Wire Material Properties Research Articles

Role of material properties on metal transfer dynamics in gas metal arc welding

In the gas metal arc welding (GMAW) process, metal transfer dynamics, influenced by wire material properties such as electrical conductivity and surface tension, serve as key sources of mass and heat for metal deposition on substrates. To elucidate the role of these material properties on metal transfer dynamics from a driving force perspective, this study examined molten droplet elongation across five distinct wires: Al, Cu, Fe, Ni, and Ti. Additionally, a unique non-transferred arc welding setup equipped with a consumable wire anode and two tungsten cathodes was introduced, allowing for observations at minimized arc lengths and preventing current concentration in molten droplets. For Al and Cu wires, while only projected-spray transfer was observed under sufficient arc length conditions, a shift to minimized arc length resulted in significant droplet elongation and a transition to streaming-spray transfer. This contrast emphasized the impact of high electrical conductivity in reducing the internal gradient of electromagnetic pressure and inhibiting the occurrence of streaming-spray transfer. Further substantiating this mechanism, Fe, Ni, and Ti wires revealed that higher electrical conductivity corresponded to an increased transition current to streaming-spray transfer. Additionally, surface tension played a crucial role in the formation of molten droplets and ensured transfer stability, with its influence varying at different current levels. These insights contribute to our comprehensive understanding of arc plasma and molten metal interactions. Our study proposes material-specific strategies to optimize metal transfer dynamics, leading to enhanced control over weld bead formation and overall mechanical properties of welded joints in the GMAW.

Gold wire bond study for automotive application

In this publication, the influence of bond wire material properties (Au 2N/4N), and plasma pre-treatment on the wire-bond strength is investigated based on Automotive Electronics Council Qualification (AEC-Q100) and customer requirements. The wire pull force capability is compared, and growth of the Au/Al intermetallic phase (IMP) is analyzed with scanning electron microscope (SEM) cross sections after High Temperature Storage Life (HTSL, 150 °C), Temperature Cycling (TC, −65 °C – 150 °C) and unbiased Humidity Accelerated Stress Test (uHAST, 130 °C/85% relative humidity (RH)). The effect of plasma treatment prior bonding on 2N and 4N wires is discussed and compared to the results without plasma treatment prior wire bonding. Furthermore, test acceleration by using elevated test temperatures (HTSL, 250 °C) is shown and the wire capability compared.

Evaluation of External Load on the Winder considering the Friction of Wire

In order to evaluate the external pressure acting on the winder by multiple-layer tension wire, in this research, a numerical analysis method was developed considering the contact of wire. By applying this method, the material properties of wire, such as the coefficient of friction of wire in the axial direction, the elastic modulus of wire in both axial direction and circumferential direction, have a great influence on the external pressure acting on the winder. However, the coefficient of friction of wire in the circumferential direction has little influence on the external pressure acting on the winder.

A multiscale and multiphysics model of strain development in a 1.5 T MRI magnet designed with 36 filament composite MgB2 superconducting wire

High temperature superconductors such as MgB2 focus on conduction cooling of electromagnets that eliminates the use of liquid helium. With the recent advances in the strain sustainability of MgB2, a full body 1.5 T conduction cooled magnetic resonance imaging (MRI) magnet shows promise. In this article, a 36 filament MgB2 superconducting wire is considered for a 1.5 T full-body MRI system and is analyzed in terms of strain development. In order to facilitate analysis, this composite wire is homogenized and the orthotropic wire material properties are employed to solve for strain development using a 2D-axisymmetric finite element analysis (FEA) model of the entire set of MRI magnet. The entire multiscale multiphysics analysis is considered from the wire to the magnet bundles addressing winding, cooling and electromagnetic excitation. The FEA solution is verified with proven analytical equations and acceptable agreement is reported. The results show a maximum mechanical strain development of 0.06% that is within the failure criteria of −0.6% to 0.4% (−0.3% to 0.2% for design) for the 36 filament MgB2 wire. Therefore, the study indicates the safe operation of the conduction cooled MgB2 based MRI magnet as far as strain development is concerned.

Material Properties of Wire for the Fabrication of Knotted Fences

This paper describes the materials properties of galvanised fencing wire, as used in the fabrication of knotted wire fences. A range of physical properties are investigated: tensile strength, ductility in tension, Young’s modulus, three-point bending, and bending span. A range of commercially available wire products were tested. The results show that most, but not all, high tensile wire samples met the minimum tensile and ductility requirements. Young’s modulus results failed to provide any meaningful insights into wire quality. Flexural modulus results also failed to provide any insight into wire quality issues, with no statistically significant differences existing between acceptable and problematic wire batches. The implications are that premature fence failures are unlikely to be caused solely by reduced tensile properties. Existing test methods, including tensile strength and ductility, are somewhat incomplete, perhaps even unreliable, as measures of wire quality.

Wire mesh design

We present a computational approach for designing wire meshes , i.e., freeform surfaces composed of woven wires arranged in a regular grid. To facilitate shape exploration, we map material properties of wire meshes to the geometric model of Chebyshev nets . This abstraction is exploited to build an efficient optimization scheme. While the theory of Chebyshev nets suggests a highly constrained design space, we show that allowing controlled deviations from the underlying surface provides a rich shape space for design exploration. Our algorithm balances globally coupled material constraints with aesthetic and geometric design objectives that can be specified by the user in an interactive design session. In addition to sculptural art, wire meshes represent an innovative medium for industrial applications including composite materials and architectural façades. We demonstrate the effectiveness of our approach using a variety of digital and physical prototypes with a level of shape complexity unobtainable using previous methods.

Modeling and Experimental Study of the Kink Formation Process in Wire Bonding

Looping is a key technology for the modern wire bonder. A kink is a critical structure in a wire loop. In order to understand the kink formation mechanism, a 2-D dynamic finite element model is developed using ANSYS/LS-DYNA, in which the air tension force, friction between capillary and wire, and real capillary trace are considered. The simulated kink formation process was verified by an experiment. With this model, the strain distribution on a gold wire was calculated, and the effects of wire material properties and capillary trace parameters on the kink number, position, and loop profiles were studied. Simulation results show that a minute average plastic strain of 0.14 is needed to form a distinct kink in a wire. Similarly, an elastic core with an average plastic strain of less than 0.08 at the center of a kink provides stiffness and sag/sway resistance for loops. A kink is a wire segment with plastic deformation outside and an elastic core inside, and the number of kinks and their positions are mainly affected by the capillary trace. In contrast, wire material properties only slightly influence the kink properties. This paper may provide helpful insights into loop design for modern microelectronics packages.

Wire ablation dynamics model and its application to imploding wire arrays of different geometries

The paper presents an extended description of the amplified wire ablation dynamics model (WADM), which accounts in a single simulation for the processes of wire ablation and implosion of a wire array load of arbitrary geometry and wire material composition. To investigate the role of wire ablation effects, the implosions of cylindrical and planar wire array loads at the university based generators Cobra (Cornell University) and Zebra (University of Nevada, Reno) have been analyzed. The analysis of the experimental data shows that the wire mass ablation rate can be described as a function of the current through the wire and some coefficient defined by the wire material properties. The aluminum wires were found to ablate with the highest rate, while the copper ablation is the slowest one. The lower wire ablation rate results in a higher inward velocity of the ablated plasma, a higher rate of the energy coupling with the ablated plasma, and a more significant delay of implosion for a heavy load due to the ablation effects, which manifest the most in a cylindrical array configuration and almost vanish in a single-planar array configuration. The WADM is an efficient tool suited for wire array load design and optimization in wide parameter ranges, including the loads with specific properties needed for the inertial confinement fusion research and laboratory astrophysics experiments. The data output from the WADM simulation can be used to simplify the radiation magnetohydrodynamics modeling of the wire array plasma.

Wire Fencing (Part 1): Determinants of Wire Quality

Knotted wire fences are fabricated on specialised machines. The input material is typically galvanised steel wire. However, the quality of the input wire used by the Fence Producer is beyond control of the Machine Manufacturer. The problem is that wire strand breakages have been reported during fabrication and subsequent field erection. This is an issue for the Fence Producer because of the lost productivity, and the potential for reputation (brand) damage for both the Manufacturer and Producer. While existing standards do exist for wire, even wire that meets these standards is known to fail during fence fabrication. Thus there is a need to better understand how the quality of wire affects the manufacturabil- ity of fences, and to identify, or if necessary create, a test for wire quality that is able to be conducted by Fence Producers. In this research, samples were obtained from known good and failed fences and wire coils, and subjected to a variety of physical and metallurgical tests. These were then statistically examined and compared to the known fate of the fence, to determine the sensitivity of the test. Four potential tests were evaluated: Tensile strength (UTS), ductility, 3-point bend- ing, microstructural, impact energy, plus a fifth novel new test called linear torsional ductility (LTD). From these tests, it was evident that the linear torsional ductility test was the most sensitive and reliable indicator for wire quality. This paper is part of a collection, with companion papers examining material properties of wire, microstructure, impact energy for wire, knot performance, and the testing of whole fences.

Closed loop control of the 3D bending process

Mechanical properties of the incoming material have a major effect on the shape stability of 3D wire bent products. The study of the wire straightening process prior to final bending showed that it could efficiently be used to control the mechanical properties as well as straightness of the wire. The core of the stabilization algorithm is a slightly modified Prager's flow rule [1,2] considering material hardening or softening as a result of accumulated small reverse plastic strains. Flow stress calculation of the incoming material is based on the measured transverse roller forces. The obtained data define the needed repositioning of the straightening rollers. The new settings stabilize the wire material properties, which reflect in the shape of the 3D bent product.

The relationship between exploding wire expansion rates and wire material properties near the boiling temperature

The energy deposited by a submicrosecond, /spl sim/1-kA current pulse in a 25-/spl mu/m diameter metal wire prior to its explosion, correlates directly with the expansion rate of the wire after the explosion. Energy deposition by resistive heating is terminated by the formation of plasma around the wire and a collapse of the voltage along the wire, and is evidently facilitated by the desorption of gases from the wire and/or the evaporation of the wire material (or impurities within it) as it heats up. Data presented here implies that the relationship between materials with the lowest resistivities and high exploding wire expansion rates found in earlier work (D. B. Sinars et al. 2000) is a result of the reduced voltage delaying the gas breakdown along such wires. This, in turn, increases the energy deposited resistively in the wire before the current shifts to the surrounding plasma. If gas breakdown does not occur until close to the full vaporization energy is deposited in the wire, the expansion rate will be more rapid than if a small fraction of the vaporization energy is deposited before voltage collapse.