Bulk Rod Research Articles

Design and Analysis of the Directional Transport Device for Bulk Rod Materials in Sand Fixation Equipment

Design and Analysis of the Directional Transport Device for Bulk Rod Materials in Sand Fixation Equipment

Plastic Zr-Al-Ni-Cu-Ag bulk glassy alloys containing quasicrystalline or β-Zr plus ω-Zr phases

Zr70–76Al7–7.5Ni13–15Cu2Ag2–5 glassy alloys were prepared by melt-spinning with Zr contents up to 76 at.%, greatly exceeding the highest Zr content of 70 at.% previously reported for Zr-based glassy alloys exhibiting a calorimetric glass transition. The 70–72Zr and 74Zr alloys were also cast as bulk rods up to 1.5 mm in diameter with glass and [glass + β-Zr + ω-Zr] phases, respectively, by ejection copper-mold casting. The crystallization temperature and Vickers hardness Hv for the glassy ribbons decrease with increasing Zr content from 70 to 76 at.%. The glassy rods show high yield strength (σy) of 1225–1346 MPa, high fracture strength (σf) of 1497–1499 MPa, and large compressive plastic strain (εp) of 9.7–3.2% for the 70–72Zr alloys. Similarly, the 74Zr rod with [glass + β-Zr + ω-Zr] phases shows σy of 1325 MPa, σf of 1472 MPa, εp of 2.4%. The 76Zr thick ribbon with [glass + β-Zr + ω-Zr] phases shows, in tension, high σy of 890 MPa, σf of 988 MPa, and plastic elongation of 0.3%. The Zr-rich glassy ribbons crystallize, showing three exothermic peaks upon heating. The first-stage peak is due to the precipitation of icosahedral quasicrystal (IQ) for the 70–72Zr ribbons, and β-Zr + ω-Zr for the 74–76Zr ribbons. These annealing-induced mixed-phase ribbons with Zr content above 72 at.% exhibit good bending plasticity, even though their HV is about 41% higher than for the as-spun glassy ribbons. Similarly, the 70Zr bulk rod, with [glass + IQ] phases obtained by annealing, shows a distinct increase in σy and σf to 1485 and 1575 MPa, respectively, as well as εp of 0.6%. Thus, the plastic Zr-rich bulk rods with glass, [glass + IQ], and [glass + β-Zr + ω-Zr] phase mixtures are encouraging for the future development of a new type of high-strength structural material.

Low-Loss Polytetrafluoroethylene Hexagonal Porous Fiber for Terahertz Pulse Transmission in the 6G Mobile Communication Window

Hexagonal porous optical fiber without a central defect is proposed and numerically analyzed with the finite element method (FEM) for transmitting terahertz (THz) electromagnetic wave pulse. In experiments, the transmission characteristics of polytetrafluoroethylene (PTFE) hexagonal porous optical fibers were measured using a THz time-domain spectroscopy (THz-TDS) system. To precisely estimate the effective material loss (EML), we measured the refractive index and absorption coefficient of PTFE in the THz range to use them in FEM analyses, and the EML of the porous fiber was estimated to be lower than that of a bulk rod as large as by a factor of 2 in the frequency range from 0.1 to 0.33 THz. In experiments, we measured the transmission characteristics of both the porous fibers and the bulk rod, to confirm a significant improvement in THz wave transmission nearly by an order of magnitude in the 6G telecommunication window, showing a better performance than theoretical estimations.

History of very thick film and bulk sample group IIIB, IVB, VB, and rare earth materials for various vacuum applications

Thick occluder film and bulk hydride materials are extremely hard to produce without flaking or cracking. This paper discusses methods of how to prepare thick films and bulk samples (i.e., rods and wires) that have reduced stress for many applications. These include accelerator research for cancer therapy, intense neutron sources, particle-beam fusion diagnostic beam focusing studies, and mass spectrometer calibration. Thick films of ∼(≥3000 to 150 000 nm thickness of various hydrides are sensitive to oxidation and are easily contaminated by improper handling. They must be specially prepared to reduce internal stresses due to temperature variations during processing, stresses due to hydriding, and substrate configuration (i.e., curved surfaces). Discussed are techniques developed at the General Electric Neutron Devices Department, in Largo, FL, in the mid-1970s to the late 1990s to produce flaking and crack free samples of thick films and bulk samples. Items studied include Er, Sc, and Ti thick film hydrides on a Cr underlay, on various substrates, Er and Sc bulk rod samples for the first basic material heat capacity and thermal diffusivity studies as a function of hydride loading, Nb and V wires in bundles of ∼30 wires, for the first tritide neutron vibration spectra studies, and Ti wires for mass spectrometer calibration studies. Film samples were prepared by standard E-beam evaporation techniques and then non-air-exposure loaded. Bulk samples were loaded with a Sievert's precise gas quantity loading system. To produce reduced intrinsic stress (strain) in samples of Er, Sc, and Ti thick films, and bulk samples of Er, Sc, Nb, V, and Ti, special processing employing slow bakeout heating and cool down rates, slow film deposition rates, slow leak in pressure hydriding rates, followed by slow cooling rates to room temperature were used. Using the process described, very successful results were obtained.

Effect of tool wear on microrods fabrication using reverse μEDM

ABSTRACTArrayed microrods are used to drill array of microholes in workpieces by Micro electrical discharge machining (μEDM). In comparison to a single microrod, the use of an array of microrods enables drilling of multiple microholes in lesser time, and hence it offers a higher productivity. The present work focuses on the effect of tool wear on the dimensions of the machined array of microrods through reverse micro electrical discharge machining (R-μEDM). The effects of the input parameters such as voltage, capacitance and feed rate on the obtained length and diameter of the microrods have been investigated. This study introduces a simple analytical model to evaluate the amount of tool wear and material removal from a bulk rod. As the levels of voltage and capacitance increase from lower to higher, the tool wear increases by 574%. At lower levels of voltage and capacitance, a straight array of microrods with a longer length of about 1.961 mm is obtained. On the other hand, at higher levels of voltage and capacitance, the obtained microrods are found to have a shorter length of 1.725 mm but with taper. Scanning electron microscope (SEM) and optical microscope images are also analyzed for describing the effects of tool wear on the shape and size of the fabricated microrods.

Ultra-high Q sphere-like cavities for cascaded stimulated Brillouin lasing

High Q microsphere optical cavity is usually fabricated from a single mode fiber. Here, we propose a new method to fabricate sphere-like cavity by melting the tip of rotating quartz-rod with a CO2 laser. The cavities with diameter from 200µm to 700µm and resonant Q factors above 108 are obtained. Due to the rich resonances of the sphere-like cavity, up to 15-order cascaded stimulated Brillouin lasings(SBL) near 1.55µm are observed in a cavity with a diameter of ~760µm by simply tuning the pump wavelength to a finely-selected resonance. We wish the ultra-high Q cavities with rich resonances and bulk rod mount can have practical applications in nonlinear optics and microwave photonics as an optical component.

Intensity-Modulated Optical Fiber Sensor for AC Magnetic Field Detection

An erbium-doped (Er3+) fiber optic laser is proposed for sensing alternated magnetic fields by measuring the laser intensity modulation. The sensor is fabricated using two partially overlapped narrow-band fiber Bragg gratings (FBGs) and a section of doped fiber in a Fabry–Perot configuration. Laser power stability and bandwidth are studied while changing the overlap. A bulk rod of TbDyFe, a magnetostrictive material, is glued to both the FBGs and the laser wavelength and power are modulated according to the magnetic field. Acquisition and processing are done using virtual instrumentation. Results have shown the possibility of detecting 11.18 $\mu \text{T}_{\mathrm {{rms}}}/\surd $ Hz for an alternating magnetic field of 4.17 mT $_{\mathrm {{rms}}}$ .

Finite element analysis of the plastic deformation in tandem process of simple shear extrusion and twist extrusion

Abstract Recently, simple shear extrusion (SSE) and twist extrusion (TE) are introduced to fabricate ultrafine grained bulk rod metallic materials. The SSE and TE processes generate significant deformation inhomogeneity, with higher and lower strains in the center, respectively, which easily causes mechanical instability of the materials. In this study, to overcome this deformation inhomogeneity problem in SSE and TE, a tandem process of SSE and TE (TST) is suggested. The finite element method is applied for plastic deformation behavior during the TST process. The results demonstrate that the TST process can produce relatively homogeneously deformed materials. In particular, the effects of back pressure and processing order on the plastic deformation behaviors in the TST process are systematically analyzed.

Manufacturing Ultrafine-Grained Ti-6Al-4V Bulk Rod Using Multi-Pass Caliber-Rolling

Ultrafine-grained (UFG) Ti-6Al-4V alloy has attracted attention from the various industries due to its good mechanical properties. Although severe plastic deformation (SPD) processes can produce such a material, its dimension is generally limited to laboratory scale. The present work utilized the multi-pass caliber-rolling process to fabricate Ti-6Al-4V bulk rod with the equiaxed UFG microstructure. The manufactured alloy mainly consisted of alpha phase and showed the fiber texture with the basal planes parallel to the rolling direction. This rod was large enough to be used in the industry and exhibited comparable tensile properties at room temperature in comparison to SPD-processed Ti-6Al-4V alloys. The material also showed good formability at elevated temperature due to the occurrence of superplasticity. Internal-variable analysis was carried out to measure the contribution of deformation mechanisms at elevated temperatures in the manufactured alloy. This revealed the increasing contribution of phase/grain-boundary sliding at 1073 K, which explained the observed superplasticity.

9 T high magnetic field annealing effects on FeN bulk sample

α″-Fe16N2 has been suggested as a promising candidate for future rare-earth-free magnets. In this paper, we report to use high magnetic field (9 T) assisted post-annealing process to enhance the Fe16N2 phase formation in FeN bulk rod samples during the α′ → α″ phase transformation and thus improve its magnetic properties. It was found by X-ray Diffraction measurement that the volume ratio of Fe16N2 phase was increased up to 22%, which corresponds to an increase in the amount of transformation from α′ → α″ up to 78%. Also, the saturation magnetization (Ms) of the prepared FeN rod sample was increased to 227 emu/g with its coercivity up to 376 Oe at room temperature. A working mechanism for the high field assisted post-annealing process was presented.

Comparative study of non-isothermal crystallization kinetics between Fe80P13C7 bulk metallic glass and melt-spun glassy ribbon

Differential scanning calorimetry was used to investigate the thermal behavior and non-isothermal crystallization kinetics of Fe80P13C7 glassy alloy in the forms of both bulk rod and the melt-spun ribbon. The apparent activation energy E of the first crystallization event for the ribbon and bulk samples are determined to be 432±17kJ/mol and 529±26kJ/mol, respectively, by Kissinger method, and 421±17kJ/mol and 514±26kJ/mol, respectively, by Ozawa method. It is proposed that larger the apparent activation energy E in the bulk sample may be ascribed to less amount of free volume in the supercooled liquid state of the bulk sample. The crystallization kinetics of the first crystallization event in the bulk and ribbon samples has been studied by non-isothermal approach and the local Avrami exponent for the first crystallization peak is evolved to reveal the crystallization mechanism. The local Avrami exponent of the bulk sample is less than 1.5 in the whole process for the first crystallization event, which means the crystallization mechanism of diffusion-controlled growth of pre-existing nuclei. While the local Avrami exponent for the ribbon sample is in the range of 1.5–2.5 in most cases, which means the crystallization mechanism is diffusion-controlled growth of the initial crystal type, at the same time, along with the nucleation rate decreases with time. The difference in the local Avrami exponent for the first crystallization event between the bulk and ribbon sample indicates that there are higher degree of short-range order in the bulk sample than that in the ribbon sample in the supercooled liquid state. These results distinctly indicate that the difference of crystallization behavior for the first crystallization event between the bulk and ribbon samples of Fe80P13C7 glassy alloy results from the difference nature in their supercooled liquid states which is related to the as-prepared state of samples.

Glass-forming ability and differences in the crystallization behavior of ribbons and rods of Cu36Zr48Al8Ag8 bulk glass-forming alloy

The crystallization behavior of melt-spun ribbons and bulk samples of the Cu36Zr48Al8Ag8 glassy alloy on heating is presented here. The crystallization kinetics and structural changes in the Cu36Zr48Al8Ag8 glassy alloy were studied using x-ray diffraction, transmission electron microscopy, differential scanning, and isothermal calorimetry methods. A clear comparison is made of the differences in the crystallization kinetics of the melt-spun ribbons and the copper-mold-cast bulk rod samples. It was suggested that the kinetics of crystallization in the rod sample, at any given temperature, are somewhat different than in the ribbon samples, probably because of size and free volume effects. Differences in the crystallization behavior of this alloy with other Cu-Zr-Al-Ag alloys have also been discussed.

Fabrication of Rod type Cu<sub>54</sub>Ni<sub>6</sub>Zr<sub>22</sub>Ti<sub>18</sub> Bulk Amorphous Alloy by Warm Extrusion Process

In this study, rod type Cu54Ni6Zr22Ti18 bulk amorphous alloy fabricated by warm extrusion of amorphous powders was investigated. To get bulk type amorphous alloy, the Cu54Ni6Zr22Ti18 amorphous powders which has a particle size below 63( and wide supercooled liquid region of 53K were prepared by a high-pressure gas atomization method. The powders were filled in a Cu can with an inner dimension 20×2×50mm in air, evacuated, sealed and then precompacted in the press. Before extrusion, the billet was heated with heating rate of 50K/min and the holding time was about 5min. The extrusion temperature was 723K and the extrusion ratio was increased from 2 to 5. By warm extrusion of amorphous powders, a fully amorphous Cu54Ni6Zr22Ti18 bulk type alloys were successfully synthesized. The conditions for extrusion were decided based on the time-temperature-transformation curve and DSC analysis. Phase analysis was performed by XRD. The result of the phase analysis indicated that Cu54Ni6Zr22Ti18 bulk rod type samples having fully amorphous phase could be obtained until extrusion ratio of 4 at extrusion temperature of 723K, but partial crystalline phase would be observed in the bulk rod type alloy fabricated at extrusion ratio of 5.

Comparative Study of Effect of Initial Sintering in Rod/Tube Shape on Jc and Fracture Strength of Bi-2223: 10 wt % Ag Bulk Rod Conductors

The effect of two different initial sintering routes, (1) initial sintering in the rod shape (RS) and (2) initial sintering in the tube shape (TS), has been studied especially on the critical current density (Jc) and diametric fracture strength (σ) of Bi-2223 as 10 wt % Ag bulk rod conductors from a cold isostatic pressing (CIP) process. Apart from studying Jc and σ, these rods have been characterized by X-ray diffraction (XRD), energy dispersive analysis for X-rays (EDAX) and scanning electron microscopy (SEM). These studies showed that the final Bi-2223 rods achieved using the tube shape initial sintering route (TSR) in a for shorter duration exhibit higher Jc and σ values compared with final rods prepared from the rod shape using the initial sintering route (RSR).

Unified approach to analyse mass sensitivities of acoustic gravimetric sensors

A unified approach based on Rayleigh's hypothesis for evaluating the mass sensitivities, Sm, of bulk, surface, plate and thin rod flexural acoustic gravimetric sensors is presented. The estimation of Sm uses the ‘equivalent depth’ which is determined by the displacement distribution of the acoustic mode. The Sm's for the lowest order torsional and longitudinal mode of a thin rod are reported for the first time.