Search

This paper discusses different techniques for making copper wire in the fourth and third centuries BCE in ancient Macedonia (Northern Greece). Wire was used to form stems on gilded wreaths, and to support berries, leaves and rosettes. Stems were made in one piece with the leaves, and are likely to have been formed in at least two ways: one involved cutting them out of sheet copper about 0.5 mm thick, which was creased and then hammered into shape; the other involves using copper rods 1mm square. Some of the square copper rods can be seen on the wreaths, and their regularity suggests they may have been formed on a swaging block. Berries were joined to the wreath circlets by round wires, formed in some cases, it is suggested, by hammering sheet metal around a central core; in other cases, these stems may have been formed by rolling a rod between stone slabs. No evidence, such as longitudinal striations, was found of drawing. Some examples of strip-twisted wire were found, but there are fewer cases of this than of wire formed by hammering. The most expensive gilded wreaths at Derveni, cist grave A, Phoinikas cist grave 5 and Sedes, sometimes had special features, such as gilded copper tubes (‘branches’) with smaller stems on either side, or square wires formed into spirals.

This paper discusses different techniques for making copper wire in the fourth and third centuries BCE in ancient Macedonia (Northern Greece). Wire was used to form stems on gilded wreaths, and to support berries, leaves and rosettes. Stems were made in one piece with the leaves, and are likely to have been formed in at least two ways: one involved cutting them out of sheet copper about 0.5 mm thick, which was creased and then hammered into shape; the other involves using copper rods 1mm square. Some of the square copper rods can be seen on the wreaths, and their regularity suggests they may have been formed on a swaging block. Berries were joined to the wreath circlets by round wires, formed in some cases, it is suggested, by hammering sheet metal around a central core; in other cases, these stems may have been formed by rolling a rod between stone slabs. No evidence, such as longitudinal striations, was found of drawing. Some examples of strip-twisted wire were found, but there are fewer cases of this than of wire formed by hammering. The most expensive gilded wreaths at Derveni, cist grave A, Phoinikas cist grave 5 and Sedes, sometimes had special features, such as gilded copper tubes ('branches') with smaller stems on either side, or square wires formed into spirals. [ABSTRACT FROM AUTHOR]

In thiswork, a 24-month two-batch fuel management strategy for the APR1400 using LEU + has been investigated, where enrichments of 5.9 and 5.2 w/o are utilized in lieu of the conventional 4–5 w/o UO2 fuel. In addition, an Accident Tolerant Fuel (ATF) clad based on the swaging technology is applied to APR1400 fuel assemblies. In this special ATF clad design, both outer and inner SS316 layers protect the conventional zircaloy clad. Erbia (Er2O3) is introduced as a burnable absorber with two-fold goals to lower the critical boron concentration in the long-cycle LEU + loaded core as well as to handle the LEU + fuel in the existing front-end fuel facilities without renewing the license. Two types of fuel assemblies with different loading of gadolinia (Gd2O3) are considered to control both the reactivity and the core radial power distribution. The erbia burnable absorber is uniformly admixed with UO2 in all fuel pins except for the gadolinia-bearing ones. In this study, two core designs were devised with different erbia loading, and core performance and safety parameters were evaluated for each case in comparison with a core design without any burnable absorbers. The core analysis was done using the two-step method. First, cross-sections are generated by the SERPENT 2 Monte Carlo code, and the 3-D neutronic analysis is performed with an in-house multi-physics nodal code KANT.

The critical study is focused on improving ductility by maintaining higher strength of swaged Zircaloy-4 through specifically optimized annealing treatment. It has led to evolution of texture to obtain stable (21¯1¯0) pyramidal type in the microstructure, enhanced elongation up to ∼20%. An excellent combination of ductility and strength was achieved through low-strain-swaging followed by annealing optimization, unlike other resource-intensive and conventional SPD techniques. Improvements in mechanical properties, especially ductility enhancement, were substantiated with the detailed and targeted microstructural analysis with EBSD and TEM.

Electron microscopy is used to study the evolution of microstructure of copper–aluminum composites, which takes place as the degree of reduction upon rotary swaging increases, and their conductivity is measured. The effect of reinforcing the copper–aluminum composites with steel fibers on the conductivity is studied. [ABSTRACT FROM AUTHOR]

In this work, three different states of Mg-9.1Y-1.8Zn alloys including as-cast, extruded and swaged were prepared by semi-continuous casting, extrusion and swaging processes, respectively. Their compositions, microstructures and hydrogen storage properties were investigated. The results show that Mg-9.1Y-1.8Zn alloys in three different states are all composed of Mg and long-period stacking ordered (LPSO) phases. The LPSO phases occurs to break and decompose after hydrogenation and in-situ forms the YH χ(χ = 2,3) nano-hydrides. The nano-hydrides can be used as in-situ catalysts to improve the hydrogen storage properties of alloys. Meanwhile, many nanocrystalline grains appear in the core of alloy after swaging, and the average grain size ranges from 80 to 200 nm. The presence of nanocrystals may increase the specific surface area of alloy, facilitating the diffusion and absorption of hydrogen. Comparatively, the swaged alloy exhibits the largest hydrogen storage capacity and excellent hydrogen sorption kinetics relative to other states of alloys. • The as-cast, extruded, and swaged Mg-9.1Y-1.8Zn alloys were prepared. • The LPSO phases decomposes and in-situ forms YH χ(χ = 2,3) hydrides upon hydrogenation. • The YH χ(χ = 2,3) hydrides present in-situ catalytic and pinning effects on Mg matrix. • The swaged alloy exhibits the highest hydrogen storage capacity. [ABSTRACT FROM AUTHOR]

The present study aimed to discover the effect of cold swaging reduction on the bulk gradient structure formation and mechanical properties of a 316-type austenitic stainless steel. The initial rod was subjected to radial swaging until 20–95% reduction of initial rod diameter, at room temperature. According to finite element simulation, higher plastic strain was accumulated in the surface layer compared to the center region during swaging. Microstructural investigations revealed three-stage gradient structure formation in the center and edge regions of the deformed rod. Meanwhile, cold swaging resulted in the development of strong 111ǁBA, 001ǁBA, and weak 111ǁBA texture components in the center and edge, respectively. Significant tensile strengthening was observed after cold swaging. For instance, the yield strength (YS) increased from 820 MPa to 930 MPa after 40–80% reduction respectively, without the loss of ductility (δ–14%). This unique aspect of the mechanical behavior was attributed to the gradient structure of the cold swaged material and explained in detail. [ABSTRACT FROM AUTHOR]

The swaging quality of self-lubricating spherical plain bearings (SSPBs) has an important influence on the safety of the aircraft. The roller swaging process has an edge on other swaging processes in low swaging load and high swaging quality. The 3D elastic–plastic finite element model of roller swaging and push-out test were developed, and the influence of the roller swaging process loading parameters, such as the swaging time, the swaging load and the rotation speed of the roller tool on the push-out load, the gap between the flanging lip of the V-groove and the housing chamfer, and the radial displacement (the inner surface of the outer ring) after roller swaging were studied. Finally, the roller swaging test was conducted, and the test results were compared with the simulation results. The research shows that the test results are consistent with the results of the simulation model, and with the increase of the swaging time, swaging load, and rotation speed of the roller tool, the gap will be increased as well, resulting in an increase in the push-out load. However, the excessive swaging load and rotation speed of the roller tool will increase the radial displacement, which will result in a reduction in the rotation flexibility of the bearing. Under the conditions of reasonable swaging time and swaging load, a good swaging quality can be obtained by controlling reasonable rotation speed of the roller tool. [ABSTRACT FROM AUTHOR]

The increased interaction time between the implant and the human body has led to the search for new materials used in the manufacture of implants. In this way, β-Ti alloys free of toxic elements have gained prominence, such as Ti-40Nb. In this work, an alloy ingot was swaged and bars with 10, 8 and 7 mm diameter were obtained. All conditions, including as-cast, had their microstructure characterized by x-ray diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy (TEM). Mechanical and physical properties were evaluated by Vickers microhardness and elastic modulus measurements. The results showed that the swaging process reduced the Vickers hardness and elastic modulus, respectively, by 31 and 19% for the Ti-40Nb alloy, around 187 HV and 61 GPa (SW8). In addition, using the TEM technique, phase separation (spinodal decomposition) was detected, as well as stress-induced omega, both at the nanoscale. [ABSTRACT FROM AUTHOR]

Long-length bimetallic conductors with a copper core and a shell from an aluminum alloy up to 2.4 mm in diameter with enhanced strength are obtained by swaging. The effect of the swaging strain on the structure, phase composition and mechanical properties of the bimetallic conductors is studied. [ABSTRACT FROM AUTHOR]

The present work describes the effect of Ni/Fe ratio on microstructure, tensile flow and work hardening behaviour of tungsten heavy alloys (WHAs) based on 92 wt. % W with varying Ni/Fe ratios in heat treated and swaged conditions. Evaluation of properties in the heat treated and swaged conditions reflect that the increasing Ni/Fe ratio has resulted in the enhancement of tensile as well as impact properties. Quantitative metallography and fractography have been conducted to identify the role of microstructural attributes on the failure behaviour in both the tensile and impact energy tests. The properties improvements at higher Ni/Fe ratios are due to the realisation of microstructure comprising relatively higher dissolved W in the matrix phase, higher volume fraction of matrix and reduced contiguity of W particles. True stress–true plastic strain curves of present alloys on log–log scale display two- and single-slopes in heat treated and swaged conditions, respectively. The instantaneous work hardening curves reveal the presence of three distinctive regimes (I, II and III) in heat treated and swaged conditions. The second derivatives of true stress–true plastic strain curves are parabola. [ABSTRACT FROM AUTHOR]

Production of Zirconium alloys for nuclear power reactor comprises of a number of steps during swaging and each step influences microstructural and mechanical properties of the finished product. The Zircaloy-4 was subjected to cold swaging to reduce its cross section gradually from 23 to 16 mm diameter via several passes of swaging followed by intermediate vacuum annealing at 732 °C for 3 h. EBSD was carried out to study the influence of twinning in the Zr-4 alloy. Twinning is observed in swaged ({11 2 ¯ 2}〈11 2 ¯ 3 ¯ 〉) and annealed ({11 2 ¯ 1}〈11 2 ¯ 6 ¯ 〉) samples. TEM was done to substantiate the role of dislocation density. It is observed that several swaging and annealing treatments have improved tensile strength and fracture toughness of the Zr-4 alloy. [ABSTRACT FROM AUTHOR]

The article discusses the Platinum Foil technique as one of the oldest method for the fabrication of porcelain veneers in cosmetic dentistry. It presents information on the history and indications of the technique. It mentions the steps of fabrication which includes cutting and swaging the platinum foil, adaptation of foil, and veneering by layering and first firing, ceramic cracking and re-adaptation, second firing, finishing and contouring, foil removal and final glaze firing. It further discusses the procedure for fitting the foil and few applications of the technique such as for treating discolored teeth and closing a diastema.

Commercially pure(CP) Ti fabricated by 135° ECAP and swaging was annealed at 100, 150, 200, 250, 300, 350, 400, 450℃ and 500℃ for 1h, respectively. The microstructure and properties of annealed commercially pure Ti were investigated by transmission electron microscopy, scanning electron microscopy, uniaxial tensile test and microhardness test. The results show that when annealing temperature is below 400℃, dislocation density reduces gradually and grain boundary becomes clear, no obvious change occurs in the microstructure,ultimate tensile strength and microhardness decrease slightly and no obvious increase occurs in the elongation;when annealing temperature is above 400℃, recrystallization occurs with the increase of annealing temperature, and the grain size increases obviously, the average size is about 5μm, the ultimate tensile strength and microhardness decrease significantly and elongation increases at the same time. The tensile fracture shows the tensile fracture of annealed commercial pure Ti by ECAP and swaging is ductile fracture. With the increase of annealing temperature, the size and depth of dimples increase.

Abstract The research aims to analyze the impact that severe plastic deformation arising during Rotary Swaging has on mechanical properties and corrosion resistance of a near-α-titanium alloy Ti-2.5Al-2.6Zr (Russian industrial name PT7M). The nature of corrosion decay in fine-grained alloys caused by hot salt corrosion is known to vary from pit corrosion to intercrystalline corrosion at the onset of recrystallization processes. Resistance to hot salt corrosion in a fine-grained titanium alloy Ti-2.5Al-2.6Zr is shown to depend on the structural-phase state of grain boundaries that varies during their migration as a result of "covering" corrosive doping elements (aluminum, zirconium) distributed in the crystal lattice of a titanium alloy. Highlights • Fine-grained (FG) structure in near-α-alloy Ti-2.5Al-2.6Zr was formed with Rotary Swaging. • Hot salt corrosion mechanisms in coarse-grained (CG) and FG alloys are studied. • Corrosion defects of type I in a CG alloy are stitched as a result of β-phase particles precipitation. • Corrosion defects of type II in a CG alloy look similar to intercrystalline corrosion (ICC). • Corrosion decay in a FG alloy changes from pit corrosion to ICC when the migration of grain boundaries starts. [ABSTRACT FROM AUTHOR]

Abstract A high performance Cu-Cr-Zr alloy with an ultimate tensile strength of 612 MPa, a uniform elongation of 5% and an electrical conductivity of 84.7% IACS was achieved by the severe rotary swaging and two-step peak-aging treatment. A perfect ultrafine grained microstructure with uniformly distributed nano-precipitates was identified to be responsible for the excellent properties of the studied alloy. The proposed method of rotary swaging in combination with the two-step aging treatment shows good potential for producing the high performance Cu-Cr-Zr alloy, which can not only fulfill the industrial requirement of strength and electrical conductivity, but also is suitable for mass production. [ABSTRACT FROM AUTHOR]

There is an increasing demand in the industry for conductive high strength copper alloys. Traditionally, alloy systems capable of precipitation hardening have been the first choice for electromechanical connector materials. Recently, ultrafine-grained materials have gained enormous attention in the materials science community as well as in first industrial applications (see, for instance, proceedings of NANO SPD conferences). In this study the potential of precipitation hardened ultra-fine grained copper alloys is outlined and discussed. For this purpose, swaging or accumulative roll-bonding is applied to typical precipitation hardened high-strength copper alloys such as Corson alloys. A detailed description of the microstructure is given by means of EBSD, Electron Channeling Imaging (ECCI) methods and consequences for mechanical properties (tensile strength as well as fatigue) and electrical conductivity are discussed. Finally the role of precipitates for thermal stability is investigated and promising concepts (e.g. tailoring of stacking fault energy for grain size reduction) and alloy systems for the future are proposed and discussed. The relation between electrical conductivity and strength is reported.

Abstract: The technologies of repairing the worn parts of metallurgical equipment using plastic deformation methods, namely, expansion, swaging, upsetting, pressing, knurling, and forge-rolling, are described. Recommendations are given to choose temperature conditions in repairing the parts and determining the deformation forces. [ABSTRACT FROM AUTHOR]

Nano-sized ZrC dispersion strengthened tungsten alloy (W-0.5wt%ZrC) rods with enhanced mechanical properties and superior high-temperature stability were fabricated by high temperature rotary swaging. The effects of swaging and annealing on the microstructure and mechanical properties of W-0.5wt%ZrC alloys were investigated. The as-swaged W-0.5%ZrC rod showed noticeable ductility at 200 °C with a total elongation of 4.2% and a tensile strength of 724 MPa, and at 500 °C the strength remains as high as 547 MPa and the total elongation is 28%. The ductile-to-brittle transition temperature (DBTT) is about 200 °C. The recrystallization start temperature of swaged W-0.5wt%ZrC is about 1500 °C, which is about 300 °C higher than that of rolled pure W. The possible mechanisms for the enhanced mechanical properties and thermal stability were discussed. [ABSTRACT FROM AUTHOR]

Highlights • Current status of Charpy impact properties of pure and modified W materials are reviewed. • Impact properties of W are dependent on fabrication methods and histories regardless of their major chemical composition. • DBTT and USE of pure W from different production routes could be integratedly understood using Hall-Petch type relations. Abstract One of the most critical issues affecting tungsten (W) as plasma facing material is ductile-to-brittle transition behavior. It is well known that the microstructure of W materials is influenced by the fabrication methods and histories, which can affect those behaviors. In this paper. the current status of Charpy impact properties (ductile-to-brittle transition temperature (DBTT) etc.) of pure and modified W materials fabricated by several methods and histories are reviewed based on the open literatures and the possibility of integrated interpretation of Charpy impact properties of W materials from different production routes is discussed. [ABSTRACT FROM AUTHOR]

Five different compositions of tungsten heavy alloy with Ni, Fe, Co and Mo were prepared through powder metallurgy route using liquid phase sintering. Three alloys were based on quaternary W-Ni-Fe-Co (with varying Ni to Fe ratio and Co content) and the other two quinary systems with Mo addition. The sintered alloy blanks (cylindrical cross section) were subjected to a thermo-mechanical treatment, which comprised three vacuum heat treatments (at 1100 °C for 1.5 h followed by oil quenching) before and in between multiple swaging operations (at 500 °C) with a total deformation of 53%. This was followed by a detailed evaluation of different microstructural parameters in all compositions. Mechanical properties such as tensile strength, % elongation and impact were evaluated at the final stage (26 mm dia and 600 mm length). Increase in Co content resulted in better strength and elongation with marginal loss in impact values. The alloy containing 0.25 wt% Mo showed the best combination of tensile and impact properties. Further increase in Mo concentration to 0.5 wt% resulted in marginal increase in strength value but rapid deterioration in elongation and impact values. Scanning electron microscopy, electron probe micro analysis, quantitative metallography and fractography were carried out to establish an inter-relationship between microstructure, properties and fracture behaviour of the alloys investigated. [ABSTRACT FROM AUTHOR]

The structure and properties of magnesium alloy WE43 are studied after homogenizing and rotary swaging deformation conducted in several stages with step lowering of the temperature from 400 to 325°C and increasing the extrusion ratio to 2.56 - 2.78. The deformation yields an ultrafine-grained (UFG) structure with a mean size of the structural components about 500 - 800 nm and particles of aMg41Nd5 phase with a mean size of about 300 - 400 nm. The formation of the UFG structure raises the strength of the alloy. The best combination of mechanical properties is provided by swaging with the final temperature 325°C. It is shown that the rotary swaging deformation does not affect the corrosion rate of the alloy measured by the methods of potentiodynamic polarization, loss in the mass and emission of hydrogen. [ABSTRACT FROM AUTHOR]

TiC reinforced titanium matrix composites are promising for advanced applications. Generally, the relative density of the composites and the interfacial bonding between the matrix and reinforced particles may have a great influence on the mechanical properties. This study presented the fabrication of the full-densified Ti-15Mo-xTiC (x = 1.5, 3.0, 4.5 wt%) composites through in-situ reactive sintering of Ti, Mo, and MoC powders and hot swaging process. Experimental results show the formation of TiC and the absence of MoC in the fabricated composites. After hot swaging, the TiC particles showed aligned distribution along the swaging direction, and exhibited well bonding with the β-Ti matrix. Increasing the TiC content leads to increase tensile strength and Young's modulus but decrease elongation. Ti-15Mo-4.5TiC offers and outstanding combination: ultimate tensile strength = 1290 MPa, yield strength = 1075 MPa, Young's modulus = 89 GPa, and tensile elongation = 3.1%. The strengthening effect is attributed to Mo solid solution in Ti matrix, β-Ti grain refinement, and TiC particle reinforcement. The specific contribution of each mechanism is quantitatively calculated, showing good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

A lightweight reliable joint is required for the selflubricating spherical plain bearing which is widely used in aerospace as a key flexible connection. And the roller swaging is a promising process for obtaining the lightweight reliable joint by the plastic deformation. The experimental setup of the roller swaging assembly process and the push-out load inspection tooling were designed and fabricated in this paper. Moreover, the 2D elastic-plastic FE models of roller swaging and push-out test were developed under the Abaqus/Explicit environment for obtaining the metal flow and equivalent strain distribution during the processes. The good agreements of joint condition and push-out load are highlights between the FE simulation and experiment. Based on the results, the optimum designs of the housing chamfer height a and angle a and roller feed distance h were carried out with a typical roller angle ß(60°). It can be found that the little chamfer height and angle are beneficial to obtain a good joint condition. However, compared with 45 and 60°, the load-carrying capacity of chamfer angle 30° is reduced by 30% at least. And the inward displacement of the outer race inner surface for chamfer height 0.7H is more than 50% larger than the ones of 1.0H and 1.2H. What is more, the larger roller reduction will enhance the load-carrying capacity and improve the joint condition, but result in a heavily inward metal flow. [ABSTRACT FROM AUTHOR]

9Cr2WVTa ferritic/martensitic steel was processed by cold-swaging and post-annealing in order to investigate the microstructure evolution and its effect on the mechanical properties. Optical microscopy, scanning electron microscopy with electron backscatter diffraction, and transmission electron microscopy were utilized for the microstructural characterization during the cold-swaging and post-annealing process, and the mechanical properties were determined by microhardness, tensile and creep tests. The results revealed that, nearly equiaxed ultrafine grains with the average size of ~ 330 nm and fine dispersed carbides with the average length of ~ 50 nm, were obtained after cold-swaging and post-annealing. In comparison with the initial normalized-tempered sample, effective grain boundary strengthening and dispersion strengthening in the post-annealed sample enhanced the strength at room and elevated temperature. The presence of fine dispersed carbides could retard the initiation and propagation of the cracks, leading to a better ductility in the post-annealed sample. During creep test, fine dispersed carbides in the post-annealed sample effectively slowed down grain boundary migration. The pinned grain boundaries and fine dispersed carbides in the post-annealed sample acted as obstacles to the motion of mobile dislocations, which resulted in the enhanced creep properties. [ABSTRACT FROM AUTHOR]

Evolutions of texture and lattice strain of swaged brass samples were investigated by neutron diffraction at STRESS-SPEC under tensile deformation using a unique tension/compression rig. The two phased sample BS1 (61% α-brass and 39% β-brass) became 100% α-brass after 400 °C annealing (sample BS2). The starting texture of the as-received material BS1 was the typical <111>, <200> double fiber. This texture develops firstly by in-situ tension to a moderate strengthening. After annealing (BS2) the <111> fiber survives with surprisingly high strength and develops by in-situ tension a very strong <111> fiber of 39 mrd. Line broadening and lattice strain behaviour shows the development of the elastic strain and plastic strain. [ABSTRACT FROM AUTHOR]