVD method (P < 0.05). The friction resistance significantly reduced at both angulations following the coating procedure. The angle between the wire and bracket had no significant effect on the frictional resistance (P > 0.05). Coating with Zn improved the tensile and load-bending strength of SS orthodontic wires and reduced their frictional resistance which might be advantageous in terms of reducing the risk of root resorption during the orthodontic treatment.

Thermal simulation of the single discharge for electro-spark deposition diamond wire saw

Due to their excellent physical and mechanical properties, third-generation super hard semiconductor materials (such as SiC, GaN) are widely used in the field of microelectronics. From the crystal bar to electronic devices, slicing is the first machining procedure that directly affects the subsequent process. Fixed diamond wire saw has been widely used in cutting hard and brittle materials. However, the diamond grits of wire saw are bonded through the binding agent’s mechanical embedding that slicing super hard crystal is very difficult and inefficient. In order to improve the slicing efficiency, it is necessary to improve the holding strength and wear resistance of the diamond wire saw. The electro-spark deposition (ESD) process can form metallurgical bonding between metal materials at low heat input. The holding strength and wear resistance of the diamond wire saw can be effectively improved. In this paper, the mechanism of the manufacturing process of ESD diamond wire saw (ESDDWS) is introduced, and the conditions of the manufacturing process of ESDDWS are put forward. A model of the surface heat source of saw wire is established considering the wire shape. The transient thermal analysis of the single discharge of ESDDWS is carried out in ANSYS, and the effect of material compaction on material physical properties is considered. According to the simulation results, the parameter range of the manufacturing process of ESDDWS is predicted. The predictions agreed with experiment observation.

Investigation structure and properties of wire from the alloy of AL-REM system obtained with the application of casting in the electromagnetic mold, combined rolling-extruding, and drawing

The paper presents the results of studies of the structure and properties of a wire with a diameter of 0.5 mm from an alloy of the Al-REM system with a rare-earth metal content of 7–9%. Wire obtained as a result of the implementation of the technology of its manufacture using the methods of casting into an electromagnetic mold (EMM), continuous extruding, and drawing. The rheological properties of the metal of continuously cast round billets from the experimental alloy obtained using an electromagnetic mold are determined. The modeling and analytical assessment of the possibility of carrying out the process of combined rolling-extruding (CRE) of such billets in a closed box-type roll groove of a continuous extruding unit are carried out. The features of metal shaping have been studied. The temperature-speed and technological parameters were found at which the CRE process can be carried out in a stable mode of operation. Data have been obtained for the forces acting on the die and rolls during rolling-extruding. The results of experimental studies of the process of obtaining longish deformed semi-finished products from an experimental alloy on the laboratory unit CRE-200 and the pilot plant unit CRE-400 are presented. The structure of the metal has been studied; data on the ultimate tensile strength, yield strength, relative elongation, and electrical resistance of hot-extruded rods and wires in cold-worked and annealed states have been obtained. It was found that the proposed processing modes make it possible to obtain by the method of combined rolling-extruding rods with a diameter of 9 mm in industrial conditions from longish billets with a diameter of 18 mm, cast by means of EMM. Wire in a cold-deformed and annealed state with a diameter of 0.5 obtained by drawing from the rods with a diameter of 9 mm from an experimental alloy of the Al-REM system containing 7–9% rare-earth metals with the required physical and mechanical properties.

Effects of hot dipping temperature on microstructure and mechanical properties of Pb40Sn60 alloy coating on copper wires

Abstract Hot dip plating was used to prepare Pb40Sn60 alloy coating on copper wires to improve weldability and corrosion resistance. The microstructure and phase composition of Pb40Sn60 alloy coatings at different hot dipping temperatures were examined by scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), and the mechanical properties of copper wires after hot dip plated Pb40Sn60 alloy coatings at different temperatures were investigated by the tensile test and hardness test. The results showed that the microstructure of Pb40Sn60 alloy coatings consisted of primary α phase and (α+β) eutectic structure, the phase were composed of α phase and β phase, and β phase was more than α phase in relative amount. With increase of hot dipping temperature from 210 °C to 250 °C, the thickness of Pb40Sn60 alloy coating on copper wire was decreased from 39.4 mm to 20.5 mm, the proportion of α phase in relative amount increased from 33.2% to 40.5%, the crystal morphology of primary α phase changed from lamellar or equiaxial to dendritic, and (α+β) eutectic structure changed from small lamellar to granular. The work hardening of copper wires can be eliminated during hot dip plating. With increase of hot dipping temperature from 210 °C to 250 °C, the strength of copper wire after hot dip plated Pb40Sn60 alloy coating decreased from 234 MPa to 213 MPa, the elongation was not obvious change, and the hardness of copper wire substrate decreased from 87 HV0.2 to 69.9 HV0.2, the hardness of coating increased from 10.1 HV0.2 to 13.4 HV0.2. It has been found that increase in the hot dipping temperature was beneficial to eliminate work hardening of copper wire substrate, while resulted in decreasing in deformation resistance, and also the decrease of coating thickness. On the contrary, decrease in the hot dipping temperature was beneficial to increase thickness of Pb40Sn60 coating, but the effects of eliminating on work hardening of copper wire were weakened.

Breaking Material Property Trade-offs via Macrodesign of Microstructure.

Many properties of materials are incompatible with each other or even completely exclusive. Here, we proposed a new concept in view of the trade-off paradox of material properties, which is to macrodirectionally design the microstructure of materials according to their specific service requirements to accurately use the properties of materials to the extreme. By using this concept, we successfully solved the paradox of high strength and high conductivity of copper contact wire in a high-speed train. Our concept can be used to solve the other property paradoxes of functional and structural materials.

Corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey)

The effect of impurities on the electrical conductivity of aluminum has been studied in detail. The electrical conductivity of aluminum is 65.45% of that of copper. The tensile strength of aluminum wire is 150–170 MPa which, at equal conductivity, is about 65% of the strength of copper wire. This strength of aluminum wire is sufficient for bearing the wire’s own weight but may be too low in case of snow, ice or wind overloads. One way to improve the strength of aluminum wire is to use aluminum alloys having higher strength combined with sufficiently high electrical conductivity, e.g. the E-AlMgSi alloy (Aldrey). The key strengthening agent of the E-AlMgSi alloy (Aldrey) is the Mg2Si phase which imparts high mechanical strength to aluminum. In this work we present experimental data on the kinetics of high-temperature oxidation and electrochemical corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey). Thermal gravimetric study has shown that indium doping and high temperature exposure increase the oxidation rate of E-AlMgSi alloy (Aldrey), with the apparent alloy oxidation activation energy decreasing from 120.5 to 91.8 kJ/mole. Alloy oxidation rate data determined using a potentiostatic technique in NaCl electrolyte media have shown that the corrosion resistance of the indium doped alloy is 20–30% superior to that of the initial alloy. With an increase in NaCl electrolyte concentration the electrochemical potentials of the alloys decrease whereas the corrosion rate increases regardless of alloy composition.

S-N Fatigue Curve Determination for Corroded High-Strength Bridge Wires

AbstractAccurate residual life evaluation is crucial for maintenance of corroded bridge wires, and a stress-life (S-N) curve is determined for the fatigue strength of steel wires after corrosion. T...