Alloy Wires Research Articles

Measurements of capture cross-section of 93Nb by activation method and half-life of 94Nb by mass analysis

ABSTRACT The thermal-neutron capture cross section (σ 0 ) and resonance integral (I 0 ) for93Nb were measured by an activation method; a half-life of 94Nb was derived by mass analysis. Niobium-93 samples were irradiated with the use of the hydraulic conveyer installed in the research reactor in Institute for Integral Radiation and Nuclear Science, Kyoto University. Gold-aluminum and cobalt-aluminum alloy wires were used to monitor thermal-neutron fluxes and Westcott’s indexes at the irradiation position. A 25-μm-thick gadolinium foil was used to separate reactions ascribed to thermal neutrons. Its thickness provided a cut-off energy of 0.133 eV. In order to attenuate the radioactivity of 182Ta produced by impurities, the Nb samples were cooled for nearly 2 years. The induced radio activity in the monitors and Nb samples was measured by gamma-ray spectroscopy. In the analysis based on Westcott’s convention, the σ 0 and I 0 values were calculated as 1.11 ± 0.04 barns and 10.5 ± 0.6 barns, respectively. After the γ-ray measurements, mass analysis was applied to the Nb samples to obtain the reaction rate. By combining data obtained by both γ-ray spectroscopy and mass analysis, a half-life of 94Nb was determined as (2.00 ± 0.15) ×104 years.

Fold, Twist, and Draw – Techniques of Copper Alloy Wire Production from Hellenistic Jebel Khalid

Abstract Copper alloy wire fragments were examined using XRF, optical light microscopy and SEM-EDS. The specimens come from archaeological excavations at Jebel Khalid in Syria, dating from the 3rd century BCE (the Hellenistic period) to the Roman period. Our results show that several techniques were employed to make the wires: forging, folding, strip twisting, and possibly ‘strip drawing’. We investigated the morphologies, treatments, and fabrications attributed to making wire from copper alloys compared to more ductile materials such as gold and silver. Evidence of extensive annealing and non-uniform, sub-round profiles, and uneven and faceted surfaces represent the challenges of working with the material. There is no obvious evidence of solid wire drawing. The metalworkers used different copper alloys to make wire, some with high levels of lead (Pb). Subtle joins were observed in some samples, whereas others had evident folds and directional structures. The findings contribute new evidence to enhance our understanding of base-metal wire development in antiquity.

A multi-scale diffusional-mechanically coupled model for super-elastic NiTi shape memory alloy wires in hydrogen-rich environment

The functional devices made by NiTi shape memory alloys (SMAs) are often serviced in hydrogen (H)-rich environment. Recently experimental results showed that the martensite transformation (MT) of NiTi SMA changed strongly after charging H, which originates from the H diffusion in the material and an additional transformation resistance caused by the absorbed H atoms. In this work, a multi-scale diffusional-mechanically coupled constitutive model is constructed to describe the super-elastic deformation of NiTi SMA wires in H-rich environment. In the grain scale, a crystal plasticity-based constitutive model is developed within the framework of irreversible thermodynamics. Four deformation mechanisms, i.e., elasticity, MT, transformation-induced plasticity (TRIP) and H expansion are taken into account. Since the H atoms can be trapped by the lattice defects, the total H concentration is further decomposed into two parts, i.e., the lattice hydrogen concentration and the trapped one. The generalized thermodynamic forces of MT and TRIP are derived from the Gibbs free energy and Clausius-Duhem inequality. The evolution of H concentration field is derived by combining the chemical potential, diffusion balance equation and the Fick's law. In the polycrystalline aggregate scale, in order to measure the interaction among the grains and obtain the overall response of the polycrystalline aggregate, a diffusional-mechanically coupled self-consistent homogenization method is developed. Meanwhile, the finite volume method is employed to calculate the H concentration in each grain. An assumption of uniform stress field in the macroscopic scale is adopted to achieve the scale transition from the polycrystalline aggregate to the whole wire. To validate the prediction capability of the proposed model, the predictions are compared with the experiments. Moreover, the influences of loading rate on the deformation of the wires in the process of in-situ charging H are predicted and discussed.

Analytical assessment of stay cable vibration mitigation using shape memory alloy wire

The stay cables are axial load-carrying members in cable-stayed bridges and are subjected to the problems of large amplitude oscillations mainly due to wind. The investigations presented in this paper attempt to tackle the problem by the application of a shape memory alloy wire, which are understood to have excellent recovery property under large deformation. The aim is to determine how the dynamic behavior of a taut steel cable changes when a Ni-Ti SMA wire is connected to the cable and which location of SMA at the taut cable may provide the best results in terms of vibration dissipation of the cable. Before the analytical study on the taut cable, the behavior of Ni-Ti SMA wire in hysteresis was studied under different strain as well as in tension and compression loadings. The responses of the cable with and without SMA wire were determined in free as well as in forced vibrations. The SMA wire was used at different locations of the cable to determine its most effective location and the damping introduced to the cable. The variation of the amplitude response is investigated at varying excitation frequencies. It is found that the SMA wire can be effectively used as a damping element in dissipating the cable oscillation. It is also found that the mid-length of the cable where maximum amplitude dissipation occurs is the best location, although not a practical one, to attach the SMA wire.

Two-Way Shape Memory Effect of a Shape Memory Composite Strip

In this work, a NiTi shape memory alloy (SMA) wire was embedded into a rubber/shape memory polymer (SMP) soft matrix to form a composite strip with a two-way reversible bending behavior. First, the elastic moduli of SMA wire were characterized as increasing about 3 times (18.6 GPa at martensite phase and 50.1 GPa at austenite phase) from 25 °C to 90 °C. Then, an SMA composite strip using SMP to replace the rubber matrix was fabricated to significantly improve the load-bearing ability (16-fold) at 28 °C. After that, the good two-way bending behaviors of the rubber/SMP-based SMA strip with high shape deploying ratio above 80% were demonstrated. Finally, the application of rubber/SMP-based composite strips in a space-deployable antenna model with two-way reversible bending behavior was developed and demonstrated through a heating and cooling temperature cycle.

Improved Super-elastic Ti-Ni Alloy Wire for Nonsurgical Treatment of Skeletal Class III Malocclusion Combined with Anterior Crowding and Anterior Crossbite Case

The article reported the use of improved super-elastic Ti-Ni alloy wire (ISW), which was developed by Tokyo Medical and Dental University, to correct a case of skeletal Class III malocclusion combined with anterior crowding and anterior crossbite. An 18-year-old male with a chief complaint of poor dental alignment and protruded lower incisors showed up in our clinic for treatment. Clinical examination revealed skeletal Class III facial profile. Anterior crowding and anterior crossbite could be also noted. Because the patient refused orthognathic surgery, we tried camouflage orthodontic treatment. First, we used ISW crossbite arch to eliminate the anterior interference in order to observe the change of the mandibular position. After that, we use ISW multiloop edgewise arch wire (MEAW) technique and intermaxillary elastics to achieve midline correction and adequate overjet with the bite raising process. The treatment was finished with the improvement of facial appearance and a stable occlusion.

Investigation of 7075 aluminum alloy TIG welding joint using 7075 aluminum alloy wire before and after heat treatment

7075 aluminum alloy butt welding was carried out by TIG welding with self-made 7075 wire. The effects of different currents on the microstructure and mechanical properties of the joint before and after heat treatment were studied. Before heat treatment, the strength and elongation of the joint are 274.84 MPa and 6.3%, which are determined by the presence of a large number of second phase precipitates with different shapes. After heat treatment, the tensile strength and elongation are increased to 511.75 MPa and 13.76%. Since most of the second phase has been dissolved, the grain size becomes the decisive factor. The fine grain size and more sufficient recrystallization degree make the mechanical properties of the low-current joint better.

Flexural capacity enhancing of notched steel beams by combining shape memory alloy wires and carbon fiber-reinforced polymer sheets

Combining shape memory alloy (SMA) and carbon fiber-reinforced polymer (CFRP) sheet can achieve a self-stressing SMA-CFRP composite, providing an innovative prestressing method for steel elements. This study applied SMA(Ni–Ti–Nb) wires and CFRP sheets to achieve composite strengthening for notched steel beams. The effectiveness of SMA-CFRP composite for flexural strengthening of notched steel beams was evaluated, and the formula for the maximum allowable moment of the strengthened beams with SMA-CFRP composites was proposed. The four-point bending test results showed that the ultimate load and flexural stiffness of the strengthened beams with SMA-CFRP composites increased by 79.2% and 57.9% more than those of the unstrengthened beams. By comparison, the CFRP-only and SMA-only strengthened beams merely achieved half the ultimate load and flexural stiffness over the strengthened beams with SMA-CFRP composite. Besides, compared to the unstrengthened beams, the notch tip yield load for the strengthened beam with SMA-CFRP composite was increased by 230%, while the notch tip yield load for strengthened beams with CFRP-only and SMA-only just increased by 70% and 125%. These indicate that the SMA-CFRP composite strengthening can significantly delay crack propagation and improve the load capacity and stiffness of notched steel beams. Moreover, the analytical results of the maximum allowable moment were in good agreement with experimental results, indicating the accuracy of the proposed analytical equations.

Biomimetic Soft Underwater Robot Inspired by the Red Muscle and Tendon Structure of Fish

Underwater robots are becoming increasingly important in various fields. Fish robots are attracting attention as an alternative to the screw-type robots currently in use. We developed a compact robot with a high swimming performance by mimicking the anatomical structure of fish. In this paper, we focus on the red muscles, tendons, and vertebrae used for steady swimming of fish. A robot was fabricated by replacing the red muscle structure with shape memory alloy wires and rigid body links. In our previous work, undulation motions with various phase differences and backward quadratically increasing inter-vertebral bending angles were confirmed in the air, while the swimming performance in insulating fluid was poor. To improve the swimming performance, an improved robot was designed that mimics the muscle contractions of mackerel using a pulley mechanism, with the robot named UEC Mackerel. In swimming experiments using the improved robot, a maximum swimming speed of 25.8 mm/s (0.11 BL/s) was recorded, which is comparable to that of other soft-swimming robots. In addition, the cost of transport (COT), representing the energy consumption required for robot movement, was calculated, and a minimum COT of 0.08 was recorded, which is comparable to that of an actual fish.

Effect of Deformation Degree on Microstructure and Texture of AZ31 Magnesium Alloy in Hot Drawing

Microstructure and texture evolution of the AZ31 magnesium alloy wire under different deformation degrees was investigated by continuous hot drawing deformation. With the increase of cumulative deformation degree, the grain refinement effect is remarkable. However, there is a critical deformation degree, and excessive deformation will increase the grain size. During the deformation process of hot drawing, the dynamic recrystallization mechanism of AZ31 magnesium alloy wire changed from twin dynamic recrystallization to rotary dynamic recrystallization. With the increase of cumulative deformation, the initial {0001} <11-20> silk texture gradually changed into {0001} <10-10> silk texture.

Study of Phase Evolution Behavior of Ti6Al4V/Inconel 718 by Pulsed Laser Melting Deposition

In this study, a pulsed laser was used as the heat source for the additive work. The Ti6Al4V/Inconel 718 alloy wire was deposited on the substrate by melting using a pulsed laser. Using the above method, single-layer and double-layer samples were printed. The sample material printed in this way is highly utilized. Compared to the complicated pre-preparation work of metal powder pre-mixing, this printing method is simple to prepare and only requires changing the wire feeding speed. The study of this paper provides a theoretical guide for the subsequent fusion deposition of heterogeneous wire materials. The samples were analyzed after molding using SEM, EDS and XRD to characterize the microstructure of the samples. The samples can be divided into three zones depending on the microstructure, the bottom columnar crystal zone, the middle mixed phase zone, and the bottom equiaxed crystal zone. From the bottom to the top of the sample, the phase microstructure changes as γ + Laves → α + β + Ti2Ni + TiNi + Ni3Ti → α + β. The hardness data show that the highest value in the transition zone is 951.4 HV. The hardness of the top part is second only to the transition zone due to a large number of equiaxed crystals. The bottom region is dominated by columnar crystals and is the softest of the three regions with the lowest hardness value of 701.4 HV.

Actuation response of typical biased shape memory alloy wire under variable electric heating rates: Experimental investigation and modeling

Electric heating is commonly used to induce the inverse martensitic transformation in shape memory alloy (SMA) wire actuators. Different actuation responses can be achieved when adjusting the heating currents. In this study, typical biased NiTi SMA wire actuators were tested under the heating currents of 1.5 A, 3 A, 4 A, and 5 A. It was found that SMA wire actuators under three typical biases (dead weight, linear spring, dead weight &amp; linear spring) behaved differently as the heating current increased. Moreover, under dead weight bias and mixed bias, high heating currents tended to cause dynamic responses during actuation. The maximum inertia load induced by dynamic responses was 2.65 times as much as the static load. In contrast, the actuation response under linear spring bias was relatively steady. A model based on the SMA constitutive equation and the dynamic equation was also established, which was capable of simulating the dynamic actuation responses of SMA wire actuators under high electric heating rates.

Life prediction of 6201-T81 aluminum alloy wires under fretting fatigue and variable amplitude loading

Fretting fatigue tests under variable amplitude loading were performed on 6201-T81 aluminum alloy wires of an AAAC 900 MCM conductor. The loading program consisted of a three-block loading history, defined using vibration data of a transmission line located in the center-west region of Brazil. Two previously developed methodologies for life prediction of wires under fretting fatigue, based on the Theory of Critical Distances and on a master fatigue curve, were extended to variable amplitude loading conditions. The good agreement between measured and predicted lives indicated that both methodologies can be useful for fatigue analysis of wires of overhead conductors.

Owl-Neck-Spine-Inspired, Additively Manufactured, Joint Assemblies with Shape Memory Alloy Wire Actuators.

Nature provides a considerable number of good examples for simple and very efficient joint assemblies. One example is the enormously flexible cervical spine of American barn owls, which consists of 14 cervical vertebrae. Each pair of vertebrae produces a comparatively small individual movement in order to provide a large overall movement of the entire cervical spine. The biomimetic replication of such joints is difficult due to the delicate and geometric unrestricted joint shapes as well as the muscles that have to be mimicked. Using X-ray as well as micro-computed tomography images and with the utilisation of additive manufacturing, it was possible to produce the owl neck vertebrae in scaled-up form, to analyse them and then to transfer them into technically usable joint assemblies. The muscle substitution of these joints was realised by smart materials actuators in the form of shape memory alloy wire actuators. This actuator technology is outstanding for its muscle-like movement and for its high-energy density. The disadvantage of this wire actuator technology is the low rate of contraction, which means that a large length of wire has to be installed to generate adequate movement. For this reason, the actuator wires were integrated into additively manufactured carrier components to mimic biological joints. This resulted in joint designs that compensate for the disadvantages of the small contraction of the actuators by intelligently installing large wire lengths on comparatively small installation spaces, while also providing a sufficient force output. With the help of a test rig, the developed technical joint variants are examined and evaluated. This demonstrated the technical applicability of this biomimetic joints.

High surface quality additive manufacturing process of titanium alloy with composite heat source

In order to solve the problems of high surface roughness and low dimensional accuracy of titanium alloy metal-wire fuse additive manufacturing, this paper proposes a high surface quality and dimensional accuracy of titanium alloy additive manufacturing with composite heat source process. On the basis of orthogonal experiments, titanium alloy wires with diameter of 0.3 mm Ti-6Al-4V were deposited in a small molten pool by laser and Joule heat source. Thin-walled titanium alloy parts with high surface quality and dimensional accuracy were obtained, and the quality, microstructure, and mechanical properties were tested. The measurement areas are shown that the average roughness Ra is 1.65 μm in the direction deposition, and the dimensional accuracy error is less than 0.28 mm. On this basis, the microstructure and mechanical properties of titanium alloy thin-walled were analyzed. The microstructures are net-like, with microhardness of about 330HV. The ultimate tensile strength of titanium alloy thin-walled parts is 917.56 MPa, and the elongation can reach 20.68%, which is comparable to the strength of casting and forging fracture. The results show that the proposed additive manufacturing process of metal-wire with composite heat source has the potential of further metal AM in high surface quality parts.

Microstructure and mechanical properties of A7N01-T4 aluminum alloy metal inert gas welded joints filled with self-designed 7A48 aluminum alloy wire

7××× aluminum alloy is a metal with a high tendency to weld cracks. In the welding process, 7××× aluminum alloy wire was seldom used but low strength matching 4××× and 5××× aluminum alloy wire was used for joining, which had poor mechanical properties of welded joints. In this paper, a self-designed low copper 7A48 wire containing scandium was used as filler material for metal inert gas (MIG) welding of 4 mm thick A7N01-T4 aluminum alloy plates. The results show that the A7N01-T4 MIG welded joints were obtained with good seam formation and no crack formation. The equiaxed dendrites in the weld zone were found. The precipitated phases were primarily Mg-rich and Zn-rich, forming a typical 7××× aluminum alloy structure. In the fusion zone, fine equiaxial crystals were found, with a width of about 100 μm. In the heat-affected zone, grains growth occurred and the precipitated phase was dissolved or aggregated. The hardness of the WZ reached 81.7% of that of the base material and the softening of the WZ was not significant. The average tensile strength and elongation of the specimens were 364.9 MPa and 17.5%, respectively. The tensile fracture occurred in WZ and the fracture was dominated by microporous aggregation shear fractures with localized cleavage fractures occurring.

A Sensitivity Analysis of Geometric Parameters of 4D-Printed Bidirectional Shape-Memory Composite in Architectural Façade Design

The 4D-printable two-way shape memory effect (TWSME) is not well known to building engineering and architecture. To better understand the thermo-mechanical complexity of TWSME in building skin design, this paper investigates the parametric uncertainty in basic deformation of a rectangular façade surface module. To this end, a 4D-printed TWSME composite was prototyped by 3D-printing shape memory polymer (SMP, digital elastomers DM9850 and 9885) design with shape memory alloy (SMA) wires (Ni 55.5%-Ti 44.5%wt.) inserted. A simulation-based global sensitivity analysis was conducted on the maximum displacement and force of the composite through the homogenized 1D approximation of bending and material property change in four different phases. It was identified that the simplified simulation well predicted the actual maximum reversible displacement of ~3.5 mm with a sectional area ratio of SMP to SMA of ~105 between 30℃ and 65℃. Our findings indicate that sectional geometry of the bending part (width and height in the rectangle) and the intensity of the SMA pre-strain determined by a degree of fiber bending are the most critical factors to predict the maximum displacement and recovery force of TWSME. The potential building application of thermo-responsive phenomena contributes to extending smart material use in architecture and knowledge in making design decisions in self-shaping climate-adaptive building.

Design of an orthopedic smart splint using nickel-titanium shape memory alloy

&lt;span lang="EN-US"&gt;People with broken bones suffer from symptoms of muscular atrophy as a result of a lack of movement, so it was necessary to find effective solutions due to the relative pain they cause and the difficulty of movement after healing. In this paper, we proposed a smart splint made of nickel-titanium shape memory alloys (SMA) wires. These alloys have unique properties compared to other materials, the most important of which is maintaining the original shape during manufacturing at a certain temperature. Temperature, pressure, as well as humidity, were analyzed and monitored while the patient wore the splint to reach the best possible results by using a microcontroller. The results showed that there was a significant improvement for the muscles in a short time when using the proposed splint, as the percentage of qualified muscle recovery increased by more than 70% when using the usual splint. The wires used had an effective role in rehabilitating these muscles by performing a permanent local massage. due to the different diameters of these wires, a different response to temperature change was recorded.&lt;/span&gt;

Additive Manufacturing of Titanium-Based Materials Using Electron Beam Wire 3D Printing Approach: Peculiarities, Advantages, and Prospects

Potential of additive manufacturing technologies, namely, xBeam 3D Metal Printing for the fabrication of uniform Ti–6Al–4V (Ti-6-4, mas.%) material as well as layered titanium-based structures, with mechanical properties sufficient for wide practical application is demonstrated. The key distinctive features of this process are titanium alloy wire as a feedstock material and hollow conical electron beam for heating and melting of the wire. 3D printed with special ‘shift strategy’ Ti-6-4 alloy meets requirements to mechanical characteristics of corresponding conventional cast and wrought products, if microstructure features, material anisotropy and crystallographic texture are controlled with proper selection of processing parameters. Production of multilayered materials consisting of combined layers of different titanium materials, viz. commercially pure titanium (CP-Ti), Ti-6-4 and high-strength T110 alloys, as well as metal matrix composites (MMC) based on Ti-6-4 matrix reinforced by fine TiC particles is considered. Microstructural features and mechanical properties of all 3D printed materials are investigated. Terminal ballistic tests are performed with different ammunition. Described results show the promising potential of 3D printing technologies, xBeam 3D Metal Printing as an example, for manufacturing of titanium-based multilayered armour materials with reduced thickness and weight, and at the same time, sufficient protection characteristics.

Seismic Retrofitting of Nonseismically Detailed Exterior Reinforced Concrete Beam-Column Joint by Active Confinement Using Shape Memory Alloy Wires

It is widely accepted that the seismic retrofitting of nonseismically detailed reinforced concrete beam-column joints (BCJs) in reinforced concrete (RC) frame buildings is an urgent necessity due to its high vulnerability and potential consequences in seismic events. As a result, considerable effort has already been put into developing efficient and practical retrofitting solutions for such BCJs. Most of the existing techniques, however, are based on either passive confinement techniques, for example, fiber reinforced polymer (FRP) wrappings, or involve a considerable joint enlargement, which, in many cases, is undesirable. In this study a new technique of retrofitting BCJs is proposed by employing a more effective method of confinement (i.e., active confinement), utilizing the shape recovery feature of shape memory alloys (SMAs). To evaluate the performance of the proposed retrofitting scheme, experimental tests were conducted on full-scale BCJ specimens. The efficacy of the proposed retrofitting scheme is evaluated in terms of enhancement in strength, ductility, energy dissipation capacity, damage reduction in the specimens, and ease of application. The results from this study suggest that the proposed retrofitting scheme could be effectively used in achieving the full capacity of the joints corresponding to beam yielding and consequently enhances the energy dissipation capacity of the system significantly. The test results demonstrated that the proposed retrofitting scheme performs excellently in reducing the joint shear strain (core damage) (to almost zero or negligible) and also in retaining the full axial load carrying capacity of the column, even at very large drift values. The proposed retrofitted scheme could also be conveniently used in cases where the capacity ratio of column-to-beam needs to be improved.