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Sample records for deformation processed metal

  1. Studies on the optimization of deformation processed metal metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Tim W. [Iowa State Univ., Ames, IA (United States)

    1994-01-04

    A methodology for the production of deformation processed metal metal matrix composites from hyper-eutectic copper-chromium alloys was developed. This methodology was derived from a basic study of the precipitation phenomena in these alloys encompassing evaluation of microstructural, electrical, and mechanical properties. The methodology developed produces material with a superior combination of electrical and mechanical properties compared to those presently available in commercial alloys. New and novel alloying procedures were investigated to extend the range of production methods available for these material. These studies focused on the use of High Pressure Gas Atomization and the development of new containment technologies for the liquid alloy. This allowed the production of alloys with a much more refined starting microstructure and lower contamination than available by other methods. The knowledge gained in the previous studies was used to develop two completely new families of deformation processed metal metal matrix composites. These composites are based on immissible alloys with yttrium and magnesium matrices and refractory metal reinforcement. This work extends the physical property range available in deformation processed metal metal matrix composites. Additionally, it also represents new ways to apply these metals in engineering applications.

  2. INVESTIGATION OF MATERIAL RESISTANCE TO PLASTIC DEFORMATION AT PROCESSING METALS BY PRESSURE WITH IMPOSING ULTRASONIC OSCILLATIONS

    Directory of Open Access Journals (Sweden)

    V. V. Klubovich

    2007-01-01

    Full Text Available The paper contains substantiation for application of experimental technique in order to investigate material resistance to plastic deformation at processing metals by pressure with imposing ultrasonic oscillations while proceeding from laws of similarity. It is shown that at modeling any metal processing by pressure with imposing ultrasonic oscillations it is possible to consider that actual elastic and plastic metal properties remain constant during processing under ultrasound action. The second aspect that requires a special attention at modeling is pulse or vibration-shock deformation at processing metals by pressure with imposing ultrasonic oscillations.

  3. Creep of crystals: High-temperature deformation processes in metals, ceramics and minerals

    Science.gov (United States)

    Poirier, J. P.

    An introductory text describing high-temperature deformation processes in metals, ceramics, and minerals is presented. Among the specific topics discussed are: the mechanical aspects of crystal deformation; lattice defects; and phenomenological and thermodynamical analysis of quasi-steady-state creep. Consideration is also given to: dislocation creep models; the effect of hydrostatic pressure on deformation; creep polygonization; and dynamic recrystallization. The status of experimental techniques for the study of transformation plasticity in crystals is also discussed.

  4. The effect of tooling deformation on process control in multistage metal forming

    NARCIS (Netherlands)

    Havinga, Gosse Tjipke; van den Boogaard, Antonius H.; Chinesta, F; Cueto, E; Abisset-Chavanne, E.

    2016-01-01

    Forming of high-strength steels leads to high loads within the production process. In multistage metal forming, the loads in different process stages are transferred to the other stages through elastic deformation of the stamping press. This leads to interactions between process steps, affecting the

  5. Ra and the average effective strain of surface asperities deformed in metal-working processes

    DEFF Research Database (Denmark)

    Bay, Niels; Wanheim, Tarras; Petersen, A. S

    1975-01-01

    Based upon a slip-line analysis of the plastic deformation of surface asperities, a theory is developed determining the Ra-value (c.l.a.) and the average effective strain in the surface layer when deforming asperities in metal-working processes. The ratio between Ra and Ra0, the Ra-value after...... and before deformation, is a function of the nominal normal pressure and the initial slope γ0 of the surface asperities. The last parameter does not influence Ra significantly. The average effective strain View the MathML sourcege in the deformed surface layer is a function of the nominal normal pressure...... and γ0. View the MathML sourcege is highly dependent on γ0, View the MathML sourcege increasing with increasing γ0. It is shown that the Ra-value and the strain are hardly affected by the normal pressure until interacting deformation of the asperities begins, that is until the limit of Amonton's law...

  6. Anelastic deformation processes in metallic glasses and activation energy spectrum model

    NARCIS (Netherlands)

    Ocelik, [No Value; Csach, K; Kasardova, A; Bengus, VZ; Ocelik, Vaclav

    1997-01-01

    The isothermal kinetics of anelastic deformation below the glass transition temperature (so-called 'stress induced ordering' or 'creep recovery' deformation) was investigated in Ni-Si-B metallic glass. The relaxation time spectrum model and two recently developed methods for its calculation from the

  7. Deformation limits of polymer coated metal sheets

    NARCIS (Netherlands)

    Van Den Bosch, M.J.W.J.P.; Schreurs, P.J.G; Geers, M.G.D.

    2005-01-01

    Polymer coated metals are increasingly used by the packaging and automotive industry. During industrial deformation processes (drawing, roll-forming, bending etc.) the polymer-metal laminate is highly deformed at high deformation rates. These forming conditions can affect the mechanical integrity

  8. Plastic Deformation of Metal Surfaces

    DEFF Research Database (Denmark)

    Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu

    2013-01-01

    of metal components. An optimization of processes and material parameters must be based on a quantification of stress and strain gradients at the surface and in near surface layer where the structural scale can reach few tens of nanometers. For such fine structures it is suggested to quantify structural...... parameters by TEM and EBSD and apply strength-structural relationships established for the bulk metal deformed to high strains. This technique has been applied to steel deformed by high energy shot peening and a calculated stress gradient at or near the surface has been successfully validated by hardness...

  9. Deformation processes in refractory metals. Progress report, 1 December 1974--30 November 1975

    International Nuclear Information System (INIS)

    Donoso, J.R.; Reed-Hill, R.E.

    1975-01-01

    Work in progress is mostly concerned with the stress-strain behavior of niobium, as affected by dynamic strain aging. An investigation of the aging phenomena in nickel containing carbon as the major interstitial impurity was also conducted. Some aspects of the deformation behavior of the hexagonal metals titanium and zirconium still warrant investigation and are also being considered. (auth)

  10. High-temperature deformation and processing maps of Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles

    Science.gov (United States)

    Chen, Jing; Liu, Huiqun; Zhang, Ruiqian; Li, Gang; Yi, Danqing; Lin, Gaoyong; Guo, Zhen; Liu, Shaoqiang

    2018-06-01

    High-temperature compression deformation of a Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles was investigated at 750 °C-950 °C with a strain rate of 0.01-1.0 s-1 and height reduction of 20%. Scanning electron microscopy was utilized to investigate the influence of the deformation conditions on the microstructure of the composite and damage to the coated surrogate fuel particles. The results indicated that the flow stress of the composite increased with increasing strain rate and decreasing temperature. The true stress-strain curves showed obvious serrated oscillation characteristics. There were stable deformation ranges at the initial deformation stage with low true strain at strain rate 0.01 s-1 for all measured temperatures. Additionally, the coating on the surface of the surrogate nuclear fuel particles was damaged when the Zr-4 matrix was deformed at conditions of high strain rate and low temperature. The deformation stability was obtained from the processing maps and microstructural characterization. The high-temperature deformation activation energy was 354.22, 407.68, and 433.81 kJ/mol at true strains of 0.02, 0.08, and 0.15, respectively. The optimum deformation parameters for the composite were 900-950 °C and 0.01 s-1. These results are expected to provide guidance for subsequent determination of possible hot working processes for this composite.

  11. Plastic deformation, residual stress, and crystalline texture measurements for in-process characterization of FCC metal alloys

    International Nuclear Information System (INIS)

    Ruud, C.O.; Jacobs, M.E.; Weedman, S.D.; Snoha, D.J.

    1989-01-01

    This paper describes the results of several on-going investigations on the measurement of plastic deformation, residual stress, and crystalline texture in nickel, copper, and aluminum base alloys by x-ray diffraction techniques. X-ray diffraction techniques have been shown to be effective in the measurement of plastic deformation, residual stress, and crystalline texture in FCC metals, from the breadth, position, and intensity of the x-ray diffraction peaks. The Ruud-Barrett position-sensitive scintillation detector has been demonstrated to be fast, non-contacting, and tolerant of detector to component distance variation -- necessary requirements for cost-effective in-process inspection of materials

  12. EBSD-based techniques for characterization of microstructural restoration processes during annealing of metals deformed to large plastic strains

    DEFF Research Database (Denmark)

    Godfrey, A.; Mishin, Oleg; Yu, Tianbo

    2012-01-01

    Some methods for quantitative characterization of the microstructures deformed to large plastic strains both before and after annealing are discussed and illustrated using examples of samples after equal channel angular extrusion and cold-rolling. It is emphasized that the microstructures...... in such deformed samples exhibit a heterogeneity in the microstructural refinement by high angle boundaries. Based on this, a new parameter describing the fraction of regions containing predominantly low angle boundaries is introduced. This parameter has some advantages over the simpler high angle boundary...... on mode of the distribution of dislocation cell sizes is outlined, and it is demonstrated how this parameter can be used to investigate the uniformity, or otherwise, of the restoration processes occurring during annealing of metals deformed to large plastic strains. © (2012) Trans Tech Publications...

  13. Nanodisturbances in deformed Gum Metal

    International Nuclear Information System (INIS)

    Gutkin, Mikhail Yu.; Ishizaki, Toshitaka; Kuramoto, Shigeru; Ovid'ko, Ilya A.

    2006-01-01

    Systematic experiments have been performed to characterize defect structures in deformed Gum Metal, a special titanium alloy with high strength, low Young's modulus, excellent cold workability and low resistance to shear in certain crystallographic planes. Results from high-resolution transmission electron microscopy characterization reveal nanodisturbances (planar nanoscopic areas of local shear) as typical elements of defect structures in deformed Gum Metal. A theoretical model is suggested describing nanodisturbances as nanoscale dipoles of non-conventional partial dislocations with arbitrary, non-quantized Burgers vectors. It is shown theoretically that the homogeneous generation of nanodisturbances is energetically favorable in Gum Metal, where they effectively carry plastic flow

  14. Modelling of real area of contact between tool and workpiece in metal forming processes including the influence of subsurface deformation

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Martins, Paulo A. F.; Bay, Niels Oluf

    2016-01-01

    New equipment for testing asperity deformation at various normal loads and subsurface elongations is presented. Resulting real contact area ratios increase heavily with increasing subsurface expansion due to lowered yield pressure on the asperities when imposing subsurface normal stress parallel ...... for estimating friction in the numerical modelling of metal forming processes.......New equipment for testing asperity deformation at various normal loads and subsurface elongations is presented. Resulting real contact area ratios increase heavily with increasing subsurface expansion due to lowered yield pressure on the asperities when imposing subsurface normal stress parallel...... to the surface. Finite element modelling supports the presentation and contributes by extrapolation of results to complete the mapping of contact area as function of normal pressure and one-directional subsurface strain parallel to the surface. Improved modelling of the real contact area is the basis...

  15. Structure of deformed metals. Struktura deformirovannykh metallov

    Energy Technology Data Exchange (ETDEWEB)

    Bernshtein, M L

    1977-01-01

    A teaching aid for students at metallurgical and machine-building institutions of higher learning. It can also be used by engineering-technical personnel and scientists. A presentation is made of physical concepts on the mechanism of plastic deformation and its effect on fine structure, structure and properties of metals and alloys. An examination is made of the processes of recovery, polygonization and recrystallization during the heating of cold-deformed metals. The influence of thermal deformation is described to account for the interaction between admixture atoms and dislocations, phase and structural transformations. An examination is made of the phenomenon of superplasticity. Special attention is given to the process of hot deformation. An analysis is made of phenomena at the basis of hardening steel as a result of thermo-mechanical processing, including controlled rolling.

  16. Anion Effects on the Ion Exchange Process and the Deformation Property of Ionic Polymer Metal Composite Actuators

    Directory of Open Access Journals (Sweden)

    Wataru Aoyagi

    2016-06-01

    Full Text Available An ionic polymer-metal composite (IPMC actuator composed of a thin perfluorinated ionomer membrane with electrodes plated on both surfaces undergoes a large bending motion when a low electric field is applied across its thickness. Such actuators are soft, lightweight, and able to operate in solutions and thus show promise with regard to a wide range of applications, including MEMS sensors, artificial muscles, biomimetic systems, and medical devices. However, the variations induced by changing the type of anion on the device deformation properties are not well understood; therefore, the present study investigated the effects of different anions on the ion exchange process and the deformation behavior of IPMC actuators with palladium electrodes. Ion exchange was carried out in solutions incorporating various anions and the actuator tip displacement in deionized water was subsequently measured while applying a step voltage. In the step voltage response measurements, larger anions such as nitrate or sulfate led to a more pronounced tip displacement compared to that obtained with smaller anions such as hydroxide or chloride. In AC impedance measurements, larger anions generated greater ion conductivity and a larger double-layer capacitance at the cathode. Based on these mechanical and electrochemical measurements, it is concluded that the presence of larger anions in the ion exchange solution induces a greater degree of double-layer capacitance at the cathode and results in enhanced tip deformation of the IPMC actuators.

  17. Deformation Recording Process In Polymer-Metal Bilayers And Its Use For Optical Storage

    Science.gov (United States)

    Cornet, Jean A.

    1983-11-01

    A non-antireflective polymer-metal bilayer structure, encapsulated inside a closed cons-truction/is used for digital data storage in the Thomson-CSF Gigadisc. In this paper, a simple model is presented for microdeformation recording in the medium. This model enables a good understanding of the readout signal as a function of the recording power and leads to some practical consequences. Useful polymers and metallic layers are identified and the disc performance is reported. It is shown that recording using laser diodes can be performed at bit rate up to 14 Mbits.s-1 with a laser power of 7 mW at the disc entry face, in case of a 1200 rpm disc speed. Moreover a working range of 4 mW, as defined by a 3 dB attenuation, is demonstrated. Discs from pilot production exhibit raw bit error rates at the level of 2.10-5. For usual environmental conditions, the disc behaviour is compatible with shelf-and archival life at scale of 10 years. Finally, the processes for both layers deposition and disc construction are easy and cost effective. It is concluded that Giaadisc can successfully enter today the market place.

  18. Deformation processes in refractory metals. Progress report, December 1, 1975--November 30, 1976

    International Nuclear Information System (INIS)

    Arey, R.W.; Boratto, F.; Wise, D.E.; Watson, P.G.; Reed-Hill, R.E.

    1976-01-01

    Two papers were published during the report period. Abstracts of these papers are included. Four others have been accepted for publication and are abstracted in included sections. In addition to this, Mr. Juan Donoso has published a dissertation which is summarized. A paper is presented which was prepared for presentation at the ''Interstitial Effects in Refractory Metals'' session of the Fall AIME meeting in Niagara Falls, New York. Other work currently under way is discussed, including new internal friction determinations of the diffusion coefficients of O and N in niobium and re-evaluation of the available relevant data in the literature. It is believed that the results of this study make it possible to rationalize apparent inconsistencies in the literature. Work on the static strain-aging in Ti is reported. A review of work on the effects of hydrogen on the yield point phenomena in niobium at the temperatures 273 and 193 0 K is presented along with transmission electron microscopy work on titanium aimed at obtaining a better insight into the causes of anomalous work hardening associated with dynamic strain-aging in this metal

  19. Deformations in micro extrusion of metals

    Directory of Open Access Journals (Sweden)

    J. Piwnik

    2010-07-01

    Full Text Available Production technologies of small dimensions metallic elements are known for a long time. They are produced by machining methods:turning, milling, polishing. Recently, methods for manufacturing small details by forming are developed – microforming. This process ischaracterized by the high dimensions accuracy and the surface smoothness of received items and the high production rate. When a forming process is scaled down to micro dimensions, the microstructure of the workpiece, the surface topology of the workpiece and that of the tooling remain unchanged. Size effect is appearing. This paper analyses specifications of a metal extrusion in micro scale. To determine the impact of the tool surface roughness on deformation process the numerical model of roughness as triangle wave were developed. In paper the influence of the wave presence on the material flow is described. Impact of the forming conditions on extrusion forces there is also characterized.

  20. Deformed metals - structure, recrystallisation and strength

    DEFF Research Database (Denmark)

    Hansen, Niels; Juul Jensen, Dorte

    2011-01-01

    It is shown how new discoveries and advanced experimental techniques in the last 25 years have led to paradigm shifts in the analysis of deformation and annealing structures of metals and in the way the strength of deformed samples is related to structural parameters. This is described in three...

  1. Collective excitations in deformed alkali metal clusters

    International Nuclear Information System (INIS)

    Lipparini, E.; Stringari, S.; Istituto Nazionale di Fisica Nucleare, Povo

    1991-01-01

    A theoretical study of collective excitations in deformed metal clusters is presented. Sum rules are used to study the splittings of the dipole surface plasma resonance originating from the cluster deformation. The vibrating potential model is developed and used to predict the occurrence of a low lying collective mode of orbital magnetic nature. (orig.)

  2. Deformation of extreme viscoelastic metals and composites

    International Nuclear Information System (INIS)

    Wang, Y.C.; Ludwigson, M.; Lakes, R.S.

    2004-01-01

    The figure of merit for structural damping and damping layer applications is the product of stiffness E and damping tan δ. For most materials, even practical polymer damping layers, E tan δ is less than 0.6 GPa. We consider several methods to achieve high values of this figure of merit: high damping metals, metal matrix composites and composites containing constituents of negative stiffness. As for high damping metals, damping of polycrystalline zinc was determined and compared with InSn studied earlier. Damping of Zn is less dependent on frequency than that of InSn, so Zn is superior at high frequency. High damping and large stiffness anomalies are possible in viscoelastic composites with inclusions of negative stiffness. Negative stiffness entails a reversal of the usual directional relationship between force and displacement in deformed objects. An isolated object with negative stiffness is unstable, but an inclusion embedded in a composite matrix can be stabilized under some circumstances. Ferroelastic domains in the vicinity of a phase transition can exhibit a region of negative stiffness. Metal matrix composites containing vanadium dioxide were prepared and studied. The concentration of embedded particles was sensitive to the processing method

  3. Plastic Deformation of Pressured Metallic Glass

    Directory of Open Access Journals (Sweden)

    Yun Cheng

    2017-11-01

    Full Text Available Although pressured metallic glass (MG has been reported in the literature; there are few studies focusing on pressure effects on the structure; dynamics and its plastic deformation. In this paper; we report on and characterize; via molecular dynamics simulation, the structure and dynamics heterogeneity of pressured MGs, and explore a causal link between local structures and plastic deformation mechanism of pressured glass. The results exhibit that the dynamical heterogeneity of metallic liquid is more pronounced at high pressure, while the MGs were less fragile after the release of external pressure, reflected by the non-Gaussian parameter (NGP. High pressure glass shows better plastic deformation; and the local strain zone distributed more uniformly than of in normal glass. Further research indicates that although the number of icosahedrons in pressured glass was much larger than that in normal glass, while the interpenetrating connections of icosahedra (ICOI exhibited spatial correlations were rather poor; In addition, the number of ‘fast’ atoms indexed by the atoms’ moving distance is larger than that in normal glass; leading to the sharp decreasing in number of icosahedrons during deformation. An uniform distribution of ‘fast’ atoms also contributed to better plastic deformation ability in the pressured glass. These findings may suggest a link between the deformation and destruction of icosahedra with short-range order.

  4. Order and chaos in nuclear and metal cluster deformation

    International Nuclear Information System (INIS)

    Radu, S.

    1995-08-01

    The vast amount of nuclear and metal cluster data indicates that shell structure and deformation are two simultaneous properties. A conflicting situation is therefore encountered as the shell structure, a firm expression of order, is apparently not compatible with the non-integrable nature of the models incorporating deformation. The main issue covered in this thesis is the intricate connection between deformation and chaotic behaviour in deformation models pertinent to nuclear structure and metal cluster physics. It is shown that, at least in some cases, it is possible to reconcile the occurrence of shell structure with non-integrability. The coupling of an axially deformed harmonic oscillator to an axially symmetric octupole term renders the problem non-integrable. The chaotic character of the motion is strongly dependent on the type of deformation, in that a prolate shape shows virtually no chaos, while in an oblate case the motion exhibits fully developed chaos when the octupole term is switched on. Whereas the problem is non-integrable, the quantum mechanical spectrum nevertheless shows some shell structure in the prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is explained in terms of classical periodic orbits which are found by employing the 'removal of resonances method'. Particular emphasis is put on the effect of the hexadecapole deformation which is important in fission processes. The combined effect of octupole and hexadecapole deformation leads to important conclusions for the experimental work as a high degree of ambiguity is signaled for the interpretation of data. The ambiguity results from the discovery of a mutual cancellation of the octupole and hexadecapole deformation in prolate superdeformed systems. The phenomenological Nilsson model is treated in a similar way. It is argued that while in nuclei it produces good results for the low-lying levels

  5. Measuring time-dependent deformations in metallic MEMS

    NARCIS (Netherlands)

    Bergers, L.I.J.C.; Hoefnagels, J.P.M.; Delhey, N.K.R.; Geers, M.G.D.

    2011-01-01

    The reliability of metallic microelectromechanical systems (MEMS) depends on time-dependent deformation such as creep. Key to this process is the interaction between microstructural length scales and dimensional length scales, so-called size-effects. As a first critical step towards studying these

  6. Deformation Mechanisms of Gum Metals Under Nanoindentation

    Science.gov (United States)

    Sankaran, Rohini Priya

    Gum Metal is a set of multi-component beta-Ti alloys designed and developed by Toyota Central R&D Labs in 2003 to have a nearly zero shear modulus in the direction. After significant amounts of cold-work (>90%), these alloys were found to have yield strengths at a significant fraction of the predicted ideal strengths and exhibited very little work hardening. It has been speculated that this mechanical behavior may be realized through an ideal shear mechanism as opposed to conventional plastic deformation mechanisms, such as slip, and that such a mechanism may be realized through a defect structure termed "nanodisturbance". It is furthermore theorized that for near ideal strength to be attained, dislocations need to be pinned at sufficiently high stresses. It is the search for these defects and pinning points that motivates the present study. However, the mechanism of plastic deformation and the true origin of specific defect structures unique to gum metals is still controversial, mainly due to the complexity of the beta-Ti alloy system and the heavily distorted lattice exhibited in cold worked gum metals, rendering interpretation of images difficult. Accordingly, the first aim of this study is to clarify the starting as-received microstructures of gum metal alloys through conventional transmission electron microscopy (TEM) and aberration-corrected high resolution scanning transmission electron microscopy with high-angle annular dark field detector (HAADF-HRSTEM) imaging. To elucidate the effects of beta-stability and starting microstructure on the deformation behavior of gum metals and thus to provide adequate context for potentially novel deformation structures, we investigate three alloy conditions: gum metal that has undergone solution heat treatment (STGM), gum metal that has been heavily cold worked (CWGM), and a solution treated alloy of nominal gum metal composition, but leaner in beta-stabilizing content (ST Ref-1). In order to directly relate observed

  7. Void growth and coalescence in metals deformed at elevated temperature

    DEFF Research Database (Denmark)

    Klöcker, H.; Tvergaard, Viggo

    2000-01-01

    For metals deformed at elevated temperatures the growth of voids to coalescence is studied numerically. The voids are assumed to be present from the beginning of deformation, and the rate of deformation considered is so high that void growth is dominated by power law creep of the material, without...... any noticeable effect of surface diffusion. Axisymmetric unit cell model computations are used to study void growth in a material containing a periodic array of voids, and the onset of the coalescence process is defined as the stage where plastic flow localizes in the ligaments between neighbouring...... voids. The focus of the study is on various relatively high stress triaxialties. In order to represent the results in terms of a porous ductile material model a set of constitutive relations are used, which have been proposed for void growth in a material undergoing power law creep....

  8. Research on geometrical model and mechanism for metal deformation based on plastic flow

    International Nuclear Information System (INIS)

    An, H P; Li, X; Rui, Z Y

    2015-01-01

    Starting with general conditions of metal plastic deformation, it analyses the relation between the percentage spread and geometric parameters of a forming body with typical machining process are studied. A geometrical model of deforming metal is set up according to the characteristic of a flowing metal particle. Starting from experimental results, the effect of technological parameters and friction between workpiece and dies on plastic deformation of a material were studied and a slippage deformation model of mass points within the material was proposed. Finally, the computing methods for strain and deformation energy and temperature rise are derived from homogeneous deformation. The results can be used to select technical parameters and compute physical quantities such as strain, deformation energy, and temperature rise. (paper)

  9. Deformation processes in refractory metals

    International Nuclear Information System (INIS)

    Beckerman, L.P.; Boratto, F.J.M.; Watson, P.G.; Reed-Hill, R.E.

    1977-01-01

    A report is presented of yield point return studies on alloys of niobium containing both oxygen and hydrogen. Here it has been observed that hydrogen has a complex effect on both the kinetics and energetics of the oxygen yield point return in niobium. Work in the area of slow strain-rate embrittlement of oxygen by niobium and its relation to dynamic strain-aging is described, along with data that has been obtained for the diffusion of oxygen and nitrogen in tantalum. They compliment similar data already published on the diffusion of oxygen and nitrogen in both niobium and vanadium. Finally, a report of the preliminary work of a study of the effects of hydrogen on both slow strain-rate embrittlement and dynamic strain aging in vanadium is presented. Because the embrittling effect of hydrogen can seriously reduce the tensile ductility it is not possible to study most aspects of dynamic strain aging using tension tests. Compression tests on the other hand do not suffer from this problem

  10. Deformation processes in refractory metals

    Energy Technology Data Exchange (ETDEWEB)

    Beckerman, L.P.; Boratto, F.J.M.; Watson, P.G.; Reed-Hill, R.E.

    1977-01-01

    A report is presented of yield point return studies on alloys of niobium containing both oxygen and hydrogen. Here it has been observed that hydrogen has a complex effect on both the kinetics and energetics of the oxygen yield point return in niobium. Work in the area of slow strain-rate embrittlement of oxygen by niobium and its relation to dynamic strain-aging is described, along with data that has been obtained for the diffusion of oxygen and nitrogen in tantalum. They compliment similar data already published on the diffusion of oxygen and nitrogen in both niobium and vanadium. Finally, a report of the preliminary work of a study of the effects of hydrogen on both slow strain-rate embrittlement and dynamic strain aging in vanadium is presented. Because the embrittling effect of hydrogen can seriously reduce the tensile ductility it is not possible to study most aspects of dynamic strain aging using tension tests. Compression tests on the other hand do not suffer from this problem.

  11. Bending and tensile deformation of metallic nanowires

    International Nuclear Information System (INIS)

    McDowell, Matthew T; Leach, Austin M; Gall, Ken

    2008-01-01

    Using molecular statics simulations and the embedded atom method, a technique for bending silver nanowires and calculating Young's modulus via continuum mechanics has been developed. The measured Young's modulus values extracted from bending simulations were compared with modulus values calculated from uniaxial tension simulations for a range of nanowire sizes, orientations and geometries. Depending on axial orientation, the nanowires exhibit stiffening or softening under tension and bending as size decreases. Bending simulations typically result in a greater variation of Young's modulus values with nanowire size compared with tensile deformation, which indicates a loading-method-dependent size effect on elastic properties at sub-5 nm wire diameters. Since the axial stress is maximized at the lateral surfaces in bending, the loading-method-dependent size effect is postulated to be primarily a result of differences in nanowire surface and core elastic modulus. The divergence of Young's modulus from the bulk modulus in these simulations occurs at sizes below the range in which experiments have demonstrated a size scale effect on elastic properties of metallic nanowires. This difference indicates that other factors beyond native metallic surface properties play a role in experimentally observed nanowire elastic modulus size effects

  12. Micromechanical modeling of the deformation of HCP metals

    Energy Technology Data Exchange (ETDEWEB)

    Graff, S. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2008-12-04

    Nowadays, intense research is conducted to understand the relation between microstructural features and mechanical properties of hexagonal close-packed (hcp) metals. Due to their hexagonal structure, hcp metals exhibit mechanical properties such as strong anisotropy, which is more pronounced than for construction metals with cubic crystal structure, and tension/compression asymmetry. Deformation mechanisms in hcp metals, dislocation motion on specific slip systems and activation of twinning, are not yet completely understood. The purpose of this work is to link the physical mechanisms developing during deformation of magnesium (Mg) on the microscale with the macroscopic yielding properties of texture Mg samples. It will be shown that the mechanical behavior of hcp metals may be understood and reproduced with the help of a visco-plastic model for crystal plasticity and a phenomenological yield criterion with appropriate hardening behavior. The study of single crystal specimens subjected to channel die compression tests reveals the active slip systems and twinning systems of the material considered. The material anisotropy at mesoscale is reproduced by using adequate critical resolved shear stresses (CRSS) for the considered deformation mechanisms. In order to describe the macroscopic behavior, texture is incorporated into polycrystalline Representative Volume Elements (RVEs) and various mechanical properties of extruded bars and rolled plates can be predicted. For RVEs exhibiting the texture of rolled plates the numerical results reveal the plate's anisotropic yielding and hardening behavior on a mesoscale. In order to extend the modeling possibilities to process simulations and to allow for time-saving simulations of structural behavior, a phenomenological yield surface accounting for anisotropy and tension/compression asymmetry has been established and implemented in a finite element code. Its numerous model parameters are calibrated by an optimization

  13. Simulation of Stamping Process of Automotive Panel Considering Die Deformation

    International Nuclear Information System (INIS)

    Keum, Y.T.; Ahn, I.H.; Lee, I.K.; Song, M.H.; Kwon, S.O.; Park, J.S.

    2005-01-01

    In order to see the effect of die deformation on the forming of sheet metals, the draw-ins, strains, and spring-backs of an automotive fender panels are numerically simulated considering the die deformation, which is found by the simultaneous structural analysis of press and dies. By coupling the forming analysis and the structural analysis, the die deformation is simultaneously taken into account in the forming process. Furthermore, for the consideration of load difference transferred among the upper die, punch, and blank holder due to the changes in sheet thickness, the gap elements are employed instead of the blank sheet in the structural analysis. The numerical simulation results of an automotive fender draw panel are compared with the measurements. The comparison of the forming and spring-back analysis results between the rigid die and the deformed die shows that the deformed tool provides more accurate forming and spring-back prediction

  14. Effect of pass schedule and groove design on the metal deformation ...

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. Effect of pass schedule and ... metal flow behaviour in a hot rolling process is a complex phenomenon, which is ... Computer based FEM simulations incorporating deformation mod- els can be used to develop ...

  15. Surface flow in severe plastic deformation of metals by sliding

    International Nuclear Information System (INIS)

    Mahato, A; Yeung, H; Chandrasekar, S; Guo, Y

    2014-01-01

    An in situ study of flow in severe plastic deformation (SPD) of surfaces by sliding is described. The model system – a hard wedge sliding against a metal surface – is representative of surface conditioning processes typical of manufacturing, and sliding wear. By combining high speed imaging and image analysis, important characteristics of unconstrained plastic flow inherent to this system are highlighted. These characteristics include development of large plastic strains on the surface and in the subsurface by laminar type flow, unusual fluid-like flow with vortex formation and surface folding, and defect and particle generation. Preferred conditions, as well as undesirable regimes, for surface SPD are demarcated. Implications for surface conditioning in manufacturing, modeling of surface deformation and wear are discussed

  16. Fabrication Process Development for Light Deformable Mirrors

    Data.gov (United States)

    National Aeronautics and Space Administration — The project objective is to develop robust, reproductibble fabrication processes to realize functional deformable membrane mirrors (DM) for a space mission in which...

  17. Structural refinement and coarsening in deformed metals

    DEFF Research Database (Denmark)

    Hansen, N.; Huang, X.; Xing, Q.

    2005-01-01

    The microstructural refinement by plastic deformation is analysed in terms of key parameters, the spacing between and the misorientation angle across the boundaries subdividing the structure. Coarsening of such structures by annealing is also characterised. For both deformed and annealed structur...

  18. QuikForm: Intelligent deformation processing of structural alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, R.J.; Wellman, G.W.

    1994-09-01

    There currently exists a critical need for tools to enhance the industrial competitiveness and agility of US industries involved in deformation processing of structural alloys. In response to this need, Sandia National Laboratories has embarked upon the QuikForm Initiative. The goal of this program is the development of computer-based tools to facilitate the design of deformation processing operations. The authors are currently focusing their efforts on the definition/development of a comprehensive system for the design of sheet metal stamping operations. The overall structure of the proposed QuikForm system is presented, and the focus of their thrust in each technical area is discussed.

  19. Cyclic deformation behavior of steels and light-metal alloys

    International Nuclear Information System (INIS)

    Walther, Frank; Eifler, Dietmar

    2007-01-01

    The detailed knowledge of the cyclic deformation behavior of metallic materials is an essential condition for the comprehensive understanding of fatigue mechanisms and a reliable lifetime calculation of cyclically loaded specimens and components. Various steels and light-metal alloys were investigated under stress and strain control on servohydraulic testing systems. In addition to mechanical stress-strain hysteresis measurements, the changes of the specimen temperature and the electrical resistance due to plastic deformation processes were measured. The plasticity-induced martensite formation in metastable austenitic steels was detected in situ with a ferritescope sensor. As advanced magnetic measuring technique giant-magneto-resistance sensors in combination with an universal eddy-current equipment were used for the on-line monitoring of fatigue processes. Due to their direct dependence on microstructural changes, all physical values show a clear interaction with the actual fatigue state. The results of the plastic strain, thermometric, electric and magnetic measuring techniques were presented versus the number of cycles as well as in Morrow and Coffin-Manson plots. The microstructures were characterized by scanning electron microscopy

  20. Cyclic deformation behavior of steels and light-metal alloys

    Energy Technology Data Exchange (ETDEWEB)

    Walther, Frank [University of Kaiserslautern, Institute of Materials Science and Engineering, P.O. Box 3049, D-67653 Kaiserslautern (Germany)], E-mail: walther@mv.uni-kl.de; Eifler, Dietmar [University of Kaiserslautern, Institute of Materials Science and Engineering, P.O. Box 3049, D-67653 Kaiserslautern (Germany)

    2007-11-15

    The detailed knowledge of the cyclic deformation behavior of metallic materials is an essential condition for the comprehensive understanding of fatigue mechanisms and a reliable lifetime calculation of cyclically loaded specimens and components. Various steels and light-metal alloys were investigated under stress and strain control on servohydraulic testing systems. In addition to mechanical stress-strain hysteresis measurements, the changes of the specimen temperature and the electrical resistance due to plastic deformation processes were measured. The plasticity-induced martensite formation in metastable austenitic steels was detected in situ with a ferritescope sensor. As advanced magnetic measuring technique giant-magneto-resistance sensors in combination with an universal eddy-current equipment were used for the on-line monitoring of fatigue processes. Due to their direct dependence on microstructural changes, all physical values show a clear interaction with the actual fatigue state. The results of the plastic strain, thermometric, electric and magnetic measuring techniques were presented versus the number of cycles as well as in Morrow and Coffin-Manson plots. The microstructures were characterized by scanning electron microscopy.

  1. Plastic Deformation of Metal Tubes Subjected to Lateral Blast Loads

    Directory of Open Access Journals (Sweden)

    Kejian Song

    2014-01-01

    Full Text Available When subjected to the dynamic load, the behavior of the structures is complex and makes it difficult to describe the process of the deformation. In the paper, an analytical model is presented to analyze the plastic deformation of the steel circular tubes. The aim of the research is to calculate the deflection and the deformation angle of the tubes. A series of assumptions are made to achieve the objective. During the research, we build a mathematical model for simply supported thin-walled metal tubes with finite length. At a specified distance above the tube, a TNT charge explodes and generates a plastic shock wave. The wave can be seen as uniformly distributed over the upper semicircle of the cross-section. The simplified Tresca yield domain can be used to describe the plastic flow of the circular tube. The yield domain together with the plastic flow law and other assumptions can finally lead to the solving of the deflection. In the end, tubes with different dimensions subjected to blast wave induced by the TNT charge are observed in experiments. Comparison shows that the numerical results agree well with experiment observations.

  2. Slip systems, dislocation boundaries and lattice rotations in deformed metals

    DEFF Research Database (Denmark)

    Winther, Grethe

    2009-01-01

    Metals are polycrystals and consist of grains, which are subdivided on a finer scale upon plastic deformation due to formation of dislocation boundaries. The crystallographic alignment of planar dislocation boundaries in face centred cubic metals, like aluminium and copper, deformed to moderate...... of the mechanical anisotropy of rolled sheets. The rotation of the crystallographic lattice in each grain during deformation also exhibits grain orientation dependence, originating from the slip systems. A combined analysis of dislocation boundaries and lattice rotations concludes that the two phenomena are coupled...

  3. Hardening by annealing and softening by deformation in nanostructured metals

    DEFF Research Database (Denmark)

    Huang, X.; Hansen, N.; Tsuji, N.

    2006-01-01

    We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation-dislocation and ......We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation....... As a consequence, the strength decreases and the ductility increases. These observations suggest that for materials such as the nanostructured aluminum studied here, deformation should be used as an optimizing procedure instead of annealing....

  4. Deformation mechanisms of nanograined metallic polycrystals

    Czech Academy of Sciences Publication Activity Database

    Saada, G.; Kruml, Tomáš

    2011-01-01

    Roč. 59, - (2011), s. 2565-2574 ISSN 1359-6454 Institutional research plan: CEZ:AV0Z20410507 Keywords : nanocrystalline materials * grain boundary defects * plastic deformation Subject RIV: JJ - Other Materials Impact factor: 3.755, year: 2011

  5. Deformation in Metallic Glass: Connecting Atoms to Continua

    Science.gov (United States)

    Hinkle, Adam R.; Falk, Michael L.; Rycroft, Chris H.; Shields, Michael D.

    Metallic glasses like other amorphous solids experience strain localization as the primary mode of failure. However, the development of continuum constitutive laws which provide a quantitative description of disorder and mechanical deformation remains an open challenge. Recent progress has shown the necessity of accurately capturing fluctuations in material structure, in particular the statistical changes in potential energy of the atomic constituents during the non-equilibrium process of applied shear. Here we directly cross-compare molecular dynamics shear simulations of a ZrCu glass with continuum shear transformation zone (STZ) theory representations. We present preliminary results for a methodology to coarse-grain detailed molecular dynamics data with the goal of initializing a continuum representation in the STZ theory. NSF Grants Awards 1107838, 1408685, and 0801471.

  6. Compressive deformation of in situ formed bulk metallic glass composites

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, B. [Lujan Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lee, S.Y. [Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011 (United States); Ustuendag, E. [Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011 (United States)]. E-mail: ustundag@iastate.edu; Kim, C.P. [Liquidmetal Technologies, Lake Forest, CA 92630 (United States); Brown, D.W. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Bourke, M.A.M. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2006-02-15

    A bulk metallic glass matrix composite with dendc second phase precipitates was investigated using neutron diffraction and self-consistent modeling (SCM) to ascertain its deformation mechanisms. The compressive behavior of both the composite and the second phase (in its monolithic form) were investigated. The diffraction data were compared to the predictions of a new SCM resulting in good agreement. For the first time, this model considered both amorphous and crystalline phases and allowed the calculation of single crystal elastic constants from polycrystalline diffraction data. It was shown that the ductile second phase yielded first upon loading, and this was followed by multiple shear band formation in the matrix, a process which enhanced the ductility of the composite.

  7. Compressive deformation of in situ formed bulk metallic glass composites

    International Nuclear Information System (INIS)

    Clausen, B.; Lee, S.Y.; Ustuendag, E.; Kim, C.P.; Brown, D.W.; Bourke, M.A.M.

    2006-01-01

    A bulk metallic glass matrix composite with dendritic second phase precipitates was investigated using neutron diffraction and self-consistent modeling (SCM) to ascertain its deformation mechanisms. The compressive behavior of both the composite and the second phase (in its monolithic form) were investigated. The diffraction data were compared to the predictions of a new SCM resulting in good agreement. For the first time, this model considered both amorphous and crystalline phases and allowed the calculation of single crystal elastic constants from polycrystalline diffraction data. It was shown that the ductile second phase yielded first upon loading, and this was followed by multiple shear band formation in the matrix, a process which enhanced the ductility of the composite

  8. Modeling of dislocation generation and interaction during high-speed deformation of metals

    DEFF Research Database (Denmark)

    Schiøtz, J.; Leffers, T.; Singh, B.N.

    2002-01-01

    Recent experiments by Kiritani et al. [1] have revealed a surprisingly high rate of vacancy production during highspeed deformation of thin foils of fcc metals. Virtually no dislocations are seen after the deformation. This is interpreted as evidence for a dislocation-free deformation mechanism...... at very high strain rates. We have used molecular-dynamics simulations to investigate high-speed deformation of copper crystals. Even though no pre-existing dislocation sources are present in the initial system, dislocations are quickly nucleated and a very high dislocation density is reached during...... the deformation. Due to the high density of dislocations, many inelastic interactions occur between dislocations, resulting in the generation of vacancies. After the deformation, a very high density of vacancies is observed, in agreement with the experimental observations. The processes responsible...

  9. New deformation model of grain boundary strengthening in polycrystalline metals

    International Nuclear Information System (INIS)

    Trefilov, V.I.; Moiseev, V.F.; Pechkovskij, Eh.P.

    1988-01-01

    A new model explaining grain boundary strengthening in polycrystalline metals and alloys by strain hardening due to localization of plastic deformation in narrow bands near grain boundaries is suggested. Occurrence of localized deformation is caused by different flow stresses in grains of different orientation. A new model takes into account the active role of stress concentrator, independence of the strengthening coefficient on deformation, influence of segregations. Successful use of the model suggested for explanation of rhenium effect in molybdenum and tungsten is alloys pointed out

  10. Ferrous Metal Processing Plants

    Data.gov (United States)

    Department of Homeland Security — This map layer includes ferrous metal processing plants in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  11. Nonferrous Metal Processing Plants

    Data.gov (United States)

    Department of Homeland Security — This map layer includes nonferrous metal processing plants in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  12. Electromigration-induced plastic deformation in passivated metal lines

    Science.gov (United States)

    Valek, B. C.; Bravman, J. C.; Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Spolenak, R.; Brown, W. L.; Batterman, B. W.; Patel, J. R.

    2002-11-01

    We have used scanning white beam x-ray microdiffraction to study microstructural evolution during an in situ electromigration experiment on a passivated Al(Cu) test line. The data show plastic deformation and grain rotations occurring under the influence of electromigration, seen as broadening, movement, and splitting of reflections diffracted from individual metal grains. We believe this deformation is due to localized shear stresses that arise due to the inhomogeneous transfer of metal along the line. Deviatoric stress measurements show changes in the components of stress within the line, including relaxation of stress when current is removed.

  13. Actinide metal processing

    International Nuclear Information System (INIS)

    Sauer, N.N.; Watkin, J.G.

    1992-01-01

    A process for converting an actinide metal such as thorium, uranium, or plutonium to an actinide oxide material by admixing the actinide metal in an aqueous medium with a hypochlorite as an oxidizing agent for sufficient time to form the actinide oxide material and recovering the actinide oxide material is described together with a low temperature process for preparing an actinide oxide nitrate such as uranyl nitrate. Additionally, a composition of matter comprising the reaction product of uranium metal and sodium hypochlorite is provided, the reaction product being an essentially insoluble uranium oxide material suitable for disposal or long term storage

  14. A double metal process

    International Nuclear Information System (INIS)

    Hawley, F.; Vasche, G.; Caywood, J.M.; Houck, B.; Boyce, J.; Tso, L.

    1988-01-01

    A dual layer metallization process is studied using a Tungsten 10% Titanium/Molybdenum sandwich (TiW/Mo) first metal with an Al/.5% Cu for the second metal. This metallization process has: 1) very reliable shallow junction contacts without junction spiking, 2) very high electromigration resistance and (3) A very smooth defect free surface throughout the process. Contact resistance of 50 and 30 ohm-um2 for P and N type silicon respectively is achieved. The TiW/Mo film stress is studied and an optimum condition for low compressive stress is defined. The TiW/Mo is etched using a corrosion free etch process. Electromigration data is presented showing TiW/Mo to be at least an order of magnitude better than Al/Si. The intermetal oxide layer is a planarized sandwich of LTO/SOG/LTO providing a smooth positive slope surface for the Metal 2. Metal l/Metal 2 via resistances are studied with 1.25 ohm-um2 values obtained

  15. Local microstructure and flow stress in deformed metals

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Hansen, Niels; Nielsen, Chris Valentin

    2017-01-01

    The microstructure and flow stress of metals are related through many well-known strength-structure relationships based on structural parameters, where grain size and dislocation density are examples. In heterogeneous structures, the local stress and strain are important as they will affect...... the bulk properties. A microstructural method is presented which allows the local stress in a deformed metal to be estimated based on microstructural parameters determined by an EBSD analysis. These parameters are the average spacing of deformation introduced boundaries and the fraction of high angle...... boundaries. The method is demonstrated for two heterogeneous structures: (i) a gradient (sub)surface structure in steel deformed by shot peening; (ii) a heterogeneous structure introduced by friction between a tool and a workpiece of aluminum. Flow stress data are calculated based on the microstructural...

  16. Adhesion along metal-polymer interfaces during plastic deformation

    NARCIS (Netherlands)

    van Tijum, R.; Vellinga, W. P.; De Hosson, J. Th. M.

    In this paper a numerical study is presented that concentrates on the influence of the interface roughness that develops during plastic deformation of a metal, on the work of adhesion and on the change of interface energy upon contact with a glassy polymer. The polymer coating is described with a

  17. Correlations between deformations, surface state and leak rate in metal to metal contact; Correlations entre deformations, etat de surface et debit de fuite au contact metal-metal

    Energy Technology Data Exchange (ETDEWEB)

    Armand, G; Lapujoulade, J; Paigne, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The study of metal to metal contact from the stand-point of the leak rate has been carried on a copper ring located between two hard-steel flanges. The analysis of the results confirms the hysteresis phenomenon already seen. Some curves (leak rate versus force and leak rate versus true deformation) in semi-logarithmic coordinates are straight lines. Likewise some curves (electrical contact resistance versus force) in bi-logarithmic coordinates are straight lines. All these results can be understood by looking at the conductance introduced by the deformations of the micro-geometry of the surfaces in contact. Some tests carried out in rising the temperature confirm these hypothesis. (authors) [French] L'etude du contact metal-metal du point de vue debit de fuite a ete poursuivie en utilisant un anneau de cuivre place entre brides d'acier dur. L'analyse des resultats confirme le phenomene d'hysteresis deja constate, montre l'influence de l'etat de surface des brides et du joint. Certaines courbes (debit de fuite/force et debit de fuite/deformation rationnelle), en coordonnees semi-logarithmiques, sont des droites. De meme, certaines courbes (resistance de contact/force) en coordonnees bi-logarithmiques, sont des droites. Ces resultats s'interpretent en considerant la conductance produite par la deformation des microgeometries des surfaces en contact. Quelques essais d'elevation de temperature confirment ces resultats. (auteurs)

  18. Grain refinement through severe plastic deformation (SPD) processing

    International Nuclear Information System (INIS)

    Izairi, N.; Vevecka - Priftaj, A.

    2012-01-01

    There is considerable current interest in processing metallic samples through procedures involving the imposition of severe plastic deformation (SPD). These procedures lead to very significant grain refinement to the submicrometer or even the nanometer level, resulting in advanced physical properties. Among various SPD processes, Equal Channel Angular Pressing, High pressure Torsion and Accumulated Roll Bonding have been widely used for many metals and alloys. In the present work, we present an overview of the most used methods of SPD for grain refinement and the production of bulk nano structured materials with enhancement in their mechanical and functional properties. In order to examine the potential for using ECAP to refine the grain size and improve the mechanical properties, two commercial 5754 Al alloy and AA 3004 , were selected for study. Processing by ECAP gives a reduction in the grain size and an increase in the microhardness. (Author)

  19. Even-Odd Differences and Shape Deformation of Metal Clusters

    OpenAIRE

    Hidetoshi, Nishioka; Yoshio, Takahashi; Department of Physics, Konan University; Faculty of General Education, Yamagata University

    1994-01-01

    The relation between even-odd difference of metal cluster and the deformation of equilibrium shape is studied in terms of two different models; (i) tri-axially deformed harmonic oscillator model, (ii) rectangular box model. Having assumed the matter density ρ kept constant for different shapes of a cluster, we can determine the equilibrium shape both for the two models. The enhancement of HOMO-LUMO gap is obtained and it is ascribed to Jahn-Teller effect. Good agreement of the calculated resu...

  20. Nucleation of recrystallization at selected sites in deformed fcc metals

    DEFF Research Database (Denmark)

    Xu, Chaoling

    The objective of this thesis is to explore nucleation of recrystallization at selected sites in selected face-centered-cubic (FCC) metals, namely cold rolled columnar-grained nickel and high purity aluminum further deformed by indenting. Various techniques, including, optical microscopy, electron...... backscattered diffraction (EBSD), electron channeling contrast (ECC) and synchrotron X-ray technique, differential-aperture X-ray microscopy (DAXM), were used to characterize the microstructures, to explore nucleation sites, orientation relationships between nuclei and deformed microstructures, and nucleation...... mechanisms. In the cold rolled nickel samples, the preference of triple junctions (TJs) and grain boundaries (GBs) as nucleation sites is observed. The majorities of the nuclei have the same orientations as the surrounding matrix or are twin-related to a surrounding deformed grain. Only a few nuclei...

  1. High rate deformation of metallic liner and its dislocation description

    International Nuclear Information System (INIS)

    Prut, V.V.; Shybaev, S.A.

    1996-01-01

    The dynamics of deformation in cylindrical liners are studied experimentally and theoretically in Z-pinch geometry, where the cylinders are deformed by a magnetic field created by a current flowing along the axis. This method allows one to obtain one-dimensional deformation and a reliable recording of magnetic field and cylinder deformation. The experiments are performed with a current amplitude of 0.8-3 MA and a current rise time of 2.5-4 μs. Aluminium and copper tubes, from 4 to 6 mm in diameter and 0.25-1 mm wall thick, are compressed. The deformation rates under study are in the range of 10 5 -10 6 s -1 . The time dependence of the radii of the copper and aluminium tubes are measured with a streak camera and by the pulsed x-ray technique. The time resolution of the streak and x-ray photographs is 10-15 ns, their spatial resolution is 10-15 μm. A rheological model describing the dynamics of compression is developed. The model includes the description of the metal as a plastic medium with moving dislocations in the solid state, and as a viscous medium in the liquid state. The one-dimensional solution to magneto-hydrodynamical equations of the liner dynamics is compared with the experimental results and thus the following rheological parameters of the metal are obtained: β, the probability of dislocation generation in plastic deformation; and σ d , the drag stress, the parameter which characterizes a drag force acting on the dislocation. (Author)

  2. Investigation of peculiarities of metal deformability during multi-operation cold working with intermediate annealings

    International Nuclear Information System (INIS)

    Bogatov, A.A.; Smirnov, S.V.; Kolmogorov, V.L.

    1979-01-01

    Deformation defects in ready products considerably deteriorate their exploitation characteristics. Recovery of plasticity reserve PSI of the cold deformed 12Kh18N10T steel during electroannealing has been investigated. Moments of micropore (PSIsub(*) approximately O.33) and microcrack (PSIsub(*) approximately 0.55) formation in a deformed metal have been found. The conclusion has been made that PSI value before annealing on a ready size in technological processes of metal treatment with pressure should be restricted by the following conditions: PSI<1 - for products suffering no considerable loadings, PSI< PSIsub(**-0.5) - for most of the products, which have restrictions over the lower strength limit, toughness, durability, and for products which operate in agressive media; PSI< PSIsub(*)=0.33 - for products intended for exploitation under ''rigid'' conditions (low temperatures, shock loadings)

  3. High Strain Rate and Shock-Induced Deformation in Metals

    Science.gov (United States)

    Ravelo, Ramon

    2012-02-01

    Large-scale non-equilibrium molecular Dynamics (MD) simulations are now commonly used to study material deformation at high strain rates (10^9-10^12 s-1). They can provide detailed information-- such as defect morphology, dislocation densities, and temperature and stress profiles, unavailable or hard to measure experimentally. Computational studies of shock-induced plasticity and melting in fcc and bcc single, mono-crystal metals, exhibit generic characteristics: high elastic limits, large directional anisotropies in the yield stress and pre-melting much below the equilibrium melt temperature for shock wave propagation along specific crystallographic directions. These generic features in the response of single crystals subjected to high strain rates of deformation can be explained from the changes in the energy landscape of the uniaxially compressed crystal lattice. For time scales relevant to dynamic shock loading, the directional-dependence of the yield strength in single crystals is shown to be due to the onset of instabilities in elastic-wave propagation velocities. The elastic-plastic transition threshold can accurately be predicted by a wave-propagation stability analysis. These strain-induced instabilities create incipient defect structures, which can be quite different from the ones, which characterize the long-time, asymptotic state of the compressed solid. With increase compression and strain rate, plastic deformation via extended defects gives way to amorphization associated with the loss in shear rigidity along specific deformation paths. The hot amorphous or (super-cooled liquid) metal re-crystallizes at rates, which depend on the temperature difference between the amorphous solid and the equilibrium melt line. This plastic-amorphous transition threshold can be computed from shear-waves stability analyses. Examples from selected fcc and bcc metals will be presented employing semi-empirical potentials of the embedded atom method (EAM) type as well as

  4. Microstructure, Properties and Atomic Level Strain in Severely Deformed Rare Metal Niobium

    Directory of Open Access Journals (Sweden)

    Lembit KOMMEL

    2012-12-01

    Full Text Available The mechanical and physical properties relationship from atomic level strain/stress causes dislocation density and electrical conductivity relationship, as well as crystallites deformation and hkl-parameter change in the severely deformed pure refractory rare metal Nb at ambient temperature and during short processing times. The above mentioned issues are discussed in this study. For ultrafine-grained and nanocrystalline microstructure forming in metal the equal-channel angular pressing and hard cyclic viscoplastic deformation were used. The flat deformation and heat treatment at different parameters were conducted as follows. The focused ion beam method was used for micrometric measures samples manufacturied under nanocrystalline microstructure study by transmission electron microscope. The microstructure features of metal were studied under different orientations by X-ray diffraction scattering method, and according to the atomic level strains, dislocation density, hkl-parameters and crystallite sizes were calculated by different computation methods. According to results the evolutions of atomic level strains/stresses, induced by processing features have great influence on the microstructure and advanced properties forming in pure Nb. Due to cumulative strain increase the tensile stress and hardness were increased significantly. In this case the dislocation density of Nb varies from 5.0E+10 cm–2 to 2.0E+11 cm–2. The samples from Nb at maximal atomic level strain in the (110 and (211 directions have the maximal values of hkl-parameters, highest tensile strength and hardness but minimal electrical conductivity. The crystallite size was minimal and relative atomic level strain maximal in (211 orientation of crystal. Next, flat deformation and heat treatment increase the atomic level parameters of severely deformed metal.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3091

  5. Multi Scale Models for Flexure Deformation in Sheet Metal Forming

    Directory of Open Access Journals (Sweden)

    Di Pasquale Edmondo

    2016-01-01

    Full Text Available This paper presents the application of multi scale techniques to the simulation of sheet metal forming using the one-step method. When a blank flows over the die radius, it undergoes a complex cycle of bending and unbending. First, we describe an original model for the prediction of residual plastic deformation and stresses in the blank section. This model, working on a scale about one hundred times smaller than the element size, has been implemented in SIMEX, one-step sheet metal forming simulation code. The utilisation of this multi-scale modeling technique improves greatly the accuracy of the solution. Finally, we discuss the implications of this analysis on the prediction of springback in metal forming.

  6. Microbiological metal extraction processes

    International Nuclear Information System (INIS)

    Torma, A.E.

    1991-01-01

    Application of biotechnological principles in the mineral processing, especially in hydrometallurgy, has created new opportunities and challenges for these industries. During the 1950's and 60's, the mining wastes and unused complex mineral resources have been successfully treated in bacterial assisted heap and dump leaching processes for copper and uranium. The interest in bio-leaching processes is the consequence of economic advantages associated with these techniques. For example, copper can be produced from mining wastes for about 1/3 to 1/2 of the costs of copper production by the conventional smelting process from high-grade sulfide concentrates. The economic viability of bio leaching technology lead to its world wide acceptance by the extractive industries. During 1970's this technology grew into a more structured discipline called 'bio hydrometallurgy'. Currently, bio leaching techniques are ready to be used, in addition to copper and uranium, for the extraction of cobalt, nickel, zinc, precious metals and for the desulfurization of high-sulfur content pyritic coals. As a developing technology, the microbiological leaching of the less common and rare metals has yet to reach commercial maturity. However, the research in this area is very active. In addition, in a foreseeable future the biotechnological methods may be applied also for the treatment of high-grade ores and mineral concentrates using adapted native and/or genetically engineered microorganisms. (author)

  7. Computer simulation of plastic deformation in irradiated metals

    International Nuclear Information System (INIS)

    Colak, U.

    1989-01-01

    A computer-based model is developed for the localized plastic deformation in irradiated metals by dislocation channeling, and it is applied to irradiated single crystals of niobium. In the model, the concentrated plastic deformation in the dislocation channels is postulated to occur by virtue of the motion of dislocations in a series of pile-tips on closely spaced parallel slip planes. The dynamics of this dislocation motion is governed by an experimentally determined dependence of dislocation velocity on shear stress. This leads to a set of coupled differential equations for the positions of the individual dislocations in the pile-up as a function of time. Shear displacement in the channel region is calculated from the total distance traveled by the dislocations. The macroscopic shape change in single crystal metal sheet samples is determined by the axial displacement produced by the shear displacements in the dislocation channels. Computer simulations are performed for the plastic deformation up to 20% engineering strain at a constant strain rate. Results of the computer calculations are compared with experimental observations of the shear stress-engineering strain curve obtained in tensile tests described in the literature. Agreement between the calculated and experimental stress-strain curves is obtained for shear displacement of 1.20-1.25 μm and 1000 active slip planes per channel, which is reasonable in the view of experimental observations

  8. Compression deformation behaviors of sheet metals at various clearances and side forces

    Directory of Open Access Journals (Sweden)

    Zhan Mei

    2015-01-01

    Full Text Available Modeling sheet metal forming operations requires understanding of plastic behaviors of sheet metals along non-proportional strain paths. The plastic behavior under reversed uniaxial loading is of particular interest because of its simplicity of interpretation and its application to material elements drawn over a die radius and underwent repeated bending. However, the attainable strain is limited by failures, such as buckling and in-plane deformation, dependent on clearances and side forces. In this study, a finite element (FE model was established for the compression process of sheet specimens, to probe the deformation behavior. The results show that: With the decrease of the clearance from a very large value to a very small value, four defects modes, including plastic t-buckling, micro-bending, w-buckling, and in-plane compression deformation will occur. With the increase of the side force from a very small value to a very large value, plastic t-buckling, w-buckling, uniform deformation, and in-plane compression will occur. The difference in deformation behaviors under these two parameters indicates that the successful compression process without failures for sheet specimens only can be carried out under a reasonable side force.

  9. Corrugated Membrane Nonlinear Deformation Process Calculation

    Directory of Open Access Journals (Sweden)

    A. S. Nikolaeva

    2015-01-01

    Full Text Available Elastic elements are widely used in instrumentation. They are used to create a particular interference between the parts, for accumulating mechanical energy, as the motion transmission elements, elastic supports, and sensing elements of measuring devices. Device reliability and quality depend on the calculation accuracy of the elastic elements. A corrugated membrane is rather common embodiment of the elastic element.The corrugated membrane properties depend largely on its profile i.e. a generatrix of the meridian surface.Unlike other types of pressure elastic members (bellows, tube spring, the elastic characteristics of which are close to linear, an elastic characteristic of the corrugated membrane (typical movement versus external load is nonlinear. Therefore, the corrugated membranes can be used to measure quantities, nonlinearly related to the pressure (e.g., aircraft air speed, its altitude, pipeline fluid or gas flow rate. Another feature of the corrugated membrane is that significant movements are possible within the elastic material state. However, a significant non-linearity of membrane characteristics leads to severe complicated calculation.This article is aimed at calculating the corrugated membrane to obtain the elastic characteristics and the deformed shape of the membrane meridian, as well as at investigating the processes of buckling. As the calculation model, a thin-walled axisymmetric shell rotation is assumed. The material properties are linearly elastic. We consider a corrugated membrane of sinusoidal profile. The membrane load is a uniform pressure.The algorithm for calculating the mathematical model of an axisymmetric corrugated membrane of constant thickness, based on the Reissner’s theory of elastic thin shells, was realized as the author's program in C language. To solve the nonlinear problem were used a method of changing the subspace of control parameters, developed by S.S., Gavriushin, and a parameter marching method

  10. Two-dimensional discrete dislocation models of deformation in polycrystalline thin metal films on substrates

    International Nuclear Information System (INIS)

    Hartmaier, Alexander; Buehler, Markus J.; Gao, Huajian

    2005-01-01

    The time-dependent irreversible deformation of polycrystalline thin metal films on substrates is investigated using two-dimensional discrete dislocation dynamics models incorporating essential parameters determined from atomistic studies. The work is focused on the mechanical properties of uncapped films, where diffusive processes play an important role. The simulations incorporate dislocation climb along the grain boundary as well as conservative glide. Despite of severe limitations of the two-dimensional dislocation models, the simulation results are found to largely corroborate experimental findings on different dominant deformation mechanisms at different film thicknesses

  11. Stability of surface plastic flow in large strain deformation of metals

    Science.gov (United States)

    Viswanathan, Koushik; Udapa, Anirduh; Sagapuram, Dinakar; Mann, James; Chandrasekar, Srinivasan

    We examine large-strain unconstrained simple shear deformation in metals using a model two-dimensional cutting system and high-speed in situ imaging. The nature of the deformation mode is shown to be a function of the initial microstructure state of the metal and the deformation geometry. For annealed metals, which exhibit large ductility and strain hardening capacity, the commonly assumed laminar flow mode is inherently unstable. Instead, the imposed shear is accommodated by a highly rotational flow-sinuous flow-with vortex-like components and large-amplitude folding on the mesoscale. Sinuous flow is triggered by a plastic instability on the material surface ahead of the primary region of shear. On the other hand, when the material is extensively strain-hardened prior to shear, laminar flow again becomes unstable giving way to shear banding. The existence of these flow modes is established by stability analysis of laminar flow. The role of the initial microstructure state in determining the change in stability from laminar to sinuous / shear-banded flows in metals is elucidated. The implications for cutting, forming and wear processes for metals, and to surface plasticity phenomena such as mechanochemical Rehbinder effects are discussed.

  12. A constitutive model of nanocrystalline metals based on competing grain boundary and grain interior deformation mechanisms

    KAUST Repository

    Gurses, Ercan; El Sayed, Tamer S.

    2011-01-01

    In this work, a viscoplastic constitutive model for nanocrystalline metals is presented. The model is based on competing grain boundary and grain interior deformation mechanisms. In particular, inelastic deformations caused by grain boundary

  13. Characteristic structures and properties of nanostructured metals prepared by plastic deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2011-01-01

    This chapter focuses on describing the characteristic microstructures of nanostructured metals produced by plastic deformation to ultrahigh strains and their correlation with hardening by annealing and softening by deformation. The results suggest that optimising microstructure and the mechanical...

  14. Extraterrestrial Metals Processing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces iron, silicon, and light metals from Mars, Moon, or asteroid resources in support of advanced human...

  15. Determination of parameters of microstructural inhomogeneity of metal deformation by the method of modelling

    International Nuclear Information System (INIS)

    Kornienko, V.T.

    1991-01-01

    A method is suggested to estimate microstructural non-uniformity of deformation in metals by means of modelling. This method includes measurement of deformation in metals by small-dimensioned dividing grid cells as well as calculation of parameters by means of model representation of microdeformation distribution. It is shown that the method of modelling gives an opportunity to objectively estimate deformation non-uniformity in metals irrespective of the selected dimension of a dividing grid cells. New structural characteristics: base and wave of variations, reflecting a degree of dividing or uniting grains in metals according to the non-uniformity of deformation are introduced

  16. Numerical Modelling of Metal-Elastomer Spring Nonlinear Response for Low-Rate Deformations

    Directory of Open Access Journals (Sweden)

    Sikora Wojciech

    2018-03-01

    Full Text Available Advanced knowledge of mechanical characteristics of metal-elastomer springs is useful in their design process and selection. It can also be used in simulating dynamics of machine where such elements are utilized. Therefore this paper presents a procedure for preparing and executing FEM modelling of a single metal-elastomer spring, also called Neidhart’s spring, for low-rate deformations. Elastomer elements were made of SBR rubber of two hardness values: 50°Sh and 70°Sh. For the description of material behaviour the Bergström-Boyce model has been used.

  17. Investigating Deformation and Failure Mechanisms in Nanoscale Multilayer Metallic Composites

    Energy Technology Data Exchange (ETDEWEB)

    Zbib, Hussein M. [Washington State Univ., Pullman, WA (United States); Bahr, David F. [Purdue Univ., West Lafayette, IN (United States)

    2014-10-22

    Over the history of materials science there are many examples of materials discoveries that have made superlative materials; the strongest, lightest, or toughest material is almost always a goal when we invent new materials. However, often these have been a result of enormous trial and error approaches. A new methodology, one in which researchers design, from the atoms up, new ultra-strong materials for use in energy applications, is taking hold within the science and engineering community. This project focused on one particular new classification of materials; nanolaminate metallic composites. These materials, where two metallic materials are intimately bonded and layered over and over to form sheets or coatings, have been shown over the past decade to reach strengths over 10 times that of their constituents. However, they are not yet widely used in part because while extremely strong (they don’t permanently bend), they are also not particularly tough (they break relatively easily when notched). Our program took a coupled approach to investigating new materials systems within the laminate field. We used computational materials science to explore ways to institute new deformation mechanisms that occurred when a tri-layer, rather than the more common bi-layer system was created. Our predictions suggested that copper-nickel or copper-niobium composites (two very common bi-layer systems) with layer thicknesses on the order of 20 nm and then layered 100’s of times, would be less tough than a copper-nickel-niobium metallic composite of similar thicknesses. In particular, a particular mode of permanent deformation, cross-slip, could be activated only in the tri-layer system; the crystal structure of the other bi-layers would prohibit this particular mode of deformation. We then experimentally validated this predication using a wide range of tools. We utilized a DOE user facility, the Center for Integrated Nanotechnology (CINT), to fabricate, for the first time, these

  18. Structural aspects of elastic deformation of a metallic glass

    International Nuclear Information System (INIS)

    Hufnagel, T. C.; Ott, R. T.; Almer, J.

    2006-01-01

    We report the use of high-energy x-ray scattering to measure strain in a Zr 57 Ti 5 Cu 20 Ni 8 Al 10 bulk metallic glass in situ during uniaxial compression in the elastic regime up to stresses of approximately 60% of the yield stress. The strains extracted in two ways--directly from the normalized scattering data and from the pair correlation functions--are in good agreement with each other for length scales greater than 4 A. The elastic modulus calculated on the basis of this strain is in good agreement with that reported for closely related amorphous alloys based on macroscopic measurements. The strain measured for atoms in the nearest-neighbor shell, however, is smaller than that for more distant shells, and the effective elastic modulus calculated from the strain on this scale is therefore larger, comparable to crystalline alloys of similar composition. These observations are in agreement with previously proposed models in which the nominally elastic deformation of a metallic glass has a significant anelastic component due to atomic rearrangements in topologically unstable regions of the structure. We also observe that the distribution of the atomic-level stresses in the glass becomes more uniform during loading. This implies that the stiffness of metallic glasses may have an entropic contribution, analogous to the entropic contribution in rubber elasticity

  19. Extraterrestrial Metals Processing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces ferrosilicon, silicon monoxide, a glassy mixed oxide slag, and smaller amounts of alkali earth...

  20. Modeling the Mechanical Behavior of Aluminum Laminated Metal Composites During High Temperature Deformation

    National Research Council Canada - National Science Library

    Grishber, R

    1997-01-01

    A constitutive model for deformation of a novel laminated metal composite (LMC) which is comprised of 21 alternating layers of Al 5182 alloy and Al 6090/SiC/25p metal matrix composite (MMC) has been proposed...

  1. Study of inelastic deformation mechanisms in metal glass volume

    International Nuclear Information System (INIS)

    Bakaj, S.A.; Neklyudov, I.M.; Savchenko, V.I.; Ehkert, Yu.

    2001-01-01

    The results of investigations of the mechanical properties and internal friction of the bulk amorphous alloy Zr 53.5 Ti 5 Cu 17.5 Ni 14.6 Al 10.4 within the temperature range from the room temperature up to glass-transition temperature are reported. The yield stress and transition from homogeneous to inhomogeneous plastic deformation are investigated. The temperature dependence of low-frequency internal friction, Q -1 (T), in the amplitude-independent limit of oscillations is obtained. The temperature range within which the homogeneous plastic deformation is observed under compression stress is determined. The superplasticity of the amorphous alloy is revealed at the temperature which is 100K lower than the glass-transition temperature. The lowest temperature, at which the superplasticity is revealed, turns to be an edge of the temperature range where Q -1 (T) increases fast. The microscopic nature of the observed phenomena are interpreted on the base of the polycluster model of the metallic glasses

  2. Low temperature uniform plastic deformation of metallic glasses during elastic iteration

    International Nuclear Information System (INIS)

    Fujita, Takeshi; Wang Zheng; Liu Yanhui; Sheng, Howard; Wang Weihua; Chen Mingwei

    2012-01-01

    Molecular dynamics simulations and dynamic mechanical analysis experiments were employed to investigate the mechanical behavior of metallic glasses subjected to iteration deformation in a nominally elastic region. It was found that cyclic deformation leads to the formation of irreversible shear transformation zones (STZs) and a permanent uniform strain. The initiation of STZs is directly correlated with the atomic heterogeneity of the metallic glass and the accumulated permanent strain has a linear relation with the number of STZs. This study reveals a new deformation mode and offers insights into the atomic mechanisms of STZ formation and low temperature uniform plastic deformation of metallic glasses.

  3. Study on Hot Deformation Behavior of 7085 Aluminum Alloy during Backward Extrusion Process

    Directory of Open Access Journals (Sweden)

    R. B. Mei

    2015-01-01

    Full Text Available Compression test was carried out and the true stress-strain curves were obtained from the hot compression of 7085 alloy. A numerical simulation on the deformation behavior of 7085 aluminum alloy during the backward extrusion was also performed by finite element method. The results show that dynamic recrystallization occurs in the hot compression of 7085 alloy and the peak stress reaches higher values as the strain rate increases and deformation temperature decreases. The backward extrusion processes include contact deformation, initial deformation, and steady deformation. Severe plastic deformation of shear and compression occurs when the metal flowed into the channel between fillet of punch and wall of die so that the grain size can be refined by backward extrusion. The deformation in the region of top of wall is too small to meet the mechanical properties of requirements and the metal usually needs to be trimmed. The experiments with the same parameters as simulation had been carried out and the experimental cup after extrusion has better quality.

  4. Molecular Dynamics Simulation of Structural Characterization of Elastic and Inelastic Deformation in ZrCu Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Shidong Feng

    2014-01-01

    Full Text Available The nanoscopic deformation behaviors in a ZrCu metallic glass model during loading-unloading process under uniaxial compression have been analyzed on the basis of the molecular dynamics (MD. The reversible degree of shear origin zones (SOZs is used as the structural indicator to distinguish the elastic deformation and inelastic deformation of ZrCu metallic glass at the atomic level. We find that the formation of SOZs is reversible at the elastic stage but irreversible at the inelastic stage during the loading and unloading processes. At the inelastic stage, the full-icosahedra fraction in SOZs is quickly reduced with increased strain and the decreasing process is also irreversible during the unloading processes.

  5. Stress analysis and deformation prediction of sheet metal workpieces based on finite element simulation

    OpenAIRE

    Ren Penghao; Wang Aimin; Wang Xiaolong; Zhang Yanlin

    2017-01-01

    After aluminum alloy sheet metal parts machining, the residual stress release will cause a large deformation. To solve this problem, this paper takes a aluminum alloy sheet aerospace workpiece as an example, establishes the theoretical model of elastic deformation and the finite element model, and places quantitative initial stress in each element of machining area, analyses stress release simulation and deformation. Through different initial stress release simulative analysis of deformation ...

  6. Nucleation reactions during deformation and crystallization of metallic glass

    International Nuclear Information System (INIS)

    Perepezko, J.H.; Imhoff, S.D.; Chen, M.W.; Gonzalez, S.; Inoue, A.

    2012-01-01

    Highlights: ► New approach to the examination and analysis of shear band nucleation. ► Discovery of multiple shear band nucleation sites. ► Identification of a method of using transient kinetic behavior to provide a more realistic evaluation of the diffusivity that is relevant to nucleation. - Abstract: Nucleation reactions play a central role in the synthesis of both bulk metallic glasses and nanostructured materials. For nanostructured materials it is necessary to promote a high nucleation density without significant growth or coarsening. Beyond crystallization reactions nucleation of shear bands is critical for promoting a homogeneous flow and useful ductility for structural applications of bulk metallic glass. The study and analysis of nucleation reactions for these different situations requires a consideration of the stochastic nature of nucleation, the influence of heterogeneous sites, and the controlling transport properties. For shear band nucleation, the stochastic nature can be effectively probed by instrumented nanoindentation tests. The analysis of a statistically significant number of measurements of the first pop-in shear band nucleation events reveals at least two main nucleation sites. In nanostructured composites, the initial nucleation stage is influenced by transient effects as reflected in the delay time prior to steady state nucleation and by heterogeneous nucleation sites that are related to medium range order regions in Al-base amorphous alloys. Moreover, the early growth characteristics are linked to the maximum achievable particle density. The new developments and insight on the fundamental understanding of nanostructure reaction mechanisms offer valuable guidance for control of nanoscale microstructures and for promoting ductile deformation behavior.

  7. Computer Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

    Science.gov (United States)

    Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

    2004-01-01

    In friction stir welding, a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. This solid-state technique has been successfully used in the joining of materials that are difficult to fusion weld such as aluminum alloys. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and thus tracks the aluminum deformation flow paths in a unique 3-dimensional manner. CT scanning is a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

  8. Investigation of crystallization kinetics and deformation behavior in supercooled liquid region of CuZr-based bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ke; Fan, Xinhui; Li, Bing; Li, Yanhong; Wang, Xin; Xu, Xuanxuan [Xi' an Technological Univ. (China). School of Material and Chemical Engineering

    2017-08-15

    In this paper, a systematic study of crystallization kinetics and deformation behavior is presented for (Cu{sub 50}Zr{sub 50}){sub 94}Al{sub 6} bulk metallic glass in the supercooled liquid region. Crystallization results showed that the activation energy for (Cu{sub 50}Zr{sub 50}){sub 94}Al{sub 6} was calculated using the Arrhenius equation in isothermal mode and the Kissinger-Akahira-Sunose method in non-isothermal mode. The activation energy was quite high compared with other bulk metallic glasses. Based on isothermal transformation kinetics described by the Johson-Mehl-Avrami model, the average Avrami exponent of about 3.05 implies a mainly diffusion controlled three-dimensional growth with an increasing nucleation rate during the crystallization. For warm deformation, the results showed that deformation behavior, composed of homogeneous and inhomogeneous deformation, is strongly dependent on strain rate and temperature. The homogeneous deformation transformed from non-Newtonian flow to Newtonian flow with a decrease in strain rate and an increase in temperature. It was found that the crystallization during high temperature deformation is induced by heating. The appropriate working temperature/strain rate combination for the alloy forming, without in-situ crystallization, was deduced by constructing an empirical deformation map. The optimum process condition for (Cu{sub 50}Zr{sub 50}){sub 94}Al{sub 6} can be expressed as T∝733 K and ∝ ε 10{sup -3} s{sup -1}.

  9. Semisolid Metal Processing Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Apelian,Diran

    2002-01-10

    Mathematical modeling and simulations of semisolid filling processes remains a critical issue in understanding and optimizing the process. Semisolid slurries are non-Newtonian materials that exhibit complex rheological behavior. There the way these slurries flow in cavities is very different from the way liquid in classical casting fills cavities. Actually filling in semisolid processing is often counter intuitive

  10. Stress analysis and deformation prediction of sheet metal workpieces based on finite element simulation

    Directory of Open Access Journals (Sweden)

    Ren Penghao

    2017-01-01

    Full Text Available After aluminum alloy sheet metal parts machining, the residual stress release will cause a large deformation. To solve this problem, this paper takes a aluminum alloy sheet aerospace workpiece as an example, establishes the theoretical model of elastic deformation and the finite element model, and places quantitative initial stress in each element of machining area, analyses stress release simulation and deformation. Through different initial stress release simulative analysis of deformation of the workpiece, a linear relationship between initial stress and deformation is found; Through simulative analysis of coupling direction-stress release, the superposing relationship between the deformation caused by coupling direction-stress and the deformation caused by single direction stress is found. The research results provide important theoretical support for the stress threshold setting and deformation controlling of the workpieces in the production practice.

  11. Analysis of Deformation and Failure Behaviors of TIG Welded Dissimilar Metal Joints Using Miniature Tensile Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji-Hwan; Jahanzeb, Nabeel; Kim, Min-Seong; Hwang, Ji-Hyun; Choi, Shi-Hoon [Sunchon National University, Suncheon (Korea, Republic of)

    2017-02-15

    The deformation and failure behaviors of dissimilar metal joints between SS400 steel and STS316L steel were investigated. The dissimilar metal joints were fabricated using the tungsten inert gas (TIG) welding process with STS309 steel as a filler metal. The microstructures of the dissimilar metal joints were investigated using an optical microscope and EBSD technique. The mechanical properties of the base metal (BM), heat affected zone (HAZ) and weld metal (WM) were measured using a micro-hardness and micro-tension tester combined with the digital image correlation (DIC) technique. The HAZ of the STS316L steel exhibited the highest micro-hardness value, and yield/tensile strengths, while the BM of the SS440 steel exhibited the lowest micro-hardness value and yield /tensile strengths. The grain size refinement in the HAZ of SS400 steel induced an enhancement of micro-hardness value and yield/tensile strengths compared to the BM of the SS400 steel. The WM, which consists of primary δ-ferrite and a matrix of austenite phase, exhibited relatively a high micro-hardness value, yield /tensile strengths and elongation compared to the BM and HAZ of the SS400 steel.

  12. METAL PLATING PROCESS

    Science.gov (United States)

    Walker, D.E.; Noland, R.A.

    1958-08-12

    A process ts described for obtaining a closely bonded coating of steel or iron on uranium. The process consists of providing, between the steel and uramium. a layer of silver. amd then pressure rolling tbe assembly at about 600 deg C until a reduction of from l0 to 50% has been obtained.

  13. Computed Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

    Science.gov (United States)

    Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

    2005-01-01

    In friction stir welding (FSW), a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and is carried with the macro-flow of the weld metal. By using CT images, a 3-dimensional (3D) image of the lead flow pattern can be reconstructed. CT imaging was found to be a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

  14. Influence of deformation rate on plasticity of metals under pressure

    International Nuclear Information System (INIS)

    Churbaev, R.V.; Dobromyslov, A.V.; Kolmogorov, V.L.; Taluts, G.G.

    1990-01-01

    Change of polycrystalline molybdenum (BCC) and titanium (HCP) plasticity under pressure depeding on the deformation rate at the room temperature is studied. It is shown that the reduction of molybdenum and titanium deformation rate leads to a substantial growth of their plastic properties with the effect being increased with pressure growth. Production of several necks testifying to the transition to a superplastic state is observed at high pressures and low deformation rates. A functional dependence of plasticity change on the deformation rate under pressure is ascertained

  15. Investigation of the deformation stability in the incremental sheet forming process

    Directory of Open Access Journals (Sweden)

    Ai S.

    2015-01-01

    Full Text Available Incremental sheet forming (ISF is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. One of the unique characters of the ISF process is the improved formability comparing to conventional sheet forming process. This may be due to the localized deformation nature, which increases the deformation stability in the ISF process. Although many hypotheses have been proposed, there is no direct modelling and calculation of the ISF deformation stability. Aiming to obtain a better understanding of the ISF process, an analytical model was developed to investigate and analyse the material deformation stability in this work. Based on the analytical evaluation of stress variations and force equilibrium, a mathematical relationship between the maximum forming angle and the process stability condition was established. To validate the developed model, experiments were carried out by forming a hyperbolic part made of AA1100 material. The maximum forming angle, as an indicator to the ISF formability, was employed compare the analytical evaluation and experimental result. It was found that the ISF deformation stability is one of the key factors that affect the ISF formability.

  16. Three-dimensional phase-field simulation on the deformation of metallic glass nanowires

    International Nuclear Information System (INIS)

    Zhang, H.Y.; Zheng, G.P.

    2014-01-01

    Highlights: • 3D phase-field modeling is developed to investigate the deformation of MG nanowires. • The surface defects significantly affect the mechanical properties of nanowires. • Multiple shear bands are initiated from the surfaces of nanowires with D < 50 nm. - Abstract: It is very challenging to investigate the deformation mechanisms in micro- and nano-scale metallic glasses with diameters below several hundred nanometers using the atomistic simulation or the experimental approaches. In this work, we develop the fully three-dimensional phase-field model to bridge this gap and investigate the sample size effects on the deformation behaviors of metallic glass nanowires. The initial deformation defects on the surface are found to significantly affect the mechanical strength and deformation mode of nanowires. The improved ductility of metallic glass nanowires could be related with the multiple shear bands initiated from the nanowire surfaces

  17. Deformation processes within wheel-rail adhesion in contact area

    Science.gov (United States)

    Albagachiev, A. Yu; Keropyan, A. M.

    2018-03-01

    The study of working surface deformation during interaction of open-pit locomotive tires allowed defining outstanding features of phenomena occurring in the contact area of interacting surfaces. It was found that processes typical for plastic saturated contact occur in the area of wheel-rail interaction of industrial railway transport. In case of plastic deformation exposed to heavy loads typical for open-pit locomotives, upon all rough surfaces of the contour contact area being fully deformed, the frame on which they are found is exposed to plastic deformation. Plastic deformation of roughness within the contact area of interacting surfaces leads to the increase in the actual area of their contact and, therefore, increases the towing capacity of mining machines. Finally, the available data on deformation characteristics with regard to processes occurring in the contact area of wheel-rail interaction will allow making theoretical forecasts on the expected design value of friction coefficient and, therefore, the towing capacity of open-pit locomotives.

  18. The Micromechanics of Deformation and Failure in Metal-Matrix Composites

    National Research Council Canada - National Science Library

    Needleman, Alan

    1997-01-01

    .... However, metal-matrix composites often have low ductility and low fracture toughness. An improved understanding of the basic deformation and failure mechanisms is needed to overcome these problems...

  19. High Rate Plastic Deformation and Failure of Tungsten-Sintered Metals

    National Research Council Canada - National Science Library

    Bjerke, Todd

    2004-01-01

    The competition between plastic deformation and brittle fracture during high rate loading of a tungsten-sintered metal is examined through impact experiments, post-experiment microscopy, and numerical simulation...

  20. Structural Changes in Deformed Soft Magnetic Ni-Based Metallic Glass

    NARCIS (Netherlands)

    Jurikova, A.; Csach, K.; Miskuf, J.; Ocelik, V.

    The effects of intensive plastic deformation of the soft magnetic metallic glass Ni Si 13 on the structural relaxation were examined. The enthalpy changes studied by differential scanning calorimetry revealed that the intensive plastic deformation was associated with the partial structural

  1. Extraction process for removing metallic impurities from alkalide metals

    Science.gov (United States)

    Royer, Lamar T.

    1988-01-01

    A development is described for removing metallic impurities from alkali metals by employing an extraction process wherein the metallic impurities are extracted from a molten alkali metal into molten lithium metal due to the immiscibility of the alkali metals in lithium and the miscibility of the metallic contaminants or impurities in the lithium. The purified alkali metal may be readily separated from the contaminant-containing lithium metal by simple decanting due to the differences in densities and melting temperatures of the alkali metals as compared to lithium.

  2. The mechanism of strength and deformation in Gum Metal

    International Nuclear Information System (INIS)

    Furuta, T.; Kuramoto, S.; Morris, J.W.; Nagasako, N.; Withey, E.; Chrzan, D.C.

    2013-01-01

    “Gum Metal” refers to β-Ti alloys that achieve exceptional elastic elongation and, with a specific alloy composition, appear to deform via a dislocation-free mechanism involving elastic instability at the limit of strength. This paper describes the current status of research on its strength, deformation mechanism and the possible role of stress-induced martensite. The theoretical basis for deformation at ideal strength is presented. The relevant experimental data is then discussed, including ex situ nanoindentation behavior and in situ pillar compression observed by transmission electron microscopy

  3. The use of radioactive inserts in the study of metal deformation during tube-making processes; Emploi de fils metalliques radioactifs pour l'etude des deformations des metaux pendant la fabrication de tubes; Ispol'zovanie radioaktivnykh vtulok dlya izucheniya deformatsii metallov pri protsesse izgotovleniya trub; Empleo de insertos radiactivos en el estudio de la deformacion de los metales durante la fabricacion de tubos

    Energy Technology Data Exchange (ETDEWEB)

    Davison, W H.T. [Tube Investments Research Laboratories, Cambridge (United Kingdom)

    1962-01-15

    This paper reports on the use of radioactive inserts in studying the deformation of steel in hot rotary piercing for tube making. Iron or steel wires are activated in the pile, inserted in tubes drilled in iron or steel billets, which are then processed under normal production conditions. Careful monitoring shows that the radiation exposures and contamination of the plant are quite negligible. On cooling, the billets are scanned in the laboratory, using a collimated scintillationcounter mounted normal to the surface of the pierced billet, and isodose curves show the shape of the deformed insert normal to the tube surface. A similar scan of a section normal to the axis of the tube gives a second plot; from a combination of the two plots, a three-dimensional picture is obtained. Some results are quoted, but the main emphasis of the paper is on the experimental technique, which has quite general applicability to metal deformation studies. The insert must be located within a millimeter or thereabouts, for which a higher resolution is required than is normal in medical scanning techniques. The problems of achieving this are discussed in terms of {gamma}-energy, collimator design and energy discrimination. (author) [French] Le present memoire traite de l'emploi de fils metalliques radioactifs pour l'etude de la deformation de l'acier durant le forage rotatif a chaud en vue de la fabrication des tubes. Des fils de fer ou d'acier sont actives dans un reacteur et places dans des cavites tabulaires menagees a l'interieur de billettes de fer ou d'acier que l'on transforme ensuite dans les conditions de fabrication normales. Un controle radiologique minutieux montre que les dangers d'irradiation et de contamination dans l'usine sont pratiquement negligeables. Apres refroidissement, les billettes sont examinees en laboratoire au moyen d'un compteur a scintillations avec collimateur de faible ouverture, monte de facon que l'axe soit perpendiculaire a la surface de la billette

  4. Two-scale characterization of deformation-induced anisotropy of polycrystalline metals

    International Nuclear Information System (INIS)

    Watanabe, Ikumu; Terada, Kenjiro

    2004-01-01

    The anisotropic macro-scale mechanical behavior of polycrystalline metals is characterized by incorporating the micro-scale constitutive model of single crystal plasticity into the two-scale modeling based on the mathematical homogenization theory. The two-scale simulations are conducted to analyze the macro-scale anisotropy induced by micro-scale plastic deformation of the polycrystalline aggregate. In the simulations, the micro-scale representative volume element (RVE) of a polycrystalline aggregate is uniformly loaded in one direction, unloaded to macroscopically zero stress in a certain stage of deformation and then re-loaded in the different directions. The last re-loading calculations provide different macro-scale responses of the RVE, which can be the appearance of material anisotropy. We then try to examine the effects of the intergranular and intragranular behaviors on the anisotropy by means of various illustrations of plastic deformation process in stead of the use of pole figures for the change of crystallographic orientations

  5. Texture-geometric deformational effects in some metal-hydrogen systems

    International Nuclear Information System (INIS)

    Spivak, L.V.; Kats, M.Ya.

    1992-01-01

    Possible deformation effects were studied in vanadium, tantalum, niobium, palladium and iron which occurred during electrolytic hydrogenation of specimens preliminarily deformed by torsion and then annealed. Noticeable texture-geometric effects were observed and related to the system tendency to enhance the degree of specimen form symmetry during hydrogenation. The latter was an off-beat realization of Le-Chatelier principle. It was assumed that the nature of deformation effects was connected with one of minimization channels for overall elastic stress fields in metals being hydrogenated. Some distinction was revealed in behaviour of 5a group metal, palladium and iron

  6. Micro-scaled products development via microforming deformation behaviours, processes, tooling and its realization

    CERN Document Server

    Fu, Ming Wang

    2014-01-01

    ‘Micro-scaled Products Development via Microforming’ presents state-of-the-art research on microforming processes, and focuses on the development of micro-scaled metallic parts via microforming processes. Microforming refers to the fabrication of microparts via micro-scaled plastic deformation and  presents a promising micromanufacturing process. When compared to other  micromanufacturing processes, microforming offers advantages such as high productivity and good mechanical properties of the deformed microparts. This book provides extensive and informative illustrations, tables and photos in order to convey this information clearly and directly to readers. Although the knowledge of macroforming processes is abundant and widely used in industry, microparts cannot be developed by leveraging existing knowledge of macroforming because the size effect presents a barrier to this knowledge transfer. Therefore systematic knowledge of microforming needs to be developed. In tandem with product miniaturization, t...

  7. Hot deformation behavior of delta-processed superalloy 718

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y., E-mail: wangyanhit@yahoo.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China); Shao, W.Z.; Zhen, L.; Zhang, B.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-03-25

    Research highlights: {yields} The peak stress for hot deformation can be described by the Z parameter. {yields} The grain size of DRX was inversely proportional to the Z parameter. {yields} The dissolution of {delta} phases was greatly accelerated under hot deformation. {yields}The {delta} phase stimulated nucleation can serve as the main DRX mechanism. - Abstract: Flow stress behavior and microstructures during hot compression of delta-processed superalloy 718 at temperatures from 950 to 1100 deg. C with strain rates of 10{sup -3} to 1 s{sup -1} were investigated by optical microscopy (OM), electron backscatter diffraction (EBSD) technique and transmission electron microscopy (TEM). The relationship between the peak stress and the deformation conditions can be expressed by a hyperbolic-sine type equation. The activation energy for the delta-processed superalloy 718 is determined to be 467 kJ/mol. The change of the dominant deformation mechanisms leads to the decrease of stress exponent and the increase of activation energy with increasing temperature. The dynamically recrystallized grain size is inversely proportional to the Zener-Hollomon (Z) parameter. It is found that the dissolution rate of {delta} phases under hot deformation conditions is much faster than that under static conditions. Dislocation, vacancy and curvature play important roles in the dissolution of {delta} phases. The main nucleation mechanisms of dynamic recrystallization (DRX) for the delta-processed superalloy 718 include the bulging of original grain boundaries and the {delta} phase stimulated DRX nucleation, which is closely related to the dissolution behavior of {delta} phases under certain deformation conditions.

  8. Numerical modelling of river processes: flow and river bed deformation

    NARCIS (Netherlands)

    Tassi, P.A.

    2007-01-01

    The morphology of alluvial river channels is a consequence of complex interaction among a number of constituent physical processes, such as flow, sediment transport and river bed deformation. This is, an alluvial river channel is formed from its own sediment. From time to time, alluvial river

  9. Recrystallization kinetics of nanostructured copper processed by dynamic plastic deformation

    DEFF Research Database (Denmark)

    Lin, Fengxiang; Zhang, Yubin; Pantleon, Wolfgang

    2012-01-01

    The recrystallization kinetics of nanostructured copper samples processed by dynamic plastic deformation was investigated by electron backscatter diffraction. It was found that the evolution of the recrystallized volume fraction as a function of annealing time has a very low slope (n=0.37) when...

  10. The role of edge dislocations in the deformation of BCC metals

    International Nuclear Information System (INIS)

    Lung, C.W.

    1994-08-01

    It was widely accepted that the screw dislocation is responsible for the strong temperature dependence of the yield stresses observed in bcc metals. In this paper, we show the role of edge dislocations in the deformation of bcc metals and point out that in some cases, its main contribution to the yield stress cannot be ignored. (author). 15 refs, 2 figs, 1 tab

  11. Tritium processing using metal hydrides

    International Nuclear Information System (INIS)

    Mallett, M.W.

    1986-01-01

    E.I. duPont de Nemours and Company is commissioned by the US Department of Energy to operate the Savannah River Plant and Laboratory. The primary purpose of the plant is to produce radioactive materials for national defense. In keeping with current technology, new processes for the production of tritium are being developed. Three main objectives of this new technology are to ease the processing of, ease the storage of, and to reduce the operating costs of the tritium production facility. Research has indicated that the use of metal hydrides offers a viable solution towards satisfying these objectives. The Hydrogen and Fuels Technology Division has the responsibility to conduct research in support of the tritium production process. Metal hydride technology and its use in the storage and transportation of hydrogen will be reviewed

  12. Thermoplastic deformation of ferromagnetic CoFe-based bulk metallic glasses

    Science.gov (United States)

    Wu, Chenguang; Hu, Renchao; Man, Qikui; Chang, Chuntao; Wang, Xinmin

    2017-12-01

    The superplastic deformation behavior of the ferromagnetic Co31Fe31Nb8B30 bulk metallic glass (BMG) in the supercooled liquid region was investigated. At a given temperature, the BMG exhibits a Newtonian behavior at low strain rates but a non-Newtonian behavior at high strain rates. The high thermal stability of this glassy alloy system offers an enough processing window to thermoplastic forming (TPF), and the strong processing ability was examined by simple micro-replication experiments. It is demonstrated that the TPF formability on length scales ranging down to nanometers can be achieved in the selected experimental condition. Based on the analysis of deformation behavior, the nearly full density sample (i.e. nearly 100%), was produced from water-atomized glassy powders and consolidated by the hot-pressing technique. The sample exhibits good soft-magnetic and mechanical properties, i.e., low coercive force of 0.43 Oe, high initial permeability of 4100 and high Vickers hardness 1398. These results suggest that the hot-pressing process opens up possibilities for the commercial exploitation of BMGs in engineering applications.

  13. Symmetry-induced deformation and reconstructive phase transformation in metal-oxide interface: the Fe (001) example

    International Nuclear Information System (INIS)

    Lahoche, L.; Universite de Technologie de Compiegne; Lorman, V.; Roelandt, J.M.; Rochal, S.B.

    1996-01-01

    A model is proposed for the structural transformation and corresponding induced deformation in physical three-dimensional interface of the metal-oxide system. The thermodynamical and elastic state of the system is described by the Landau-Ginzbourg free energy. Calculated theoretical phase diagram shows several different types of isothermal growth processes. The model is applied to the case of the oxidation of the (001) Fe surface. (orig.)

  14. PROCESS FOR PREPARING URANIUM METAL

    Science.gov (United States)

    Prescott, C.H. Jr.; Reynolds, F.L.

    1959-01-13

    A process is presented for producing oxygen-free uranium metal comprising contacting iodine vapor with crude uranium in a reaction zone maintained at 400 to 800 C to produce a vaporous mixture of UI/sub 4/ and iodine. Also disposed within the maction zone is a tungsten filament which is heated to about 1600 C. The UI/sub 4/, upon contacting the hot filament, is decomposed to molten uranium substantially free of oxygen.

  15. Recent improvements in modelling fission gas release and rod deformation on metallic fuel in LMR

    International Nuclear Information System (INIS)

    Hwang, Woan; Lee, Byoung-Oon; Kim, Young Jin

    2000-01-01

    Metallic fuel design is a key feature to assure LMR core safety goals. To date, a large effort has been devoted to the development of the MACSIS code for metallic fuel rod design and the evaluation of operational limits under irradiation conditions. The updated models of fission gas release, fuel core swelling, and rod deformation are incorporated into the correspondence routines in MACSIS MOD1. The MACSIS MOD1 which is a new version of MACSIS, has been partly benchmarked on FGR, fuel swelling and rod deformation comparing with the results of U-Zr and U-Pu-Zr metal fuels irradiated in LMRs. The MACSIS MOD1 predicts, relatively well, the absolute magnitudes and trends of the gas release and rod deformations depending on burn-up, and it gives better agreement with the experimental data than the previous predictions of MACSIS and the results of the empirical model

  16. Residual strain evolution during the deformation of single fiber metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Hanan, J.C.; Uestuendag, E.; Clausen, B. [Dept. of Materials Science, California Inst. of Tech., Pasadena, CA (United States); Sivasambu, M.; Beyerlein, I.J. [Theoretical Div., Los Alamos National Lab., Los Alamos, NM (United States); Brown, D.W.; Bourke, M.A.M. [Materials Science and Technology Div., Los Alamos National Lab., Los Alamos, NM (United States)

    2002-07-01

    Successful application of metal matrix composites often requires strength and lifetime predictions that account for the deformation of each phase. Yet, the deformation of individual phases in composites usually differs significantly from their respective monolithic behaviors. An approach is presented that quantifies the deformation parameters of each phase using neutron diffraction measurements before, during, and after failure under tensile loading in model composites consisting of a single alumina fiber embedded in an aluminum matrix. The evolution of residual strains after loading was examined including the effects of fiber failure. (orig.)

  17. Atomic-scale simulations of the mechanical deformation of nanocrystalline metals

    DEFF Research Database (Denmark)

    Schiøtz, Jakob; Vegge, Tejs; Di Tolla, Francesco

    1999-01-01

    that the main deformation mode is sliding in the grain boundaries through a large number of uncorrelated events, where a few atoms (or a few tens of atoms) slide with respect to each other. Little dislocation activity is seen in the grain interiors. The localization of the deformation to the grain boundaries......Nanocrystalline metals, i.e., metals in which the grain size is in the nanometer range, have a range of technologically interesting properties including increased hardness and yield strength. We present atomic-scale simulations of the plastic behavior of nanocrystalline copper. The simulations show...

  18. Numerical modelling of stresses and deformations in casting processes

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri

    1997-01-01

    Keywords: Stresses and deformations, casting, governing equations, thermal strain, control volume method......Keywords: Stresses and deformations, casting, governing equations, thermal strain, control volume method...

  19. Electron microscopy and plastic deformation of HCP metals and alloys

    International Nuclear Information System (INIS)

    Poirier, J.-P.; Le Hazif, Roger

    1976-01-01

    The recent literature on the slip systems of the h.c.p. metals is reviewed and the contribution of transmission electron microscopy assessed. It is now clear that the stress-strain curves and the dislocation configurations in the slip plane are very similar, whether the principal slip system is basal or prismatic. The important problem of the relative ease of slip systems is linked to the ease of splitting of dislocations in the slip planes and to the electronic band structure of the metal [fr

  20. Compression deformation behaviors of sheet metals at various clearances and side forces

    OpenAIRE

    Zhan Mei; Wang Xianxian; Cao Jian; Yang He

    2015-01-01

    Modeling sheet metal forming operations requires understanding of plastic behaviors of sheet metals along non-proportional strain paths. The plastic behavior under reversed uniaxial loading is of particular interest because of its simplicity of interpretation and its application to material elements drawn over a die radius and underwent repeated bending. However, the attainable strain is limited by failures, such as buckling and in-plane deformation, dependent on clearances and side forces. I...

  1. Inspection and Reconstruction of Metal-Roof Deformation under Wind Pressure Based on Bend Sensors

    OpenAIRE

    Yang, Liman; Cui, Langfu; Li, Yunhua; An, Chao

    2017-01-01

    Metal roof sheathings are widely employed in large-span buildings because of their light weight, high strength and corrosion resistance. However, their severe working environment may lead to deformation, leakage and wind-lift, etc. Thus, predicting these damages in advance and taking maintenance measures accordingly has become important to avoid economic losses and personal injuries. Conventionally, the health monitoring of metal roofs mainly relies on manual inspection, which unavoidably com...

  2. Boundary-integral equation formulation for time-dependent inelastic deformation in metals

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V; Mukherjee, S

    1977-01-01

    The mathematical structure of various constitutive relations proposed in recent years for representing time-dependent inelastic deformation behavior of metals at elevated temperatues has certain features which permit a simple formulation of the three-dimensional inelasticity problem in terms of real time rates. A direct formulation of the boundary-integral equation method in terms of rates is discussed for the analysis of time-dependent inelastic deformation of arbitrarily shaped three-dimensional metallic bodies subjected to arbitrary mechanical and thermal loading histories and obeying constitutive relations of the kind mentioned above. The formulation is based on the assumption of infinitesimal deformations. Several illustrative examples involving creep of thick-walled spheres, long thick-walled cylinders, and rotating discs are discussed. The implementation of the method appears to be far easier than analogous BIE formulations that have been suggested for elastoplastic problems.

  3. Use of state variables in the description of irradiation creep and deformation of metals

    International Nuclear Information System (INIS)

    Hart, E.W.; Li, C.Y.

    1976-01-01

    The understanding of the effects of irradiation on metal creep and deformation are not yet satisfactory, owing in part to the limitations on experimentation in radiation environment. Because of such limitations, theoretical considerations must play a strong role. Virtually all of the theoretical considerations currently employed are based on micro-mechanical models for the deformation behavior. The recent theoretical and experimental development of a plastic equation of state for metal deformation has led to the identification of some of the principal micro-mechanisms in phenomenological terms. The role of the individual mechanisms can be related to the state variables of the description, and those variables are directly accessible measurable quantities. This paper explores how irradiation might affect this description. It is shown that the radiation flux and the radiation fluence are expected to affect different components of the equation of state. The resultant description makes considerable use of the information developed in radiation-free environment. 5 fig

  4. Atomistic simulation study of the shear-band deformation mechanism in Mg-Cu metallic glasses

    DEFF Research Database (Denmark)

    Bailey, Nicholas; Schiøtz, Jakob; Jacobsen, Karsten Wedel

    2006-01-01

    We have simulated plastic deformation of a model Mg-Cu metallic glass in order to study shear banding. In uniaxial tension, we find a necking instability occurs rather than shear banding. We can force the latter to occur by deforming in plane strain, forbidding the change of length in one...... of the transverse directions. Furthermore, in most of the simulations a notch is used to initiate shear bands, which lie at a 45 degrees angle to the tensile loading direction. The shear bands are characterized by the Falk and Langer local measure of plastic deformation D-min(2), averaged here over volumes...... observe a slight decrease in density, up to 1%, within the shear band, which is consistent with notions of increased free volume or disorder within a plastically deforming amorphous material....

  5. Tailoring dislocation structures and mechanical properties of nanostructured metals produced by plastic deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2009-01-01

    The presence of a dislocation structure associated with low-angle dislocation boundaries and interior dislocations is a common and characteristic feature in nanostructured metals produced by plastic deformation, and plays an important role in determining both the strength and ductility...

  6. The role of deformation microstructure in recovery and recrystallization of heavily strained metals

    DEFF Research Database (Denmark)

    Hansen, Niels

    2012-01-01

    Metals deformed to high and ultrahigh strains are characterized by a nanoscale microstructure, a large fraction of high angle boundaries and a high dislocation density. Another characteristic of such a microstructure is a large stored energy that combines elastic energy due to dislocations and bo...

  7. Multi-Axial Deformation Setup for Microscopic Testing of Sheet Metal to Fracture

    NARCIS (Netherlands)

    Tasan, C.C.; Hoefnagels, J.P.M.; Dekkers, E.C.A.; Geers, M.G.D.

    2012-01-01

    While the industrial interest in sheet metal with improved specific-properties led to the design of new alloys with complex microstructures, predicting their safe forming limits and understanding their microstructural deformation mechanisms remain as significant challenges largely due to the

  8. Creep deformation behavior of weld metal and heat affected zone on 316FR steel thick plate welded joint

    International Nuclear Information System (INIS)

    Hongo, Hiromichi; Yamazaki, Masayoshi; Watanabe, Takashi; Kinugawa, Junichi; Tanabe, Tatsuhiko; Monma, Yoshio; Nakazawa, Takanori

    1999-01-01

    Using hot-rolled 316FR stainless plate (50 mm thick) and 16Cr-8Ni-2Mo filler wire, a narrow-gap welded joint was prepared by GTAW (gas tungsten arc welding) process. In addition to conventional round bar specimens of base metals and weld metal, full-thickness joint specimens were prepared for creep test. Creep tests were conducted at 550degC in order to examine creep deformation and rupture behavior in the weld metal of the welded joint. Creep strain distribution on the surface of the joint specimen was measured by moire interferometry. In the welded joint, creep strength of the weld metal zone apart from the surface was larger than that in the vicinity of the surface due to repeating heat cycles during welding. Creep strain and creep rate within the HAZ adjacent to the weld metal zone were smaller than those within the base metal zone. Creep rate of the weld metal zone in the welded joint was smaller than that of the weld metal specimen due to the restraint of the hardened HAZ adjacent to the zone. The full-thickness welded joint specimens showed longer lives than weld metal specimens, though the lives of the latter was shorter than those of the base metal (undermatching). In the full-thickness welded joint specimen, crack started from the last pass layer of the weld metal zone and fracture occurred at the zone. From the results mentioned above, in order to evaluate the creep properties of the welded joint correctly, it is necessary to conduct the creep test using the full-thickness welded joint specimen which includes the weakest zones of the weld metal, the front and back sides of the plate. (author)

  9. A mechanical deformation model of metallic fuel pin under steady state conditions

    International Nuclear Information System (INIS)

    Lee, D. W.; Lee, B. W.; Kim, Y. I.; Han, D. H.

    2004-01-01

    As a mechanical deformation model of the MACSIS code predicts the cladding deformation due to the simple thin shell theory, it is impossible to predict the FCMI(Fuel-Cladding Mechanical Interaction). Therefore, a mechanical deformation model used the generalized plane strain is developed. The DEFORM is a mechanical deformation routine which is used to analyze the stresses and strains in the fuel and cladding of a metallic fuel pin of LMRs. The accuracy of the program is demonstrated by comparison of the DEFORM predictions with the result of another code calculations or experimental results in literature. The stress/strain distributions of elastic part under free thermal expansion condition are completely matched with the results of ANSYS code. The swelling and creep solutions are reasonably well agreed with the simulations of ALFUS and LIFE-M codes, respectively. The predicted cladding strains are under estimated than experimental data at the range of high burnup. Therefore, it is recommended that the fine tuning of the DEFORM based on various range of experimental data

  10. Assessment of oil sand process water toxicity in wetlands of northern Alberta using Chironomid mentum deformities

    Energy Technology Data Exchange (ETDEWEB)

    Whelly, M. P.; Ciborowski, J. J. H. [Windsor, Univ., Windsor, ON (Canada)

    1998-07-01

    The effects of oil sands process water (OSPW) on aquatic invertebrates in wetlands near Fort McMurray, Alberta, are assessed. Principal components analysis and cluster analysis of environmental characteristics of 15 wetlands were used to identify three pairs of environmentally similar wetlands that differed mainly in exposure to or absence of OSPW. Large larvae of Chironomidae were collected and examined for mentum deformities (missing or extra teeth) for use as a biomarker. Invertebrate taxa richness and abundance was only moderately lower at OSPW -affected sites than at corresponding reference sites. The incidence of teeth deformities in midges (Chironomidae spp.) from OSPW-affected and corresponding reference wetlands was found to be moderate, and homogeneous among sites and between paired reference and OSPW-affected wetlands. This finding led to the conclusion that the suspected trace metals and PAHs may not be bioavailable in these highly humic wetlands.

  11. Assessment of oil sand process water toxicity in wetlands of northern Alberta using Chironomid mentum deformities

    Energy Technology Data Exchange (ETDEWEB)

    Whelly, M. P.; Ciborowski, J. J. H. [Windsor, Univ., Windsor, ON (Canada)

    1998-12-31

    The effects of oil sands process water (OSPW) on aquatic invertebrates in wetlands near Fort McMurray, Alberta, are assessed. Principal components analysis and cluster analysis of environmental characteristics of 15 wetlands were used to identify three pairs of environmentally similar wetlands that differed mainly in exposure to or absence of OSPW. Large larvae of Chironomidae were collected and examined for mentum deformities (missing or extra teeth) for use as a biomarker. Invertebrate taxa richness and abundance was only moderately lower at OSPW -affected sites than at corresponding reference sites. The incidence of teeth deformities in midges (Chironomidae spp.) from OSPW-affected and corresponding reference wetlands was found to be moderate, and homogeneous among sites and between paired reference and OSPW-affected wetlands. This finding led to the conclusion that the suspected trace metals and PAHs may not be bioavailable in these highly humic wetlands.

  12. Assessment of oil sand process water toxicity in wetlands of northern Alberta using Chironomid mentum deformities

    International Nuclear Information System (INIS)

    Whelly, M. P.; Ciborowski, J. J. H.

    1998-01-01

    The effects of oil sands process water (OSPW) on aquatic invertebrates in wetlands near Fort McMurray, Alberta, are assessed. Principal components analysis and cluster analysis of environmental characteristics of 15 wetlands were used to identify three pairs of environmentally similar wetlands that differed mainly in exposure to or absence of OSPW. Large larvae of Chironomidae were collected and examined for mentum deformities (missing or extra teeth) for use as a biomarker. Invertebrate taxa richness and abundance was only moderately lower at OSPW -affected sites than at corresponding reference sites. The incidence of teeth deformities in midges (Chironomidae spp.) from OSPW-affected and corresponding reference wetlands was found to be moderate, and homogeneous among sites and between paired reference and OSPW-affected wetlands. This finding led to the conclusion that the suspected trace metals and PAHs may not be bioavailable in these highly humic wetlands

  13. Mechanism for microstructural evolution induced by high temperature deformation in Zr-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Cheng, Sirui; Wang, Chunju; Ma, Mingzhen; Shan, Debin; Guo, Bin

    2016-01-01

    In the Zr_4_1_._2Ti_1_3_._8Cu_1_2_._5Ni_1_0Be_2_2_._5 (Vit1) alloy undergoing high temperature deformation, its thermal properties and microstructure are quite different from those in the annealing alloy. In order to research the coupled effect of temperature and plastic strain on microstructural evolution of Zr-based amorphous, uniaxial compression test of Vit1 alloy with good amorphous nature has been performed, and then the structural state and thermal properties of Vit1 alloy after thermal deformation and isothermal annealing in the supercooled liquid region were investigated. It is revealed that the deformed specimens possess higher characteristic temperature and lower enthalpy change of microstructural relaxation. In addition, the smaller inter-atomic distance and higher order degree of atomic arrangement can be observed in those deformed Vit1 alloy. That can be deduced that thermal deformation is in favor of the microstructural evolution from a metastable amorphous state to stable crystallization state, because plastic strain promotes the annihilation of free volume and provide excess driving force of atomic diffusion. However, upon increasing the ambient temperature, the influence of plastic deformation on microstructure gradually decreased owing to the decreasing proportion of the plastic deformation-induced annihilation of free volume during the whole thermal deformation process. - Highlights: • The deformed specimens possess closer microstructure and higher characteristic temperatures. • The order degree of microstructures in deformed specimens is higher than that in annealed specimens. • Thermal deformation accelerates the microstructural evolution of Zr-based BMGs. • The influence of thermal deformation on microstructure decreases with the temperature increasing.

  14. Mechanism for microstructural evolution induced by high temperature deformation in Zr-based bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Sirui [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Chunju [Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin 150080 (China); School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Mingzhen [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Shan, Debin, E-mail: shandebin@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin 150080 (China); School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Guo, Bin [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2016-08-15

    In the Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} (Vit1) alloy undergoing high temperature deformation, its thermal properties and microstructure are quite different from those in the annealing alloy. In order to research the coupled effect of temperature and plastic strain on microstructural evolution of Zr-based amorphous, uniaxial compression test of Vit1 alloy with good amorphous nature has been performed, and then the structural state and thermal properties of Vit1 alloy after thermal deformation and isothermal annealing in the supercooled liquid region were investigated. It is revealed that the deformed specimens possess higher characteristic temperature and lower enthalpy change of microstructural relaxation. In addition, the smaller inter-atomic distance and higher order degree of atomic arrangement can be observed in those deformed Vit1 alloy. That can be deduced that thermal deformation is in favor of the microstructural evolution from a metastable amorphous state to stable crystallization state, because plastic strain promotes the annihilation of free volume and provide excess driving force of atomic diffusion. However, upon increasing the ambient temperature, the influence of plastic deformation on microstructure gradually decreased owing to the decreasing proportion of the plastic deformation-induced annihilation of free volume during the whole thermal deformation process. - Highlights: • The deformed specimens possess closer microstructure and higher characteristic temperatures. • The order degree of microstructures in deformed specimens is higher than that in annealed specimens. • Thermal deformation accelerates the microstructural evolution of Zr-based BMGs. • The influence of thermal deformation on microstructure decreases with the temperature increasing.

  15. Process Modeling and Validation for Metal Big Area Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, Srdjan [ORNL; Nycz, Andrzej [ORNL; Noakes, Mark W. [ORNL; Chin, Charlie [Dassault Systemes; Oancea, Victor [Dassault Systemes

    2017-05-01

    Metal Big Area Additive Manufacturing (mBAAM) is a new additive manufacturing (AM) technology based on the metal arc welding. A continuously fed metal wire is melted by an electric arc that forms between the wire and the substrate, and deposited in the form of a bead of molten metal along the predetermined path. Objects are manufactured one layer at a time starting from the base plate. The final properties of the manufactured object are dependent on its geometry and the metal deposition path, in addition to depending on the basic welding process parameters. Computational modeling can be used to accelerate the development of the mBAAM technology as well as a design and optimization tool for the actual manufacturing process. We have developed a finite element method simulation framework for mBAAM using the new features of software ABAQUS. The computational simulation of material deposition with heat transfer is performed first, followed by the structural analysis based on the temperature history for predicting the final deformation and stress state. In this formulation, we assume that two physics phenomena are coupled in only one direction, i.e. the temperatures are driving the deformation and internal stresses, but their feedback on the temperatures is negligible. The experiment instrumentation (measurement types, sensor types, sensor locations, sensor placements, measurement intervals) and the measurements are presented. The temperatures and distortions from the simulations show good correlation with experimental measurements. Ongoing modeling work is also briefly discussed.

  16. Low temperature irradiation effects on plastic deformation in BCC metals

    International Nuclear Information System (INIS)

    Aono, Yasuhisa

    1984-01-01

    Low temperature electron beam experiment was carried out on high purity iron and molybdenum single crystals, and its effect on the plastic deformation was examined. As the characteristics of the irradiated iron below 77 K, remarkable softening occurred in all orientations. This phenomenon is based on the interaction of self interstitial atoms and screw dislocations, and the other features such as the absorption of interstitial atoms into screw dislocations and the slip on maximum shearing stress planes were shown. On the other hand, the aggregate of interstitial atoms formed by annealing showed the different plastic characteristics from those of interstitial atoms, and gave the results corresponding to respective stages of the electric resistance recovery curves. Regarding molybdenum, the transfer of its self interstitial atoms is near 40 K, therefore at 77 K, cluster is formed, and it largely affects abnormal slip, which is one of the features of the plasticity of molybdenum. The peculiar dependence of the yield stress on the crystalline orientation was shown. The property of the interaction of the aggregate of interstitial atoms formed and grown by the annealing from 77 K to 500 K with dislocations corresponded to the information of defects obtained by the X-ray research of Maeta, and the similarity to the aggregate of iron was observed. (Kako, I.)

  17. PLASTICITY OF SELECTED METALLIC MATERIALS IN DYNAMIC DEFORMATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Jacek PAWLICKI

    2014-06-01

    Full Text Available Characteristics of a modernized flywheel machine has been presented in the paper. The laboratory stand enables to perform dynamic tensile tests and impact bending with a linear velocity of the enforcing element in the range of 5÷40 m/s. A new data acquisition system, based on the tensometric sensors, allows for significant qualitative improvement of registered signals. Some preliminary dynamic forming tests were performed for the selected group of metallic materials. Subsequent microstructural examinations and identification of the fracture type enabled to describe a correlation between strain rate, strain and microstructure.

  18. Process for improving metal production in steelmaking processes

    Science.gov (United States)

    Pal, Uday B.; Gazula, Gopala K. M.; Hasham, Ali

    1996-01-01

    A process and apparatus for improving metal production in ironmaking and steelmaking processes is disclosed. The use of an inert metallic conductor in the slag containing crucible and the addition of a transition metal oxide to the slag are the disclosed process improvements.

  19. Fabrication of subwavelength metallic structures by using a metal direct imprinting process

    International Nuclear Information System (INIS)

    Hsieh, C W; Hsiung, H Y; Lu, Y T; Sung, C K; Wang, W H

    2007-01-01

    This work employs a metal direct imprinting process, which possesses the characteristics of simplicity, low-cost and high resolution, for the fabrication of subwavelength structures on a metallic thin film. Herein, the mould featuring periodic line structures is manufactured by using E-beam lithography and followed by a dry etching process; meanwhile, the thin film is fabricated by sputtering Al on a silicon substrate. AFM section analyses are employed to measure imprinting depths of the subwavelength metallic structures and it is found that the uniformity of the imprinting depths is affected by the designed patterns, the material property of thin film and mould deformation. The process temperature and the mould filling that influence the transferred quality are investigated. In addition, TEM is also utilized to examine defects in the subwavelength metallic structures. Finally, good quality subwavelength metallic structures are fabricated under a pressure of 300 MPa for 60 s at room temperature. In this study, we have demonstrated that subwavelength metallic structures with a minimum linewidth of less than 100 nm on the Al thin film are successfully constructed by the metal direct imprinting process

  20. Experimental studies on the deformation and rupture of thin metal plates subject to underwater shock wave loading

    Directory of Open Access Journals (Sweden)

    Chen Pengwan

    2015-01-01

    Full Text Available In this paper, the dynamic deformation and rupture of thin metal plates subject to underwater shock wave loading are studied by using high-speed 3D digital image correlation (3D-DIC. An equivalent device consist of a gas gun and a water anvil tube was used to supplying an exponentially decaying pressure in lieu of explosive detonation which acted on the panel specimen. The thin metal plate is clamped on the end of the shock tube by a flange. The deformation and rupture process of the metal plates subject to underwater shock waves are recorded by two high-speed cameras. The shape, displacement fields and strain fields of the metal plates under dynamic loading are obtained by using VIC-3D digital image correlation software. The strain gauges also were used to monitor the structural response on the selected position for comparison. The DIC data and the strain gauges results show a high level of correlation, and 3D-DIC is proven to be an effective method to measure 3D full-field dynamic response of structures under underwater impact loading. The effects of pre-notches on the failure modes of thin circular plate were also discussed.

  1. Mechanical deformation of atomic-scale metallic contacts: Structure and mechanisms

    DEFF Research Database (Denmark)

    Sørensen, Mads Reinholdt; Brandbyge, Mads; Jacobsen, Karsten Wedel

    1998-01-01

    We have simulated the mechanical deformation of atomic-scale metallic contacts under tensile strain using molecular dynamics and effective medium theory potentials. The evolution of the structure of the contacts and the underlying deformation mechanisms are described along with the calculated......, but vacancies can be permanently present. The transition states and energies for slip mechanisms have been determined using the nudged elastic band method, and we find a size-dependent crossover from a dislocation-mediated slip to a homogeneous slip when the contact diameter becomes less than a few nm. We show...

  2. Modelling plastic deformation of metals over a wide range of strain rates using irreversible thermodynamics

    International Nuclear Information System (INIS)

    Huang Mingxin; Rivera-Diaz-del-Castillo, Pedro E J; Zwaag, Sybrand van der; Bouaziz, Olivier

    2009-01-01

    Based on the theory of irreversible thermodynamics, the present work proposes a dislocation-based model to describe the plastic deformation of FCC metals over wide ranges of strain rates. The stress-strain behaviour and the evolution of the average dislocation density are derived. It is found that there is a transitional strain rate (∼ 10 4 s -1 ) over which the phonon drag effects appear, resulting in a significant increase in the flow stress and the average dislocation density. The model is applied to pure Cu deformed at room temperature and at strain rates ranging from 10 -5 to 10 6 s -1 showing good agreement with experimental results.

  3. Discontinuities of Plastic Deformation in Metallic Glasses with Different Glass Forming Ability

    Science.gov (United States)

    Hurakova, Maria; Csach, Kornel; Miskuf, Jozef; Jurikova, Alena; Demcak, Stefan; Ocelik, Vaclav; Hosson, Jeff Th. M. De

    The metallic ribbons Fe40Ni40B20, Cu47Ti35Zr11Ni6Si1 and Zr65Cu17.5Ni10Al7.5 with different microhardness and glass forming ability were studied at different loading rates from 0.05 to 100 mN/s. We describe in details the differences in elemental discontinuities on the loading curves for the studied alloys. It was found that the discontinuities began at a certain local deformation independently on the macroscopic mechanical properties of a ribbon. More developed discontinuities at higher deformations are created for the materials with lower microhardness and so lower strength.

  4. The deformation of Gum Metal through in situ compression of nanopillars

    International Nuclear Information System (INIS)

    Withey, E.A.; Minor, A.M.; Chrzan, D.C.; Morris, J.W.; Kuramoto, S.

    2010-01-01

    The name 'Gum Metal' has been given to a set of β-Ti alloys that achieve exceptional elastic elongation and, with appropriate preparation, appear to deform by a dislocation-free mechanism triggered by elastic instability at the limit of strength. We have studied the compressive deformation of these materials with in situ nanocompression in a quantitative stage in a transmission electron microscope. The samples studied are cylindrical nanopillars 80-250 nm in diameter. The deformation pattern is monitored in real time using bright-field microscopy, dark-field microscopy or electron diffraction. Interesting results include the following: (i) nanopillars approach, and in several examples appear to reach, ideal strength; (ii) in contrast to conventional crystalline materials, there is no substantial 'size effect' in pillar strength; (iii) the deformation mode is fine-scale with respect to the sample dimension, even in pillars of 100 nm size; (iv) shear bands ('giant faults') do form in some tests, but only after yield and plastic deformation; and (v) a martensitic transformation to the base-centered orthorhombic α'' phase is sometimes observed, but is an incidental feature of the deformation rather than a significant cause of it.

  5. A work-hardening rule for finite elastic-plastic deformation of metals at elevated temperatures

    International Nuclear Information System (INIS)

    Lee, L.H.N.; Horng, J.T.

    1975-01-01

    The paper is concerned with an extension of Prager-Ziegler's kinematic work-hardening rule for infinitesimal elastic-plastic deformation to a work-hardening rule for finite elastic-plastic deformation of a polycrystalline metal. It is shown that the finite work-hardening rule, which accounts for the Bauschinger and temperature effects within certain pressure and temperature ranges, satisfies certain invariant, continuity and thermodynamic requirements. A description of the kinematics of an elastic-plastic body is employed with reference to three separate configurations: initial, current and an intermediate configuration. The intermediate configuration is a conceptual, local configuration obtained by removing the stress and temperature changes in the neighborhood of an element. A rigid body rotation of the intermediate configuration is allowed. Piola-Kirchhoff stresses and Green deformation tensors referred to the initial and intermediate configurations are employed as stress and strain measures. The plastic deformation has been associated with the motion and production of dislocations. It has been observed that the motion of mobile dislocations usually occur in the narrow slip bands in each grain, leaving the basic lattice structure practically intact, so that the macroscopic elastic properties of the material are essentially independent of plastic deformation. Employing this fact and the thermodynamic laws, a simplified elastic stress-strain relationship of the plastically deformed material, which agrees with the results of Naghdi and Trapp, is obtained

  6. Property optimization of nanostructured ARB-processed Al by post-process deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu; Kamikawa, Naoya; Hansen, Niels

    2008-01-01

    The effect of post-process deformation on the mechanical properties of nanostructured aluminum (99.2% purity) has been investigated by cold rolling of samples which have been processed by accumulative roll bonding (ARB) to a strain of epsilon(vM) = 4.8. Samples have been cold rolled to 10, 15...... material. In contrary, cold rolling to large strain (50%) results in significant strengthening. This leads to the suggestion of a transition strain within the range of 25-35% reduction by rolling. The microstructural evolution during post-process deformation has been followed by transmission electron...

  7. Phase engineering of monolayer transition-metal dichalcogenide through coupled electron doping and lattice deformation

    International Nuclear Information System (INIS)

    Ouyang, Bin; Lan, Guoqiang; Song, Jun; Guo, Yinsheng; Mi, Zetian

    2015-01-01

    First-principles calculations were performed to investigate the phase stability and transition within four monolayer transition-metal dichalcogenide (TMD) systems, i.e., MX 2 (M = Mo or W and X = S or Se) under coupled electron doping and lattice deformation. With the lattice distortion and electron doping density treated as state variables, the energy surfaces of different phases were computed, and the diagrams of energetically preferred phases were constructed. These diagrams assess the competition between different phases and predict conditions of phase transitions for the TMDs considered. The interplay between lattice deformation and electron doping was identified as originating from the deformation induced band shifting and band bending. Based on our findings, a potential design strategy combining an efficient electrolytic gating and a lattice straining to achieve controllable phase engineering in TMD monolayers was demonstrated

  8. Development of Metal Plate with Internal Structure Utilizing the Metal Injection Molding (MIM Process

    Directory of Open Access Journals (Sweden)

    Kwangho Shin

    2013-12-01

    Full Text Available In this study, we focus on making a double-sided metal plate with an internal structure, such as honeycomb. The stainless steel powder was used in the metal injection molding (MIM process. The preliminary studies were carried out for the measurement of the viscosity of the stainless steel feedstock and for the prediction of the filling behavior through Computer Aided Engineering (CAE simulation. PE (high density polyethylene (HDPE and low density polyethylene (LDPE and polypropylene (PP resins were used to make the sacrificed insert with a honeycomb structure using a plastic injection molding process. Additionally, these sacrificed insert parts were inserted in the metal injection mold, and the metal injection molding process was carried out to build a green part with rectangular shape. Subsequently, debinding and sintering processes were adopted to remove the sacrificed polymer insert. The insert had a suitable rigidity that was able to endure the filling pressure. The core shift analysis was conducted to predict the deformation of the insert part. The 17-4PH feedstock with a low melting temperature was applied. The glass transition temperature of the sacrificed polymer insert would be of a high grade, and this insert should be maintained during the MIM process. Through these processes, a square metal plate with a honeycomb structure was made.

  9. A constitutive model of nanocrystalline metals based on competing grain boundary and grain interior deformation mechanisms

    KAUST Repository

    Gurses, Ercan

    2011-12-01

    In this work, a viscoplastic constitutive model for nanocrystalline metals is presented. The model is based on competing grain boundary and grain interior deformation mechanisms. In particular, inelastic deformations caused by grain boundary diffusion, grain boundary sliding and dislocation activities are considered. Effects of pressure on the grain boundary diffusion and sliding mechanisms are taken into account. Furthermore, the influence of grain size distribution on macroscopic response is studied. The model is shown to capture the fundamental mechanical characteristics of nanocrystalline metals. These include grain size dependence of the strength, i.e., both the traditional and the inverse Hall-Petch effects, the tension-compression asymmetry and the enhanced rate sensitivity. © 2011 Elsevier B.V. All rights reserved.

  10. Free volume model: High-temperature deformation of a Zr-based bulk metallic glass

    International Nuclear Information System (INIS)

    Bletry, M.; Guyot, P.; Blandin, J.J.; Soubeyroux, J.L.

    2006-01-01

    The homogeneous deformation of a zirconium-based bulk metallic glass is investigated in the glass transition region. Compression tests at different temperatures and strain rates have been conducted. The mechanical behavior is analyzed in the framework of the free volume model, taking into account the dependence of the flow defect concentration on deformation. The activation volume is evaluated and allows one to gather the viscosity data (for the different strain rates and temperatures) on a unique master curve. It is also shown that, due to the relation between flow defect concentration and free volume, it is not possible to deduce the equilibrium flow defect concentration directly from mechanical measurements. However, if this parameter is arbitrarily chosen, mechanical measurements give access to the other parameters of the model, these parameters for the alloy under investigation being of the same order of magnitude as those for other metallic glasses

  11. Evaluation of Package Stress during Temperature Cycling using Metal Deformation Measurement and FEM Simulation

    International Nuclear Information System (INIS)

    Hoeglauer, J.; Bohm, C.; Otremba, R.; Maerz, J.; Nelle, P.; Stecher, M.; Alpern, P.

    2006-01-01

    Plastic encapsulated devices that are exposed to Temperature Cycling (TC) tests undergo an excessive mechanical stress due to different Coefficients of Thermal Expansion (CTE) of the various materials used in the system. Especially in the corners of the die, passivation cracks and shifted metal lines can be observed, which demonstrates an increasing mechanical stress from chip center to the corners of the die. This effect has been known for a long time. This paper presents a simple measurement technique to quantify the mechanical shear stress at the chip-Mold Compound (MC) interface by measuring the deformation of a periodical metal structure. Based on this deformation measurement, we evaluated the stress distribution within the package, and the influence of different parameters such as number of cycles and chip size. Furthermore, these experimental results were compared with FEM simulation, and showed good agreement but could not account in all cases for the total amount of observed shift

  12. Plastic deformation and failure mechanisms in nano-scale notched metallic glass specimens under tensile loading

    Science.gov (United States)

    Dutta, Tanmay; Chauniyal, Ashish; Singh, I.; Narasimhan, R.; Thamburaja, P.; Ramamurty, U.

    2018-02-01

    In this work, numerical simulations using molecular dynamics and non-local plasticity based finite element analysis are carried out on tensile loading of nano-scale double edge notched metallic glass specimens. The effect of acuteness of notches as well as the metallic glass chemical composition or internal material length scale on the plastic deformation response of the specimens are studied. Both MD and FE simulations, in spite of the fundamental differences in their nature, indicate near-identical deformation features. Results show two distinct transitions in the notch tip deformation behavior as the acuity is increased, first from single shear band dominant plastic flow localization to ligament necking, and then to double shear banding in notches that are very sharp. Specimens with moderately blunt notches and composition showing wider shear bands or higher material length scale characterizing the interaction stress associated with flow defects display profuse plastic deformation and failure by ligament necking. These results are rationalized from the role of the interaction stress and development of the notch root plastic zones.

  13. Process for making rare earth metal chlorides

    International Nuclear Information System (INIS)

    Kruesi, P.R.

    1981-01-01

    An uncombined metal or a metal compound such as a sulfide, oxide, carbonate or sulfate is converted in a liquid salt bath to the corresponding metal chloride by reacting it with chlorine gas or a chlorine donor. The process applies to metals of groups 1b, 2a, 2b, 3a, 3b, 4a, 5a and 8 of the periodic table and to the rare earth metals. The chlorine donor may be ferric or sulfur chloride. The liquid fused salt bath is made up of chlorides of alkali metals, alkaline earth metals, ammonia, zinc and ferric iron. Because the formed metal chlorides are soluble in the liquid fused salt bath, they can be recovered by various conventional means

  14. Review of friction modeling in metal forming processes

    DEFF Research Database (Denmark)

    Nielsen, C.V.; Bay, N.

    2018-01-01

    Abstract In metal forming processes, friction between tool and workpiece is an important parameter influencing the material flow, surface quality and tool life. Theoretical models of friction in metal forming are based on analysis of the real contact area in tool-workpiece interfaces. Several...... research groups have studied and modeled the asperity flattening of workpiece material against tool surface in dry contact or in contact interfaces with only thin layers of lubrication with the aim to improve understanding of friction in metal forming. This paper aims at giving a review of the most...... conditions, normal pressure, sliding length and speed, temperature changes, friction on the flattened plateaus and deformation of the underlying material. The review illustrates the development in the understanding of asperity flattening and the methods of analysis....

  15. A Deformation Model of TRU Metal Dispersion Fuel Rod for HYPER

    International Nuclear Information System (INIS)

    Lee, Byoung Oon; Hwang, Woan; Park, Won S.

    2002-01-01

    Deformation analysis in fuel rod design is essential to assure adequate fuel performance and integrity under irradiation conditions. An in-reactor performance computer code for a dispersion fuel rod is being developed in the conceptual design stage of blanket fuel for HYPER. In this paper, a mechanistic deformation model was developed and the model was installed into the DIMAC program. The model was based on the elasto-plasticity theory and power-law creep theory. The preliminary deformation calculation results for (TRU-Zr)-Zr dispersion fuel predicted by DIMAC were compared with those of silicide dispersion fuel predicted by DIFAIR. It appeared that the deformation levels for (TRU-Zr)-Zr dispersion fuel were relatively higher than those of silicide fuel. Some experimental tests including in-pile and out-pile experiments are needed for verifying the predictive capability of the DIMAC code. An in-reactor performance analysis computer code for blanket fuel is being developed at the conceptual design stage of blanket fuel for HYPER. In this paper, a mechanistic deformation model was developed and the model was installed into the DIMAC program. The model was based on the elasto-plasticity theory and power-law creep theory. The preliminary deformation calculation results for (TRUZr)- Zr dispersion fuel predicted by DIMAC were compared with those of silicide dispersion fuel predicted by DIFAIR. It appears that the deformation by swelling within fuel meat is very large for both fuels, and the major deformation mechanism at cladding is creep. The swelling strain is almost constant within the fuel meat, and is assumed to be zero in the cladding made of HT9. It is estimated that the deformation levels for (TRU-Zr)-Zr dispersion fuel were relatively higher than those of silicide fuel, and the dispersion fuel performance may be limited by swelling. But the predicted volume change of the (TRU-Zr)-Zr dispersion fuel models is about 6.1% at 30 at.% burnup. The value of cladding

  16. Formation of nanocrystalline surface layers in various metallic materials by near surface severe plastic deformation

    Directory of Open Access Journals (Sweden)

    Masahide Sato, Nobuhiro Tsuji, Yoritoshi Minamino and Yuichiro Koizumi

    2004-01-01

    Full Text Available The surface of the various kinds of metallic materials sheets were severely deformed by wire-brushing at ambient temperature to achieve nanocrystalline surface layer. The surface layers of the metallic materials developed by the near surface severe plastic deformation (NS-SPD were characterized by means of TEM. Nearly equiaxed nanocrystals with grain sizes ranging from 30 to 200 nm were observed in the near surface regions of all the severely scratched metallic materials, which are Ti-added ultra-low carbon interstitial free steel, austenitic stainless steel (SUS304, 99.99 wt.%Al, commercial purity aluminum (A1050 and A1100, Al–Mg alloy (A5083, Al-4 wt.%Cu alloy, OFHC-Cu (C1020, Cu–Zn alloy (C2600 and Pb-1.5%Sn alloy. In case of the 1050-H24 aluminum, the depth of the surface nanocrystalline layer was about 15 μm. It was clarified that wire-brushing is an effective way of NS-SPD, and surface nanocrystallization can be easily achieved in most of metallic materials.

  17. Process for cleaning radioactively contaminated metal surfaces

    International Nuclear Information System (INIS)

    Mihram, R.G.; Snyder, G.A.

    1975-01-01

    A process is described for removing radioactive scale from a ferrous metal surface, including the steps of initially preconditioning the surface by contacting it with an oxidizing solution (such as an aqueous solution of an alkali metal permanganate or hydrogen peroxide), then, after removal or decomposition of the oxidizing solution, the metallic surface is contacted with a cleaning solution which is a mixture of a mineral acid and a complexing agent (such as sulfuric acid and oxalic acid), and which preferably contains a corrosion inhibitor. A final step in the process is the treatment of the spent cleaning solution containing radioactive waste materials in solution by adding a reagent selected from the group consisting of calcium hydroxide or potassium permanganate and an alkali metal hydroxide to thereby form easily recovered metallic compounds containing substantially all of the dissolved metals and radioactivity. (auth)

  18. Research of state of metal welded joint by deformation and corrosion surface projection parameters

    Directory of Open Access Journals (Sweden)

    Demchenko Maria Vyacheslavovna

    2017-10-01

    Full Text Available At industrial enterprises in building structures and equipment one can see corrosion damage, as well as damage accumulated during operation period. The areas of stress concentration are welded joints as their structure is heterogeneous. From the point of view of the scale hierarchy, the welded joint represents the welded and base metal zones at the meso-macrolevel, the weld zone, the thermal zone, the base metal at the micro-mesolevel, the grain constituents at the nano-microlevel. Borders are the stress concentrators at different scale levels, thus they becomes the most dangerous places of metal structure. Modeling by the molecular dynamics method at the atomic level has shown nanocracks initiation in triple junctions of grain boundaries and on the ledges of the grain boundaries. Due to active development of nanotechnology, it became possible to evaluate the state of the weld metal at the nanoscale, where irreversible changes take place from the very beginning. Existing methods of nondestructive testing can detect damage only at the meso- and macrolevel. Modern equipment makes it possible to use other methods of control and approaches. For example, according to GOST R55046-2012 and R57223-2016, the analysis of the parameters of the surface projection deformation performed by confocal laser scanning microscopy should be taken into account when the evaluation of state of metal pipelines is carried out. However, there is a problem to monitore it due to various factors affecting the surface during operation. The paper proposes an additional method to estimate the state of weld metal at any stage of deformation that uses 3D analysis of the parameters of the «artificial» corrosion relief of surface. During the operation period changes in the stress-strain state and structure of the metal take place, as the result the character and depth of etching of the grains of the structural components and their boundaries change too. Evaluation of the

  19. Deformation microstructures

    DEFF Research Database (Denmark)

    Hansen, N.; Huang, X.; Hughes, D.A.

    2004-01-01

    Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales...... of the order of 10 nm, produced by deformation under large sliding loads. Limits to the evolution of microstructural parameters during monotonic loading have been investigated based on a characterization by transmission electron microscopy. Such limits have been observed at an equivalent strain of about 10...

  20. Creep Deformation and Fracture Processes in OF and OFP Copper

    International Nuclear Information System (INIS)

    Bowyer, William H.

    2004-10-01

    The literature on creep processes in many materials, including copper, has been thoroughly reviewed and complemented by Ashby and co-workers. They have provided physical models which describe the deformation and fracture processes with good qualitative and quantitative agreement with experimental data for many cases. A description of the deformation and fracture models is provided and the relevant equations are included in the appendices. Published data from the canister development programme has been compared with the predictions from the models. The purpose was to improve our understanding of (1) a reported benefit to creep performance which arises from additions of 50 ppm phosphorus to oxygen free (OF) copper, and (2) an observed transition from brittle to ductile failure in OF copper. The models adequately describe the general variations in the observed creep behaviour of the experimental materials. Steady state creep rates for OF copper are observed to be up to one order of magnitude higher than the model predicts for pure copper across a wide range of temperatures and stresses in the power law and power law breakdown regimes. For OF copper with 50ppm of phosphorus added (OFP copper), observed steady state creep rates in the power law breakdown regime are up to one order of magnitude lower than the model predicts for pure copper. Creep lives in the experimental OFP material are also higher than creep lives for OF material under similar conditions. The lower creep deformation rates and the longer creep lives of OFP material are attributed the known effects of phosphorus on recovery in copper. The model predicts that the same mechanism will improve creep lives under repository conditions. It is suggested that the factor of improvement under repository conditions will be less than the factor which is observed in the power law breakdown regime. Predicted creep lives, based on measured steady state creep rates and stress exponents ('n' values) are in good agreement

  1. Synthetically chemical-electrical mechanism for controlling large scale reversible deformation of liquid metal objects

    Science.gov (United States)

    Zhang, Jie; Sheng, Lei; Liu, Jing

    2014-11-01

    Reversible deformation of a machine holds enormous promise across many scientific areas ranging from mechanical engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible deformation through controlling the working materials via the synthetically chemical-electrical mechanism (SCHEME). Such activity incorporates an object of liquid metal gallium whose surface area could spread up to five times of its original size and vice versa under low energy consumption. Particularly, the alterable surface tension based on combination of chemical dissolution and electrochemical oxidation is ascribed to the reversible shape transformation, which works much more flexible than many former deformation principles through converting electrical energy into mechanical movement. A series of very unusual phenomena regarding the reversible configurational shifts are disclosed with dominant factors clarified. This study opens a generalized way to combine the liquid metal serving as shape-variable element with the SCHEME to compose functional soft machines, which implies huge potential for developing future smart robots to fulfill various complicated tasks.

  2. Modelling of the plastic deformation and primary creep of metals coupled with DC in terms of the synthetic theory of irrecoverable deformation

    Science.gov (United States)

    Rusinko, Andrew; Varga, Peter

    2018-04-01

    The paper deals with modelling of the plastic and creep deformation of metals coupled with current. The passage of DC manifests itself in the increase in creep deformation and leads to primary creep time shortening. With plastic deformation, a short electric impulse results in the step-wise decrease of stress (stress-drop) on the stress-strain diagram. To catch these phenomena, we utilize the synthetic theory of recoverable deformation. The constitutive equation of this theory is supplemented by a term taking into account the intensity of DC. Further, we introduce DC intensity into the function governing transient creep. As a result, we predict the parameters of transient creep and calculate the stress-drop as a function of current intensity. The model results show good agreement with experimental data.

  3. Process for electrolytically preparing uranium metal

    Science.gov (United States)

    Haas, Paul A.

    1989-01-01

    A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

  4. Numerical Simulation of Multiphase Magnetohydrodynamic Flow and Deformation of Electrolyte-Metal Interface in Aluminum Electrolysis Cells

    Science.gov (United States)

    Hua, Jinsong; Rudshaug, Magne; Droste, Christian; Jorgensen, Robert; Giskeodegard, Nils-Haavard

    2018-06-01

    A computational fluid dynamics based multiphase magnetohydrodynamic (MHD) flow model for simulating the melt flow and bath-metal interface deformation in realistic aluminum reduction cells is presented. The model accounts for the complex physics of the MHD problem in aluminum reduction cells by coupling two immiscible fluids, electromagnetic field, Lorentz force, flow turbulence, and complex cell geometry with large length scale. Especially, the deformation of bath-metal interface is tracked directly in the simulation, and the condition of constant anode-cathode distance (ACD) is maintained by moving anode bottom dynamically with the deforming bath-metal interface. The metal pad deformation and melt flow predicted by the current model are compared to the predictions using a simplified model where the bath-metal interface is assumed flat. The effects of the induced electric current due to fluid flow and the magnetic field due to the interior cell current on the metal pad deformation and melt flow are investigated. The presented model extends the conventional simplified box model by including detailed cell geometry such as the ledge profile and all channels (side, central, and cross-channels). The simulations show the model sensitivity to different side ledge profiles and the cross-channel width by comparing the predicted melt flow and metal pad heaving. In addition, the model dependencies upon the reduction cell operation conditions such as ACD, current distribution on cathode surface and open/closed channel top, are discussed.

  5. Influence of a cold deformation process by drawing on the electrical properties of copper wires

    Directory of Open Access Journals (Sweden)

    Rafael da Silva Bernardo

    Full Text Available Abstract This article presents a study of the drawing, deformation, hardening and heat treatment of copper wire, in order to investigate the influence of combinations of operating variables (annealing factor, oil emulsion temperature and machine speed during the drawing process on the electrical conductivity of copper wires. The results showed that when the metal is deformed, the value of electrical conductivity suffers a decrease due to the hardening phenomenon. Because of this, it is necessary to heat treat the material. So, it was observed that the annealing factor, which is associated with the thermal treatment temperature, showed a high degree of correlation with the electrical conductivity. This fact is explained by the annealing factor which is responsible for the intensity of the heat treatment. The speed at which the drawing occurs also showed a direct correlation with electric conductivity because the higher the value, the greater the heat treatment temperature and consequently, the greater the electrical conductivity of the material. On the other hand, it had not been possible to establish a conclusion about the correlation between the electrical conductivity and oil emulsion temperature during the drawing process.

  6. Kinetics of transformation of deformation processed gold-matrix composite

    Science.gov (United States)

    Wongpreedee, Kageeporn

    Gold matrix Ḏeformation-processed M&barbelow;etal M&barbelow;etal C&barbelow;omposites (DMMC) have been developed that have better strength and conductivity than conventional gold alloys. However, DMMC possess metastable two-phase microstructures, and their strength and conductivity decrease after prolonged exposure to elevated temperatures. The kinetics of the transformation from the metastable two-phase microstructure to the equilibrium single-phase solid solution is of interest. This document describes a study of the elevated temperature stability of Au DMMC's and the relationship between microstructure and resistivity of three compositions: Au-7 vol %Ag, Au-14 vol %Ag, and Au-vol 7%Pt. DMMC samples were prepared by a powder metallurgy technique and mechanical processes. The smallest final diameter of these wires was 120 mum. Avrami and Arrhenius relations were used to evaluate the kinetic transformation. The extensive deformation used to produce these composites reshaped the initially equi-axed powder particles into a nanofilamentary composite. Electrical resistivity measurements were used to determine the degree of transformation from the initial metastable nano-filamentary composite to the equilibrium solid solution condition. These measurements indicated that this transformation in Au-14 at%Ag, Au-7 at %Ag Au and Au-7 at %Pt DMMC wires proceeded with activation energies of 141, 156, and 167 kJ/mol, respectively. It is thought that these empirically determined activation energies differ from those determined in single crystal, planar interface Au-Ag and Au-Pt diffusion couples due to chemical potential, surface curvature, and strain effects. The DMMC systems reach the equilibrium solid solution condition faster than single crystal, planar interface systems for two reasons: (1) far more defects (dislocations, grain boundaries, vacancies from non-conservative dislocation motion, etc.) are present in the Au-Ag and Au-Pt DMMC composites, and (2) the small

  7. Deformation behavior, corrosion resistance, and cytotoxicity of Ni-free Zr-based bulk metallic glasses.

    Science.gov (United States)

    Liu, L; Qiu, C L; Chen, Q; Chan, K C; Zhang, S M

    2008-07-01

    Two Ni-free bulk metallic glasses (BMGs) of Zr(60)Nb(5)Cu(22.5)Pd(5)Al(7.5) and Zr(60)Nb(5)Cu(20)Fe(5)Al(10) were successfully prepared by arc-melting and copper mold casting. The thermal stability and crystallization were studied using differential scanning calorimetry. It demonstrates that the two BMGs exhibit very good glass forming ability with a wide supercooled liquid region. A multi-step process of crystallization with a preferential formation of quasicrystals occurred in both BMGs under continuous heating. The deformation behavior of the two BMGs was investigated using quasi-static compression testing. It reveals that the BMGs exhibit not only superior strength but also an extended plasticity. Corrosion behaviors of the BMGs were investigated in phosphate buffered solution by electrochemical polarization. The result shows that the two BMGs exhibit excellent corrosion resistance characterized by low corrosion current densities and wide passive regions. X-ray photoelectron spectroscopy analysis revealed that the passive film formed after anodic polarization was highly enriched in zirconium, niobium, and aluminum oxides. This is attributed to the excellent corrosion resistance. Additionally, the potential cytotoxicity of the two Ni-free BMGs was evaluated through cell culture for 1 week followed by 3-(4,5-Dimethylthiazol-2-yl-)-2,5-diphenyltetrazolium bromide assay and SEM observation. The results indicate that the two Ni-free BMGs exhibit as good biocompatibility as Ti-6Al-4V alloy, and thus show a promising potential for biomedical applications. (c) 2007 Wiley Periodicals, Inc.

  8. On the fast amorphous phase growth in plastically deformed metallic couples

    International Nuclear Information System (INIS)

    Mazzone, G.; Montone, A.; Antisari, M.V.

    1993-01-01

    The authors have modeled the kinetics of glass formation at the Ni-Zr interface of plastically deformed diffusion couples on the basis of a free volume description of glass structure, taking also into account the structural effects of an externally applied stress. Owing to the complexity of the problem several approximations have necessarily been introduced, the main ones being probably the simplified description of the structure and of the tensile behavior of a metallic glass and the use of the Spaepen Eqs. in an alloy system. However, these approximations do not seem to significantly affect the main trends displayed by the computations, that is the high value of D, the exponential dependence of x on var-epsilon and the low value of the activation energy, in agreement with experimental trends (3) not easily attributable to other causes. Of course, the numerical values of the free parameters have to be considered an approximate evaluation of the corresponding physical quantities. However, despite of the above limitations, their values are physically plausible. In conclusion the authors have shown that the present model describes in a quantitative way the kinetics of solid state amorphization at the interface of a diffusion couple plastically deformed during the reaction. The effective diffusion coefficient increases by several orders of magnitude as a consequence of a small increase in vf driven by the stress required to deform the growing film. The effects of strain rate and deformation time balance each other almost exactly so that the film thickness increases exponentially with the total deformation of the diffusion couple

  9. Catalytic extraction processing of contaminated scrap metal

    International Nuclear Information System (INIS)

    Griffin, T.P.; Johnston, J.E.; Payea, B.M.; Zeitoon, B.M.

    1995-01-01

    Molten Metal Technology was awarded a contract to demonstrate the applicability of the Catalytic Extraction Process, a proprietary process that could be applied to US DOE's inventory of low level mixed waste. This paper is a description of that technology, and included within this document are discussions of: (1) Program objectives, (2) Overall technology review, (3) Organic feed conversion to synthetic gas, (4) Metal, halogen, and transuranic recovery, (5) Demonstrations, (6) Design of the prototype facility, and (7) Results

  10. Catalytic extraction processing of contaminated scrap metal

    International Nuclear Information System (INIS)

    Griffin, T.P.; Johnston, J.E.

    1994-01-01

    The contract was conceived to establish the commercial capability of Catalytic Extraction Processing (CEP) to treat contaminated scrap metal in the DOE inventory. In so doing, Molten Metal Technology, Inc. (MMT), pursued the following objectives: demonstration of the recycling of ferrous and non-ferrous metals--to establish that radioactively contaminated scrap metal can be converted to high-grade, ferrous and non-ferrous alloys which can be reused by DOE or reintroduced into commerce; immobilize radionuclides--that CEP will concentrate the radionuclides in a dense vitreous phase, minimize secondary waste generation and stabilize and reduce waste volume; destroy hazardous organics--that CEP will convert hazardous organics to valuable industrial gases, which can be used as feed gases for chemical synthesis or as an energy source; recovery volatile heavy metals--that CEP's off-gas treatment system will capture volatile heavy metals, such as mercury and lead; and establish that CEP is economical for processing contaminated scrap metal in the DOE inventory--that CEP is a more cost-effective and, complete treatment and recycling technology than competing technologies for processing contaminated scrap. The process and its performance are described

  11. Interactions of reactor helium and simulating gas mixtures with high-temperature metals with particular regard to simultaneous deformation

    International Nuclear Information System (INIS)

    Berchtold, L.

    1983-01-01

    For the observation of multicomponent alloys (Inconel 617 and 713LC, chroman (Ni20Cr), vacromium (Ni20Cr+Si), TZM) in multicomponent HTR atmospheres (HHT search gas), interaction between gases and metals was studied, both in theoretical descriptions and experimentally. From the experimental viewpoint, gradual simplification employs, on the one hand, tests effected in undiluted atmospheres with exclusively oxidizing or carburizing properties; on the other hand, more simple alloys and pure metals are applied specifically in the helium atmosphere. For an evaluation of the materials, it is maintained that in a strongly oxidizing (H 2 O-rich) atmosphere, e.g. in HHT search gas, materials with sufficient chrome content (e.g. 20% Cr in Ni alloys such as IN 617) offer favourable conditions for an almost complete interruption of carburizing reactions. In that case, the maintenance of the shielding effect of coating during rapid deformation and a tendency to planar delamination during deformation, which becomes stronger as the layer thickness increases, appear to be critical. Concentrations of oxide-forming agents stronger than chromium offer disadvantages rather than advantages. Owing to its tendency to flake off as the covering oxide SiO 2 or as part of a cover layer, silicon may more than destroy the light advantage of a slowed down process of carbon diffusion. The cast alloy IN 713LC shows a deep-reaching carburation in HHT search gas, both with and without deformation. No deep-reaching corrosive damage is noticeable on the molybdenum alloy TZM. (orig./MM) [de

  12. Disciplinary maintenance of process of overcoming of deformations of professional-pedagogical authentication of future teachers

    Directory of Open Access Journals (Sweden)

    Zhanna P. Pavlova

    2011-04-01

    Full Text Available In the article examined disciplinary maintenance of process of overcoming of deformations of professional-pedagogical authentication of future teachers and maintenance of process of overcoming of deformations, which is built on module principle on the basis of disciplinary connections.

  13. Optimization and control of metal forming processes

    NARCIS (Netherlands)

    Havinga, Gosse Tjipke

    2016-01-01

    Inevitable variations in process and material properties limit the accuracy of metal forming processes. Robust optimization methods or control systems can be used to improve the production accuracy. Robust optimization methods are used to design production processes with low sensitivity to the

  14. Metals and Alloys Material Stabilization Process Plan

    Energy Technology Data Exchange (ETDEWEB)

    RISENMAY, H.R.; BURK, R.A.

    2000-05-18

    This Plan outlines the process for brushing metal and alloys in accordance with the path forward discussed in the Integrated Project Management Plan for the Plutonium Finishing Plant Stabilization and Deactivation Project, HNF-3617, and requirements set forth in the Project Management Plan for Materials Stabilization, HNF-3605. This plan provides the basis for selection of the location to process, the processes involved, equipment to be used, and the characterization of the contents of the can. The scope of the process is from retrieval of metals and alloys from storage to transfer back to storage in a repackaged configuration.

  15. Metals and Alloys Material Stabilization Process Plan

    International Nuclear Information System (INIS)

    RISENMAY, H.R.; BURK, R.A.

    2000-01-01

    This Plan outlines the process for brushing metal and alloys in accordance with the path forward discussed in the Integrated Project Management Plan for the Plutonium Finishing Plant Stabilization and Deactivation Project, HNF-3617, and requirements set forth in the Project Management Plan for Materials Stabilization, HNF-3605. This plan provides the basis for selection of the location to process, the processes involved, equipment to be used, and the characterization of the contents of the can. The scope of the process is from retrieval of metals and alloys from storage to transfer back to storage in a repackaged configuration

  16. On the role of initial void geometry in plastic deformation of metallic thin films: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yanqing [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0340 (United States); Xu, Shuozhi, E-mail: shuozhixu@gatech.edu [GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405 (United States)

    2016-12-15

    Void growth is usually considered one of the most critical phases leading to dynamic fracture of ductile materials. Investigating the detailed process of void growth at the nanoscale aids in understanding the damage mechanism of metals. While most atomistic simulations by far assume circular or spherical voids for simplicity, recent studies highlight the significance of the initial void ellipticity in mechanical response of voided metals. In this work, we perform large scale molecular dynamics simulations with millions of atoms to investigate the void growth in plastic deformation of thin films in face-centered cubic Cu. It is found that the initial ellipticity and the initial orientation angle of the void have substantial impacts on the dislocation nucleation, the void evolution, and the stress-strain response. In particular, the initial dislocation emission sites and the sequence of slip plane activation vary with the initial void geometry. For the void size evolution, three regimes are identified: (I) the porosity increases relatively slowly in the absence of dislocations, (II) the porosity grows much more rapidly after dislocations start to glide on different slip planes, and (III) the rate of porosity variation becomes much more slowly when dislocations are saturated in the model, and the void surface becomes irregular, non-smooth. In terms of the stress-strain response, the effects of the initial orientation angle are more pronounced when the initial void ellipticity is large; the influence of the initial void ellipticity is different for different initial orientation angles. The effects of the temperature, the strain rate, the loading direction, and the initial porosity in the void growth are also explored. Our results reveal the underlying mechanisms of initial void geometry-dependent plastic deformation of metallic thin films and shed light on informing more accurate theoretical models.

  17. On the role of initial void geometry in plastic deformation of metallic thin films: A molecular dynamics study

    International Nuclear Information System (INIS)

    Su, Yanqing; Xu, Shuozhi

    2016-01-01

    Void growth is usually considered one of the most critical phases leading to dynamic fracture of ductile materials. Investigating the detailed process of void growth at the nanoscale aids in understanding the damage mechanism of metals. While most atomistic simulations by far assume circular or spherical voids for simplicity, recent studies highlight the significance of the initial void ellipticity in mechanical response of voided metals. In this work, we perform large scale molecular dynamics simulations with millions of atoms to investigate the void growth in plastic deformation of thin films in face-centered cubic Cu. It is found that the initial ellipticity and the initial orientation angle of the void have substantial impacts on the dislocation nucleation, the void evolution, and the stress-strain response. In particular, the initial dislocation emission sites and the sequence of slip plane activation vary with the initial void geometry. For the void size evolution, three regimes are identified: (I) the porosity increases relatively slowly in the absence of dislocations, (II) the porosity grows much more rapidly after dislocations start to glide on different slip planes, and (III) the rate of porosity variation becomes much more slowly when dislocations are saturated in the model, and the void surface becomes irregular, non-smooth. In terms of the stress-strain response, the effects of the initial orientation angle are more pronounced when the initial void ellipticity is large; the influence of the initial void ellipticity is different for different initial orientation angles. The effects of the temperature, the strain rate, the loading direction, and the initial porosity in the void growth are also explored. Our results reveal the underlying mechanisms of initial void geometry-dependent plastic deformation of metallic thin films and shed light on informing more accurate theoretical models.

  18. Modelling the deformation process of flexible stamps for nanoimprint lithography

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard

    of PTFE against steel on micro-scale is presented. The 2D axisymmetric model is verified through an experiment, in which a PTFE sheet with a predefined square grid pattern on the surface is deformed by a steel sphere mounted in a uniaxial tensile test machine. Good agreement between simulations...

  19. Microscopic study of gum-metal alloys: A role of trace oxygen for dislocation-free deformation

    International Nuclear Information System (INIS)

    Nagasako, Naoyuki; Asahi, Ryoji; Isheim, Dieter; Seidman, David N.; Kuramoto, Shigeru; Furuta, Tadahiko

    2016-01-01

    A class of Ti–Nb–Ta–Zr–O alloys called gum metal are known to display high strength, low Young's modulus and high elastic deformability up to 2.5%, simultaneously, and considered to deform by a dislocation-free deformation mechanism. A trace of oxygen (∼1%) in gum metal is indispensable to realize such significant properties; however, the detailed mechanism and the role of the oxygen has not been understood. To investigate an effect of trace oxygen included in gum metal, first-principles calculations for gum-metal approximants including zirconium and oxygen are performed. Calculated results clearly indicate that oxygen site with less neighboring Nb atom is energetically favorable, and that Zr–O bonding has an important role to stabilize the bcc structure of gum metal. The three-dimensional atom-probe tomography (3-D APT) measurements for gum metal were also performed to identify compositional inhomogeneity attributed to the trace elements. From the 3-D APT measurements, Zr ions bonding with oxygen ions are observed, which indicates existence of Zr–O nano-clusters in gum metal. Consequently, it is found that (a) coexistence of Zr atom and oxygen atom improves elastical stability of gum metal, (b) inhomogeneous distribution of the compositions induced by the trace elements causes anisotropical change of shear moduli, and (c) Zr–O nano-clusters existing in gum metal are expected to be obstacles to suppress movemen of dislocations.

  20. Direct observation of radial distribution change during tensile deformation of metallic glass by high energy X-ray diffraction method

    Energy Technology Data Exchange (ETDEWEB)

    Nasu, Toshio, E-mail: nasu@kekexafs.kj.yamagata-u.ac.j [Faculty of Education, Arts and Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata, Yamagata, 990-8560 (Japan); Sasaki, Motokatsu [Faculty of Education, Arts and Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata, Yamagata, 990-8560 (Japan); Usuki, Takeshi; Sekine, Mai [Faculty of Science, Yamagata University, Yamagata 990-8560 (Japan); Takigawa, Yorinobu; Higashi, Kenji [Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Kohara, Shinji [Japan Synchrotron Radiation Research Institute, Harima Science Garden City, Sayo town, Hyogo 679-5198 (Japan); Sakurai, Masaki; Wei Zhang; Inoue, Akihisa [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2009-08-26

    The purpose of this research is to investigate the micro-mechanism of deformation behavior of metallic glasses. We report the results of direct observations of short-range and medium-range structural change during tensile deformation of metallic glasses by high energy X-ray diffraction method. Cu{sub 50}Zr{sub 50} and Ni{sub 30}Zr{sub 70} metallic glass samples in the ribbon shape (1.5 mm width and 25 mum) were made by using rapid quenching method. Tensile deformation added to the sample was made by using special equipment adopted for measuring the high energy X-ray diffraction. The peaks in pair distribution function g(r) for Cu{sub 50}Zr{sub 50} and N{sub 30}iZr{sub 70} metallic glasses move zigzag into front and into rear during tensile deformation. These results of direct observation on atomic distribution change for Cu{sub 50}Zr{sub 50} and Ni{sub 30}Zr{sub 70} metallic glass ribbons during tensile deformation suggest that the micro-relaxations occur.

  1. Scaling laws for dislocation microstructures in monotonic and cyclic deformation of fcc metals

    International Nuclear Information System (INIS)

    Kubin, L.P.; Sauzay, M.

    2011-01-01

    This work reviews and critically discusses the current understanding of two scaling laws, which are ubiquitous in the modeling of monotonic plastic deformation in face-centered cubic metals. A compilation of the available data allows extending the domain of application of these scaling laws to cyclic deformation. The strengthening relation tells that the flow stress is proportional to the square root of the average dislocation density, whereas the similitude relation assumes that the flow stress is inversely proportional to the characteristic wavelength of dislocation patterns. The strengthening relation arises from short-range reactions of non-coplanar segments and applies all through the first three stages of the monotonic stress vs. strain curves. The value of the proportionality coefficient is calculated and simulated in good agreement with the bulk of experimental measurements published since the beginning of the 1960's. The physical origin of what is called similitude is not understood and the related coefficient is not predictable. Its value is determined from a review of the experimental literature. The generalization of these scaling laws to cyclic deformation is carried out on the base of a large collection of experimental results on single and polycrystals of various materials and on different microstructures. Surprisingly, for persistent slip bands (PSBs), both the strengthening and similitude coefficients appear to be more than two times smaller than the corresponding monotonic values, whereas their ratio is the same as in monotonic deformation. The similitude relation is also checked in cell structures and in labyrinth structures. Under low cyclic stresses, the strengthening coefficient is found even lower than in PSBs. A tentative explanation is proposed for the differences observed between cyclic and monotonic deformation. Finally, the influence of cross-slip on the temperature dependence of the saturation stress of PSBs is discussed in some detail

  2. Influence of thermally activated processes on the deformation behavior during low temperature ECAP

    Science.gov (United States)

    Fritsch, S.; Scholze, M.; F-X Wagner, M.

    2016-03-01

    High strength aluminum alloys are generally hard to deform. Therefore, the application of conventional severe plastic deformation methods to generate ultrafine-grained microstructures and to further increase strength is considerably limited. In this study, we consider low temperature deformation in a custom-built, cooled equal channel angular pressing (ECAP) tool (internal angle 90°) as an alternative approach to severely plastically deform a 7075 aluminum alloy. To document the maximum improvement of mechanical properties, these alloys are initially deformed from a solid solution heat-treated condition. We characterize the mechanical behavior and the microstructure of the coarse grained initial material at different low temperatures, and we analyze how a tendency for the PLC effect and the strain-hardening rate affect the formability during subsequent severe plastic deformation at low temperatures. We then discuss how the deformation temperature and velocity influence the occurrence of PLC effects and the homogeneity of the deformed ECAP billets. Besides the mechanical properties and these microstructural changes, we discuss technologically relevant processing parameters (such as pressing forces) and practical limitations, as well as changes in fracture behavior of the low temperature deformed materials as a function of deformation temperature.

  3. Mass fractionation processes of transition metal isotopes

    Science.gov (United States)

    Zhu, X. K.; Guo, Y.; Williams, R. J. P.; O'Nions, R. K.; Matthews, A.; Belshaw, N. S.; Canters, G. W.; de Waal, E. C.; Weser, U.; Burgess, B. K.; Salvato, B.

    2002-06-01

    Recent advances in mass spectrometry make it possible to utilise isotope variations of transition metals to address some important issues in solar system and biological sciences. Realisation of the potential offered by these new isotope systems however requires an adequate understanding of the factors controlling their isotope fractionation. Here we show the results of a broadly based study on copper and iron isotope fractionation during various inorganic and biological processes. These results demonstrate that: (1) naturally occurring inorganic processes can fractionate Fe isotope to a detectable level even at temperature ˜1000°C, which challenges the previous view that Fe isotope variations in natural system are unique biosignatures; (2) multiple-step equilibrium processes at low temperatures may cause large mass fractionation of transition metal isotopes even when the fractionation per single step is small; (3) oxidation-reduction is an importation controlling factor of isotope fractionation of transition metal elements with multiple valences, which opens a wide range of applications of these new isotope systems, ranging from metal-silicate fractionation in the solar system to uptake pathways of these elements in biological systems; (4) organisms incorporate lighter isotopes of transition metals preferentially, and transition metal isotope fractionation occurs stepwise along their pathways within biological systems during their uptake.

  4. Impact of silver metallization and electron irradiation on the mechanical deformation of polyimide films

    Science.gov (United States)

    Muradov, A. D.; Mukashev, K. M.; Yar-Mukhamedova, G. Sh.; Korobova, N. E.

    2017-11-01

    The impact of silver metallization and electron irradiation on the physical and mechanical properties of polyimide films has been studied. The metal that impregnated the structure of the polyimide substrate was 1-5 μm. The surface coatings contained 80-97% of the relative silver mirror in the visible and infrared regions. Irradiation was performed at the ELU-6 linear accelerator with an average beam electron energy of 2 MeV, an integral current of up to 1000 μA, a pulse repetition rate of 200 Hz, and a pulse duration of 5 μs. The absorbed dose in the samples was 10, 20, 30, and 40 MGy. The samples were deformed at room temperature under uniaxial tension on an Instron 5982 universal testing system. The structural changes in the composite materials that result from the impact of the physical factors were studied using an X-ray diffractometer DRON-2M in air at 293 K using Cu K α radiation (λαCu = 1.5418 Å). A substantial growth of mechanical characteristics resulting from the film metallization, as compared to the pure film, was observed. The growth of the ultimate strength by Δσ = 105 MPa and the plasticity by Δɛ = 75% is connected with the characteristics of the change of structure of the metallized films and the chemical etching conditions. The electron irradiation of the metallized polyimide film worsens its elastic and strength characteristics due to the formation of new phases in the form of silver oxide in the coating. The concentration of these phases increased with increasing dose, which was also the result of the violation of the ordered material structure, namely, the rupture of polyimide macromolecule bonds and the formation of new phases of silver in the coating. A mathematical model was obtained that predicts the elastic properties of silver metallized polyimide films. This model agrees with the experimental data.

  5. Processing facility for metal waste

    International Nuclear Information System (INIS)

    Awano, Toshihiko; Kataoka, Yoshitsune.

    1998-01-01

    Each steps of temporarily storing materials to be reduced in the volume to a storage vessel, transferring them to a weighing machine by a conveyor, weighing them by a weighing machine, drying them by a drying means, packing them in containing canisters, sealing and welding them, carrying out the containing canisters after sealing are conducted independently respectively or optionally simultaneously in parallel. Accordingly, isolation from peripheral circumstances is ensured, and improvement of working efficiency, ensuring of safety and simplification of structure of processing devices can be attained. (T.M.)

  6. Pyrometallurgical process of actinide metal

    International Nuclear Information System (INIS)

    Yoo, Jae Hyung; Kang, Young Ho; Woo, Mun Sik; Hwang, Sung Chan

    1999-06-01

    Major subject on pyrometallurgical partitioning technology is to separate transmutation elements (TRU) from rare earth elements(RE). Distribution coefficients of TRU and RE between molten chloride and liquid cadmium were measured for reductive extraction, and TRU were separated from RE in simplified molten chloride system by electrorefining. And separation efficiency between TRU and RE were estimated by using thermodynamics data. The results indicate that uranium, neptunium and plutonium are easy to separate from RE but some amount of RE accompany americium, and that processes have to be optimized to attain good separation efficiency of TRU. (author)

  7. Atomization process for metal powder

    International Nuclear Information System (INIS)

    Lagutkin, Stanislav; Achelis, Lydia; Sheikhaliev, Sheikhali; Uhlenwinkel, Volker; Srivastava, Vikas

    2004-01-01

    A new atomization process has been developed, which combines pressure and gas atomization. The melt leaves the pressure nozzle as a hollow thin film cone. After the pre-filming step, the melt is atomized by a gas stream delivered by a ring nozzle. The objectives of this investigation are to achieve a narrow size distribution and low specific gas consumption compared to conventional gas atomization techniques. Both lead to a higher efficiency and low costs. Tin and some alloys have been atomized successfully with this technique. The mass median diameters from different experiments are between 20 and 100 μm. Sieving analysis of the tin powder shows close particle size distributions

  8. Forming processes and mechanics of sheet metal forming

    NARCIS (Netherlands)

    Burchitz, I.A.

    2004-01-01

    The report is dealing with the numerical analysis of forming processes. Forming processes is the large group of manufacturing processes used to obtain various product shapes by means of plastic deformations. The report is organized as follows. An overview of the deformation processes and the

  9. EBSD Analysis of Deformed and Partially Recrystallized Microstructures in ECAE-Processed Copper

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bowen, Jacob R.; Godfrey, A.

    2012-01-01

    The deformed microstructure and recrystallization behavior of copper samples processed using equal channel angular extrusion (ECAE) have been investigated. The heavily deformed microstructure was found to be non-uniform through the sample thickness and to vary in a manner consistent with the non...

  10. An analysis of heat field of metal sheet during elastic-plastic deformation

    International Nuclear Information System (INIS)

    Li, S.X.; Huang, Y.; Shih, C.H.

    1985-08-01

    This paper describes the application of the finite element analysis to calculate the temperature distribution generated during the process of elastic-plastic deformation. A better agreement is found between the results of heat field computed by use of the finite element analysis and that measured by use of an infrared camera. The results indicate that the method of finite element analysis used for heat field evaluation is reliable. (author)

  11. Effect of rolling deformation on the microstructure of bulk Cu60Zr20Ti20 metallic glass and its crystallization

    DEFF Research Database (Denmark)

    Cao, Q.P.; Li, J.F.; Zhou, Y.H.

    2006-01-01

    Bulk Cu60Zr20Ti20 metallic glass has been rolled at room temperature (RT) and cryogenic temperature (CIF) up to 97% in thickness reduction, and the dependences of microstructure on the strain and temperature have been investigated. It is revealed that as the deformation proceeds below a critical...... thickness reduction, which is 87% at RT and 89% at CT, only the shear band density and the free-volume content increase, whereas the thermal stability of the deformed glass remains unchanged. Deformation above the critical thickness reduction results in phase separation plus nanocrystallization at RT...

  12. Process for etching zirconium metallic objects

    International Nuclear Information System (INIS)

    Panson, A.J.

    1988-01-01

    In a process for etching of zirconium metallic articles formed from zirconium or a zirconium alloy, wherein the zirconium metallic article is contacted with an aqueous hydrofluoric acid-nitric acid etching bath having an initial ratio of hydrofluoric acid to nitric acid and an initial concentration of hydrofluoric and nitric acids, the improvement, is described comprising: after etching of zirconium metallic articles in the bath for a period of time such that the etching rate has diminished from an initial rate to a lesser rate, adding hydrofluoric acid and nitric acid to the exhausted bath to adjust the concentration and ratio of hydrofluoric acid to nitric acid therein to a value substantially that of the initial concentration and ratio and thereby regenerate the etching solution without removal of dissolved zirconium therefrom; and etching further zirconium metallic articles in the regenerated etching bath

  13. Cyclic Deformation and Fatigue Behaviors of Alloy 617 Base Metal and Weldments at 900℃ for VHTR Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Jin; Kim, Byung Tak; Dewa, Rando T.; Hwang, Jeong Jun; Kim, Tae Su [Pukyong National Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Eung Seon [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    An analysis of cyclic deformation can contribute to a deeper understanding of the fatigue fracture mechanisms as well as to improvements in the design and application of VHTR system. However, the studies associated with cyclic deformation and low cycle fatigue (LCF) properties of Alloy 617 have focused mainly on the base metal, with little attention given to the weldments. Totemeier studied on high-temperature creep-fatigue of Alloy 617 base metal and weldments. Current research activities at PKNU and KAERI focus on the study of cyclic deformation and LCF behaviors of Alloy 617 base metal (BM) and weldments (WM) specimens were machined from GTAW buttwelded plates at very high-temperature of 900℃. In this work, the cyclic deformation characteristics and fatigue behaviors of Alloy 617 BM and WM are studied and discussed with respect to LCF. In this paper, cyclic deformation and low cycle fatigue behaviors of Alloy 617 base metal and weldments was evaluated using strain-controlled LCF tests at 900℃for 0.6% total strain range. Results of the current experiments can be concluded; The WM specimen has shown a higher cyclic stress response than the BM specimen. The fatigue life of WM specimen was reduced relative to that of BM specimen.

  14. Controlling microstructure and texture in magnesium alloy sheet by shear-based deformation processing

    Science.gov (United States)

    Sagapuram, Dinakar

    Application of lightweight Mg sheet is limited by its low workability, both in production of sheet (typically by multistep hot and cold-rolling) and forming of sheet into components. Large strain extrusion machining (LSEM), a constrained chip formation process, is used to create Mg alloy AZ31B sheet in a single deformation step. The deformation in LSEM is shown to be intense simple shear that is confined to a narrow zone, which results in significant deformation-induced heating up to ~ 200°C and reduces the need for pre-heating to realize continuous sheet forms. This study focuses on the texture and microstructure development in the sheet processed by LSEM. Interestingly, deep, highly twinned steady-state layer develops in the workpiece subsurface due to the compressive field ahead of the shear zone. The shear deformation, in conjunction with this pre-deformed twinned layer, results in tilted-basal textures in the sheet with basal planes tilted well away from the surface. These textures are significantly different from those in rolled sheet, where basal planes are nearly parallel to the surface. By controlling the strain path, the basal plane inclination from the surface could be varied in the range of 32-53°. B-fiber (basal plane parallel to LSEM shear plane), associated with basal slip, is the major texture component in the sheet. An additional minor C2-fiber component appears above 250°C due to the thermal activation of pyramidal slip. Together with these textures, microstructure ranges from severely cold-worked to (dynamically) recrystallized type, with the corresponding grain sizes varying from ultrafine- (~ 200 nm) to fine- (2 mum) grained. Small-scale limiting dome height (LDH) confirmed enhanced formability (~ 50% increase in LDH) of LSEM sheet over the conventional rolled sheet. Premature, twinning-driven shear fractures are observed in the rolled sheet with the basal texture. In contrast, LSEM sheet with a tilted-basal texture favorably oriented for

  15. Processing method of radioactive metal wastes

    International Nuclear Information System (INIS)

    Uetake, Naoto; Urata, Megumu; Sato, Masao.

    1985-01-01

    Purpose: To reduce the volume and increase the density of radioactive metal wastes easily while preventing scattering of radioactivity and process them into suitable form to storage and treatment. Method: Metal wastes mainly composed of zirconium are discharged from nuclear power plants or fuel re-processing plants, and these metals such as zirconium and titanium vigorously react with hydrogen and rapidly diffuse as hydrides. Since the hydrides are extremely brittle and can be pulverized easily, they can be volume-reduced. However, since metal hydrides have no ductility, dehydrogenation is applied for the molding fabrication in view of the subsequent storage and processing. The dehydrogenation is easy like the hydrogenation and fine metal pieces can be molded in a small compression device. For the dehydrogenation, a temperature is slightly increased as compared with that in the hydrogenation, pressure is reduced through the vacuum evacuation system and the removed hydrogen is purified for reuse. The upper limit for the temperature of the hydrogenation is 680 0 C in order to prevent the scttering of radioactivity. (Kamimura, M.)

  16. Laser Processing Technology using Metal Powders

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jeong-Hwan; Moon, Young-Hoon [Pusan National University, Busan (Korea, Republic of)

    2012-03-15

    The purpose of this paper is to review the state of laser processing technology using metal powders. In recent years, a series of research and development efforts have been undertaken worldwide to develop laser processing technologies to fabricate metal-based parts. Layered manufacturing by the laser melting process is gaining ground for use in manufacturing rapid prototypes (RP), tools (RT) and functional end products. Selective laser sintering / melting (SLS/SLM) is one of the most rapidly growing rapid prototyping techniques. This is mainly due to the processes's suitability for almost any materials, including polymers, metals, ceramics and many types of composites. The interaction between the laser beam and the powder material used in the laser melting process is one of the dominant phenomena defining feasibility and quality. In the case of SLS, the powder is not fully melted during laser scanning, therefore the SLS-processed parts are not fully dense and have relatively low strength. To overcome this disadvantage, SLM and laser cladding (LC) processes have been used to enable full melting of the powder. Further studies on the laser processing technology will be continued due to the many potential applications that the technology offers.

  17. Process for production of a metal hydride

    Science.gov (United States)

    Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

    2014-08-12

    A process for production of a metal hydride compound MH.sub.x, wherein x is one or two and M is an alkali metal, Be or Mg. The process comprises combining a compound of formula (R.sup.1O).sub.xM with aluminum, hydrogen and at least one metal selected from among titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula MH.sub.x. R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group. A mole ratio of aluminum to (R.sup.1O).sub.xM is from 0.1:1 to 1:1. The catalyst is present at a level of at least 200 ppm based on weight of aluminum.

  18. Cell response to nanocrystallized metallic substrates obtained through severe plastic deformation.

    Science.gov (United States)

    Bagherifard, Sara; Ghelichi, Ramin; Khademhosseini, Ali; Guagliano, Mario

    2014-06-11

    Cell-substrate interface is known to control the cell response and subsequent cell functions. Among the various biophysical signals, grain structure, which indicates the repeating arrangement of atoms in the material, has also proved to play a role of significant importance in mediating the cell activities. Moreover, refining the grain size through severe plastic deformation is known to provide the processed material with novel mechanical properties. The potential application of such advanced materials as biomedical implants has recently been evaluated by investigating the effect of different substrate grain sizes on a wide variety of cell activities. In this review, recent advances in biomedical applications of severe plastic deformation techniques are highlighted with special attention to the effect of the obtained nano/ultra-fine-grain size on cell-substrate interactions. Various severe plastic deformation techniques used for this purpose are discussed presenting a brief description of the mechanism for each process. The results obtained for each treatment on cell morphology, adhesion, proliferation, and differentiation, as well as the in vivo studies, are discussed. Finally, the advantages and challenges regarding the application of these techniques to produce multifunctional bio-implant materials are addressed.

  19. 3-D Modelling of Electromagnetic, Thermal, Mechanical and Metallurgical Couplings in Metal Forming Processes

    International Nuclear Information System (INIS)

    Chenot, Jean-Loup; Bay, Francois

    2007-01-01

    The different stages of metal forming processes often involve - beyond the mechanical deformations processes - other physical coupled problems, such as heat transfer, electromagnetism or metallurgy. The purpose of this paper is to focus on problems involving electromagnetic couplings. After a brief recall on electromagnetic modeling, we shall then focus on induction heating processes and present some results regarding heat transfer, as well as mechanical couplings. A case showing coupling for metallurgic microstructure evolution will conclude this paper

  20. INVESTIGATION OF THE METAL MELTING PROCESS

    Directory of Open Access Journals (Sweden)

    V. I. Timoshpolskij

    2006-01-01

    Full Text Available The nonlinear mathematical model of calculation of temperature fields in the process of metal melting is formulated and solved using the method of equivalent source taking into account nonlinearity of thermophysical properties of material and variable terms of heat exchange.

  1. Process technology - rare and refractory metals

    International Nuclear Information System (INIS)

    Gupta, C.K.; Bose, D.K.

    1989-01-01

    India has fairly rich resreves of rare and refractory metals. Abundant sources of ilmenite, rutile, zircon and rare earths are found in the placer deposits of the southern and eastern coasts of the country. Columbite-tantalite occur in mica and the mining belts of Bihar and cassiterite deposits are found in Bastar (Madhya Pradesh). Vanadium as a minor associate occurs in bauxites and in the vast deposits of titaniferrous magnetites. Over the years, research and development and pilot plant works in many research organisations in India have built up a sound technological base in the country for process metallurgy of many refractory and rare earth metals starting from their indigenous sources. The present paper provides a comprehensive view of the developments that have taken place till now on the processing of various refractory and rare earth metals with particular reference to the extensive work carried out at the Department of Atomic Energy. The coverage includes mineral benification separation of individual elements, preparation of pure intermediates, techniques of reduction to metal and final purification. The paper also reviews some of the recent developments that have been taken place in these fields and the potential application of these metals in the foreseeable future. (author). 22 refs., 18 fi g., 7 tabs

  2. Acoustic softening in metals during ultrasonic assisted deformation via CP-FEM

    KAUST Repository

    Siddiq, Amir

    2011-01-01

    In this paper, a phenomenological crystal plasticity model is modified to account for acoustic (ultrasonic) softening effects based on the level of ultrasonic intensity supplied to single and polycrystalline metals. The material parameters are identified using the inverse modeling approach by interfacing the crystal plasticity model with an optimization tool. The proposed model is validated and verified by comparing the microstructure evolution with experimental EBSD results reported in the literature. The model is able to capture the ultrasonic softening effect and the results show that as the ultrasonic intensity increases, the plastic deformation also increases. Differences in the stress-strain response are explained based on the slip system orientation tensor (Schmidt factors) which depends upon the crystal orientation. © 2010 Elsevier B.V. All rights reserved.

  3. Constitutive equations for energy balance evaluation in metals under inelastic deformation

    Science.gov (United States)

    Kostina, A.; Plekhov, O.; Venkatraman, B.

    2017-12-01

    The work is devoted to the development of constitutive equations for energy balance evaluation in plastically deformed metals. The evolution of the defect system is described by a previously obtained model based on the Boltzmann-Gibbs statistics. In the framework of this model, a collective behavior of mesodefect ensembles is taken into account by the introduction of an internal variable representing additional structural strain. This parameter enables the partition of plastic work into dissipated heat and stored energy. The proposed model is applied to energy balance calculation in a Ti-1Al-1Mn specimen subjected to cyclic loading. Simulation results have shown that the model is able to describe an upward trend in the stored energy value with the increase in the load ratio.

  4. Transient regimes during high-temperature deformation of a bulk metallic glass: A free volume approach

    International Nuclear Information System (INIS)

    Bletry, M.; Guyot, P.; Brechet, Y.; Blandin, J.J.; Soubeyroux, J.L.

    2007-01-01

    The homogeneous deformation of a zirconium-based bulk metallic glass is investigated in the glass transition range. Compression and stress-relaxation tests have been conducted. The stress-strain curves are modeled in the framework of the free volume theory, including transient phenomena (overshoot and undershoot). This approach allows several physical parameters (activation volume, flow defect creation and relaxation coefficient) to be determined from a mechanical experiment. This model is able to rationalize the dependency of stress overshoot on relaxation time. It is shown that, due to the relationship between flow defect concentration and free volume model, it is impossible to determine the equilibrium flow defect concentration. However, the relative variation of flow defect is always the same, and all the model parameters depend on the equilibrium flow defect concentration. The methodology presented in this paper should, in the future, allow the consistency of the free volume model to be assessed

  5. Local Stress States and Microstructural Damage Response Associated with Deformation Twins in Hexagonal Close Packed Metals

    Directory of Open Access Journals (Sweden)

    Indranil Basu

    2017-12-01

    Full Text Available The current work implements a correlative microscopy method utilizing electron back scatter diffraction, focused ion beam and digital image correlation to accurately determine spatially resolved stress profiles in the vicinity of grain/twin boundaries and tensile deformation twin tips in commercially pure titanium. Measured local stress gradients were in good agreement with local misorientation values. The role of dislocation-boundary interactions on the buildup of local stress gradients is elucidated. Stress gradients across the twin-parent interface were compressive in nature with a maximum stress magnitude at the twin boundary. Stress profiles near certain grain boundaries initially display a local stress minimum, followed by a typically observed “one over square root of distance” variation, as was first postulated by Eshelby, Frank and Nabarro. The observed trends allude to local stress relaxation mechanisms very close to the grain boundaries. Stress states in front of twin tips showed tensile stress gradients, whereas the stress state inside the twin underwent a sign reversal. The findings highlight the important role of deformation twins and their corresponding interaction with grain boundaries on damage nucleation in metals.

  6. Development of mathematical models for automation of strength calculation during plastic deformation processing

    Science.gov (United States)

    Steposhina, S. V.; Fedonin, O. N.

    2018-03-01

    Dependencies that make it possible to automate the force calculation during surface plastic deformation (SPD) processing and, thus, to shorten the time for technological preparation of production have been developed.

  7. Codeformation processing of mechanically-dissimilar metal/intermetallic composites

    Science.gov (United States)

    Marte, Judson Sloan

    A systematic and scientific approach has been applied to the study of codeformation processing. A series of composites having mechanically-dissimilar phases were developed in which the high temperature flow behavior of the reinforcement material could be varied independent of the matrix. This was accomplished through the use of a series of intermetallic matrix composites (IMCs) as discontinuous reinforcements in an otherwise conventional metal matrix composite. The IMCs are produced using an in-situ reaction synthesis technique, called the XD(TM) process. The temperature of the exothermic synthesis reaction, called the adiabatic temperature, has been calculated and shown to increase with increasing volume percentage of TiB2 reinforcement. Further, this temperature has been shown to effect the size and spacing of the TiB2, microstructural features which are often used in discontinuous composite strength models. Study of the high temperature flow behavior of the components of the metal/IMC composite is critical to the development of an understanding of codeformation. A series of compression tests performed at 1000° to 1200°C and strain-rates of 10-3 and 10-4 sec-1. Peak flow stresses were used to evaluate the influence of material properties and process conditions. These data were incorporated into phenomenologically-based constitutive equations that have been used to predict the flow behavior. It has been determined that plastic deformation of the IMCs occurs readily, and is largely TiB2 independent, at temperatures approaching the melting point of the intermetallic matrices. Ti-6Al-4V/IMC powder blends were extruded at high temperatures to achieve commensurately deformed microstructures. The results of codeformation processing were analyzed in terms of the plastic strain of the IMC particulates. IMC particle deformation was shown to increase with increasing IMC particle size, volume percentage of IMC, extrusion temperature, homologous temperature, extrusion

  8. Sensing the gas metal arc welding process

    Science.gov (United States)

    Carlson, N. M.; Johnson, J. A.; Smartt, H. B.; Watkins, A. D.; Larsen, E. D.; Taylor, P. L.; Waddoups, M. A.

    1994-01-01

    Control of gas metal arc welding (GMAW) requires real-time sensing of the process. Three sensing techniques for GMAW are being developed at the Idaho National Engineering Laboratory (INEL). These are (1) noncontacting ultrasonic sensing using a laser/EMAT (electromagnetic acoustic transducer) to detect defects in the solidified weld on a pass-by-pass basis, (2) integrated optical sensing using a CCD camera and a laser stripe to obtain cooling rate and weld bead geometry information, and (3) monitoring fluctuations in digitized welding voltage data to detect the mode of metal droplet transfer and assure that the desired mass input is achieved.

  9. Relaxation processes during amorphous metal alloys heating

    International Nuclear Information System (INIS)

    Malinochka, E.Ya.; Durachenko, A.M.; Borisov, V.T.

    1982-01-01

    Behaviour of Te+15 at.%Ge and Fe+13 at.%P+7 at.%C amorphous metal alloys during heating has been studied using the method of differential scanning calorimetry (DSC) as the most convenient one for determination of the value of heat effects, activation energies, temperature ranges of relaxation processes. Thermal effects corresponding to high-temperature relaxation processes taking place during amorphous metal alloys (AMA) heating are detected. The change of ratio of relaxation peaks values on DSC curves as a result of AMA heat treatment can be explained by the presence of a number of levels of inner energy in amorphous system, separated with potential barriers, the heights of which correspond to certain activation energies of relaxation processes

  10. Generalized vibrating potential model for collective excitations in spherical, deformed and superdeformed systems: (1) atomic nuclei, (2) metal clusters

    International Nuclear Information System (INIS)

    Nesterenko, V.O.; Kleinig, W.

    1995-01-01

    The self-consistent vibrating potential model (VPM) is extended for description of Eλ collective excitations in atomic nuclei and metal clusters with practically any kind of static deformation. The model is convenient for a qualitative analysis and provides the RPA accuracy of numerical calculations. The VPM is applied to study Eλ giant resonances in spherical metal clusters and deformed and superdeformed nuclei. It is shown that the deformation splitting of superdeformed nuclei results in a very complicated (''jungle-like'') structure of the resonances, which makes the experimental observation of E2 and E3 giant resonances in superdeformed nuclei quite problematic. Calculations of E1 giant resonance in spherical sodium clusters Na 8 , Na 20 and Na 40 are presented, as a test of the VPM in this field. The results are in qualitative agreement with the experimental data. (orig.)

  11. Prediction of deformations of steel plate by artificial neural network in forming process with induction heating

    International Nuclear Information System (INIS)

    Nguyen, Truong Thinh; Yang, Young Soo; Bae, Kang Yul; Choi, Sung Nam

    2009-01-01

    To control a heat source easily in the forming process of steel plate with heating, the electro-magnetic induction process has been used as a substitute of the flame heating process. However, only few studies have analyzed the deformation of a workpiece in the induction heating process by using a mathematical model. This is mainly due to the difficulty of modeling the heat flux from the inductor traveling on the conductive plate during the induction process. In this study, the heat flux distribution over a steel plate during the induction process is first analyzed by a numerical method with the assumption that the process is in a quasi-stationary state around the inductor and also that the heat flux itself greatly depends on the temperature of the workpiece. With the heat flux, heat flow and thermo-mechanical analyses on the plate to obtain deformations during the heating process are then performed with a commercial FEM program for 34 combinations of heating parameters. An artificial neural network is proposed to build a simplified relationship between deformations and heating parameters that can be easily utilized to predict deformations of steel plate with a wide range of heating parameters in the heating process. After its architecture is optimized, the artificial neural network is trained with the deformations obtained from the FEM analyses as outputs and the related heating parameters as inputs. The predicted outputs from the neural network are compared with those of the experiments and the numerical results. They are in good agreement

  12. Improved leaching process for metal ores

    International Nuclear Information System (INIS)

    Kar-Kwan Yung, K.; Barlow, C.B.; Glass, J.R.

    1980-01-01

    The general overall sequence of process steps in the technique of the invention in set forth. In sequence, the ore is crushed, and solubilizing reagents and moisture are added to the crushed ore in preselected controlled portions. The mixture of ore, reagent, and moisture is then cured followed in the preferred process by conditioning for filtration. The slurry that is produced from conditioning is then subjected to multiple stage washing on a belt filter. The filtrate is further processed for metal value recovery and the solids are transported to tailings disposal

  13. Description of Latvian Metal Production and Processing Enterprises' Air Emissions

    OpenAIRE

    Pubule, J; Zahare, D; Blumberga, D

    2010-01-01

    The metal production and processing sector in Latvia has acquired a stable position in the national economy. Smelting of ferrous and nonferrous metals, production of metalware, galvanisation, etc. are developed in Latvia. The metal production and processing sector has an impact on air quality due to polluting substances which are released in the air from metal treatment processes. Therefore it is necessary to determine the total volume of emissions produced by the metal production and process...

  14. Laser processing of metals and alloys

    International Nuclear Information System (INIS)

    Goswami, G.L.; Kumar, Dilip; Roy, P.R.

    1988-01-01

    Laser, due to its high degree of coherence can produce powder density in the range of 10 3 -10 11 W/mm 2 . This high power density of the laser beam enables it to be utilized for many industrial applications, e.g. welding, cutting, drilling, surface treatment, etc. Laser processing of materials has many advantages, e.g. good quality product at high processing speed, least heat affected zone, minimum distortion, etc. In addition, the same laser system can be utilized for different applications, a very cost effective factor for any industry. Therefore laser has been adopted for processing of different materials for a wide range of applications and is now replacing conventional materials processing techniques on commercial merits with several economic and metallurgical advantages. Applications of laser to process materials of different thicknesses varying from 0.1 mm to 100 mm have demonstrat ed its capability as an important manufacturing tool for engineering industries. While lasers have most widely been utilized in welding, cutting and drilling they have also found applications in surface treatment of metals and alloys, e.g. transfor mation hardening and annealing. More recently, there has been significant amount of research being undertaken in laser glazing, laser surface alloying and laser cladding for obtaining improved surface properties. This report reviews the stat us of laser processing of metals and alloys emphasising its metallurgical aspects a nd deals with the different laser processes like welding, cutting, drilling and surface treatment highlighting the types and choice of laser and its interaction with metals and alloys and the applications of these processes. (author). 93 refs., 32 figs., 7 tables

  15. Coercivities of hot-deformed magnets processed from amorphous and nanocrystalline precursors

    International Nuclear Information System (INIS)

    Tang, Xin; Sepehri-Amin, H.; Ohkubo, T.; Hioki, K.; Hattori, A.; Hono, K.

    2017-01-01

    Hot-deformed magnets have been processed from amorphous and nanocrystalline precursors and their hard magnetic properties and microstructures have been investigated in order to explore the optimum process route. The hot-deformed magnets processed from an amorphous precursor exhibited the coercivity of 1.40 T that is higher than that processed from nanocrystalline powder, ∼1.28 T. The average grain size was larger in the magnets processed from amorphous precursor. Detailed microstructure analyses by aberration corrected scanning transmission electron microscopy revealed that the Nd + Pr concentrations in the intergranular phases were higher in the hot-deformed magnet processed from the amorphous precursor, which is considered to lead to the enhanced coercivity due to a stronger pinning force against magnetic domain wall motion.

  16. Inverse mathematical modelling and identification in metal powder compaction process

    International Nuclear Information System (INIS)

    Gakwaya, A.; Hrairi, M.; Guillot, M.

    2000-01-01

    An online assessment of the quality of advanced integrated computer aided manufacturing systems require the knowledge of accurate and reliable non-linear constitutive material behavior. This paper is concerned with material parameter identification based on experimental data for which non uniform distribution of stresses and deformation within the volume of the specimen is considered. Both geometric and material non linearities as well interfacial frictional contact are taken into account during the simulation. Within the framework of finite deformation theory, a multisurface multiplicative plasticity model for metal powder compaction process is presented. The model is seen to involve several parameters which are not always activated by a single state variable even though it may be technologically important in assessing the final product quality and manufacturing performance. The resulting expressions are presented in spatial setting and gradient based descent method utilizing the modified Levenberg-Marquardt scheme is used for the minimization of least square functional so as to obtain the best agreement between relevant experimental data and simulated data in a specified energy norm. The identification of a subset of material parameters of the cap model for stainless steel powder compaction is performed. The obtained parameters are validated through a simulation of an industrial part manufacturing case. A very good agreement between simulated final density and measured density is obtained thus demonstrating the practical usefulness of the proposed approach. (author)

  17. Some modifications to the process of discontinuous deformation analysis

    Directory of Open Access Journals (Sweden)

    Yong Yu

    2015-02-01

    Full Text Available This paper presents a modified method of discontinuous deformation analysis (DDA. In the presented method, open-close iteration may not be needed, small penetration is permitted among blocks, and springs are added between contacting block pairs only when a penetration takes place. The three contact patterns (i.e. sliding, locking and opening in original DDA method are not involved, and the recognition of these contact patterns and treatment of transformation among patterns are not required either, significantly saving the computing time. In a convex to concave contact, there are two candidate entrance edges which may cause uncertainty. In this case, we propose the angle bisector criterion to determine the entrance edge. The spring stiffness is much larger than Young's modulus in the original DDA, however we find that the correct results can still be obtained when it is much smaller than Young's modulus. Finally, the penetrations by using penalty method and augmented Lagrangian method are compared. Penetration of the latter is 1/4 of the former. The range of spring stiffness for the latter is wider than the former, being 0.01–1 of the former. Both methods can lead to correct contact forces.

  18. Solar Convective Furnace for Metals Processing

    Science.gov (United States)

    Patidar, Deepesh; Tiwari, Sheetanshu; Sharma, Piyush; Pardeshi, Ravindra; Chandra, Laltu; Shekhar, Rajiv

    2015-11-01

    Metals processing operations, primarily soaking, heat treatment, and melting of metals are energy-intensive processes using fossil fuels, either directly or indirectly as electricity, to operate furnaces at high temperatures. Use of concentrated solar energy as a source of heat could be a viable "green" option for industrial heat treatment furnaces. This paper introduces the concept of a solar convective furnace which utilizes hot air generated by an open volumetric air receiver (OVAR)-based solar tower technology. The potential for heating air above 1000°C exists. Air temperatures of 700°C have already been achieved in a 1.5-MWe volumetric air receiver demonstration plant. Efforts to retrofit an industrial aluminium soaking furnace for integration with a solar tower system are briefly described. The design and performance of an OVAR has been discussed. A strategy for designing a 1/15th-scale model of an industrial aluminium soaking furnace has been presented. Preliminary flow and thermal simulation results suggest the presence of recirculating flow in existing furnaces that could possibly result in non-uniform heating of the slabs. The multifarious uses of concentrated solar energy, for example in smelting, metals processing, and even fuel production, should enable it to overcome its cost disadvantage with respect to solar photovoltaics.

  19. Mesoporous metal oxides and processes for preparation thereof

    Energy Technology Data Exchange (ETDEWEB)

    Suib, Steven L.; Poyraz, Altug Suleyman

    2018-03-06

    A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.

  20. Irreversible thermodynamics models and constitutive equations of the irradiation induced deformation and damage accumulating processes

    International Nuclear Information System (INIS)

    Wassilew, C.

    1989-11-01

    This report gives an overall evaluation of several in-reactor deformation and creep-rupture experiments performed in BR-2, FFTF, and Rapsodie on pressurised tubes of the stabilized austenitic stainless steels 1.4970, 1.4981, 1.4988, and the nickel base alloy Hastelloy-X. The irradiation induced deformation processes observed in the components operating in a neutron environment can be divided into two main groups: 1. volume conserving creep and 2. volumetric swelling. Since the observed deformation as well as damage accumulating phenomena are caused by the same constrained generated and free disposable point defects and helium atoms, it is obvious and advisable to analyze, and to model simultaneously the ensemble of the elementary mechanisms and processes effective at the same time. Phenomenological models based on the thermodynamics of irreversible processes have been developed, with the aim of: 1. grasping the partial relationships between the external variables and the response functions (creep, swelling, creep driven swelling, and time to rupture), 2. fathoming the rate-controlling mechanisms, 3. providing insight into the structural details and changes occurring during the deformation and the damage accumulating processes, 4. integrating the damage accumulating processes comprehensively, and 5. formulating the constitutive equations required to describe the elementary processes that generate plastic deformations as well as damage accumulation. (orig./MM)

  1. 3D finite element modelling of sheet metal blanking process

    Science.gov (United States)

    Bohdal, Lukasz; Kukielka, Leon; Chodor, Jaroslaw; Kulakowska, Agnieszka; Patyk, Radoslaw; Kaldunski, Pawel

    2018-05-01

    The shearing process such as the blanking of sheet metals has been used often to prepare workpieces for subsequent forming operations. The use of FEM simulation is increasing for investigation and optimizing the blanking process. In the current literature a blanking FEM simulations for the limited capability and large computational cost of the three dimensional (3D) analysis has been largely limited to two dimensional (2D) plane axis-symmetry problems. However, a significant progress in modelling which takes into account the influence of real material (e.g. microstructure of the material), physical and technological conditions can be obtained by using 3D numerical analysis methods in this area. The objective of this paper is to present 3D finite element analysis of the ductile fracture, strain distribution and stress in blanking process with the assumption geometrical and physical nonlinearities. The physical, mathematical and computer model of the process are elaborated. Dynamic effects, mechanical coupling, constitutive damage law and contact friction are taken into account. The application in ANSYS/LS-DYNA program is elaborated. The effect of the main process parameter a blanking clearance on the deformation of 1018 steel and quality of the blank's sheared edge is analyzed. The results of computer simulations can be used to forecasting quality of the final parts optimization.

  2. Deformation Partitioning: The Missing Link Between Outcrop-Scale Observations And Orogen-Scale Processes

    Science.gov (United States)

    Attia, S.; Paterson, S. R.; Jiang, D.; Miller, R. B.

    2017-12-01

    Structural studies of orogenic deformation fields are mostly based on small-scale structures ubiquitous in field exposures, hand samples, and under microscopes. Relating deformation histories derived from such structures to changing lithospheric-scale deformation and boundary conditions is not trivial due to vast scale separation (10-6 107 m) between characteristic lengths of small-scale structures and lithospheric plates. Rheological heterogeneity over the range of orogenic scales will lead to deformation partitioning throughout intervening scales of structural development. Spectacular examples of structures documenting deformation partitioning are widespread within hot (i.e., magma-rich) orogens such as the well-studied central Sierra Nevada and Cascades core of western North America: (1) deformation partitioned into localized, narrow, triclinic shear zones separated by broad domains of distributed pure shear at micro- to 10 km scales; (2) deformation partitioned between plutons and surrounding metamorphic host rocks as shown by pluton-wide magmatic fabrics consistently oriented differently than coeval host rock fabrics; (3) partitioning recorded by different fabric intensities, styles, and orientations established from meter-scale grid mapping to 100 km scale domainal analyses; and (4) variations in the causes of strain and kinematics within fold-dominated domains. These complex, partitioned histories require synthesized mapping, geochronology, and structural data at all scales to evaluate partitioning and in the absence of correct scaling can lead to incorrect interpretations of histories. Forward modeling capable of addressing deformation partitioning in materials containing multiple scales of rheologically heterogeneous elements of varying characteristic lengths provides the ability to upscale the large synthesized datasets described above to plate-scale tectonic processes and boundary conditions. By comparing modeling predictions from the recently developed

  3. Catalysed electrolytic metal oxide dissolution processes

    International Nuclear Information System (INIS)

    Machuron-Mandard, X.

    1994-01-01

    The hydrometallurgical processes designed for recovering valuable metals from mineral ores as well as industrial wastes usually require preliminary dissolution of inorganic compounds in aqueous media before extraction and purification steps. Unfortunately, most of the minerals concerned hardly or slowly dissolve in acidic or basic solutions. Metallic oxides, sulfides and silicates are among the materials most difficult to dissolve in aqueous solutions. They are also among the main minerals containing valuable metals. The redox properties of such materials sometimes permit to improve their dissolution by adding oxidizing or reducing species to the leaching solution, which leads to an increase in the dissolution rate. Moreover, limited amounts of redox promoters are required if the redox agent is regenerated continuously thanks to an electrochemical device. Nuclear applications of such concepts have been suggested since the dissolution of many actinide compounds (e.g., UO 2 , AmO 2 , PuC, PuN,...) is mainly based on redox reactions. In the 1980s, improvements of the plutonium dioxide dissolution process have been proposed on the basis of oxidation-reduction principles, which led a few years later to the design of industrial facilities (e.g., at Marcoule or at the french reprocessing plant of La Hague). General concepts and well-established results obtained in France at the Atomic Energy Commission (''Commissariat a l'Energie Atomique'') will be presented and will illustrate applications to industrial as well as analytical problems. (author)

  4. Non-proportional deformation paths for sheet metal: experiments and models

    NARCIS (Netherlands)

    van den Boogaard, Antonius H.; van Riel, M.; Hora, P.

    2009-01-01

    For mild steel, after significant plastic deformation in one direction, a subsequent deformation in an orthogonal direction shows a typical stress overshoot compared to monotonic deformation. This phenomenon is investigated experimentally and numerically on a DC06 material. Two models that

  5. Influences of rolling method on deformation force in cold roll-beating forming process

    Science.gov (United States)

    Su, Yongxiang; Cui, Fengkui; Liang, Xiaoming; Li, Yan

    2018-03-01

    In process, the research object, the gear rack was selected to study the influence law of rolling method on the deformation force. By the mean of the cold roll forming finite element simulation, the variation regularity of radial and tangential deformation was analysed under different rolling methods. The variation of deformation force of the complete forming racks and the single roll during the steady state under different rolling modes was analyzed. The results show: when upbeating and down beating, radial single point average force is similar, the tangential single point average force gap is bigger, the gap of tangential single point average force is relatively large. Add itionally, the tangential force at the time of direct beating is large, and the dire ction is opposite with down beating. With directly beating, deformation force loading fast and uninstall slow. Correspondingly, with down beating, deformat ion force loading slow and uninstall fast.

  6. Analysis and Modeling of Process of Residual Deformations Accumulation in Soils and Granular Materials

    Science.gov (United States)

    Aleksandrov, A. S.; Dolgih, G. V.; Kalinin, A. L.

    2017-11-01

    It is established that under the influence of repeated loads the process of plastic deformation in soils and discrete materials is hereditary. To perform the mathematical modeling of plastic deformation, the authors applied the integral equation by solution of which they manage to obtain the power and logarithmic dependencies connecting plastic deformation with the number of repeated loads, the parameters of the material and components of the stress tensor in the principal axes. It is shown that these dependences generalize a number of models proposed earlier in Russia and abroad. Based on the analysis of the experimental data obtained during material testing in the dynamic devices of triaxial compression at different values of the stress deviator, the coefficients in the proposed models of deformation are determined. The authors determined the application domain for logarithmic and degree dependences.

  7. Reliable processing of graphene using metal etchmasks

    Directory of Open Access Journals (Sweden)

    Peltekis Nikos

    2011-01-01

    Full Text Available Abstract Graphene exhibits exciting properties which make it an appealing candidate for use in electronic devices. Reliable processes for device fabrication are crucial prerequisites for this. We developed a large area of CVD synthesis and transfer of graphene films. With patterning of these graphene layers using standard photoresist masks, we are able to produce arrays of gated graphene devices with four point contacts. The etching and lift off process poses problems because of delamination and contamination due to polymer residues when using standard resists. We introduce a metal etch mask which minimises these problems. The high quality of graphene is shown by Raman and XPS spectroscopy as well as electrical measurements. The process is of high value for applications, as it improves the processability of graphene using high-throughput lithography and etching techniques.

  8. Method of processing radioactive metal wastes

    International Nuclear Information System (INIS)

    Inoue, Yoichi; Kitagawa, Kazuo; Tsuzura, Katsuhiko.

    1980-01-01

    Purpose: To enable long and safety storage for radioactive metal wastes such as used fuel cans after the procession or used pipe, instruments and the likes polluted with various radioactive substances, by compacting them to solidify. Method: Metal wastes such as used fuel cans, which have been cut shorter and reprocessed, are pressed into generally hexagonal blocks. The block is charged in a capsule of a hexagonal cross section made of non-gas permeable materials such as soft steels, stainless steels and the likes. Then, the capsule is subjected to static hydraulic hot pressing as it is or after deaeration and sealing. While various combinations are possible for temperature, pressure and time as the conditions for the static hydraulic hot pressing, dense block with no residual gas pores can be obtained, for example, under the conditions of 900 0 C, 1000 Kg/cm 2 and one hour where the wastes are composed of zircaloy. (Kawakami, Y.)

  9. DETERMINING PULL – OUT DEFORMATIONS OF BONDED METAL ANCHORS EMBEDDED IN CONCRETE BY MEANS OF PHOTOGRAMMETRY

    Directory of Open Access Journals (Sweden)

    E. O. Avsar

    2012-07-01

    Full Text Available Chemical anchorages are applied in many engineering implementations, particularly strengthening of reinforced concrete structures. During strengthening procedure; chemical anchorages should be tested, since they supply to transfer the load between existing construction elements and newly added elements. Therefore; the study of the quality of chemical anchorages is an important issue in construction materials science. In this context; the most important experiment is to determine the pull-out loads of embedded anchorage reinforcement by applying axial loads. In this study; it is aimed to determine the displacements of steel reinforcements, embedded into concrete by using chemical anchorages, while applying axial pulling loads. In order to determine the displacements and load – deformation graphs; starting conditions and every 10 bar pressure applied conditions of the steel reinforcements were captured by the cameras. The obtained images were evaluated by using photogrammetric software. Based on the photogrammetric post-processing results, the load – deformation graphs were plotted and the loads at loss of adhesion were determined.

  10. Process Development And Simulation For Cold Fabrication Of Doubly Curved Metal Plate By Using Line Array Roll Set

    International Nuclear Information System (INIS)

    Shim, D. S.; Jung, C. G.; Seong, D. Y.; Yang, D. Y.; Han, J. M.; Han, M. S.

    2007-01-01

    For effective manufacturing of a doubly curved sheet metal, a novel sheet metal forming process is proposed. The suggested process uses a Line Array Roll Set (LARS) composed of a pair of upper and lower roll assemblies in a symmetric manner. The process offers flexibility as compared with the conventional manufacturing processes, because it does not require any complex-shaped die and loss of material by blank-holding is minimized. LARS allows flexibility of the incremental forming process and adopts the principle of bending deformation, resulting in a slight deformation in thickness. Rolls composed of line array roll sets are divided into a driving roll row and two idle roll rows. The arrayed rolls in the central lines of the upper and lower roll assemblies are motor-driven so that they deform and transfer the sheet metal using friction between the rolls and the sheet metal. The remaining rolls are idle rolls, generating bending deformation with driving rolls. Furthermore, all the rolls are movable in any direction so that they are adaptable to any size or shape of the desired three-dimensional configuration. In the process, the sheet is deformed incrementally as deformation proceeds simultaneously in rolling and transverse directions step by step. Consequently, it can be applied to the fabrication of doubly curved ship hull plates by undergoing several passes. In this work, FEM simulations are carried out for verification of the proposed incremental forming system using the chosen design parameters. Based on the results of the simulation, the relationship between the roll set configuration and the curvature of a sheet metal is determined. The process information such as the forming loads and torques acting on every roll is analyzed as important data for the design and development of the manufacturing system

  11. Texture evolution maps for upset deformation of body-centered cubic metals

    International Nuclear Information System (INIS)

    Lee, Myoung-Gyu; Wang, Jue; Anderson, Peter M.

    2007-01-01

    Texture evolution maps are used as a tool to visualize texture development during upset deformation in body-centered cubic metals. These maps reveal initial grain orientations that tend toward normal direction (ND)|| versus ND|| . To produce these maps, a finite element analysis (FEA) with a rate-dependent crystal plasticity constitutive relation for tantalum is used. A reference case having zero workpiece/die friction shows that ∼64% of randomly oriented grains rotate toward ND|| and ∼36% rotate toward ND|| . The maps show well-established trends that increasing strain rate sensitivity and decreasing latent-to-self hardening ratio reduce both and percentages, leading to more diffuse textures. Reducing operative slip systems from both {1 1 0}/ and {1 1 2}/ to just {1 1 0}/ has a mixed effect: it increases the percentage but decreases the percentage. Reducing the number of slip systems and increasing the number of FEA integration points per grain strengthen - texture bands that are observed experimentally

  12. Plastic deformation behavior of Fe–Co–B–Si–Nb–Cr bulk metallic glasses under nanoindentation

    International Nuclear Information System (INIS)

    Kim, J.T.; Hong, S.H.; Lee, C.H.; Park, J.M.; Kim, T.W.; Lee, W.H.; Yim, H.I.; Kim, K.B.

    2014-01-01

    Highlights: • Additional Cr modulation of atomic structure of Fe-Co-B-Si-Nb BMGs. • An amount of free volume characterized by a combination of nanoindentation and AFM. • Free volume determined by height measurement of AFM after nanoindentation. -- Abstract: In this work, we investigate the effect of Cr addition on thermal properties and indentation behavior of Fe 52 Co 20−x B 20 Si 4 Nb 4 Cr x alloys with x = 0, 1, 3 and 5 at.%, respectively. Among all studied alloys, the Fe 52 Co 17 B 20 Si 4 Nb 4 Cr 3 bulk metallic glass (BMG) exhibits the highest thermal stability with large supercooled liquid region of 40 K and the pronounced plastic deformation features which is serrated flow (pop-in event) and significant pile-up of materials around indents. This demonstrates that the appropriate addition of Cr in Fe-based BMG can induce the internal atomic structure modulation and promote the mechanical softening, which are discussed in terms of free volume concept

  13. Plastic deformation behavior of Fe–Co–B–Si–Nb–Cr bulk metallic glasses under nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.T.; Hong, S.H.; Lee, C.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, J.M., E-mail: jinman_park@hotmail.com [Materials Research Center, Samsung Advanced Institute of Technology (SAIT), San 14-1, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of); Kim, T.W.; Lee, W.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Yim, H.I. [Department of Physics, Sookmyung Women’s University, Hyochangwongil 52, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Kim, K.B., E-mail: kbkim@sejong.ac.kr [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2014-02-25

    Highlights: • Additional Cr modulation of atomic structure of Fe-Co-B-Si-Nb BMGs. • An amount of free volume characterized by a combination of nanoindentation and AFM. • Free volume determined by height measurement of AFM after nanoindentation. -- Abstract: In this work, we investigate the effect of Cr addition on thermal properties and indentation behavior of Fe{sub 52}Co{sub 20−x}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub x} alloys with x = 0, 1, 3 and 5 at.%, respectively. Among all studied alloys, the Fe{sub 52}Co{sub 17}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub 3} bulk metallic glass (BMG) exhibits the highest thermal stability with large supercooled liquid region of 40 K and the pronounced plastic deformation features which is serrated flow (pop-in event) and significant pile-up of materials around indents. This demonstrates that the appropriate addition of Cr in Fe-based BMG can induce the internal atomic structure modulation and promote the mechanical softening, which are discussed in terms of free volume concept.

  14. Strength and deformability of concrete beams reinforced by non-metallic fiber and composite rebar

    Science.gov (United States)

    Kudyakov, K. L.; Plevkov, V. S.; Nevskii, A. V.

    2015-01-01

    Production of durable and high-strength concrete structures with unique properties has always been crucial. Therefore special attention has been paid to non-metallic composite and fiber reinforcement. This article describes the experimental research of strength and deformability of concrete beams with dispersed and core fiber-based reinforcement. As composite reinforcement fiberglass reinforced plastic rods with diameters 6 mm and 10 mm are used. Carbon and basalt fibers are used as dispersed reinforcement. The developed experimental program includes designing and production of flexural structures with different parameters of dispersed fiber and composite rebar reinforcement. The preliminary testing of mechanical properties of these materials has shown their effectiveness. Structures underwent bending testing on a special bench by applying flexural static load up to complete destruction. During the tests vertical displacements were recorded, as well as value of actual load, slippage of rebars in concrete, crack formation. As a result of research were obtained structural failure and crack formation graphs, value of fracture load and maximum displacements of the beams at midspan. Analysis of experimental data showed the effectiveness of using dispersed reinforcement of concrete and the need for prestressing of fiberglass composite rebar.

  15. METAL CHIP HEATING PROCESS INVESTIGATION (Part I

    Directory of Open Access Journals (Sweden)

    O. M. Dyakonov

    2007-01-01

    Full Text Available The main calculation methods for heat- and mass transfer in porous heterogeneous medium have been considered. The paper gives an evaluation of the possibility to apply them for calculation of metal chip heating process. It has been shown that a description of transfer processes in a chip has its own specific character that is attributed to difference between thermal and physical properties of chip material and lubricant-coolant components on chip surfaces. It has been determined that the known expressions for effective heat transfer coefficients can be used as basic ones while approaching mutually penetrating continuums. A mathematical description of heat- and mass transfer in chip medium can be considered as a basis of mathematical modeling, numerical solution and parameter optimization of the mentioned processes.

  16. New process for weld metal reliability

    International Nuclear Information System (INIS)

    Hebel, A.G.

    1985-01-01

    The industry-wide nature of weld cracking alerts one to the possibility that there is a fundamental law being overlooked. And in overlooking this law, industry is unable to counteract it. That law mandates that restraint during welding causes internal stress; internal stress causes weld metal to crack. Component restraint during welding, according to the welding standard, is the major cause of weld metal failures. When the metal working industry accepts this fact and begins to counter the effects of restraint, the number of weld failures experienced fall dramatically. Bonal Technologies, inc., of Detroit, has developed the first consistently effective non-thermal process to relieve stress caused by restraint during welding. Bonal's patented Mets-Lax sub-resonant stress relief acts as a restraint neutralizer when used during welding. Meta-Lax weld conditioning produces a finer more uniform weld grain structure. A finer, more uniform grain structure is a clear metallurgical indication of improved mechanical weld properties. Other benefits like less internal stress, and less warpage are also achieved

  17. In-situ deformation studies of an aluminum metal-matrix composite in a scanning electron microscope

    Science.gov (United States)

    Manoharan, M.; Lewandowski, J. J.

    1989-01-01

    Tensile specimens made of a metal-matrix composite (cast and extruded aluminum alloy-based matrix reinforced with Al2O3 particulate) were tested in situ in a scanning electron microscope equipped with a deformation stage, to directly monitor the crack propagation phenomenon. The in situ SEM observations revealed the presence of microcracks both ahead of and near the crack-tip region. The microcracks were primarily associated with cracks in the alumina particles. The results suggest that a region of intense deformation exists ahead of the crack and corresponds to the region of microcracking. As the crack progresses, a region of plastically deformed material and associated microcracks remains in the wake of the crack.

  18. Evaluation of Dynamic Deformation Behaviors in Metallic Materials under High Strain-Rates Using Taylor Bar Impact Test

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Kyung Oh; Shin, Hyung Seop [Andong National Univ., Andong (Korea, Republic of)

    2016-09-15

    To ensure the reliability and safety of various mechanical systems in accordance with their high-speed usage, it is necessary to evaluate the dynamic deformation behavior of structural materials under impact load. However, it is not easy to understand the dynamic deformation behavior of the structural materials using experimental methods in the high strain-rate range exceeding 10{sup 4} s{sup -1}. In this study, the Taylor bar impact test was conducted to investigate the dynamic deformation behavior of metallic materials in the high strain-rate region, using a high-speed photography system. Numerical analysis of the Taylor bar impact test was performed using AUTODYN S/W. The results of the analysis were compared with the experimental results, and the material behavior in the high strain-rate region was discussed.

  19. Simulation of the metallic powders compaction process

    International Nuclear Information System (INIS)

    Prado, J.M.; Riera, M.D.

    1998-01-01

    The simulation by means of finite elements of the forming processes of mechanical components is a very useful tool for their design and validation. In this work, the simulation of the compaction of a metal powder is presented. The finite element software ABAQUS is used together with the modified CAM-clay plasticity model in order to represent the elastoplastic behaviour of the material. Density distributions are obtained and therefore the motion of the compaction punches which improve this distribution can be found. Stress distribution in the different parts of the mould can also be determined. (Author) 9 refs

  20. Nd-Fe-B-Cu hot deformation processing: a comparison of deformation modes, microstructural development and magnetic properties

    International Nuclear Information System (INIS)

    Ferrante, M.; Sinka, V.; Assis, O.B.G.; Oliveira, I. de; Freitas, E. de

    1996-01-01

    Due to its relative simplicity and low cost the hot deformation of Nd-Fe-B ingots is rapidly reaching the status of a valid alternative to sintering. Among the possible deformation modes, pressing, rolling and forging are perhaps the most successful. This paper describes the research programme undertaken so far, by discussing the relationship between deformation mode, microstructure and magnetic properties of magnets produced by hot deformation mode, microstructure and magnetic properties of magnets produced by hot deformation of a number of Nd-fe-B-Cu alloys. Microstructural observation showed that both pressed and forged samples are characterized by a heterogeneous microstructure and from magnetic measurements it was concluded that magnetic properties differ when taken in the center or in the periphery of the sample. On the other hand roller magnets were homogeneous both in terms of microstructure and magnetic properties, and interpretations of the mechanisms of texture development and of microstructural development of hot deformed magnets is put forward. (author)

  1. Deformation-induced amorphization of crystalline particles in a Cu-Ti metallic glass

    International Nuclear Information System (INIS)

    Kamentzky, E.A.; Askenazy, P.D.; Johnson, W.L.; Tanner, L.E.

    1987-01-01

    Crystalline particles and grains embedded in Cu 35 Ti 65 glass ribbons have been amorphized by isothermal cold rolling. The structural evolution has been studied by X-ray diffraction and TEM techniques. Initial particle morphologies are spherulitic and spherical, the latter with sizes ranging between 10 and 100 nm. The new amorphous phase seems to nucleate at crystalline-amorphous matrix interfaces. Initially there is a well defined interface between the new and the existing amorphous phases but it disappears as rolling progresses. Crystallites on a nanoscale still present in the final stages of particle amorphization have been observed by convergent beam electron diffraction. After sufficient deformation the consolidated ribbon becomes a completely glassy. A morphological description of the transformation process in terms of crystal destabilization and solid- state particle melting is presented

  2. Effect of cooling rate on microstructure and deformation behavior of Ti-based metallic glassy/crystalline powders

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.J. [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China); School of Mechanical and Mining Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Huang, Y.J. [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China); Shen, J., E-mail: junshen@hit.edu.cn [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China); Wu, Y.Q.; Huang, H. [School of Mechanical and Mining Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Zou, J., E-mail: j.zou@uq.edu.au [School of Mechanical and Mining Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD 4072 (Australia)

    2010-08-20

    The microstructures and deformation behavior of Ti-based metallic powders were comprehensively investigated. It has been found that, with increasing the powder size, the phase constituent alters from pure glassy to glassy with crystalline phases (face centered cubic structured NiSnZr and hexagonal structured Ti{sub 3}Sn phases). Our results suggest that the synergetic effect of the thermodynamics and kinetics determines the subsequent characteristics of the crystalline precipitations. Through comparative nanoindentation tests, it was found that the small powders exhibit more pop-in events and a larger pile-up ratio, suggesting that the plastic deformation of the metallic powders is governed by the combined effects of the free volume and the crystallization, which are determined by the cooling rate.

  3. Deformation twinning in metals and ordered intermetallics-Ti and Ti-aluminides

    Science.gov (United States)

    Yoo, M. H.; Fu, C. L.; Lee, J. K.

    1991-06-01

    The role of deformation twinning in the strength and ductility of metals and ordered intermetallic alloys is examined on the basis of crystallography, energetics and kinetics of deformation twinning. A systematic analysis is made by taking Ti, Ti3AI, TiAl, and A13Ti as four model systems. In comparison with profuse twinning in Ti, the intrinsic difficulty of twinning in Ti3A1 is rationalized in terms of the interchange shuffling mechanism. A fault (SISF) dragging mechanism based on the interaction torque explains the physical source for the low mobility of screw superdislocations in TiAl, which may lead to (111) [ 11bar{2}] twin nucleation. In TiAl and A13Ti alloys, the twin-slip (ordinary) conjugate relationship makes an important contribution to the strain compatibility for high-temperature plasticity. Potentially beneficial alloying additions to promote twinning are discussed. Les conséquences de la déformation par maclage sur la fracture et la ductilité des métaux et alliages intermétalliques ordonnés sont étudiées en fonction de la cristallographie, de l'énergie et de la cinétique des déformations par maclage. Une analyse systématique a été faite en considérant Ti, Ti3AI, TiAl et A13Ti comme quatre systèmes modèles. En comparaison avec le nombre important de maclages observés dans Ti, la difficulté intrinsèque des maclages dans Ti3AI est rationalisée en terme de mécanisme d'“interchange shuffling”. Un mécanisme de “dragging fault” basé sur l'interaction “torque” explique l'origine physique de la faible mobilité des superdislocations vissées dans TiAl qui peuvent conduire à la nucléation des macles (111) 112. Dans les alliages tels TiAl et A13Ti, la relation conjuguée entre la macle et le glissement (ordinaire) contribue de façon importante à la compatibilité des contraintes lors de la déformation plastique à haute température. Des effets bénéfiques potentiels liés à des éléments d'addition sur le processus

  4. Deformational mass transport and invasive processes in soil evolution

    Science.gov (United States)

    Brimhall, George H.; Chadwick, Oliver A.; Lewis, Chris J.; Compston, William; Williams, Ian S.; Danti, Kathy J.; Dietrich, William E.; Power, Mary E.; Hendricks, David; Bratt, James

    1992-01-01

    Channels left in soil by decayed roots and burrowing animals allow organic and inorganic precipitates and detritus to move through soil from above, to depths at which the minuteness of pores restricts further passage. Consecutive translocation-and-root-growth phases stir the soil, constituting an invasive, dilatational process which generates cumulative strains. Below the depths thus affected, mineral dissolution by descending organic acids leads to internal collapse; this softened/condensed precursor horizon is then transformed into soil via biological activity that mixes and expands the evolving residuum through root and micropore-network invasion.

  5. Deformation Behavior during Processing in Carbon Fiber Reinforced Plastics

    Science.gov (United States)

    Ogihara, Shinji; Kobayashi, Satoshi

    In this study, we manufacture the device for measuring the friction between the prepreg curing process and subjected to pull-out tests with it The prepreg used in this study is a unidirectional carbon/epoxy, produced by TORAY designation of T700SC/2592.When creating specimens 4-ply prepregs are prepared and laminated. The 2-ply prepregs in the middle are shifted 50mm. In order to measure the friction between the prepreg during the cure process, we simulate the environment in the autoclave in the device, and we experiment in pull-out test. Test environment simulating temperature and pressure. The speed of displacement should be calculated by coefficient of thermal expansions (CTE). By calculation, 0.05mm/min gives the order of magnitude of displacement speed. In this study, 3 pull-out speeds are used: 0.01, 0.05 and 0.1mm/min. The specimen was heated by a couple of heaters, and we controlled the heaters with a temperature controller along the curing conditions of the prepreg. We put pressure using 4 bolts. Two strain gages were put on the bolt. We can understand the load applied to the specimen from the strain of the bolt. Pressure was adjusted the tightness of the bolt according to curing conditions. By using such a device, the pull-out test performed by tensile testing machine while adding temperature and pressure. During the 5 hours, we perform experiments while recording the load and stroke. The shear stress determined from the load and the stroke, and evaluated.

  6. Non-proportional deformation paths for sheet metal: experiments and models

    OpenAIRE

    van den Boogaard, Antonius H.; van Riel, M.; Hora, P.

    2009-01-01

    For mild steel, after significant plastic deformation in one direction, a subsequent deformation in an orthogonal direction shows a typical stress overshoot compared to monotonic deformation. This phenomenon is investigated experimentally and numerically on a DC06 material. Two models that incorporate the observed overshoot are compared. In the Teodosiu-Hu model, pre-strain influences the rate of kinematic hardening by a rather complex set of evolution equations. The shape of the elastic doma...

  7. Concerning the problem of the plastic deformation mechanism changeover in neutron-irradiated metals and alloys

    International Nuclear Information System (INIS)

    Kolesnikov, A.N.; Krasnoselov, V.A.; Prokhorov, V.I.

    1982-01-01

    With a phenomenological model of plastic deformation instability as a basis, an analysis was made of the neutron irradition effects on the characteristics of strength and plasticity vs. structural parameters and radiation damage morphology. It was demonstrated that the enchanced plasticity in the initial stage of neutron irradiation has to do with the solid solution disintegration. Introduction of indestructible strengthening barriers enhances the stress-resistance of the neck-formation by 1.22 times. The ''big grain'' effect is observable during the deformation channel production only. Both the deformation twinning and deformation-induced martensite transformation raise the plastic flow stability

  8. Modelling ground deformation patterns associated with volcanic processes at the Okataina Volcanic Centre

    Science.gov (United States)

    Holden, L.; Cas, R.; Fournier, N.; Ailleres, L.

    2017-09-01

    The Okataina Volcanic Centre (OVC) is one of two large active rhyolite centres in the modern Taupo Volcanic Zone (TVZ) in the North Island of New Zealand. It is located in a complex section of the Taupo rift, a tectonically active section of the TVZ. The most recent volcanic unrest at the OVC includes the 1315 CE Kaharoa and 1886 Tarawera eruptions. Current monitoring activity at the OVC includes the use of continuous GPS receivers (cGPS), lake levelling and seismographs. The ground deformation patterns preceding volcanic activity the OVC are poorly constrained and restricted to predictions from basic modelling and comparison to other volcanoes worldwide. A better understanding of the deformation patterns preceding renewed volcanic activity is essential to determine if observed deformation is related to volcanic, tectonic or hydrothermal processes. Such an understanding also means that the ability of the present day cGPS network to detect these deformation patterns can also be assessed. The research presented here uses the finite element (FE) modelling technique to investigate ground deformation patterns associated with magma accumulation and diking processes at the OVC in greater detail. A number of FE models are produced and tested using Pylith software and incorporate characteristics of the 1315 CE Kaharoa and 1886 Tarawera eruptions, summarised from the existing body of research literature. The influence of a simple ring fault structure at the OVC on the modelled deformation is evaluated. The ability of the present-day continuous GPS (cGPS) GeoNet monitoring network to detect or observe the modelled deformation is also considered. The results show the modelled horizontal and vertical displacement fields have a number of key features, which include prominent lobe based regions extending northwest and southeast of the OVC. The results also show that the ring fault structure increases the magnitude of the displacements inside the caldera, in particular in the

  9. A study with ESI PAM-STAMP® on the influence of tool deformation on final part quality during a forming process

    Science.gov (United States)

    Vrolijk, Mark; Ogawa, Takayuki; Camanho, Arthur; Biasutti, Manfredi; Lorenz, David

    2018-05-01

    As a result from the ever increasing demand to produce lighter vehicles, more and more advanced high-strength materials are used in automotive industry. Focusing on sheet metal cold forming processes, these materials require high pressing forces and exhibit large springback after forming. Due to the high pressing forces deformations occur in the tooling geometry, introducing dimensional inaccuracies in the blank and potentially impact the final springback behavior. As a result the tool deformations can have an impact on the final assembly or introduce cosmetic defects. Often several iterations are required in try-out to obtain the required tolerances, with costs going up to as much as 30% of the entire product development cost. To investigate the sheet metal part feasibility and quality, in automotive industry CAE tools are widely used. However, in current practice the influence of the tool deformations on the final part quality is generally neglected and simulations are carried out with rigid tools to avoid drastically increased calculation times. If the tool deformation is analyzed through simulation it is normally done at the end of the drawing prosses, when contact conditions are mapped on the die structure and a static analysis is performed to check the deflections of the tool. But this method does not predict the influence of these deflections on the final quality of the part. In order to take tool deformations into account during drawing simulations, ESI has developed the ability to couple solvers efficiently in a way the tool deformations can be real-time included in the drawing simulation without high increase in simulation time compared to simulations with rigid tools. In this paper a study will be presented which demonstrates the effect of tool deformations on the final part quality.

  10. Process for the disposal of alkali metals

    International Nuclear Information System (INIS)

    Lewis, L.C.

    1979-01-01

    The invention describes a method of disposing of alkali metals by forming a solid waste for storage. The method comprises preparing an aqueous disposal solution of at least 55 weight percent alkali metal hydroxide, heating the alkali metal to melting temperature to form a feed solution, and spraying the molten feed solution into the disposal solution. The alkali metal reacts with the water in the disposal solution in a controlled reaction which produces alkali metal hydroxide, hydrogen and heat and thereby forms a solution of alkali metal hydroxides. Water is added to the solution in amounts sufficient to maintain the concentration of alkali metal hydroxides in the solution at 70 to 90 weight percent, and to maintain the temperature of the solution at about the boiling point. Removing and cooling the alkali metal hydroxide solution thereby forms a solid waste for storage. The method is particularly applicable to radioactive alkali metal reactor coolant. (auth)

  11. The Use of the Analytic Hierarchy Process to Aid Decision Making in Acquired Equinovarus Deformity

    NARCIS (Netherlands)

    van Til, Janine Astrid; Renzenbrink, G.J.; Dolan, J.G.; IJzerman, Maarten Joost

    2008-01-01

    Objective: To increase the transparency of decision making about treatment in patients with equinovarus deformity poststroke. - Design: The analytic hierarchy process (AHP) was used as a structured methodology to study the subjective rationale behind choice of treatment. - Setting: An 8-hour meeting

  12. Metal processing with ultrashort laser pulses

    Science.gov (United States)

    Banks, Paul S.; Felt, M. D.; Komashko, Aleksey M.; Perry, Michael D.; Rubenchik, Alexander M.; Stuart, Brent C.

    2000-08-01

    Femtosecond laser ablation has been shown to produce well-defined cuts and holes in metals with minimal heat effect to the remaining material. Ultrashort laser pulse processing shows promise as an important technique for materials processing. We will discuss the physical effects associated with processing based experimental and modeling results. Intense ultra-short laser pulse (USLP) generates high pressures and temperatures in a subsurface layer during the pulse, which can strongly modify the absorption. We carried out simulations of USLP absorption versus material and pulse parameters. The ablation rate as function of the laser parameters has been estimated. Since every laser pulse removes only a small amount of material, a practical laser processing system must have high repetition rate. We will demonstrate that planar ablation is unstable and the initially smooth crater bottom develops a corrugated pattern after many tens of shots. The corrugation growth rate, angle of incidence and the polarization of laser electric field dependence will be discussed. In the nonlinear stage, the formation of coherent structures with scales much larger than the laser wavelength was observed. Also, there appears to be a threshold fluence above which a narrow, nearly perfectly circular channel forms after a few hundred shots. Subsequent shots deepen this channel without significantly increasing its diameter. The role of light absorption in the hole walls will be discussed.

  13. Laser Processing of Metals and Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Singaravelu, Senthilraja [Old Dominion Univ., Norfolk, VA (United States)

    2012-05-01

    A laser offers a unique set of opportunities for precise delivery of high quality coherent energy. This energy can be tailored to alter the properties of material allowing a very flexible adjustment of the interaction that can lead to melting, vaporization, or just surface modification. Nowadays laser systems can be found in nearly all branches of research and industry for numerous applications. Sufficient evidence exists in the literature to suggest that further advancements in the field of laser material processing will rely significantly on the development of new process schemes. As a result they can be applied in various applications starting from fundamental research on systems, materials and processes performed on a scientific and technical basis for the industrial needs. The interaction of intense laser radiation with solid surfaces has extensively been studied for many years, in part, for development of possible applications. In this thesis, I present several applications of laser processing of metals and polymers including polishing niobium surface, producing a superconducting phase niobium nitride and depositing thin films of niobium nitride and organic material (cyclic olefin copolymer). The treated materials were examined by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), atomic force microscopy (AFM), high resolution optical microscopy, surface profilometry, Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). Power spectral density (PSD) spectra computed from AFM data gives further insight into the effect of laser melting on the topography of the treated niobium.

  14. Catalytic extraction processing of contaminated scrap metal

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, T.P.; Johnston, J.E.; Payea, B.M. [Molten Metal Technology, Inc., Waltham, MA (United States)] [and others

    1995-10-01

    The U.S. Department of Energy issued a Planned Research and Development Announcement (PRDA) in 1993, with the objective of identifying unique technologies which could be applied to the most hazardous waste streams at DOE sites. The combination of radioactive contamination with additional contamination by hazardous constituents such as those identified by the Resource Conservation and Recovery Act (RCRA) pose an especially challenging problem. Traditional remediation technologies are increasingly becoming less acceptable to stakeholders and regulators because of the risks they pose to public health and safety. Desirable recycling technologies were described by the DOE as: (1) easily installed, operated, and maintained; (2) exhibiting superior environmental performance; (3) protective of worker and public health and safety; (4) readily acceptable to a wide spectrum of evaluators; and (5) economically feasible. Molten Metal Technology, Inc. (MMT) was awarded a contract as a result of the PRDA initiative to demonstrate the applicability of Catalytic Extraction Processing (CEP), MMT`s proprietary elemental recycling technology, to DOE`s inventory of low level mixed waste. This includes DOE`s inventory of radioactively- and RCRA-contaminated scrap metal and other waste forms expected to be generated by the decontamination and decommissioning (D&D) of DOE sites.

  15. Catalytic extraction processing of contaminated scrap metal

    International Nuclear Information System (INIS)

    Griffin, T.P.; Johnston, J.E.; Payea, B.M.

    1995-01-01

    The U.S. Department of Energy issued a Planned Research and Development Announcement (PRDA) in 1993, with the objective of identifying unique technologies which could be applied to the most hazardous waste streams at DOE sites. The combination of radioactive contamination with additional contamination by hazardous constituents such as those identified by the Resource Conservation and Recovery Act (RCRA) pose an especially challenging problem. Traditional remediation technologies are increasingly becoming less acceptable to stakeholders and regulators because of the risks they pose to public health and safety. Desirable recycling technologies were described by the DOE as: (1) easily installed, operated, and maintained; (2) exhibiting superior environmental performance; (3) protective of worker and public health and safety; (4) readily acceptable to a wide spectrum of evaluators; and (5) economically feasible. Molten Metal Technology, Inc. (MMT) was awarded a contract as a result of the PRDA initiative to demonstrate the applicability of Catalytic Extraction Processing (CEP), MMT's proprietary elemental recycling technology, to DOE's inventory of low level mixed waste. This includes DOE's inventory of radioactively- and RCRA-contaminated scrap metal and other waste forms expected to be generated by the decontamination and decommissioning (D ampersand D) of DOE sites

  16. Process of diffractive scattering and disintegration of complex particles by nonspherical deformed nuclei

    International Nuclear Information System (INIS)

    Evlanov, M.V.

    1989-01-01

    The differential and integral cross sections of diffractive elastic and inelastic scattering and of the disintegration of complex particles by axial and nonaxial deformed nuclei are investigated depending on the shape, deformability and diffuseness of nuclear boundary as well as on the structure of the incident particles and of the rescattering processes. It is shown that the complicated coincidence experiments and experimnts on inelastic scattering with excitation of the target nucleus collective states are satisfactorily described taking simultaneously into account all factors mentioned above and the final-state interaction between the disintegration products of the incident particle

  17. Radiative processes as a condensation phenomenon and the physical meaning of deformed canonical structures

    International Nuclear Information System (INIS)

    Gamboa, J.; Mendez, F.; Grigorio, L.S.; Guimaraes, M.S.; Wotzasek, C.

    2008-01-01

    We study the radiative corrections of QED 3 from the dual point of view and show that this process is the exact dual to the Julia-Toulouse mechanism introduced by Quevedo and Trugenberger [F. Quevedo, C.A. Trugenberger, Nucl. Phys. B 501 (1997) 143] some years ago. We discuss the physics behind this mechanism that involves condensation of topological defects. It is shown that the dual Stuckelberg mechanism is responsible for the 'rank-jump' phenomenon that transforms the scalar field (dual to Maxwell in this dimensionality) into the vectorial self-dual field. This phenomenon is studied using the ideas of noncommutative fields theory that examines possible deformations of the canonical structure of some well-known models in (2+1)D. A deformation is constructed linking the massless scalar field theory with the self-dual theory. This is the exact dual of the known deformation connecting the Maxwell theory with the Maxwell-Chern-Simons theory. Duality, radiative corrections, the Julia-Toulouse mechanism and canonical deformations are then used to establish a web of relations between the mentioned theories and to propose a physical picture of the deformation procedure adopted

  18. Translation-rotation plasticity as basic mechanism of plastic deformation in macro-, micro- and nanoindentation processes

    International Nuclear Information System (INIS)

    Grabco, D; Shikimaka, O; Harea, E

    2008-01-01

    This paper presents a brief review of multilateral examinations for the purpose of detection of interrelation between processes occuring in solids at different levels of action of exterior loading, namely, at macro-, micro- and nanoindentation. Convincing arguments supporting the rotation deformation mechanism alongside the recognized dislocation one are adduced. It has been shown that the decrease in dislocation mobility leads at all scales to the intensification of rotation plasticity and to the involvement of other plastic deformation mechanisms, such as appearance and interaction of disclinations, twinning, phase transition and compression of material. The conversion from translation plasticity to the rotation-translation one means transition to the higher level of plastic deformation, the mesolevel, when the possibilities of the previous microscopic level are exhausted. It was established that the plastic deformation zone in the vicinity of indentations could be separated into two main specific regions: (i) peripheral region predominantly with the dislocation deformation mechanism; otherwise, translation mechanism: microlevel, and (ii) quasidestructured region mainly with the disclination or the intergranular sliding mechanism: rotation mechanism, mesolevel

  19. Thermally induced processes in mixtures of aluminum with organic acids after plastic deformations under high pressure

    Science.gov (United States)

    Zhorin, V. A.; Kiselev, M. R.; Roldugin, V. I.

    2017-11-01

    DSC is used to measure the thermal effects of processes in mixtures of solid organic dibasic acids with powdered aluminum, subjected to plastic deformation under pressures in the range of 0.5-4.0 GPa using an anvil-type high-pressure setup. Analysis of thermograms obtained for the samples after plastic deformation suggests a correlation between the exothermal peaks observed around the temperatures of degradation of the acids and the thermally induced chemical reactions between products of acid degradation and freshly formed surfaces of aluminum particles. The release of heat in the mixtures begins at 30-40°C. The thermal effects in the mixtures of different acids change according to the order of acid reactivity in solutions. The extreme baric dependences of enthalpies of thermal effects are associated with the rearrangement of the electron subsystem of aluminum upon plastic deformation at high pressures.

  20. Deformation characteristics of {delta} phase in the delta-processed Inconel 718 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Y., E-mail: haiyanzhang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, S.H., E-mail: shzhang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Cheng, M. [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Z.X. [Beijing Institute of Aeronautica1 Materials, Beijing 100095 (China)

    2010-01-15

    The hot working characteristics of {delta} phase in the delta-processed Inconel 718 alloy during isothermal compression deformation at temperature of 950 deg. C and strain rate of 0.005 s{sup -1}, were studied by using optical microscope, scanning electron microscope and quantitative X-ray diffraction technique. The results showed that the dissolution of plate-like {delta} phase and the precipitation of spherical {delta} phase particles coexisted during the deformation, and the content of {delta} phase decreased from 7.05 wt.% to 5.14 wt.%. As a result of deformation breakage and dissolution breakage, the plate-like {delta} phase was spheroidized and transferred to spherical {delta} phase particles. In the center with largest strain, the plate-like {delta} phase disappeared and spherical {delta} phase appeared in the interior of grains and grain boundaries.

  1. Semantic modeling of the structural and process entities during plastic deformation of crystals and rocks

    Science.gov (United States)

    Babaie, Hassan; Davarpanah, Armita

    2016-04-01

    We are semantically modeling the structural and dynamic process components of the plastic deformation of minerals and rocks in the Plastic Deformation Ontology (PDO). Applying the Ontology of Physics in Biology, the PDO classifies the spatial entities that participate in the diverse processes of plastic deformation into the Physical_Plastic_Deformation_Entity and Nonphysical_Plastic_Deformation_Entity classes. The Material_Physical_Plastic_Deformation_Entity class includes things such as microstructures, lattice defects, atoms, liquid, and grain boundaries, and the Immaterial_Physical_Plastic_Deformation_Entity class includes vacancies in crystals and voids along mineral grain boundaries. The objects under the many subclasses of these classes (e.g., crystal, lattice defect, layering) have spatial parts that are related to each other through taxonomic (e.g., Line_Defect isA Lattice_Defect), structural (mereological, e.g., Twin_Plane partOf Twin), spatial-topological (e.g., Vacancy adjacentTo Atom, Fluid locatedAlong Grain_Boundary), and domain specific (e.g., displaces, Fluid crystallizes Dissolved_Ion, Void existsAlong Grain_Boundary) relationships. The dynamic aspect of the plastic deformation is modeled under the dynamical Process_Entity class that subsumes classes such as Recrystallization and Pressure_Solution that define the flow of energy amongst the physical entities. The values of the dynamical state properties of the physical entities (e.g., Chemical_Potential, Temperature, Particle_Velocity) change while they take part in the deformational processes such as Diffusion and Dislocation_Glide. The process entities have temporal parts (phases) that are related to each other through temporal relations such as precedes, isSubprocessOf, and overlaps. The properties of the physical entities, defined under the Physical_Property class, change as they participate in the plastic deformational processes. The properties are categorized into dynamical, constitutive

  2. Preface to the Viewpoint Set: Nanostructured metals - Advances in processing, characterization and application

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2009-01-01

    with increasingly finer structures in order to improve properties and sustainability. The structural scale of interest in such materials is therefore reduced to the nanometer range, which means that characterization and modeling of nanostructured metals now address an audience including not only physicists...... and materials scientists but also technologists and engineers. The present Viewpoint Set therefore covers metallic materials with a structural scale ranging from micrometer to nanometer in dimensions and focuses on processing techniques such as plastic deformation and phase transformations. As a result......The theme of two viewpoint sets has been nanostructured metals: one in 2003 on “Mechanical properties of fully dense nanocrystalline metals” (Scripta Materialia 2003;49:625–680) and one in 2004 on “Metals and alloys with a structural scale from the micrometer to the atomic dimensions” (Scripta...

  3. Process for the enhanced capture of heavy metal emissions

    Science.gov (United States)

    Biswas, Pratim; Wu, Chang-Yu

    2001-01-01

    This invention is directed to a process for forming a sorbent-metal complex. The process includes oxidizing a sorbent precursor and contacting the sorbent precursor with a metallic species. The process further includes chemically reacting the sorbent precursor and the metallic species, thereby forming a sorbent-metal complex. In one particular aspect of the invention, at least a portion of the sorbent precursor is transformed into sorbent particles during the oxidation step. These sorbent particles then are contacted with the metallic species and chemically reacted with the metallic species, thereby forming a sorbent-metal complex. Another aspect of the invention is directed to a process for forming a sorbent metal complex in a combustion system. The process includes introducing a sorbent precursor into a combustion system and subjecting the sorbent precursor to an elevated temperature sufficient to oxidize the sorbent precursor and transform the sorbent precursor into sorbent particles. The process further includes contacting the sorbent particles with a metallic species and exposing the sorbent particles and the metallic species to a complex-forming temperature whereby the metallic species reacts with the sorbent particles thereby forming a sorbent-metal complex under UV irradiation.

  4. Mouthpart deformities in Chironomidae (Diptera) as bioindicators of heavy metals pollution in Shiroro Lake, Niger State, Nigeria.

    Science.gov (United States)

    Arimoro, Francis O; Auta, Yohanna I; Odume, Oghenekaro N; Keke, Unique N; Mohammed, Adamu Z

    2018-03-01

    In this study, mouthpart deformities in Chironomid larvae (Diptera) were investigated in relation to sediment contamination in the Shiroro Lake in Nigeria. Metals and chironomids were sampled monthly at three stations (A-C) between August 2013 and January 2014. Across the stations, zinc ranged (3.9-75mg/g), manganese (1.29-1.65mg/g), lead (0.00-0.10mg/g), iron (101-168mg/g) and copper (0.13-0.17mg/g). The metal ions did not differ significantly (P > 0.05) between the sampling stations. However, zinc and iron ions were significantly different between the sampling seasons (P < 0.05). Thirteen chironomid species were recorded, with Chironomus sp., Polypedilum sp. and Ablabesmyia sp. dominating the assemblage structure. Mouthpart deformities were significantly higher at Station A compared with Station C, and seasonally significantly higher during dry season compared with wet season. Elevated incidences of deformity were recorded in Chironomus spp larvae as compared to other genera therefore for further studies in this region assessments should be based solely on Chironomus species and ignoring the rest. Strategies need to be developed to reduce the contaminations and the biological effects. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Size effects of nano-spaced basal stacking faults on the strength and deformation mechanisms of nanocrystalline pure hcp metals

    Science.gov (United States)

    Wang, Wen; Jiang, Ping; Yuan, Fuping; Wu, Xiaolei

    2018-05-01

    The size effects of nano-spaced basal stacking faults (SFs) on the tensile strength and deformation mechanisms of nanocrystalline pure cobalt and magnesium have been investigated by a series of large-scale 2D columnar and 3D molecular dynamics simulations. Unlike the strengthening effect of basal SFs on Mg alloys, the nano-spaced basal SFs are observed to have no strengthening effect on the nanocrystalline pure cobalt and magnesium from MD simulations. These observations could be attributed to the following two reasons: (i) Lots of new basal SFs are formed before (for cobalt) or simultaneously with (for magnesium) the other deformation mechanisms (i.e. the formation of twins and the edge dislocations) during the tensile deformation; (ii) In hcp alloys, the segregation of alloy elements and impurities at typical interfaces, such as SFs, can stablilise them for enhancing the interactions with dislocation and thus elevating the strength. Without such segregation in pure hcp metals, the edge dislocations can cut through the basal SFs although the interactions between the dislocations and the pre-existing SFs/newly formed SFs are observed. The nano-spaced basal SFs are also found to have no restriction effect on the formation of deformation twins.

  6. Effects of thermal residual stresses and fiber packing on deformation of metal-matrix composites

    International Nuclear Information System (INIS)

    Nakamura, T.; Suresh, S.

    1993-01-01

    The combined effects of thermal residual stresses and fiber spatial distribution on the deformation of a 6061 aluminum alloy containing a fixed concentration unidirectional boron fibers have been analyzed using detailed finite element models. The geometrical structure includes perfectly periodic, uniformly space fiber arrangements in square and hexagonal cells, as well as different cells in which either 30 or 60 fibers are randomly placed in the ductile matrix. The model involves an elastic-plastic matrix, elastic fibers, and mechanically bonded interfaces. The results indicate that both fiber packing and thermal residual stresses can have a significant effect on the stress-strain characteristics of the composite. The thermal residual stresses cause pronounced matrix yielding which also influences the apparent overall stiffness of the composite during the initial stages of subsequent far-field loading along the axial and transverse direction. Furthermore, the thermal residual stresses apparently elevate the flow stress of the composite during transverse tension. Such effects can be traced back to the level of constraint imposed on the matrix by local fiber spacing. The implications of the present results to the processing of the composites are also briefly addressed

  7. A method of increasing the depth of the plastically deformed layer in the roller burnishing process

    Science.gov (United States)

    Kowalik, Marek; Trzepiecinski, Tomasz

    2018-05-01

    The subject of this paper is an analysis of the determination of the depth of the plastically deformed layer in the process of roller burnishing a shaft using a newly developed method in which a braking moment is applied to the roller. It is possible to increase the depth of the plastically deformed layer by applying the braking moment to the roller during the burnishing process. The theoretical considerations presented are based on the Hertz-Bielayev and Huber-Mises theories and permit the calculation of the depth of plastic deformation of the top layer of the burnished shaft. The theoretical analysis has been verified experimentally and using numerical calculations based on the finite element method using the Msc.MARC program. Experimental tests were carried out on ring-shaped samples made of C45 carbon steel. The samples were burnished at different values of roller force and different values of braking moment. A significant increase was found in the depth of the plastically deformed surface layer of roller burnished shafts. Usage of the phenomenon of strain hardening of steel allows the technology presented here to increase the fatigue life of the shafts.

  8. On the applicability of deformed jellium model to the description of metal clusters

    DEFF Research Database (Denmark)

    Lyalin, Andrey G.; Matveentsev, Anton; Solov'yov, Ilia

    2003-01-01

    -density approximation deformed jellium model we have calculated the binding energies per atom, ionization potentials, deformation parameters and the optimized values of the Wigner-Seitz radii for neutral and singly charged sodium clusters with the number of atoms $N0$. These characteristics are compared...... shape deformations in the formation cluster properties and the quite reasonable level of applicability of the deformed jellium model.......This work is devoted to the elucidation the applicability of jellium model to the description of alkali cluster properties on the basis of comparison the jellium model results with those derived from experiment and within ab initio theoretical framework. On the basis of the Hartree-Fock and local...

  9. Spatiotemporal processing of gated cardiac SPECT images using deformable mesh modeling

    International Nuclear Information System (INIS)

    Brankov, Jovan G.; Yang Yongyi; Wernick, Miles N.

    2005-01-01

    In this paper we present a spatiotemporal processing approach, based on deformable mesh modeling, for noise reduction in gated cardiac single-photon emission computed tomography images. Because of the partial volume effect (PVE), clinical cardiac-gated perfusion images exhibit a phenomenon known as brightening--the myocardium appears to become brighter as the heart wall thickens. Although brightening is an artifact, it serves as an important diagnostic feature for assessment of wall thickening in clinical practice. Our proposed processing algorithm aims to preserve this important diagnostic feature while reducing the noise level in the images. The proposed algorithm is based on the use of a deformable mesh for modeling the cardiac motion in a gated cardiac sequence, based on which the images are processed by smoothing along space-time trajectories of object points while taking into account the PVE. Our experiments demonstrate that the proposed algorithm can yield significantly more-accurate results than several existing methods

  10. Springback prediction in sheet metal forming process based on the hybrid SA

    International Nuclear Information System (INIS)

    Guo Yuqin; Jiang Hong; Wang Xiaochun; Li Fuzhu

    2005-01-01

    In terms of the intensive similarity between the sheet metal forming-springback process and that of the annealing of metals, it is suggested that the simulation of the sheet metal forming process is performed with the Nonlinear FEM and the springback prediction is implemented by solving the large-scale combinational optimum problem established on the base of the energy descending and balancing in deformed part. The BFGS-SA hybrid SA approach is proposed to solve this problem and improve the computing efficiency of the traditional SA and its capability of obtaining the global optimum solution. At the same time, the correlative annealing strategies for the SA algorithm are determined in here. By comparing the calculation results of sample part with those of experiment measurement at the specified sections, the rationality of the schedule of springback prediction used and the validity of the BFGS-SA algorithm proposed are verified

  11. Process to separate alkali metal salts from alkali metal reacted hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John Howard; Alvare, Javier; Larsen, Dennis; Killpack, Jeff

    2017-06-27

    A process to facilitate gravimetric separation of alkali metal salts, such as alkali metal sulfides and polysulfides, from alkali metal reacted hydrocarbons. The disclosed process is part of a method of upgrading a hydrocarbon feedstock by removing heteroatoms and/or one or more heavy metals from the hydrocarbon feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase containing alkali metal salts and reduced heavy metals, and an upgraded hydrocarbon feedstock. The inorganic phase may be gravimetrically separated from the upgraded hydrocarbon feedstock after mixing at a temperature between about 350.degree. C. to 400.degree. C. for a time period between about 15 minutes and 2 hours.

  12. Metals Processing Laboratory Users (MPLUS) Facility Annual Report FY 2002 (October 1, 2001-September 30, 2002)

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, P

    2004-04-27

    The Metals Processing Laboratory Users Facility (MPLUS) is a Department of Energy (DOE), Energy Efficiency and Renewable Energy, Industrial Technologies Program, user facility designated to assist researchers in key industries, universities, and federal laboratories in improving energy efficiency, improving environmental aspects, and increasing competitiveness. The goal of MPLUS is to provide access to the specialized technical expertise and equipment needed to solve metals processing issues that limit the development and implementation of emerging metals processing technologies. The scope of work can also extend to other types of materials. MPLUS has four primary user centers: (1) Processing--casting, powder metallurgy, deformation processing (including extrusion, forging, rolling), melting, thermomechanical processing, and high-density infrared processing; (2) Joining--welding, monitoring and control, solidification, brazing, and bonding; (3) Characterization--corrosion, mechanical properties, fracture mechanics, microstructure, nondestructive examination, computer-controlled dilatometry, and emissivity; and (4) Materials/Process Modeling--mathematical design and analyses, high-performance computing, process modeling, solidification/deformation, microstructure evolution, thermodynamic and kinetic, and materials databases A fully integrated approach provides researchers with unique opportunities to address technologically related issues to solve metals processing problems and probe new technologies. Access is also available to 16 additional Oak Ridge National Laboratory (ORNL) user facilities ranging from state-of-the-art materials characterization capabilities, and high-performance computing to manufacturing technologies. MPLUS can be accessed through a standardized user-submitted proposal and a user agreement. Nonproprietary (open) or proprietary proposals can be submitted. For open research and development, access to capabilities is provided free of charge

  13. Metals Processing Laboratory Users (MPLUS) Facility Annual Report: October 1, 2000 through September 30, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, P

    2004-04-27

    The Metals Processing Laboratory Users Facility (MPLUS) is a Department of Energy (DOE), Energy Efficiency and Renewable Energy, Industrial Technologies Program user facility designated to assist researchers in key industries, universities, and federal laboratories in improving energy efficiency, improving environmental aspects, and increasing competitiveness. The goal of MPLUS is to provide access to the specialized technical expertise and equipment needed to solve metals processing issues that limit the development and implementation of emerging metals processing technologies. The scope of work can also extend to other types of materials. MPLUS has four primary User Centers including: (1) Processing--casting, powder metallurgy, deformation processing including (extrusion, forging, rolling), melting, thermomechanical processing, high density infrared processing; (2) Joining--welding, monitoring and control, solidification, brazing, bonding; (3) Characterization--corrosion, mechanical properties, fracture mechanics, microstructure, nondestructive examination, computer-controlled dilatometry, and emissivity; (4) Materials/Process Modeling--mathematical design and analyses, high performance computing, process modeling, solidification/deformation, microstructure evolution, thermodynamic and kinetic, and materials data bases. A fully integrated approach provides researchers with unique opportunities to address technologically related issues to solve metals processing problems and probe new technologies. Access is also available to 16 additional Oak Ridge National Laboratory (ORNL) user facilities ranging from state of the art materials characterization capabilities, high performance computing, to manufacturing technologies. MPLUS can be accessed through a standardized User-submitted Proposal and a User Agreement. Nonproprietary (open) or proprietary proposals can be submitted. For open research and development, access to capabilities is provides free of charge while

  14. The effect of elevated die temperature on deformation of deep drawn round metal cup

    Science.gov (United States)

    Basril, M. A. M.; Hafsyam, Y. M.; Azuddin, M.; Choudhury, I. A.

    2017-06-01

    One of the major considerations in the current deep drawing practice is the product quality. In this research, the effect of heating temperature on the drawability of the round metal cup has been investigated. Firstly, round metal cups of aluminium and mild steel were drawn from the blank diameters of 60 mm, 65 mm and 70 mm. The experiment conducted at room temperature first, then at 50°C and 100°C. The elongation of the major and minor strains along the cup profile after the process is measured and analysed. On the other hand, the defects from the experiment output and ABAQUS/CAE simulation are compared. The result from experiment shows that the highest major elongation is 11.64 mm and it is happened to a deep drawn aluminium round cup with LDR of 1.69 at temperature of 100°C. On the other hand, for deep drawn mild steel round cup, shows highest major elongation of 12.44 mm for a cup with LDR of 1.56 at 100°C. Both of these statements indicates that the higher temperature could improve the formability of the deep drawn parts besides reducing the probability of the defect to be happened.

  15. Process Modelling of Curing Process-Induced Internal Stress and Deformation of Composite Laminate Structure with Elastic and Viscoelastic Models

    Science.gov (United States)

    Li, Dongna; Li, Xudong; Dai, Jianfeng

    2018-06-01

    In this paper, two kinds of transient models, the viscoelastic model and the linear elastic model, are established to analyze the curing deformation of the thermosetting resin composites, and are calculated by COMSOL Multiphysics software. The two models consider the complicated coupling between physical and chemical changes during curing process of the composites and the time-variant characteristic of material performance parameters. Subsequently, the two proposed models are implemented respectively in a three-dimensional composite laminate structure, and a simple and convenient method of local coordinate system is used to calculate the development of residual stresses, curing shrinkage and curing deformation for the composite laminate. Researches show that the temperature, degree of curing (DOC) and residual stresses during curing process are consistent with the study in literature, so the curing shrinkage and curing deformation obtained on these basis have a certain referential value. Compared the differences between the two numerical results, it indicates that the residual stress and deformation calculated by the viscoelastic model are more close to the reference value than the linear elastic model.

  16. Noble Metal/Ceramic Composites in Flame Processes

    DEFF Research Database (Denmark)

    Schultz, Heiko; Madler, Lutz; Strobel, Reto

    conditions influence the resulting noble metal particles size in those systems [1]. For every specific application the particle size and the metal/metal oxide interaction affect the performance of these nano-composite materials [2]. Recently, aerosol processes have been successfully used to produce platinum...

  17. Deformation of Ordinary Chondrite Under Very Reducing Conditons: Implications for Liquid Metal Compositions, HSE Partitioning and Enstatite Chondrites

    Science.gov (United States)

    Rushmer, T.; Corgne, A.

    2008-12-01

    One important method in which to gain insight into metallic liquid compositions and their ability to control HSE (highly siderophile element) distribution is through experimentation. Deformation experiments can additionally provide information into mechanisms and chemical consequences of dynamic liquid metal segregation under a variety of conditions. We report results on metallic liquid HSE compositions and their distribution from a set of deformation experiments on a natural H6 ordinary chondrite, performed under very reducing conditions and a series of phase equilibria experiments focused on HSE partitioning between Si-rich and S-rich Fe molten alloys. The deformation experiments were conducted at temperatures between 925°C and 950°C, at 1.3 GPa confining pressure with a strain rate of 10-4/s. Major element analyses of both silicate and metal phases show that they are considerably reduced and the typically lithophile elements are behaving like siderophiles. Fe-Ni-Si compositions are found in the shear zones produced during the deformation experiment. Metallic compositions also include (Mg,Fe,Ca)S, Fe-Ni-Si, FeP, and Fe-Ni-S quench metal. Silicate phases include forsterite (Fo92-96) and enstatite (En98). Highly siderophile element (HSE) concentrations have been measured in the sulphide ((Fe,Mg,Ca)S) and metal (Fe- Ni-Si) phases by LA-ICPMS and compared with results from an earlier set of experiments on the same material but which were not performed under reducing conditions. The partitioning of the PGE is modified by the changing conditions with elements such as Ir and Os having higher DMetal/Sulphide values under reducing conditions. Partitioning experiments between molten FeS and Ni-, Si-bearing molten Fe were performed at 1.5-5.0 GPa and 1500-1750° to further investigate this observation. The starting material is synthetic, doped with a range of trace and HSE elements. The results confirm the preference of the HSE for the metallic phase with DMetal

  18. Application of Hydroforming Process in Sheet Metal Formation

    OpenAIRE

    GRIZELJ, Branko; CUMIN, Josip; ERGIĆ, Todor

    2009-01-01

    This article deals with the theory and application of a hydroforming process. Nowadays automobile manufacturers use high strength sheet metal plates. This high strength steel sheet metal plates are strain hardened in the process of metal forming. With the use of high strength steel, cars are made lightweight, which is intended for low fuel consumption because of high energy prices. Some examples of application of a hydroforming process are simulated with FEM.

  19. Research on the drawing process with a large total deformation wires of AZ31 alloy

    International Nuclear Information System (INIS)

    Bajor, T; Muskalski, Z; Suliga, M

    2010-01-01

    Magnesium and their alloys have been extensively studied in recent years, not only because of their potential applications as light-weight engineering materials, but also owing to their biodegradability. Due to their hexagonal close-packed crystallographic structure, cold plastic processing of magnesium alloys is difficult. The preliminary researches carried out by the authors have indicated that the application of the KOBO method, based on the effect of cyclic strain path change, for the deformation of magnesium alloys, provides the possibility of obtaining a fine-grained structure material to be used for further cold plastic processing with large total deformation. The main purpose of this work is to present research findings concerning a detailed analysis of mechanical properties and changes occurring in the structure of AZ31 alloy wire during the multistage cold drawing process. The appropriate selection of drawing parameters and the application of multistep heat treatment operations enable the deformation of the AZ31 alloy in the cold drawing process with a total draft of about 90%.

  20. Process for the disposal of alkali metals

    International Nuclear Information System (INIS)

    Lewis, L.C.

    1977-01-01

    Large quantities of alkali metals may be safely reacted for ultimate disposal by contact with a hot concentrated caustic solution. The alkali metals react with water in the caustic solution in a controlled reaction while steam dilutes the hydrogen formed by the reaction to a safe level. 6 claims

  1. Constitutive Behavior and Processing Map of T2 Pure Copper Deformed from 293 to 1073 K

    Science.gov (United States)

    Liu, Ying; Xiong, Wei; Yang, Qing; Zeng, Ji-Wei; Zhu, Wen; Sunkulp, Goel

    2018-02-01

    The deformation behavior of T2 pure copper compressed from 293 to 1073 K with strain rates from 0.01 to 10 s-1 was investigated. The constitutive equations were established by the Arrhenius constitutive model, which can be expressed as a piecewise function of temperature with two sections, in the ranges 293-723 K and 723-1073 K. The processing maps were established according to the dynamic material model for strains of 0.2, 0.4, 0.6, and 0.8, and the optimal processing parameters of T2 copper were determined accordingly. In order to obtain a better understanding of the deformation behavior, the microstructures of the compressed samples were studied by electron back-scattered diffraction. The grains tend to be more refined with decreases in temperature and increases in strain rate.

  2. A mesh density study for application to large deformation rolling process evaluation

    International Nuclear Information System (INIS)

    Martin, J.A.

    1997-12-01

    When addressing large deformation through an elastic-plastic analysis the mesh density is paramount in determining the accuracy of the solution. However, given the nonlinear nature of the problem, a highly-refined mesh will generally require a prohibitive amount of computer resources. This paper addresses finite element mesh optimization studies considering accuracy of results and computer resource needs as applied to large deformation rolling processes. In particular, the simulation of the thread rolling manufacturing process is considered using the MARC software package and a Cray C90 supercomputer. Both mesh density and adaptive meshing on final results for both indentation of a rigid body to a specified depth and contact rolling along a predetermined length are evaluated

  3. InSAR Deformation Time Series Processed On-Demand in the Cloud

    Science.gov (United States)

    Horn, W. B.; Weeden, R.; Dimarchi, H.; Arko, S. A.; Hogenson, K.

    2017-12-01

    During this past year, ASF has developed a cloud-based on-demand processing system known as HyP3 (http://hyp3.asf.alaska.edu/), the Hybrid Pluggable Processing Pipeline, for Synthetic Aperture Radar (SAR) data. The system makes it easy for a user who doesn't have the time or inclination to install and use complex SAR processing software to leverage SAR data in their research or operations. One such processing algorithm is generation of a deformation time series product, which is a series of images representing ground displacements over time, which can be computed using a time series of interferometric SAR (InSAR) products. The set of software tools necessary to generate this useful product are difficult to install, configure, and use. Moreover, for a long time series with many images, the processing of just the interferograms can take days. Principally built by three undergraduate students at the ASF DAAC, the deformation time series processing relies the new Amazon Batch service, which enables processing of jobs with complex interconnected dependencies in a straightforward and efficient manner. In the case of generating a deformation time series product from a stack of single-look complex SAR images, the system uses Batch to serialize the up-front processing, interferogram generation, optional tropospheric correction, and deformation time series generation. The most time consuming portion is the interferogram generation, because even for a fairly small stack of images many interferograms need to be processed. By using AWS Batch, the interferograms are all generated in parallel; the entire process completes in hours rather than days. Additionally, the individual interferograms are saved in Amazon's cloud storage, so that when new data is acquired in the stack, an updated time series product can be generated with minimal addiitonal processing. This presentation will focus on the development techniques and enabling technologies that were used in developing the time

  4. Interaction of Degradation, Deformation and Transport Processes in Municipal Solid Waste Landfills

    OpenAIRE

    Bente, Sonja

    2010-01-01

    In this thesis a model for the complex interactions between deformation, degradation and transport processe in municipal solid waste landfills is presented. Key aspects of the model are a joint continuum mechanical framework and a monolithic solution of the governing equations within the Theory of Porous Media. Interactions are considered by coupling the governing physical fields over the domain of a representative elementary volume via selected state variables. A simplified two-stage degrada...

  5. Mechanisms operating during plastic deformation of metals under concurrent production of cascades and dislocations

    DEFF Research Database (Denmark)

    Trinkaus, H.; Singh, Bachu Narain

    Recent in-reactor tensile tests (IRTs) on pure copper have revealed a deformation behaviour which is significantly different from that observed in post-irradiation tensile tests (PITs). In IRTs, the material deforms uniformly and homogeneously without yield drop and plastic instability as commonly...... observed in PITs. An increase in the pre-yield dose results in an increase in the level of hardening over the whole test periods and a decrease in the uniform elongation suggesting that the materials “remember” the impact of the pre-yield damage level. These features are modelled in terms of the decoration...... and deformation, moving dislocations are decorated by the sweeping of matrix loops. The interaction of dislocations with loops and between loops is discussed as a function of the relevant parameters. On this basis, the kinetics of decoration is treated in terms of fluxes of loops to and reactions with each other...

  6. Progressive softening of brittle-ductile transition due to interplay between chemical and deformation processes

    Science.gov (United States)

    Jeřábek, Petr; Bukovská, Zita; Morales, Luiz F. G.

    2017-04-01

    The micro-scale shear zones (shear bands) in granitoids from the South Armorican Shear Zone reflect localization of deformation and progressive weakening in the conditions of brittle-ductile transition. We studied microstructures in the shear bands with the aim to establish their P-T conditions and to derive stress and strain rates for specific deformation mechanisms. The evolving microstructure within shear bands documents switches in deformation mechanisms related to positive feedbacks between deformation and chemical processes and imposes mechanical constraints on the evolution of the brittle-ductile transition in the continental transform fault domains. The metamorphic mineral assemblage present in the shear bands indicate their formation at 300-350 ˚ C and 100-400 MPa. Focusing on the early development of shear bands, we identified three stages of shear band evolution. The early stage I associated with initiation of shear bands occurs via formation of microcracks with possible yielding differential stress of up to 250 MPa (Diamond and Tarantola, 2015). Stage II is associated with subgrain rotation recrystallization and dislocation creep in quartz and coeval dissolution-precipitation creep of microcline. Recrystallized quartz grains in shear bands show continual increase in size, and decrease in stress and strain rates from 94 MPa to 17-26 MPa (Stipp and Tullis, 2003) and 3.8*10-12 s-1- 1.8*10-14 s-1 (Patterson and Luan, 1990) associated with deformation partitioning into weaker microcline layer and shear band widening. The quartz mechanical data allowed us to set some constrains for coeval dissolution-precipitation of microcline which at our estimated P-T conditions suggests creep at 17-26 MPa differential stress and 3.8*10-13 s-1 strain rate. Stage III is characterized by localized slip along interconnected white mica bands accommodated by dislocation creep at strain rate 3.8*10-12 s-1 and stress 9.36 MPa (Mares and Kronenberg, 1993). The studied example

  7. Low-level radioactive waste from rare metals processing facilities

    International Nuclear Information System (INIS)

    Eng, J.; Hendricks, D.W.; Feldman, J.; Giardina, P.A.

    1980-01-01

    This paper reviews the situations at the existing Teledyne Wah Chang Co., Inc. located at Albany, Oregon, and the former Carborundum Corp./Amax Specialty Metals, Inc., facilities located at Parkersburg, West Virginia, and Akron, New York, in order to show the extent of the radioactivity problem at rare metals processing facilities and the need to identify for radiological review other rare metal and rare earth processing sites

  8. Correlation between relaxations and plastic deformation, and elastic model of flow in metallic glasses and glass-forming liquids

    International Nuclear Information System (INIS)

    Wang Weihua

    2011-01-01

    We study the similarity and correlations between relaxations and plastic deformation in metallic glasses (MGs) and MG-forming liquids. It is shown that the microscope plastic events, the initiation and formation of shear bands, and the mechanical yield in MGs where the atomic sites are topologically unstable induced by applied stress, can be treated as the glass to supercooled liquid state transition induced by external shear stress. On the other hand, the glass transition, the primary and secondary relaxations, plastic deformation and yield can be attributed to the free volume increase induced flow, and the flow can be modeled as the activated hopping between the inherent states in the potential energy landscape. We then propose an extended elastic model to describe the flow based on the energy landscape theory. That is, the flow activation energy density is linear proportional to the instantaneous elastic moduli, and the activation energy density ρ E is determined to be a simple expression of ρ E =(10/11)G+(1/11)K. The model indicates that both shear and bulk moduli are critical parameters accounting for both the homogeneous and inhomogeneous flows in MGs and MG-forming liquids. The elastic model is experimentally certified. We show that the elastic perspectives offers a simple scenario for the flow in MGs and MG-forming liquids and are suggestive for understanding the glass transition, plastic deformation, and nature and characteristics of MGs

  9. Micromechanics of deformation of metallic-glass-matrix composites from in situ synchrotron strain measurements and finite element modeling

    International Nuclear Information System (INIS)

    Ott, R.T.; Sansoz, F.; Molinari, J.F.; Almer, J.; Ramesh, K.T.; Hufunagel, T.C.

    2005-01-01

    In situ X-ray scattering and finite element modeling (FEM) were used to examine the micromechanics of deformation of in situ formed metallic-glass-matrix composites consisting of Ta-rich particles dispersed in an amorphous matrix. The strain measurements show that under uniaxial compression the second-phase particles yield at an applied stress of approx. 325 MPa. After yielding, the particles do not strain harden significantly; we show that this is due to an increasingly hydrostatic stress state arising from the lateral constraint on deformation of the particles imposed by the elastic matrix. Shear band initiation in the matrix is not due to the difference in elastic properties between the matrix and the particles. Rather, the development of a plastic misfit strain causes stress concentrations around the particles, resulting in localized yielding of the matrix by shear band formation at an applied stress of approx. 1450 MPa, considerably lower than the macroscopic yield stress of the composite (approx. 1725 MPa). Shear bands do not propagate at the lower stress because the yield criterion of the matrix is only satisfied in the region immediately around the particles. At the higher stresses, the yield criterion is satisfied in large regions of the matrix, allowing extensive shear band propagation and significant macroscopic plastic deformation. However, the presence of the particles makes the stress state highly inhomogeneous, which may partially explain why fracture is suppressed in the composite, allowing the development of large plastic strains

  10. A new numerical modelling method for deformation behaviour of metallic porous materials using X-ray computed microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Doroszko, M., E-mail: m.doroszko@pb.edu.pl; Seweryn, A., E-mail: a.seweryn@pb.edu.pl

    2017-03-24

    Microtomographic devices have limited imaging accuracy and are often insufficient for proper mapping of small details of real objects (e.g. elements of material mesostructures). This paper describes a new method developed to compensate the effect of X-ray computed microtomography (micro-CT) inaccuracy in numerical modelling of the deformation process of porous sintered 316 L steel. The method involves modification of microtomographic images where the pore shapes are separated. The modification consists of the reconstruction of fissures and small pores omitted by micro-CT scanning due to the limited accuracy of the measuring device. It enables proper modelling of the tensile deformation process of porous materials. In addition, the proposed approach is compared to methods described in the available literature. As a result of numerical calculations, stress and strain distributions were obtained in deformed sintered 316 L steel. Based on the results, macroscopic stress-strain curves were received. Maximum principal stress distributions obtained by the proposed calculation model, indicated specific locations, where the stress reached a critical value, and fracture initiation occurred. These are bridges with small cross sections and notches in the shape of pores. Based on calculation results, the influence of the deformation mechanism of the material porous mesostructures on their properties at the macroscale is described.

  11. A new numerical modelling method for deformation behaviour of metallic porous materials using X-ray computed microtomography

    International Nuclear Information System (INIS)

    Doroszko, M.; Seweryn, A.

    2017-01-01

    Microtomographic devices have limited imaging accuracy and are often insufficient for proper mapping of small details of real objects (e.g. elements of material mesostructures). This paper describes a new method developed to compensate the effect of X-ray computed microtomography (micro-CT) inaccuracy in numerical modelling of the deformation process of porous sintered 316 L steel. The method involves modification of microtomographic images where the pore shapes are separated. The modification consists of the reconstruction of fissures and small pores omitted by micro-CT scanning due to the limited accuracy of the measuring device. It enables proper modelling of the tensile deformation process of porous materials. In addition, the proposed approach is compared to methods described in the available literature. As a result of numerical calculations, stress and strain distributions were obtained in deformed sintered 316 L steel. Based on the results, macroscopic stress-strain curves were received. Maximum principal stress distributions obtained by the proposed calculation model, indicated specific locations, where the stress reached a critical value, and fracture initiation occurred. These are bridges with small cross sections and notches in the shape of pores. Based on calculation results, the influence of the deformation mechanism of the material porous mesostructures on their properties at the macroscale is described.

  12. Failure Analysis of a Sheet Metal Blanking Process Based on Damage Coupling Model

    Science.gov (United States)

    Wen, Y.; Chen, Z. H.; Zang, Y.

    2013-11-01

    In this paper, a blanking process of sheet metal is studied by the methods of numerical simulation and experimental observation. The effects of varying technological parameters related to the quality of products are investigated. An elastoplastic constitutive equation accounting for isotropic ductile damage is implemented into the finite element code ABAQUS with a user-defined material subroutine UMAT. The simulations of the damage evolution and ductile fracture in a sheet metal blanking process have been carried out by the FEM. In order to guarantee computation accuracy and avoid numerical divergence during large plastic deformation, a specified remeshing technique is successively applied when severe element distortion occurs. In the simulation, the evolutions of damage at different stage of the blanking process have been evaluated and the distributions of damage obtained from simulation are in proper agreement with the experimental results.

  13. Effects of crystal structure and grain orientation on the roughness of deformed polycrystalline metals

    NARCIS (Netherlands)

    Wouters, Onne; Vellinga, WP; van Tijum, Redmer; De Hosson, JTM

    Surface roughening during tensile deformation of polycrystalline aluminum, iron and zinc is investigated using white light confocal microscopy and orientation imaging microscopy. A height-height correlation technique is used to analyze the data. The surface obeys self-affine scaling on length scales

  14. Antipollution processing of a used refining catalyst and metal recovery

    Energy Technology Data Exchange (ETDEWEB)

    Trinh Dinh Chan; Llido, E.

    1992-04-30

    The used catalyst, containing metals such as vanadium, nickel and iron, is unloaded from the plant and is first processed by stripping; it is then calcined in critical conditions, and the catalyst metals are leached with a sodium hydroxide or sodium carbonate aqueous solution. The antipollution process can be applied to oil fraction hydroconversion or hydroprocessing catalysts.

  15. Higher harmonic imaging of tensile plastic deformation in loading and reloading processes by local resonance method

    International Nuclear Information System (INIS)

    Kawashima, Koichiro; Yasui, Hajime

    2015-01-01

    We have imaged plastically deformed region in a 5052 aluminum plate under tensile loading, unloading and reloading processes by using an immersion local resonance method. By transmitting large-amplitude burst wave of which frequency is a through-thickness resonant frequency of the plate, dislocation loops in plastic zone are forced to vibrate. The higher harmonic amplitude excited by the dislocation movement is mapped for the transducer position. The extension of plastic zone under monotonically increased loading, decrease in harmonic amplitude under unloading process and marked extension of plastic zone in reloading up to 0.4% plastic strain are clearly imaged. (author)

  16. Different deformation patterns using GPS in the volcanic process of El Hierro (Canary Island) 2011-2013

    Science.gov (United States)

    García-Cañada, Laura; José García-Arias, María; Pereda de Pablo, Jorge; Lamolda, Héctor; López, Carmen

    2014-05-01

    Ground deformation is one of the most important parameter in volcano monitoring. The detected deformations in volcanic areas can be precursors of a volcanic activity and contribute with useful information to study the evolution of an unrest, eruption or any volcanic process. GPS is the most common technique used to measure volcano deformations. It can be used to detect slow displacement rates or much larger and faster deformations associated with any volcanic process. In volcanoes the deformation is expected to be a mixed of nature; during periods of quiescence it will be slow or not present, while increased activity slow displacement rates can be detected or much larger and faster deformations can be measure due to magma intrusion, for example in the hours to days prior a eruption beginning. In response to the anomalous seismicity detected at El Hierro in July 2011, the Instituto Geográfico Nacional (IGN) improved its volcano monitoring network in the island with continuous GPS that had been used to measure the ground deformation associated with the precursory unrest since summer 2011, submarine eruption (October 2011-March 2012) and the following unrest periods (2012-2013). The continuous GPS time series, together with other techniques, had been used to evaluate the activity and to detect changes in the process. We investigate changes in the direction and module of the deformation obtained by GPS and they show different patterns in every unrest period, very close to the seismicity locations and migrations.

  17. Interface Microstructure and Deformation Behavior of an Al-Cu Dissimilar Metal Plate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Seok; Lee, Su Eun; Kwon, Yong-Nam [Korea Institute of Materials Science, Changwon (Korea, Republic of); Kim, Jung Su [Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Min Jung; Bae, Dong Hyun [Korea Clad Tech. Co. Ltd., Daegu (Korea, Republic of)

    2013-07-15

    The aim of this article is to elucidate the influence of reduction ratio during roll bonding on the microstructural evolution, mechanical properties and room-temperature formability of Al-Cu 2-ply clad metal. The evolution of the interface microstructure was first characterized by a scanning electron microscope (SEM) and transmission electron microscope (TEM) attached with energy dispersive spectroscopy (EDS). The presence of an intermetallic compound as well as severe grain refinement was detected at the interface of the Al-Cu bimetal fabricated under the highest reduction ratio of 65% adopted in this study. Taking into account the difference of the microstructure with a reduction the ratio, mechanical properties and bonding strength were then evaluated by uniaxial tensile and peel tests. It was observed that the bonding strength, elongation and tensile strength for Al-Cu 2-ply sheets were incomparably reduced by decreasing the reduction ratio during the roll bonding process, which directly correlated with the microstructural evolution at the interface. Moreover, the higher reduction ratio during the roll bonding, the more room temperature formability could be achieved for Al-Cu 2-ply sheet by applying both three-point bending and Erichsen tests.

  18. Calculation of electromagnetic force in electromagnetic forming process of metal sheet

    International Nuclear Information System (INIS)

    Xu Da; Liu Xuesong; Fang Kun; Fang Hongyuan

    2010-01-01

    Electromagnetic forming (EMF) is a forming process that relies on the inductive electromagnetic force to deform metallic workpiece at high speed. Calculation of the electromagnetic force is essential to understand the EMF process. However, accurate calculation requires complex numerical solution, in which the coupling between the electromagnetic process and the deformation of workpiece needs be considered. In this paper, an appropriate formula has been developed to calculate the electromagnetic force in metal work-piece in the sheet EMF process. The effects of the geometric size of coil, the material properties, and the parameters of discharge circuit on electromagnetic force are taken into consideration. Through the formula, the electromagnetic force at different time and in different positions of the workpiece can be predicted. The calculated electromagnetic force and magnetic field are in good agreement with the numerical and experimental results. The accurate prediction of the electromagnetic force provides an insight into the physical process of the EMF and a powerful tool to design optimum EMF systems.

  19. The transformation of spinal curvature into spinal deformity: pathological processes and implications for treatment

    Directory of Open Access Journals (Sweden)

    Hawes Martha C

    2006-03-01

    Full Text Available Abstract Background This review summarizes what is known about the pathological processes (e.g. structural and functional changes, by which spinal curvatures develop and evolve into spinal deformities. Methods Comprehensive review of articles (English language only published on 'scoliosis,' whose content yielded data on the pathological changes associated with spinal curvatures. Medline, Science Citation Index and other searches yielded > 10,000 titles each of which was surveyed for content related to 'pathology' and related terms such as 'etiology,' 'inheritance,' 'pathomechanism,' 'signs and symptoms.' Additional resources included all books published on 'scoliosis' and available through the Arizona Health Sciences Library, Interlibrary Loan, or through direct contact with the authors or publishers. Results A lateral curvature of the spine–'scoliosis'–can develop in association with postural imbalance due to genetic defects and injury as well as pain and scarring from trauma or surgery. Irrespective of the factor that triggers its appearance, a sustained postural imbalance can result, over time, in establishment of a state of continuous asymmetric loading relative to the spinal axis. Recent studies support the longstanding hypothesis that spinal deformity results directly from such postural imbalance, irrespective of the primary trigger, because the dynamics of growth within vertebrae are altered by continuous asymmetric mechanical loading. These data suggest that, as long as growth potential remains, evolution of a spinal curvature into a spinal deformity can be prevented by reversing the state of continuous asymmetric loading. Conclusion Spinal curvatures can routinely be diagnosed in early stages, before pathological deformity of the vertebral elements is induced in response to asymmetric loading. Current clinical approaches involve 'watching and waiting' while mild reversible spinal curvatures develop into spinal deformities with

  20. Fabrication of metal-matrix composites and adaptive composites using ultrasonic consolidation process

    International Nuclear Information System (INIS)

    Kong, C.Y.; Soar, R.C.

    2005-01-01

    Ultrasonic consolidation (UC) has been used to embed thermally sensitive and damage intolerant fibres within aluminium matrix structures using high frequency, low amplitude, mechanical vibrations. The UC process can induce plastic flow in the metal foils being bonded, to allow the embedding of fibres at typically 25% of the melting temperature of the base metal and at a fraction of the clamping force when compared to fusion processes. To date, the UC process has successfully embedded Sigma silicon carbide (SiC) fibres, shape memory alloy wires and optical fibres, which are presented in this paper. The eventual aim of this research is targeted at the fabrication of adaptive composite structures having the ability to measure external stimuli and respond by adapting their structure accordingly, through the action of embedded active and passive functional fibres within a freeform fabricated metal-matrix structure. This paper presents the fundamental studies of this research to identify embedding methods and working range for the fabrication of adaptive composite structures. The methods considered have produced embedded fibre specimens in which large amounts of plastic flow have been observed, within the matrix, as it is deformed around the fibres, resulting in fully consolidated specimens without damage to the fibres. The microscopic observation techniques and macroscopic functionality tests confirms that the UC process could be applied to the fabrication of metal-matrix composites and adaptive composites, where fusion techniques are not feasible and where a 'cold' process is necessary

  1. Towards high velocity deformation characterisation of metals and composites using Digital Image Correlation

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Normann Wilken; Berggreen, Christian; Boyd, S.W

    2010-01-01

    images and then extracting deformation data using Digital Image Correlation (DIC) from tensile testing in the intermediate strain rate regime available with the test machines. Three different materials, aluminium alloy 1050, S235 steel and glass fibre reinforced plastic (GFRP) were tested at different......Characterisation of materials subject to high velocity deformation is necessary as many materials behave differently under such conditions. It is particularly important for accurate numerical simulation of high strain rate events. High velocity servo-hydraulic test machines have enabled material...... testing in the strain rate regime from 1 – 500 ε/s. The range is much lower than that experienced under ballistic, shock or impact loads, nevertheless it is a useful starting point for the application of optical techniques. The present study examines the possibility of using high speed cameras to capture...

  2. Change and anisotropy of elastic modulus in sheet metals due to plastic deformation

    Science.gov (United States)

    Ishitsuka, Yuki; Arikawa, Shuichi; Yoneyama, Satoru

    2015-03-01

    In this study, the effect of the plastic deformation on the microscopic structure and the anisotropy of the elastic modulus in the cold-rolled steel sheet (SPCC) is investigated. Various uniaxial plastic strains (0%, 2.5%, 5%, 7.5%, and 10%) are applied to the annealed SPCC plates, then, the specimens for the tensile tests are cut out from them. The elastic moduli in the longitudinal direction and the transverse direction to the direction that are pre-strained are measured by the tensile tests. Cyclic tests are performed to investigate the effects of the internal friction caused by the movable dislocations in the elastic deformation. Also, the movable dislocations are quantified by the boundary tracking for TEM micrographs. In addition, the behaviors of the change of the elastic modulus in the solutionized and thermal aged aluminum alloy (A5052) are measured to investigate the effect on the movable dislocations with the amount of the depositions. As a result in SPCC, the elastic moduli of the 0° and 90° directions decrease more than 10% as 10% prestrain applied. On the other hand, the elastic modulus shows the recovery behavior after the strain aging and the annealing. The movable dislocation and the internal friction show a tendency to increase as the plastic strain increases. The marked anisotropy is not observed in the elastic modulus and the internal friction. The elastic modulus in A5052 with many and few depositions decreases similarly by the plastic deformation. From the above, the movable dislocations affect the elastic modulus strongly without depending on the deposition amount. Moreover, the elastic modulus recovers after the plastic deformation by reducing the effects of them with the strain aging and the heat treatment.

  3. Chapter 4. Fundamental mechanisms of the low temperature plastic deformation of metals

    International Nuclear Information System (INIS)

    Fouquet, J. de

    1976-01-01

    The influence of microstructure, grain boundaries, and strain hardening, on the low temperature plasticity of polycristals is studied. The experimental data on flow stress, work hardening, temperature and strain rate effects, alloying elements and grain size effect are firstly considered, on a macroscopic scale. The mechanisms of the low temperature plastic deformation, and the strain-stress relations are then described in terms of slip modes, mobility, configuration and distributions and interactions of dislocations [fr

  4. Deformation properties of sedimentary rocks in the process of underground coal gasification

    Directory of Open Access Journals (Sweden)

    Mirosława Bukowska

    2015-01-01

    Full Text Available The article presents results of research into changes in deformation properties of rocks, under influence of temperature, during the process of underground coal gasification. Samples of carboniferous sedimentary rocks (claystones and sandstones, collected in different areas of Upper Silesian Coal Basin (GZW, were heated at the temperature of between 100 and 1000–1200 °C, and then subjected to uniaxial compression tests to obtain a full stress-strain curves of the samples and determine values of residual strain and Poisson's ratio. To compare the obtained values of deformation parameters of rocks, tested in dry-air state and after heating in a given range of temperature, normalised values of residual strain and Poisson's ratio were determined. Based on them, coefficient of influence of temperature on tested deformation parameters was determined. The obtained values of the coefficient can be applied in mining practice to forecast deformability of gangue during underground coal gasification, when in the direct surrounding of a georeactor there are claystones or sandstones. The obtained results were analysed based on classification of uniaxial compression strength of GZW gangue, which formed the basis for dividing claystones and sandstones into very low, low, medium and high uniaxial compression strength rocks. Based on the conducted tests it was concluded that the influence of uniaxial compression strength on the value of residual strain, unlike the influence of grain size of sandstones, is unambiguous within the range of changes in the parameter. Among claystones changes in the value of Poisson's ratio depending on their initial strength were observed. Sandstones of different grain size either increased or decreased the value of Poisson's ratio in comparison with the value determined at room temperature in dry-air conditions.

  5. Compensation of equipment housing elements of reactor units with heavy liquid metal coolant vessel temperature deformations

    International Nuclear Information System (INIS)

    Lebedevich, V.; Ahmetshin, M.; Mendes, D.; Kaveshnikov, S.; Vinogradov, A.

    2015-01-01

    In Russia a lot of different versions of fast reactors (FRs) are investigated and one of these is FR cooled by liquid lead and liquid lead-bismuth alloy. In this poster we are interested by FR with concrete vessel; its components are placed in cavities inside the vessel, and connected by a channel system. During the installation the equipment components are placed in several equipment housings. Between these housings there are cavities with coolant. The alignment of the housings should be provided. It can be broken by irregular concrete vessel heating during FR starting or other transition regimes. Our goal is to suggest a list of designing steps to compensate temperature deformations of equipment housing elements. A simplified model of equipment housing was suggested. It consists of two cylinders - tunnels in the concrete vessel, separated by a cavity filled by coolant and inert gas. The bottom part was considered as heated to 420 C. degrees while in the top part temperature decreased to 45 C. degrees (on the concrete surface). According to this data, results show that temperature gradient leads to a concrete layer dislocation of about 12.5 mm, which can lead to damage and breaking alignment. We propose the following solution to compensate for temperature deformation: -) to chisel out part of the upper top of the insulating concrete; -) to install an adequate misalignment of equipment housing elements preliminary; and -) to use a torsion system like a piston-type device for providing additional strength in order to compensate deformation and vibrations

  6. A new constitutive equation for strain hardening and softening of fcc metals during severe plastic deformation

    International Nuclear Information System (INIS)

    Wei, W.; Wei, K.X.; Fan, G.J.

    2008-01-01

    The stress-strain relationship for strain hardening and softening of high-purity aluminum and copper, which were deformed by equal channel angular pressing (ECAP) at ambient temperature, was analyzed by combining the Estrin and Mecking (EM) model and an Avrami-type equation with experimental data during severe plastic deformation. The initial strain hardening can be described by the EM model, while the flow stress arrives at the peak stress after it was saturated. However, strain softening similar to plastic deformation at high temperatures is observed after the peak stress. Moreover, the peak strain at the maximum flow stress is ∼4 for copper and ∼2 for aluminum. A new constitutive equation was developed to describe strain softening at high strain levels, which was supported well by tensile, compression and microhardness tests at room temperature and low strain rate. It was observed that dynamic recovery and recrystallization occurs in copper, and recrystallized grains and their growth in aluminum. The results indicate that dynamic recovery and recrystallization was the dominant softening mechanism, which was confirmed by scanning electron microscopy-electron channeling contrast observations and the abnormal relationship between the imposed strain during ECAP and subsequent recrystallization temperature after ECAP

  7. Manufacturing processes of cellular metals. Part I. Liquid route processes

    International Nuclear Information System (INIS)

    Fernandez, P.; Cruz, L. J.; Coleto, J.

    2008-01-01

    With its interesting and particular characteristics, cellular metals are taking part of the great family of new materials. They can have open or closed porosity. At the present time, the major challenge for the materials researchers is based in the manufacturing techniques improvement in order to obtain reproducible and reliable cellular metals with quality. In the present paper, the different production methods to manufacture cellular metals by liquid route are reviewed; making a short description about the main parameters involved and the advantages and drawbacks in each of them. (Author) 106 refs

  8. Prediction Of Formability In Sheet Metal Forming Processes Using A Local Damage Model

    International Nuclear Information System (INIS)

    Teixeira, P.; Santos, Abel; Cesar Sa, J.; Andrade Pires, F.; Barata da Rocha, A.

    2007-01-01

    The formability in sheet metal forming processes is mainly conditioned by ductile fracture resulting from geometric instabilities due to necking and strain localization. The macroscopic collapse associated with ductile failure is a result of internal degradation described throughout metallographic observations by the nucleation, growth and coalescence of voids and micro-cracks. Damage influences and is influenced by plastic deformation and therefore these two dissipative phenomena should be coupled at the constitutive level. In this contribution, Lemaitre's ductile damage model is coupled with Hill's orthotropic plasticity criterion. The coupling between damaging and material behavior is accounted for within the framework of Continuum Damage Mechanics (CDM). The resulting constitutive equations are implemented in the Abaqus/Explicit code, for the prediction of fracture onset in sheet metal forming processes. The damage evolution law takes into account the important effect of micro-crack closure, which dramatically decreases the rate of damage growth under compressive paths

  9. Separation of Metals From Spent Catalysts Waste by Bioleaching Process

    OpenAIRE

    Sirin Fairus, Tria Liliandini, M.Febrian, Ronny Kurniawan

    2010-01-01

    A kind of waste that hard to be treated is a metal containing solid waste. Leaching method is one thealternative waste treatment. But there still left an obstacle on this method, it is the difficulty to find theselective solvent for the type of certain metal that will separated. Bioleaching is one of the carry ablealternative waste treatments to overcome that obstacle. Bioleaching is a metal dissolving process orextraction from a sediment become dissolve form using microorganisms. On this met...

  10. Acoustic softening in metals during ultrasonic assisted deformation via CP-FEM

    KAUST Repository

    Siddiq, Amir; El Sayed, Tamer S.

    2011-01-01

    In this paper, a phenomenological crystal plasticity model is modified to account for acoustic (ultrasonic) softening effects based on the level of ultrasonic intensity supplied to single and polycrystalline metals. The material parameters

  11. Investigating deformation processes in AM60 magnesium alloy using the acoustic emission technique

    International Nuclear Information System (INIS)

    Mathis, K.; Chmelik, F.; Janecek, M.; Hadzima, B.; Trojanova, Z.; Lukac, P.

    2006-01-01

    Microstructure changes in an AM60 magnesium alloy were monitored using the acoustic emission (AE) technique during tensile tests in the temperature range from 20 to 300 deg. C. The correlation of the AE signal and the deformation processes is discussed. It is shown, using transmission electron and light microscopy, that the character of the AE response is associated with various modes of mechanical twinning at lower temperatures, whereas at higher temperatures also the influence of non-basal dislocations on the AE response must be taken into account

  12. Modeling of the inhomogeneity of grain refinement during combined metal forming process by finite element and cellular automata methods

    Energy Technology Data Exchange (ETDEWEB)

    Majta, Janusz; Madej, Łukasz; Svyetlichnyy, Dmytro S.; Perzyński, Konrad; Kwiecień, Marcin, E-mail: mkwiecie@agh.edu.pl; Muszka, Krzysztof

    2016-08-01

    The potential of discrete cellular automata technique to predict the grain refinement in wires produced using combined metal forming process is presented and discussed within the paper. The developed combined metal forming process can be treated as one of the Severe Plastic Deformation (SPD) techniques that consists of three different modes of deformation: asymmetric drawing with bending, namely accumulated angular drawing (AAD), wire drawing (WD) and wire flattening (WF). To accurately replicate complex stress state both at macro and micro scales during subsequent deformations two stage modeling approach was used. First, the Finite Element Method (FEM), implemented in commercial ABAQUS software, was applied to simulate entire combined forming process at the macro scale level. Then, based on FEM results, the Cellular Automata (CA) method was applied for simulation of grain refinement at the microstructure level. Data transferred between FEM and CA methods included set of files with strain tensor components obtained from selected integration points in the macro scale model. As a result of CA simulation, detailed information on microstructure evolution during severe plastic deformation conditions was obtained, namely: changes of shape and sizes of modeled representative volume with imposed microstructure, changes of the number of grains, subgrains and dislocation cells, development of grain boundaries angle distribution as well as changes in the pole figures. To evaluate CA model predictive capabilities, results of computer simulation were compared with scanning electron microscopy and electron back scattered diffraction images (SEM/EBSD) studies of samples after AAD+WD+WF process.

  13. Method of processing radioactive metallic sodium with recycling alcohols

    International Nuclear Information System (INIS)

    Sakai, Takuhiko; Mitsuzuka, Norimasa.

    1980-01-01

    Purpose: To employ high safety alcohol procession and decrease the amount of wastes in the procession of radioactive metallic sodium discharged from LMFBR type reactors. Method: Radioactive metallic sodium containing long half-decay period nuclides such as cesium, strontium, barium, cerium, lanthanum or zirconium is dissolved in an alcohol at about 70% purity. After extracting the sodium alcoholate thus formed, gaseous hydrochloride is blown-in to separate the sodium alcoholate into alcohol and sodium chloride, and regenerated alcohol is used again for dissolving sodium metal. The sodium chloride thus separated is processed into solid wastes. (Furukawa, Y.)

  14. Multiaxial Cycle Deformation and Low-Cycle Fatigue Behavior of Mild Carbon Steel and Related Welded-Metal Specimen

    Directory of Open Access Journals (Sweden)

    Weilian Qu

    2017-01-01

    Full Text Available The low-cycle fatigue experiments of mild carbon Q235B steel and its related welded-metal specimens are performed under uniaxial, in-phase, and 90° out-of-phase loading conditions. Significant additional cyclic hardening for 90° out-of-phase loading conditions is observed for both base metal and its related weldment. Besides, welding process produces extra additional hardening under the same loading conditions compared with the base metal. Multiaxial low-cycle fatigue strength under 90° out-of-phase loading conditions is significantly reduced for both base-metal and welded-metal specimens. The weldment has lower fatigue life than the base metal under the given loading conditions, and the fatigue life reduction of weldment increases with the increasing strain amplitude. The KBM, FS, and MKBM critical plane parameters are evaluated for the fatigue data obtained. The FS and MKBM parameters are found to show better correlation with fatigue lives for both base-metal and welded-metal specimens.

  15. A bioseparation process for removing heavy metals from waste ...

    African Journals Online (AJOL)

    The role of cell structure, cell wall, micropores and macropores is evaluated in terms of the potential of these biosorbents for metal sequestration. Binding mechanisms are discussed, including the key functional groups involved and the ion-exchange process. Quantification of metal-biomass interactions is fundamental to the ...

  16. Mechanisms operating during plastic deformation of metals under concurrent production of cascades and dislocations

    Energy Technology Data Exchange (ETDEWEB)

    Trinkaus, H. [Institut fuer Festkoerperforschung, Forschungszentrum Juelich (Germany); Singh, B.N. [Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Materials Research Dept., Roskilde (Denmark)

    2008-04-15

    Recent in-reactor tensile tests (IRTs) on pure copper have revealed a deformation behaviour which is significantly different from that observed in post-irradiation tensile tests (PITs). In IRTs, the material deforms uniformly and homogeneously without yield drop and plastic instability as commonly observed in PITs. An increase in the pre-yield dose results in an increase in the level of hardening over the whole test periods and a decrease in the uniform elongation suggesting that the materials 'remember' the impact of the pre-yield damage level. These features are modelled in terms of the decoration of dislocations with glissile dislocation loops. During pre-yield irradiation, dislocation decoration is due to the one-dimensional (1D) diffusion of cascade induced self-interstitial (SIA) clusters and their trapping in the stress field of the static grown-in dislocations. During post-yield irradiation and deformation, moving dislocations are decorated by the sweeping of matrix loops. The interaction of dislocations with loops and between loops is discussed as a function of the relevant parameters. On this basis, the kinetics of decoration is treated in terms of fluxes of loops to and reactions with each other in a conceived 2D space of decoration. In this space, loop coalescence, alignment and mutual blocking reactions are characterised by appropriate reaction cross sections. In the kinetic equations for 'dynamic decoration' under deformation, the evolution of the dislocation density is taken into account. Simple solutions of the kinetic equations are discussed. The apparent memory of the system for the pre-yield dose is identified as the result of simultaneous and closely parallel transient evolutions of the cascade damage and the dislocations up to the end of the IRTs. The contributions of dislocation decoration to yield and flow stresses are attributed to the interaction of dislocations with aligned loops temporarily or permanently immobilized

  17. Mechanisms operating during plastic deformation of metals under concurrent production of cascades and dislocations

    International Nuclear Information System (INIS)

    Trinkaus, H.; Singh, B.N.

    2008-04-01

    Recent in-reactor tensile tests (IRTs) on pure copper have revealed a deformation behaviour which is significantly different from that observed in post-irradiation tensile tests (PITs). In IRTs, the material deforms uniformly and homogeneously without yield drop and plastic instability as commonly observed in PITs. An increase in the pre-yield dose results in an increase in the level of hardening over the whole test periods and a decrease in the uniform elongation suggesting that the materials 'remember' the impact of the pre-yield damage level. These features are modelled in terms of the decoration of dislocations with glissile dislocation loops. During pre-yield irradiation, dislocation decoration is due to the one-dimensional (1D) diffusion of cascade induced self-interstitial (SIA) clusters and their trapping in the stress field of the static grown-in dislocations. During post-yield irradiation and deformation, moving dislocations are decorated by the sweeping of matrix loops. The interaction of dislocations with loops and between loops is discussed as a function of the relevant parameters. On this basis, the kinetics of decoration is treated in terms of fluxes of loops to and reactions with each other in a conceived 2D space of decoration. In this space, loop coalescence, alignment and mutual blocking reactions are characterised by appropriate reaction cross sections. In the kinetic equations for 'dynamic decoration' under deformation, the evolution of the dislocation density is taken into account. Simple solutions of the kinetic equations are discussed. The apparent memory of the system for the pre-yield dose is identified as the result of simultaneous and closely parallel transient evolutions of the cascade damage and the dislocations up to the end of the IRTs. The contributions of dislocation decoration to yield and flow stresses are attributed to the interaction of dislocations with aligned loops temporarily or permanently immobilized by other loops or

  18. Acoustic emission generated by dislocation mechanisms during the deformation of metals

    Energy Technology Data Exchange (ETDEWEB)

    Heiple, C.R.

    1978-01-01

    Acoustic emission is a transient elastic wave generated by the rapid release of energy within a material. A wide variety of mechanisms have been proposed as possible sources of acoustic emission. Proposed mechanisms have included crack propagation, precipitate fracture, twin formation, martensite formation, dislocation motion and/or multiplication. This paper is concerned with acoustic emission generated by dislocation mechanisms operating during plastic deformation. Twinning and martensitic phase transformations are excluded even though dislocation motion is involved in the nucleation and growth of twins and the growth of martensite.

  19. Hydrogen induced crack propagation in metal under plain-strain deformation

    International Nuclear Information System (INIS)

    Fishgojt, A.V.; Kolachev, B.A.

    1981-01-01

    A model of subcritical crack propagation conditioned by the effect of dissolved hydrogen in the case of plane-strain deformation of high-strength materials, is suggested. It is supposed that diffusion takes place in the isotropic material and hydrogen diffuses in the region of tensile stress maximum before crack tip under the effect of the stress gradient. When hydrogen achieves the critical concentration, microcrack growth takes place. Values of crack growth rates experimentally obtained agree with values calculated according to the suggested formula. Calculation and experimental data on the Ti-6Al-4V alloy, are presented [ru

  20. Acoustic emission generated by dislocation mechanisms during the deformation of metals

    International Nuclear Information System (INIS)

    Heiple, C.R.

    1978-01-01

    Acoustic emission is a transient elastic wave generated by the rapid release of energy within a material. A wide variety of mechanisms have been proposed as possible sources of acoustic emission. Proposed mechanisms have included crack propagation, precipitate fracture, twin formation, martensite formation, dislocation motion and/or multiplication. This paper is concerned with acoustic emission generated by dislocation mechanisms operating during plastic deformation. Twinning and martensitic phase transformations are excluded even though dislocation motion is involved in the nucleation and growth of twins and the growth of martensite

  1. Nucleation of recrystallization observed in situ in the bulk of a deformed metal

    International Nuclear Information System (INIS)

    Larsen, Axel W.; Poulsen, Henning F.; Margulies, Lawrence; Gundlach, Carsten; Xing Qingfeng; Huang Xiaoxu; Jensen, Dorte Juul

    2005-01-01

    Nucleation of recrystallization is studied in situ in the bulk by three-dimensional X-ray diffraction. Copper samples cold rolled 20% are investigated. The crystallographic orientations near triple junction lines are characterized before, during and after annealing. Three nuclei are identified and it is shown that two nuclei are twin related to their parent grain and one nucleus has an orientation, which is neither present in the deformed parent grains nor first order twin related to any of them. Data on the nucleation kinetics is also presented

  2. Time evolution of absorption process in nonlinear metallic photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R.; Hatef, Ali [Department of Physics and Astronomy, University of Western Ontario, London (Canada)

    2009-05-15

    The time evolution of the absorption coefficient in metallic photonic crystals has been studied numerically. These crystals are made from metallic spheres which are arranged periodically in air. The refractive index of the metallic spheres depends on the plasma frequency. Probe and pump fields are applied to monitor the absorption process. Ensembles of three-level particles are embedded in the crystal. Nanoparticles are interacting with the metallic crystals via the electron-photon interaction. It is found that when the resonance states lie away from the band edges system goes to transparent state. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Determination of reduction yield of lithium metal reduction process

    International Nuclear Information System (INIS)

    Choi, In Kyu; Cho, Young Hwan; Kim, Taek Jin; Jee, Kwang Young

    2004-01-01

    Metal reduction of spent oxide fuel is the first step for the effective storage of spent fuel in Korea as well as transmutation purpose of long-lived radio-nuclides. During the reduction of uranium oxide by lithium metal to uranium metal, lithium oxide is stoichiometrically produced. By determining the concentration of lithium oxide in lithium chloride, we can estimate that how much uranium oxide is converted to uranium metal. Previous method to determine the lithium oxide concentration in lithium chloride is tedious and timing consuming. This paper describe the on-line monitoring method of lithium oxide during the reduction process

  4. Deformation behaviors of Cu29Zr32Ti15Al5Ni19 high entropy bulk metallic glass during nanoindentation

    Science.gov (United States)

    Fang, Qihong; Yi, Ming; Li, Jia; Liu, Bin; Huang, Zaiwang

    2018-06-01

    The deformation behaviors of Cu29Zr32Ti15Al5Ni19 high entropy bulk metallic glass (HE-BMG) during the nanoindentation are presented via the large-scale molecular dynamics (MD) simulations. The indentation tests are carried out using spherical rigid indenter to investigate the microstructural evolution on the mechanical properties of HE-BMGs in terms of shear strain, indentation force, and surface morphology as well as radial distribution function (RDF). Based on the Hertzian fitting the load-displacement curve, HE-BMG Cu29Zr32Ti15Al5Ni19 has the Young's modulus of 93.1 GPa and hardness of 8.8 GPa. The indentation force requiring for the continual increasing contacted area between the indenter and the substrate goes up with the increasing of indentation depth. In addition, the symmetrical distribution of atomic displacement reveals the isotropic of HE-BMG after the indentation treatment. In the deformation region, the Al element would lead to the serious fluctuation in the first peak of RDF, which is much stronger than the other elements. The severe distortion from the atomic size difference maybe reduce the activation energy to the occurrence of shear deformation in HE-BMG, leading to the transition from brittle to ductile observed by the whole sliding of the local atom group. Through the indentation load-displacement curves at various temperatures, the softening of HE-BMG at high temperatures is in qualitative agreement with the experimental findings. Moreover, this effective strategy is used to accelerate the discovery of excellent mechanical properties of HE-BMGs by means of MD simulation, as well as understand the fundamental nanoindentation response of HE-BMGs.

  5. PROCESSING OF URANIUM-METAL-CONTAINING FUEL ELEMENTS

    Science.gov (United States)

    Moore, R.H.

    1962-10-01

    A process is given for recovering uranium from neutronbombarded uranium- aluminum alloys. The alloy is dissolved in an aluminum halide--alkali metal halide mixture in which the halide is a mixture of chloride and bromide, the aluminum halide is present in about stoichiometric quantity as to uranium and fission products and the alkali metal halide in a predominant quantity; the uranium- and electropositive fission-products-containing salt phase is separated from the electronegative-containing metal phase; more aluminum halide is added to the salt phase to obtain equimolarity as to the alkali metal halide; adding an excess of aluminum metal whereby uranium metal is formed and alloyed with the excess aluminum; and separating the uranium-aluminum alloy from the fission- productscontaining salt phase. (AEC)

  6. On the manufacturing of a gas turbine engine part through metal spinning process

    Science.gov (United States)

    Hassanin, A. El; Astarita, A.; Scherillo, F.; Velotti, C.; Squillace, A.; Liguori, A.

    2018-05-01

    Metal spinning processes represents an interesting alternative to traditional sheet metal forming processes in several industrial contexts, such as automotive and aerospace. In this work, the production of a combustion chamber liner top prototype using AISI 304L stainless steel is proposed, in order to evaluate the process feasibility for the required part geometry. The prototypes production was carried out using a two-stage semiautomatic spinning process. The effects in terms of wall thickness reduction were investigated. Using optical microscopy and Scanning Electron Microscopy (SEM) techniques, the microstructural behavior of the metal subjected to the forming process was investigated, while for an evaluation of the influence on the mechanical properties Vickers micro-indentation tests were performed. The main result of the process, as observed from all the investigation techniques adopted, is the formation of strain induced martensite due to the severe plastic deformation and cold reduction of the material, ranging in this case from 30% to 50%. In some areas of the part section, some rips indicating an excessive tensile stress were also detected.

  7. Investigations on thermal properties, stress and deformation of Al/SiC metal matrix composite based on finite element method

    Directory of Open Access Journals (Sweden)

    K. A. Ramesh Kumar

    2014-09-01

    Full Text Available AlSiC is a metal matrix composite which comprises of aluminium matrix with silicon carbide particles. It is characterized by high thermal conductivity (180-200 W/m K, and its thermal expansion are attuned to match other important materials that finds enormous demand in industrial sectors. Although its application is very common, the physics behind the Al-SiC formation, functionality and behaviors are intricate owing to the temperature gradient of hundreds of degrees, over the volume, occurring on a time scale of a few seconds, involving multiple phases. In this study, various physical, metallurgical and numerical aspects such as equation of continuum for thermal, stress and deformation using finite element (FE matrix formulation, temperature dependent material properties, are analyzed. Modelling and simulation studies of Al/SiC composites are a preliminary attempt to view this research work from computational point of view.

  8. Effect of Chord Splice Joints on Force Distribution and Deformations in Trusses with Punched Metal Plate Fasteners

    DEFF Research Database (Denmark)

    Ellegaard, Peter

    2007-01-01

    The span of roof trusses with punched metal plate fasteners (nail plates) makes it often necessary to use splice joints in the top and bottom chords. In the finite element models used for design of the trusses these splice joints are normally assumed to be either rotationally stiff or pinned....... Timber-to-timber contact and non-linear elastic behaviour are included in the model. Results from tests with joints under fourpoint bending are compared with predictions given by TrussLab, and a good agreement is found. Splice joints in trusses with nail plates may be assumed to be rotationally stiff...... if their deformation has no significant effect upon the distribution of member forces according to Eurocode 5. Two simple guidelines for the design and location of splice joints are given in Eurocode 5 for treating the splice joints as rotationally stiff. The reasonability of these guidelines and the influence...

  9. Process of treating surfaces of metals

    International Nuclear Information System (INIS)

    Kimura, T.; Murao, A.; Kuwahara, T.

    1975-01-01

    Both higher corrosion resistance and paint adherence are given to films formed on the surfaces of metals by treating the surfaces with aqueous solutions of one or more materials selected from the group consisting of water soluble vinyl monomer or water soluble high polymer and then irradiating with ionizing radioactive rays on the nearly dried surface film. When a water soluble inorganic compound is mixed with the above mentioned aqueous solution, the film properties are greatly improved. The inorganic ionic material should contain a cation from the group consisting of Ca, Mg, Zn, Cr, Al, Fe, and Ni. Electron beams may be used. (U.S.)

  10. Electrochemical activity of heavy metal oxides in the process of ...

    Indian Academy of Sciences (India)

    Unknown

    2002-02-02

    Feb 2, 2002 ... Electrochemical activity of heavy metal oxides in the process of chloride induced .... represents the protective barrier moderating the chloride attack which ... inhibitors and their influence on the physical properties of. Portland ...

  11. Hopper design for metallic powders used in additive manufacturing processes

    CSIR Research Space (South Africa)

    Visagie, N

    2013-10-01

    Full Text Available The influence of hopper geometry on the flow behaviour of typical metallic powders used in additive manufacturing processes is investigated. Bulk hopper theory provides a method of determining critical hopper parameters for bulk amounts...

  12. Deformation processes in functional materials studied by in situ neutron diffraction and ultrasonic techniques

    International Nuclear Information System (INIS)

    Sittner, P.; Novak, V.; Landa, M.; Lukas, P.

    2007-01-01

    The unique thermomechanical functions of shape memory alloys (hysteretic stress-strain-temperature responses) not their structural properties (as strength, fatigue, corrosion resistance, etc.) are primarily utilized in engineering applications. In order to better understand and predict the functional behavior, we have recently employed two dedicated non-invasive in situ experimental methods capable to follow the deformation/transformation processes in thermomechanically loaded polycrystalline samples. The in situ neutron diffraction method takes advantage of the ability of thermal neutrons to penetrate bulk samples. As a diffraction technique sensitive to interplanar spacings in crystalline solids, it provides in situ information on the changes in crystal structure, phase composition, phase stress and texture in the transforming samples. The combined in situ ultrasonic and electric resistance method follows variations of the electric resistance as well as speed and attenuation of acoustic waves propagating through the transforming sample. The acoustic waves are mainly sensitive to changes of elastic properties accompanying the deformation/transformation processes. The latter method thus follows the changes in interatomic bonds rather than changes in the interplanar lattice spacings focused in the neutron diffraction method. The methods are thus complementary. They are briefly described and selected experimental results obtained recently on NiTi alloys are presented and discussed

  13. Titanium and zirconium metal powder spheroidization by thermal plasma processes

    OpenAIRE

    Bissett, H.; van der Walt, I.J.; Havenga, J.L.; Nel, J.T.

    2015-01-01

    New technologies used to manufacture high-quality components, such as direct laser sintering, require spherical powders of a narrow particle size distribution as this affects the packing density and sintering mechanism. The powder also has to be chemically pure as impurities such as H, O, C, N, and S causes brittleness, influence metal properties such as tensile strength, hardness, and ductility, and also increase surface tension during processing. Two new metal powder processes have been dev...

  14. Metal Catalyzed Fusion: Nuclear Active Environment vs. Process

    Science.gov (United States)

    Chubb, Talbot

    2009-03-01

    To achieve radiationless dd fusion and/or other LENR reactions via chemistry: some focus on environment of interior or altered near-surface volume of bulk metal; some on environment inside metal nanocrystals or on their surface; some on the interface between nanometal crystals and ionic crystals; some on a momentum shock-stimulation reaction process. Experiment says there is also a spontaneous reaction process.

  15. Non-newtonian deformation of co-based metallic glass at low stresses

    NARCIS (Netherlands)

    Fursova, YV; Khonik, VA; Csach, K; Ocelik, Vaclav

    2000-01-01

    The results of precision measurements of creep in Co-based metallic glass are presented. It is shown that, in spite of generally accepted concepts, plastic flow at low stresses under intense structural relaxation conditions is of a non-Newtonian type. Consequences of this fact are considered. (C)

  16. Deformation-strengthening during rolling Cu60Zr20Ti20 bulk metallic glass

    DEFF Research Database (Denmark)

    Cao, Q.P.; Li, J.F.; Hu, Yuyan

    2007-01-01

    Mechanical strength evolutions during rolling the Cu60Zr20Ti20 bulk metallic glass (BMG) at room temperature (RT) and cryogenic temperature (CT) have been investigated by measuring the microhardness. The hardness slightly increases during the initial rolling stage as a result of the gradually...

  17. Influence of cutting parameters on the depth of subsurface deformed layer in nano-cutting process of single crystal copper.

    Science.gov (United States)

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Su, Hao; Wang, Zhiguo; Xie, Wenkun

    2015-12-01

    Large-scale molecular dynamics simulation is performed to study the nano-cutting process of single crystal copper realized by single-point diamond cutting tool in this paper. The centro-symmetry parameter is adopted to characterize the subsurface deformed layers and the distribution and evolution of the subsurface defect structures. Three-dimensional visualization and measurement technology are used to measure the depth of the subsurface deformed layers. The influence of cutting speed, cutting depth, cutting direction, and crystallographic orientation on the depth of subsurface deformed layers is systematically investigated. The results show that a lot of defect structures are formed in the subsurface of workpiece during nano-cutting process, for instance, stair-rod dislocations, stacking fault tetrahedron, atomic clusters, vacancy defects, point defects. In the process of nano-cutting, the depth of subsurface deformed layers increases with the cutting distance at the beginning, then decreases at stable cutting process, and basically remains unchanged when the cutting distance reaches up to 24 nm. The depth of subsurface deformed layers decreases with the increase in cutting speed between 50 and 300 m/s. The depth of subsurface deformed layer increases with cutting depth, proportionally, and basically remains unchanged when the cutting depth reaches over 6 nm.

  18. Sol-gel processing with inorganic metal salt precursors

    Science.gov (United States)

    Hu, Zhong-Cheng

    2004-10-19

    Methods for sol-gel processing that generally involve mixing together an inorganic metal salt, water, and a water miscible alcohol or other organic solvent, at room temperature with a macromolecular dispersant material, such as hydroxypropyl cellulose (HPC) added. The resulting homogenous solution is incubated at a desired temperature and time to result in a desired product. The methods enable production of high quality sols and gels at lower temperatures than standard methods. The methods enable production of nanosize sols from inorganic metal salts. The methods offer sol-gel processing from inorganic metal salts.

  19. Process for the regeneration of metallic catalysts

    Science.gov (United States)

    Katzer, James R.; Windawi, Hassan

    1981-01-01

    A method for the regeneration of metallic hydrogenation catalysts from the class consisting of Ni, Rh, Pd, Ir, Pt and Ru poisoned with sulfur, with or without accompanying carbon deposition, comprising subjecting the catalyst to exposure to oxygen gas in a concentration of about 1-10 ppm. intermixed with an inert gas of the group consisting of He, A, Xe, Kr, N.sub.2 and air substantially free of oxygen to an extent such that the total oxygen molecule throughout is in the range of about 10 to 20 times that of the hydrogen sulfide molecular exposure producing the catalyst poisoning while maintaining the temperature in the range of about 300.degree. to 500.degree. C.

  20. Trend and Development of Semisolid Metal Joining Processing

    Directory of Open Access Journals (Sweden)

    M. N. Mohammed

    2015-01-01

    Full Text Available The semisolid metal joining (SSMJ process or thixojoining process has recently been developed based on the principles of SSM processing, which is a technology that involves the formation of metal alloys between solidus and liquidus temperatures. Thixojoining has many potential benefits, which has encouraged researchers to carry out feasibility studies on various materials that could be utilized in this process and which could transform the production of metal components. This paper reviews the findings in the literature to date in this evolving field, specifically, the experimental details, technology considerations for industrialization, and advantages and disadvantages of the various types of SSMJ methods that have been proposed. It also presents details of the range of materials that have been joined by using the SSMJ process. Furthermore, it highlights the huge potential of this process and future directions for further research.

  1. Processing routes evaluation of severely deformed Mg-Fe alloys for hydrogen storage applications

    International Nuclear Information System (INIS)

    Antiqueira, F.J.; Leiva, D.R.; Ishikawa, T.T.; Jorge Junior, A.M.; Botta, W.J.

    2016-01-01

    MgH 2 is considered an interesting material for safe hydrogen storage in the solid state, due to its high gravimetric nominal capacity of 7,6%, and the relative low cost of magnesium. In this study, we attempted to improve the performance of the MgH 2 in the hydrogen storage. Different processing routes for Mg and Mg-Fe by severe plastic deformation were evaluated. The prepared materials were characterized by X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopy (TEM). The hydrogen storage properties were evaluated by differential scanning calorimetry and the Sievert's method. The results indicate superior properties to materials catalyzed with iron, as well as a high dependence of hydrogen absorption / desorption kinetic in accordance with the microstructures obtained through the various processing routes. (author)

  2. Ceramic/metal nanocomposites by lyophilization: Processing and HRTEM study

    International Nuclear Information System (INIS)

    Gutierrez-Gonzalez, C.F.; Agouram, S.; Torrecillas, R.; Moya, J.S.; Lopez-Esteban, S.

    2012-01-01

    Highlights: ► A cryogenic route has been used to obtain ceramic/metal nanostructured powders. ► The powders present good homogeneity and dispersion of metal. ► The metal nanoparticle size distributions are centred in 17–35 nm. ► Both phases, ceramic and metal, present a high degree of crystallinity. ► Good metal/ceramic interfaces due to epitaxial growth, studied by HRTEM. -- Abstract: This work describes a wet-processing route based on spray-freezing and subsequent lyophilization designed to obtain nanostructured ceramic/metal powders. Starting from the ceramic powder and the corresponding metal salt, a water-based suspension is sprayed on liquid nitrogen. The frozen powders are subsequently freeze-dried, calcined and reduced. The material was analyzed using X-ray diffraction analysis at all stages. High resolution transmission electron microscopy studies showed a uniform distribution of metal nanoparticles on the ceramic grain surfaces, good interfaces and high crystallinity, with an average metal particle size in the nanometric range.

  3. Strain Localization and Weakening Processes in Viscously Deforming Rocks: Numerical Modeling Based on Laboratory Torsion Experiments

    Science.gov (United States)

    Doehmann, M.; Brune, S.; Nardini, L.; Rybacki, E.; Dresen, G.

    2017-12-01

    Strain localization is an ubiquitous process in earth materials observed over a broad range of scales in space and time. Localized deformation and the formation of shear zones and faults typically involves material softening by various processes, like shear heating and grain size reduction. Numerical modeling enables us to study the complex physical and chemical weakening processes by separating the effect of individual parameters and boundary conditions. Using simple piece-wise linear functions for the parametrization of weakening processes allows studying a system at a chosen (lower) level of complexity (e.g. Cyprych et al., 2016). In this study, we utilize a finite element model to test two weakening laws that reduce the strength of the material depending on either the I) amount of accumulated strain or II) deformational work. Our 2D Cartesian models are benchmarked to single inclusion torsion experiments performed at elevated temperatures of 900 °C and pressures of up to 400 MPa (Rybacki et al., 2014). The experiments were performed on Carrara marble samples containing a weak Solnhofen limestone inclusion at a maximum strain rate of 2.0*10-4 s-1. Our models are designed to reproduce shear deformation of a hollow cylinder equivalent to the laboratory setup, such that material leaving one side of the model in shear direction enters again on the opposite side using periodic boundary conditions. Similar to the laboratory tests, we applied constant strain rate and constant stress boundary conditions.We use our model to investigate the time-dependent distribution of stress and strain and the effect of different parameters. For instance, inclusion rotation is shown to be strongly dependent on the viscosity ratio between matrix and inclusion and stronger ductile weakening increases the localization rate while decreasing shear zone width. The most suitable weakening law for representation of ductile rock is determined by combining the results of parameter tests with

  4. The effect of various deformation processes on the corrosion behavior of casing and tubing carbon steels in sweet environment

    Science.gov (United States)

    Elramady, Alyaa Gamal

    The aim of this research project is to correlate the plastic deformation and mechanical instability of casing steel materials with corrosion behavior and surface change, in order to identify a tolerable degree of deformation for casing steel materials. While the corrosion of pipeline and casing steels has been investigated extensively, corrosion of these steels in sweet environments with respect to plastic deformation due to bending, rolling, autofrettage, or handling needs more investigation. Downhole tubular expansion of pipes (casings) is becoming standard practice in the petroleum industry to repair damaged casings, shutdown perforations, and ultimately achieve mono-diameter wells. Tubular expansion is a cold-drawing metal forming process, which consists of running conical mandrels through casings either mechanically using a piston or hydraulically by applying a back pressure. This mechanism subjects the pipes to large radial plastic deformations of up to 30 pct. of the inner diameter. It is known that cold-working is a way of strengthening materials such as low carbon steel, but given that this material will be subjected to corrosive environments, susceptibility to stress corrosion cracking (SCC) should be investigated. This research studies the effect of cold-work, in the form of cold-rolling and cold-expansion, on the surface behavior of API 5CT steels when it is exposed to a CO2-containing environment. Cold-work has a pronounced influence on the corrosion behavior of both API 5CT K55 and P110 grade steels. The lowest strength grade steel, API 5CT K55, performed poorly in a corrosive environment in the slow strain rate test. The ductile material exhibited the highest loss in strength and highest susceptibility to stress corrosion cracking in a CO 2-containing environment. The loss in strength declined with cold-rolling, which can be ascribed to the surface compressive stresses induced by cold-work. On the other hand, API 5CT P110 grade steels showed higher

  5. Analysis of metal forming processes by using physical modeling and new plastic similarity condition

    International Nuclear Information System (INIS)

    Gronostajski, Z.; Hawryluk, M.

    2007-01-01

    In recent years many advances have been made in numerical methods, for linear and non-linear problems. However the success of them depends very much on the correctness of the problem formulation and the availability of the input data. Validity of the theoretical results can be verified by an experiment using the real or soft materials. An essential reduction of time and costs of the experiment can be obtained by using soft materials, which behaves in a way analogous to that of real metal during deformation. The advantages of using of the soft materials are closely connected with flow stress 500 to 1000 times lower than real materials. The accuracy of physical modeling depend on the similarity conditions between physical model and real process. The most important similarity conditions are materials similarity in the range of plastic and elastic deformation, geometrical, frictional and thermal similarities. New original plastic similarity condition for physical modeling of metal forming processes is proposed in the paper. It bases on the mathematical description of similarity of the flow stress curves of soft materials and real ones

  6. Image processing for quantifying fracture orientation and length scale transitions during brittle deformation

    Science.gov (United States)

    Rizzo, R. E.; Healy, D.; Farrell, N. J.

    2017-12-01

    We have implemented a novel image processing tool, namely two-dimensional (2D) Morlet wavelet analysis, capable of detecting changes occurring in fracture patterns at different scales of observation, and able of recognising the dominant fracture orientations and the spatial configurations for progressively larger (or smaller) scale of analysis. Because of its inherited anisotropy, the Morlet wavelet is proved to be an excellent choice for detecting directional linear features, i.e. regions where the amplitude of the signal is regular along one direction and has sharp variation along the perpendicular direction. Performances of the Morlet wavelet are tested against the 'classic' Mexican hat wavelet, deploying a complex synthetic fracture network. When applied to a natural fracture network, formed triaxially (σ1>σ2=σ3) deforming a core sample of the Hopeman sandstone, the combination of 2D Morlet wavelet and wavelet coefficient maps allows for the detection of characteristic scale orientation and length transitions, associated with the shifts from distributed damage to the growth of localised macroscopic shear fracture. A complementary outcome arises from the wavelet coefficient maps produced by increasing the wavelet scale parameter. These maps can be used to chart the variations in the spatial distribution of the analysed entities, meaning that it is possible to retrieve information on the density of fracture patterns at specific length scales during deformation.

  7. Hot Deformation Behavior and Processing Maps of Diamond/Cu Composites

    Science.gov (United States)

    Zhang, Hongdi; Liu, Yue; Zhang, Fan; Zhang, Di; Zhu, Hanxing; Fan, Tongxiang

    2018-06-01

    The hot deformation behaviors of 50 vol pct uncoated and Cr-coated diamond/Cu composites were investigated using hot isothermal compression tests under the temperature and strain rate ranging from 1073 K to 1273 K (800 °C to 1000 °C) and from 0.001 to 5 s-1, respectively. Dynamic recrystallization was determined to be the primary restoration mechanism during deformation. The Cr3C2 coating enhanced the interfacial bonding and resulted in a larger flow stress for the Cr-coated diamond/Cu composites. Moreover, the enhanced interfacial affinity led to a higher activation energy for the Cr-coated diamond/Cu composites (238 kJ/mol) than for their uncoated counterparts (205 kJ/mol). The strain-rate-dependent constitutive equations of the diamond/Cu composites were derived based on the Arrhenius model, and a high correlation ( R = 0.99) was observed between the calculated flow stresses and experimental data. With the help of processing maps, hot extrusions were realized at 1123 K/0.01 s-1 and 1153 K/0.01 s-1 (850 °C/0.01 s-1 and 880 °C/0.01 s-1) for the uncoated and coated diamond/Cu composites, respectively. The combination of interface optimization and hot extrusion led to increases of the density and thermal conductivity, thereby providing a promising route for the fabrication of diamond/Cu composites.

  8. A layman's guide to radiation-induced deformation processes in zirconium alloys

    International Nuclear Information System (INIS)

    Dutton, R.

    1990-07-01

    The fuel channel (comprising a pressure tube and a calandria tube fabricated from zirconium alloys) in a CANDU reactor undergoes shape changes because of radiation-induced deformation. This is a consequence of the microstructural modification arising from radiation damage produced by the fast-neutron flux. This report summarizes our current understanding of the physical processes responsible for the deformation. With the non-specialist reader in mind, the underlying mechanisms are described in a manner that avoids much of the associated technical terminology. Thus, the basic concepts of plasticity in a crystalline material are introduced and related to the various microstructural defects created during irradiation. In particular, the mechanisms of creep (a time-dependent strain activated by an applied stress) and growth (a time-dependent strain occurring in the absence of stress) are discussed in a non-technical language assisted by simple diagrams. Reference is made to both theoretical investigations (avoiding mathematical complexity) and experimental measurements. It is shown how the qualitative and quantitative knowledge can be used to derive a predictive model for reactor designers and operators. The current status of such a model is evaluated and suggestions for future improvements made

  9. Low Computational-Cost Footprint Deformities Diagnosis Sensor through Angles, Dimensions Analysis and Image Processing Techniques

    Directory of Open Access Journals (Sweden)

    J. Rodolfo Maestre-Rendon

    2017-11-01

    Full Text Available Manual measurements of foot anthropometry can lead to errors since this task involves the experience of the specialist who performs them, resulting in different subjective measures from the same footprint. Moreover, some of the diagnoses that are given to classify a footprint deformity are based on a qualitative interpretation by the physician; there is no quantitative interpretation of the footprint. The importance of providing a correct and accurate diagnosis lies in the need to ensure that an appropriate treatment is provided for the improvement of the patient without risking his or her health. Therefore, this article presents a smart sensor that integrates the capture of the footprint, a low computational-cost analysis of the image and the interpretation of the results through a quantitative evaluation. The smart sensor implemented required the use of a camera (Logitech C920 connected to a Raspberry Pi 3, where a graphical interface was made for the capture and processing of the image, and it was adapted to a podoscope conventionally used by specialists such as orthopedist, physiotherapists and podiatrists. The footprint diagnosis smart sensor (FPDSS has proven to be robust to different types of deformity, precise, sensitive and correlated in 0.99 with the measurements from the digitalized image of the ink mat.

  10. Investigating the Mechanical Behavior and Deformation Mechanisms of Ultrafinegrained Metal Films Using Ex-situ and In-situ TEM Techniques

    Science.gov (United States)

    Izadi, Ehsan

    Nanocrystalline (NC) and Ultrafine-grained (UFG) metal films exhibit a wide range of enhanced mechanical properties compared to their coarse-grained counterparts. These properties, such as very high strength, primarily arise from the change in the underlying deformation mechanisms. Experimental and simulation studies have shown that because of the small grain size, conventional dislocation plasticity is curtailed in these materials and grain boundary mediated mechanisms become more important. Although the deformation behavior and the underlying mechanisms in these materials have been investigated in depth, relatively little attention has been focused on the inhomogeneous nature of their microstructure (particularly originating from the texture of the film) and its influence on their macroscopic response. Furthermore, the rate dependency of mechanical response in NC/UFG metal films with different textures has not been systematically investigated. The objectives of this dissertation are two-fold. The first objective is to carry out a systematic investigation of the mechanical behavior of NC/UFG thin films with different textures under different loading rates. This includes a novel approach to study the effect of texture-induced plastic anisotropy on mechanical behavior of the films. Efforts are made to correlate the behavior of UFG metal films and the underlying deformation mechanisms. The second objective is to understand the deformation mechanisms of UFG aluminum films using in-situ transmission electron microscopy (TEM) experiments with Automated Crystal Orientation Mapping. This technique enables us to investigate grain rotations in UFG Al films and to monitor the microstructural changes in these films during deformation, thereby revealing detailed information about the deformation mechanisms prevalent in UFG metal films.

  11. Research of Tool Durability in Surface Plastic Deformation Processing by Burnishing of Steel Without Metalworking Fluids

    Science.gov (United States)

    Grigoriev, S. N.; Bobrovskij, N. M.; Melnikov, P. A.; Bobrovskij, I. N.

    2017-05-01

    Modern vector of development of machining technologies aimed at the transition to environmentally safe technologies - “green” technologies. The concept of “green technology” includes a set of signs of knowledge intended for practical use (“technology”). One of the ways to improve the quality of production is the use of surface plastic deformation (SPD) processing methods. The advantage of the SPD is a capability to combine effects of finishing and strengthening treatment. The SPD processing can replace operations: fine turning, grinding or polishing. The SPD is a forceful contact impact of indentor on workpiece’s surface in condition of their relative motion. It is difficult to implement the core technology of the SPD (burnishing, roller burnishing, etc.) while maintaining core technological advantages without the use of lubricating and cooling technology (metalworking fluids, MWF). The “green” SPD technology was developed by the authors for dry processing and has not such shortcomings. When processing with SPD without use of MWF requirements for tool’s durability is most significant, especially in the conditions of mass production. It is important to determine the period of durability of tool at the design stage of the technological process with the purpose of wastage preventing. This paper represents the results of durability research of natural and synthetic diamonds (polycrystalline diamond - ASPK) as well as precision of polycrystalline superabrasive tools made of dense boron nitride (DBN) during SPD processing without application of MWF.

  12. Application of molten salts in pyrochemical processing of reactive metals

    International Nuclear Information System (INIS)

    Mishra, B.; Olson, D.L.; Averill, W.A.

    1992-01-01

    Various mixes of chloride and fluoride salts are used as the media for conducting pyrochemical processes in the production and purification of reactive metals. These processes generate a significant amount of contaminated waste that has to be treated for recycling or disposal. Molten calcium chloride based salt systems have been used in this work to electrolytically regenerate calcium metal from calcium oxide for the in situ reduction of reactive metal oxides. The recovery of calcium is characterized by the process efficiency to overcome back reactions in the electrowinning cell. A thermodynamic analysis, based on fundamental rate theory, has been performed to understand the process parameters controlling the metal deposition, rate, behavior of the ceramic anode-sheath and influence of the back-reactions. It has been observed that the deposition of calcium is dependent on the ionic diffusion through the sheath. It has also been evidenced that the recovered calcium is completely lost through the back-reactions in the absence of a sheath. A practical scenario has also been presented where the electrowon metal can be used in situ as a reductant to reduce another reactive metal oxide

  13. Deformation and fracture properties of metals with non-metallic inclusions; Verformung und Bruch von Metallen mit nichtmetallischen Einschluessen

    Energy Technology Data Exchange (ETDEWEB)

    Schmauder, S.; Soppa, E. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt

    1998-12-31

    Microstructural effects due to formation of non-uniform lines of non-metallic inclusions in the matrix are examined with respect to their macro-, meso-, and micromechanical effects in the alloy Al(6061) reinforced by SiC inclusions. A comparative analysis of results obtained with various microstructures reveals essential differences in the formation of shear bands, stress peaks, and strain concentrations in the material structure. The maxima and the distribution of those field variables are determined not only by the arrangement of inclusions clusters in the stringers but also depend on the presence and number of single-particle inclusions in pure matrix material. The banding of the microstructure causes a strongly anisotropic behaviour in terms of stress and strain distributions. (orig./CB) [Deutsch] In diesem Beitrag werden Gefuegeeinfluesse aufgrund unterschiedlich starker zeiliger Anordnungen der Teilchen in der Matrix im Hinblick auf ihre makro-, meso- und mikromechanischen Auswirkungen am Beispiel einer SiC-teilchenverstaerkten Aluminiumlegierung Al(6061) untersucht. Ein Vergleich der Ergebnisse verschiedener Gefuege zeigt wesentliche Unterschiede hinsichtlich der Ausbildung von Scherbaendern, Spannungsspitzen und von Dehnungskonzentrationen im Werkstoffgefuege. Die Maxima und die Verteilung dieser Feldgroessen sind nicht nur abhaengig davon, wie die Teilchen in den Zeilen angeordnet sind, sondern auch davon, ob einzelne Teilchen in reinen Matrixbereichen vorhanden sind. Die Zeiligkeit des Gefueges fuehrt zu einem stark anisotropen Verhalten hinsichtlich Spannungs- und Dehnungsverteilungen. (orig.)

  14. Modeling The Interaction Effects Between Tools And The Work Piece For Metal Forming Processes

    International Nuclear Information System (INIS)

    Franzke, Martin; Puchhala, Sreedhar; Dackweiler, Harald

    2007-01-01

    In metal forming processes especially in cold forming, elastic deformation of the tools has a big impact on the final shape of the work-piece. Computation of such processes considering the plastic effects of the work-piece and elastic deformations of the tools at a time in a single FE model complicates to manage the convergence criteria. This situation is even aggravated if the contact situations (between working and support rolls) have to be considered in the simulation, which requires a very fine discretization of the contact zones of both the tool and work piece. This paper presents recently developed concept which meets the above mentioned demands very effectively. Within this concept, the computation of the elastic effects of the tools is separated from the process simulation (which considers elastic-plastic effects of the work-piece). Both simulations are coupled via automatic data interchange, which is bi-directional, because both simulations influence each other. The advantages of this concept include a quite easy to handle contact situations in process simulation, smaller stiffness matrix compared to single model approach and good convergence of the computation. This concept is highly generalized and successfully applied to simulate rolling, drawing, extrusion and forging processes. The above mentioned concept is being implemented into the FE package PEP and LARSTRAN/SHAPE. Rolling experiments are conducted in duo and quarto configuration. Optical three-dimensional digitalizing system was used to measure the deformations within the machine and work-piece profile. These results are used for the validation of FE simulations. This work is being sponsored by the German Research Foundation (DFG) through the project ''Interaction effects between processes and structures-SPP1180''

  15. Description of vertical displacements in the active process of rock strata deformation under conditions of mining operations

    Energy Technology Data Exchange (ETDEWEB)

    Piwowarski, W. (Akademia Gorniczo-Hutnicza, Cracow (Poland))

    1989-01-01

    Analyzes modeling vertical displacement in the evolution process of rock strata deformation caused by underground coal mining. The modeling results in a continuous description of the deformation process. Assumptions concerning model structure account for geometry of the phenomenon, while development of the deformation process is based on one physical mechanism. As a result of the analysis it has been stated that the deformation process is quantitatively similar to diffusion. On that basis the problem is described by differential equations. The class and order of the differential equations result from energy balance of the displacement field, while the analysis of the gradient of changes in the displacement field leads to a parabolic equation. The vertical displacement process in a transient state is characterized as a parabolic problem: one-dimensional, two-dimensional solenoidal, two-dimensional with one source of displacements. Equation solutions are based on Green's identity with boundary conditions. Modeling rock strata displacement in a transient state of deformation includes integration of differential equations and optimization of model parameters. The algorithm solution is written in form of a program for PC IBM/XT class computers. 41 refs.

  16. GPS data processing of networks with mixed single- and dual-frequency receivers for deformation monitoring

    Science.gov (United States)

    Zou, X.; Deng, Z.; Ge, M.; Dick, G.; Jiang, W.; Liu, J.

    2010-07-01

    In order to obtain crustal deformations of higher spatial resolution, existing GPS networks must be densified. This densification can be carried out using single-frequency receivers at moderate costs. However, ionospheric delay handling is required in the data processing. We adapt the Satellite-specific Epoch-differenced Ionospheric Delay model (SEID) for GPS networks with mixed single- and dual-frequency receivers. The SEID model is modified to utilize the observations from the three nearest dual-frequency reference stations in order to avoid contaminations from more remote stations. As data of only three stations are used, an efficient missing data constructing approach with polynomial fitting is implemented to minimize data losses. Data from large scale reference networks extended with single-frequency receivers can now be processed, based on the adapted SEID model. A new data processing scheme is developed in order to make use of existing GPS data processing software packages without any modifications. This processing scheme is evaluated using a sub-network of the German SAPOS network. The results verify that the new scheme provides an efficient way to densify existing GPS networks with single-frequency receivers.

  17. Overview of friction modelling in metal forming processes

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Bay, Niels Oluf

    2017-01-01

    In metal forming processes, friction between tool and workpiece is an important parameter influencing the material flow, surface quality and tool life. Theoretical models of friction in metal forming are based on analysis of the real contact area in tool-workpiece interfaces. Several research...... groups have studied and modelled the asperity flattening of workpiece material against tool surface in dry contact or in contact interfaces with only thin layers of lubrication with the aim to improve understanding of friction in metal forming. This paper aims at giving a review of the most important...... future work in order to advance further in modelling of real contact area in relation to implementation of frictional conditions existing finite element codes for simulation of metal forming processes. © 2017 The Authors. Published by Elsevier Ltd....

  18. Synthesis and processing of composites by reactive metal penetration

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E.; Ewsuk, K.G. [Sandia National Laboratories, Albuquerque, NM (United States); Tomsia, A.P. [Pask Research and Engineering, Berkeley, CA (United States)] [and others

    1995-05-01

    Ceramic-metal composites are being developed because their high stiffness-to weight ratios, good fracture toughness, and variable electrical and thermal properties give them advantages over more conventional materials. However, because ceramic-metal composite components presently are more expensive than monolithic materials, improvements in processing are required to reduce manufacturing costs. Reactive metal penetration is a promising new method for making ceramic- and metal-matrix composites that has the advantage of being inherently a net-shape process. This technique, once fully developed, will provide another capability for manufacturing the advanced ceramic composites that are needed for many light-weight structural and wear applications. The lower densities of these composites lead directly to energy savings in use. Near-net-shape fabrication of composite parts should lead to additional savings because costly and energy intensive grinding and machining operations are significantly reduced, and the waste generated from such finishing operations is minimized. The goals of this research program are: (1) to identify feasible compositional systems for making composites by reactive metal penetration; (2) to understand the mechanism(s) of composite formation by reactive metal penetration; and (3) to learn how to control and optimize reactive metal penetration for economical production of composites and composite coatings.

  19. Processes in Environmental Depositional Systems and Deformation in Sedimentary Basins: Goals for Exoloration in Mexico

    Science.gov (United States)

    Sandoval-Ochoa, J.

    2005-05-01

    Among the recent needs to establish new goals in the mexican energy industry to increase the petroleum reserves, has been necessary to recapitulate on some academic an operative concepts and definitions applied to the Petroliferous Basins Exploration; first of all, in order to understand the Petroleum System in given tectonophysical framework. The tectonophysical environment experienced by the petroliferous basin in the southwestern Gulf of Mexico, merely in the Campeche Sound and adjacent terrestrial regions (Figure 1); has been the result of interaction among the tectonic plates, the Coco's Plate with impingement and subduction beneath the Northamerican Plate and the Yucatán Microplate and even in very deep connection with the oceanic crust of southwesternmost portion of the Gulf of Mexico and the one of the Caribbean sea beneath the gulf of Belize-Honduras. The tectonosedimentary effects in the Campeche Bay starting with the skeleton formed for the Cenozoic Era, kept simultaneous conditions in depositions and deformations because of strain, stress and collapse fields, acted through this Era up to the present day, as observed in the surface Aguayo et al, 1999 and Sandoval, 2000. The involved portions of the crust and its boundaries have also been performing the relative sinking of the mere southwestern centre of the Gulf of Mexico, and the rising of the southeastern lands of Mexico. In the middle contiguity are found the productive Tertiary basins of: Comalcalco, Macuspana, Salina del Itsmo, Campeche-Champoton and other in deep waters; all of them, in an arrangement of basins among distensive faulted blocks in echelon, falling down to the deep centre of the Gulf Sandoval, op cit. With this scenario and that ones of other basins, a recapitulation on concepts and definitions, has been made on the regional natural processes of the environmental depositional systems and on the basins analysis in the tectonophysical framework, in order to reflect on the

  20. Valuable metals - recovery processes, current trends, and recycling strategies

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, Peter; Lorenz, Tom; Martin, Gunther; Brett, Beate; Bertau, Martin [Institut fuer Technische Chemie, TU Bergakademie Freiberg, Leipziger Strasse 29, 09599, Freiberg (Germany)

    2017-03-01

    This Review provides an overview of valuable metals, the supply of which has been classified as critical for Europe. Starting with a description of the current state of the art, novel approaches for their recovery from primary resources are presented as well as recycling processes. The focus lies on developments since 2005. Chemistry strategies which are used in metal recovery are summarized on the basis of the individual types of deposit and mineral. In addition, the economic importance as well as utilization of the metals is outlined. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Survey of electrochemical metal winning processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vaaler, L.E.

    1979-03-01

    The subject program was undertaken to find electrometallurgical technology that could be developed into energy saving commercial metal winning processes. Metals whose current production processes consume significant energy (excepting copper and aluminum) are magnesium, zinc, lead, chromium, manganese, sodium, and titanium. The technology of these metals, with the exception of titanium, was reviewed. Growth of titanium demand has been too small to justify the installation of an electrolyte process that has been developed. This fact and the uncertainty of estimates of future demand dissuaded us from reviewing titanium technology. Opportunities for developing energy saving processes were found for magnesium, zinc, lead, and sodium. Costs for R and D and demonstration plants have been estimated. It appeared that electrolytic methods for chromium and manganese cannot compete energywise or economically with the pyrometallurgical methods of producing the ferroalloys, which are satisfactory for most uses of chromium and manganese.

  2. Process for removing heavy metal compounds from heavy crude oil

    Science.gov (United States)

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  3. Prediction of microstructure, residual stress, and deformation in laser powder bed fusion process

    Science.gov (United States)

    Yang, Y. P.; Jamshidinia, M.; Boulware, P.; Kelly, S. M.

    2017-12-01

    Laser powder bed fusion (L-PBF) process has been investigated significantly to build production parts with a complex shape. Modeling tools, which can be used in a part level, are essential to allow engineers to fine tune the shape design and process parameters for additive manufacturing. This study focuses on developing modeling methods to predict microstructure, hardness, residual stress, and deformation in large L-PBF built parts. A transient sequentially coupled thermal and metallurgical analysis method was developed to predict microstructure and hardness on L-PBF built high-strength, low-alloy steel parts. A moving heat-source model was used in this analysis to accurately predict the temperature history. A kinetics based model which was developed to predict microstructure in the heat-affected zone of a welded joint was extended to predict the microstructure and hardness in an L-PBF build by inputting the predicted temperature history. The tempering effect resulting from the following built layers on the current-layer microstructural phases were modeled, which is the key to predict the final hardness correctly. It was also found that the top layers of a build part have higher hardness because of the lack of the tempering effect. A sequentially coupled thermal and mechanical analysis method was developed to predict residual stress and deformation for an L-PBF build part. It was found that a line-heating model is not suitable for analyzing a large L-PBF built part. The layer heating method is a potential method for analyzing a large L-PBF built part. The experiment was conducted to validate the model predictions.

  4. Prediction of microstructure, residual stress, and deformation in laser powder bed fusion process

    Science.gov (United States)

    Yang, Y. P.; Jamshidinia, M.; Boulware, P.; Kelly, S. M.

    2018-05-01

    Laser powder bed fusion (L-PBF) process has been investigated significantly to build production parts with a complex shape. Modeling tools, which can be used in a part level, are essential to allow engineers to fine tune the shape design and process parameters for additive manufacturing. This study focuses on developing modeling methods to predict microstructure, hardness, residual stress, and deformation in large L-PBF built parts. A transient sequentially coupled thermal and metallurgical analysis method was developed to predict microstructure and hardness on L-PBF built high-strength, low-alloy steel parts. A moving heat-source model was used in this analysis to accurately predict the temperature history. A kinetics based model which was developed to predict microstructure in the heat-affected zone of a welded joint was extended to predict the microstructure and hardness in an L-PBF build by inputting the predicted temperature history. The tempering effect resulting from the following built layers on the current-layer microstructural phases were modeled, which is the key to predict the final hardness correctly. It was also found that the top layers of a build part have higher hardness because of the lack of the tempering effect. A sequentially coupled thermal and mechanical analysis method was developed to predict residual stress and deformation for an L-PBF build part. It was found that a line-heating model is not suitable for analyzing a large L-PBF built part. The layer heating method is a potential method for analyzing a large L-PBF built part. The experiment was conducted to validate the model predictions.

  5. Micro-deformation behavior in micro-compression with high-purity aluminum processed by ECAP

    Directory of Open Access Journals (Sweden)

    Xu Jie

    2015-01-01

    Full Text Available Ultrafine-grained (UFG materials have a potential for applications in micro-forming since grain size appears to be the dominant factor which determines the limiting size of the geometrical features. In this research, high-purity Al was processed by equal-channel angular pressing (ECAP at room temperature through 1–8 passes. Analysis shows that processing by ECAP produces a UFG structure with a grain size of ~1.3 μm and with microhardness and microstructural homogeneity. Micro-compression testing was carried out with different specimen dimensions using the annealed sample and after ECAP processing through 1–8 passes. The results show the flow stress increases significantly after ECAP processing by comparison with the annealed material. The flow stress generally reaches a maximum value after 2 passes which is consistent with the results of microhardness. The flow stress decreases with decreasing specimen diameter from 4 mm to 1 mm which demonstrates that size effects also exist in the ultrafine-grained materials. However, the deformation mechanism in ultrafine-grained pure Al changes from strain strengthening to softening by dynamic recovery by comparison with the annealed material.

  6. Process control for sheet-metal stamping process modeling, controller design and shop-floor implementation

    CERN Document Server

    Lim, Yongseob; Ulsoy, A Galip

    2014-01-01

    Process Control for Sheet-Metal Stamping presents a comprehensive and structured approach to the design and implementation of controllers for the sheet metal stamping process. The use of process control for sheet-metal stamping greatly reduces defects in deep-drawn parts and can also yield large material savings from reduced scrap. Sheet-metal forming is a complex process and most often characterized by partial differential equations that are numerically solved using finite-element techniques. In this book, twenty years of academic research are reviewed and the resulting technology transitioned to the industrial environment. The sheet-metal stamping process is modeled in a manner suitable for multiple-input multiple-output control system design, with commercially available sensors and actuators. These models are then used to design adaptive controllers and real-time controller implementation is discussed. Finally, experimental results from actual shopfloor deployment are presented along with ideas for further...

  7. Solution processed metal oxide thin film hole transport layers for high performance organic solar cells

    Science.gov (United States)

    Steirer, K. Xerxes; Berry, Joseph J.; Chesin, Jordan P.; Lloyd, Matthew T.; Widjonarko, Nicodemus Edwin; Miedaner, Alexander; Curtis, Calvin J.; Ginley, David S.; Olson, Dana C.

    2017-01-10

    A method for the application of solution processed metal oxide hole transport layers in organic photovoltaic devices and related organic electronics devices is disclosed. The metal oxide may be derived from a metal-organic precursor enabling solution processing of an amorphous, p-type metal oxide. An organic photovoltaic device having solution processed, metal oxide, thin-film hole transport layer.

  8. Deformation and Phase Transformation Processes in Polycrystalline NiTi and NiTiHf High Temperature Shape Memory Alloys

    Science.gov (United States)

    Benafan, Othmane

    2012-01-01

    The deformation and transformation mechanisms of polycrystalline Ni49.9Ti50.1 and Ni50.3Ti29.7Hf20 (in at.%) shape memory alloys were investigated by combined experimental and modeling efforts aided by an in situ neutron diffraction technique at stress and temperature. The thermomechanical response of the low temperature martensite, the high temperature austenite phases, and changes between these two states during thermomechanical cycling were probed and reported. In the cubic austenite phase, stress-induced martensite, deformation twinning and slip processes were observed which helped in constructing a deformation map that contained the limits over which each of the identified mechanisms was dominant. Deformation of the monoclinic martensitic phase was also investigated where the microstructural changes (texture, lattice strains, and phase fractions) during room-temperature deformation and subsequent thermal cycling were compared to the bulk macroscopic response. When cycling between these two phases, the evolution of inelastic strains, along with the shape setting procedures were examined and used for the optimization of the transformation properties as a function of deformation levels and temperatures. Finally, this work was extended to the development of multiaxial capabilities at elevated temperatures for the in situ neutron diffraction measurements of shape memory alloys on the VULCAN Diffractometer at Oak Ridge National Laboratory.

  9. Comparative study of resist stabilization techniques for metal etch processing

    Science.gov (United States)

    Becker, Gerry; Ross, Matthew F.; Wong, Selmer S.; Minter, Jason P.; Marlowe, Trey; Livesay, William R.

    1999-06-01

    This study investigates resist stabilization techniques as they are applied to a metal etch application. The techniques that are compared are conventional deep-UV/thermal stabilization, or UV bake, and electron beam stabilization. The electron beam tool use din this study, an ElectronCure system from AlliedSignal Inc., ELectron Vision Group, utilizes a flood electron source and a non-thermal process. These stabilization techniques are compared with respect to a metal etch process. In this study, two types of resist are considered for stabilization and etch: a g/i-line resist, Shipley SPR-3012, and an advanced i-line, Shipley SPR 955- Cm. For each of these resist the effects of stabilization on resist features are evaluated by post-stabilization SEM analysis. Etch selectivity in all cases is evaluated by using a timed metal etch, and measuring resists remaining relative to total metal thickness etched. Etch selectivity is presented as a function of stabilization condition. Analyses of the effects of the type of stabilization on this method of selectivity measurement are also presented. SEM analysis was also performed on the features after a compete etch process, and is detailed as a function of stabilization condition. Post-etch cleaning is also an important factor impacted by pre-etch resist stabilization. Results of post- etch cleaning are presented for both stabilization methods. SEM inspection is also detailed for the metal features after resist removal processing.

  10. ANALYSIS OF DEFORMATION PROCESSES IN THE LITHOSPHERE FROM GEODETIC MEASUREMENTS BASED ON THE EXAMPLE OF THE SAN ANDREAS FAULT

    Directory of Open Access Journals (Sweden)

    Yury V. Gabsatarov

    2012-01-01

    Full Text Available Analysis of data from permanent GPS observation stations located in tectonically active regions provides for direct observation of deformation processes of the earth's surface which result from elastic interaction of the lithospheric plates and also occur when accumulated stresses are released by seismic events and postseismic processes.This article describes the methodology of applying the regression analysis of time series of data from GPS-stations for identification of individual components of the stations’ displacements caused by the influence of various deformation processes. Modelling of the stations’ displacements caused only by deformations of the marginal zone, wherein the lithospheric plates interact, allows us to study variations of the steady-state deformation in the marginal zone.he proposed methodology is applied to studies of variations of fields of cumulative surface displacements, surface displacement velocity and maximum shear strain velocity which are determined from the GPS data recorded prior to the Parkfield earthquake of 28 September 2004 (Mw=6.0.Combined analysis of the variations of the above-mentioned fields shows that measurable anomalies of the elastic deformation of the transform fault’s edge took place prior to the seismic event of 28 September 2004, and such anomalies were coincident in space and time with the focal area of the future seismic event.

  11. [Exposure to metal compounds in occupational galvanic processes].

    Science.gov (United States)

    Surgiewicz, Jolanta; Domański, Wojciech

    2006-01-01

    Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

  12. Stability of medium range order in Al-based metallic glass compacted by severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, Zs.; Henits, P. [Department of Materials Physics, Eötvös University, P.O.B. 32, H-1518 Budapest (Hungary); Varga, L.K. [Research Institute for Solid state Physics and Optics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Schafler, E. [Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, A-1090 Vienna (Austria); Révész, Á., E-mail: reveszadam@ludens.elte.hu [Department of Materials Physics, Eötvös University, P.O.B. 32, H-1518 Budapest (Hungary)

    2013-06-05

    Highlights: ► High pressure torsion has been applied to produce low-porosity bulk Al-based amorphous specimens. ► The compacted disks possess higher hardness than the original glass. ► Mechanical and thermal impacts have only minor effects on the glassy structure. ► Medium range order is an inherent feature of the amorphous state. -- Abstract: High pressure torsion has successfully been applied to produce low-porosity, bulk specimens from Al-based metallic glass ribbons (Al{sub 85}Y{sub 8}Ni{sub 5}Co{sub 2}, Al{sub 85}Ce{sub 8}Ni{sub 5}Co{sub 2} and Al{sub 85}Gd{sub 8}Ni{sub 5}Co{sub 2}). The compacted disks possess higher hardness than the original glass and have substantial glass fraction with nanocrystalline precipitations. Mechanical and thermal impacts have only minor effects on the glassy structure as demonstrated by the stability of the X-ray diffraction halo positions. Unchanged halos reveal that medium range order is a key characteristic of the amorphous state.

  13. Deformation Characteristics and Sealing Performance of Metallic O-rings for a Reactor Pressure Vessel

    Directory of Open Access Journals (Sweden)

    Mingxue Shen

    2016-04-01

    Full Text Available This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV. A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

  14. Deformation characteristics and sealing performance of metallic-O-ring for a reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Ming Xue; Peng, Xudong; Xie, Linjun; Meng, Xiang Kai [Engineering Research Center of Process Equipment and Its Remanufacture, Ministry of Education, Zhejiang University of Technology, Hangzhou (China); Li, Xing Gen [Ningbo Tiansheng Sealing Packing Co., Ltd., Ningbo (China)

    2016-04-15

    This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV). A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap) have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

  15. Modeling of optimization strategies in the incremental CNC sheet metal forming process

    International Nuclear Information System (INIS)

    Bambach, M.; Hirt, G.; Ames, J.

    2004-01-01

    Incremental CNC sheet forming (ISF) is a relatively new sheet metal forming process for small batch production and prototyping. In ISF, a blank is shaped by the CNC movements of a simple tool in combination with a simplified die. The standard forming strategies in ISF entail two major drawbacks: (i) the inherent forming kinematics set limits on the maximum wall angle that can be formed with ISF. (ii) since elastic parts of the imposed deformation can currently not be accounted for in CNC code generation, the standard strategies can lead to undesired deviations between the target and the sample geometry.Several enhancements have recently been put forward to overcome the above limitations, among them a multistage forming strategy to manufacture steep flanges, and a correction algorithm to improve the geometric accuracy. Both strategies have been successful in improving the forming of simple parts. However, the high experimental effort to empirically optimize the tool paths motivates the use of process modeling techniques.This paper deals with finite element modeling of the ISF process. In particular, the outcome of different multistage strategies is modeled and compared to collated experimental results regarding aspects such as sheet thickness and the onset of wrinkling. Moreover, the feasibility of modeling the geometry of a part is investigated as this is of major importance with respect to optimizing the geometric accuracy. Experimental validation is achieved by optical deformation measurement that gives the local displacements and strains of the sheet during forming as benchmark quantities for the simulation

  16. Microstructure characteristics of nickel reinforced metal matrix composites (Ni/AC8A) by low-pressure metal infiltration process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jun; Rong, Hua Wei; Jun, Ji Ang; Park, Sung Ho; Huh, Sun Chul; Park, Won Jo [Gyeongsang National University, Jinju (Korea, Republic of)

    2009-07-01

    MMCs(Metal Matrix Composites) can obtain mechanical characteristics of application purposes that a single material is difficult to obtain. Al alloy composite material that nickel is added by reinforcement is used for piston of diesel engine, because high temperature properties, strength, corrosion resistant are improved excellently than existent Al alloy. And, in case of processing, interface between Ni and Al improves wear resistant by intermetallic compound of high hardness. Also, in the world, industrial circles are proceeding research to apply excellent composite material. Existent process methods of MMC using preform were manufactured by high-pressure. But, it cause deformation of preform or fault of completed MMC. Using low-pressure as infiltration pressure can prevent this problem, and there is an advantage that is able to reduce the cost of production by small scale of production equipment. Accordingly, process methods of MMC have to consider low-pressure infiltration for the strength of preform, and nowadays, there are many studies about reducing infiltration pressure. In this study produced Al composite material that Ni is added by reinforcement by low-pressure infiltration, and observed microstructure of completed MMCs.

  17. Modelling of deformation process for the layer of elastoviscoplastic media under surface action of periodic force of arbitrary type

    Science.gov (United States)

    Mikheyev, V. V.; Saveliev, S. V.

    2018-01-01

    Description of deflected mode for different types of materials under action of external force plays special role for wide variety of applications - from construction mechanics to circuits engineering. This article con-siders the problem of plastic deformation of the layer of elastoviscolastic soil under surface periodic force. The problem was solved with use of the modified lumped parameters approach which takes into account close to real distribution of normal stress in the depth of the layer along with changes in local mechanical properties of the material taking place during plastic deformation. Special numeric algorithm was worked out for computer modeling of the process. As an example of application suggested algorithm was realized for the deformation of the layer of elasoviscoplastic material by the source of external lateral force with the parameters of real technological process of soil compaction.

  18. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue; Ge, Qingchun; Liu, Xiangyang; Chung, Neal Tai-Shung

    2014-01-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  19. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue

    2014-10-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  20. Modeling and simulation of the deformation process of PTFE flexiblestamps for nanoimprint lithography on curved surfaces

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Smistrup, K.; Hannibal, Morten

    2015-01-01

    -viscoplastic. This behavior was described in a temperature dependent constitutive model consisting of a Zenerbody for the viscoelastic deformation and the Johnson-Cook model for the description of the viscoplastic deformation. The constitutive model was implemented in the general purpose finite element software ABAQUS...

  1. Quantification of the free volume in Zr45.0Cu39.3Al7.0Ag8.7 bulk metallic glasses subjected to plastic deformation by calorimetric and dilatometric measurements

    International Nuclear Information System (INIS)

    Zhang Yue; Hahn, Horst

    2009-01-01

    Zr 45.0 Cu 39.3 Al 7.0 Ag 8.7 bulk metallic glasses (BMGs) were prepared using suction casting technique. Plastic deformations were carried out by cold rolling and high-pressure torsion (HPT). The absolute contents of free volume in the as-cast, preheated and deformed samples were determined by differential scanning calorimetry (DSC) and dilatometry using the free volume model (FVM). The parameters required in the FVM are experimentally determined to be b = 0.107, β = 642.1 kJ/mol, D * = 10.3 and T 0 = 496.9 K, respectively. The equilibrium free volume determined by these parameters is in good agreement with that calculated from previous enthalpy relaxation experiments, showing the reliability of the values of the parameters. It is found that the content of free volume in the as-cast sample is 0.533% with respect to the atomic volume of the BMG. The free volume in the HPT deformed sample is determined to be 0.672%, which is the largest among all the samples. The excess free volume introduced by cold rolling is found to increase with the deformation strain and show weak strain rate dependent behavior. Finally, attempts are made to simulate the experimental DSC curve using a bimolecular kinetics in the flow defect model. However, the result shows that the kinetics of free volume may be more complicated than as described as a bimolecular process.

  2. Polyimide and Metals MEMS Multi-User Processes

    KAUST Repository

    Arevalo, Arpys

    2016-11-01

    The development of a polyimide and metals multi-user surface micro-machining process for Micro-electro-mechanical Systems (MEMS) is presented. The process was designed to be as general as possible, and designed to be capable to fabricate different designs on a single silicon wafer. The process was not optimized with the purpose of fabricating any one specific device but can be tweaked to satisfy individual needs depending on the application. The fabrication process uses Polyimide as the structural material and three separated metallization layers that can be interconnected depending on the desired application. The technology allows the development of out-of-plane compliant mechanisms, which can be combined with six variations of different physical principles for actuation and sensing on a single processed silicon wafer. These variations are: electrostatic motion, thermal bimorph actuation, capacitive sensing, magnetic sensing, thermocouple-based sensing and radio frequency transmission and reception.

  3. Room temperature deformation mechanisms in ultrafine-grained materials processed by hot isostatic pressing

    International Nuclear Information System (INIS)

    Cao, W.Q.; Dirras, G.F.; Benyoucef, M.; Bacroix, B.

    2007-01-01

    Ultrafine-grained (uf-g) and microcrystalline-grained (mc-g) irons have been fabricated by hot isostatic pressing of nanopowders. The mechanical properties have been characterized by compressive tests at room temperature and the resulting microstructures and textures have been determined by combining electron back scatter diffraction and transmission electron microscopy. A transition of the deformation mode, from work hardening to work softening occurs for grain sizes below ∼1 μm, reflecting a transition of the deformation mode from homogeneous to localized deformation into shear bands (SBs). The homogeneous deformation is found to be lattice dislocation-based while the deformation within SBs involves lattice dislocations as well as boundary-related mechanisms, possibly grain boundary sliding accommodated by boundary opening

  4. Fine grained 304 ASS processed by a severe plastic deformation and subsequent annealing; microstructure and mechanical properties evaluation

    Science.gov (United States)

    Salout, Shima Ahmadzadeh; Shirazi, Hasan; Nili-Ahmadabadi, Mahmoud

    2018-01-01

    The current research is an attempt to study the effect of a novel severe plastic deformation technique so called "repetitive corrugation and straightening by rolling" (RCSR) and subsequent annealing on the microstructure and mechanical properties of AISI type 304 austenitic stainless steel. In this study, RCSR process was carried out at 200 °C on the 304 austenitic stainless steel (above Md30 temperature that is about 50 °C for this stainless steel) in order to avoid the formation of martensite phase when a high density of dislocations was introduced into the austenite phase and also high density of mechanical twins was induced in the deformed 304 austenitic stainless steel. Because of relationship between deformation temperature, stacking fault energy (SFE) and mechanisms of deformation. Thereafter subsequently, annealing treatment was applied into deformed structure in order to refine the microstructure of 304 stainless s teel. The specimens were examined by means of optical microscopy (OM), scanning electron microscopy (SEM), tensile and micro-hardness tests. The results indicate that by increasing the cycles of RCSR process (increasing applied strain), further mechanical twins are induced, the hardness and in particular, the yield stress of specimens have been increased.

  5. The diffusion behaviour of hydrogen in a low alloyed carbon steel with respect to the deformation level and to the passivation process in alkaline solutions

    International Nuclear Information System (INIS)

    Juilfs, G.G.

    2001-01-01

    The diffusion behaviour of hydrogen in a low alloyed carbon steel with respect to the deformation level and to the passivation process in alkaline solutions. The influence of plastic strain on the diffusion behaviour of hydrogen in a low alloyed structural steel (FeE 690T) was investigated using the electrochemical permeation technique. The plastic deformation was introduced either by cold rolling or by tensile straining. Specially prepared C(T)-specimen enabled the direct determination of the diffusion coefficient in the highly deformed region ahead of a blunting crack. It was shown, that the apparent diffusion coefficient depends on the plastic strain and on the overall hydrogen concentration, whereas the maximum hydrogen flux remained almost unchanged. These observations are interpreted in terms of variations in the dislocation density, which act as 'sinks' for the diffusable hydrogen atoms. The results are compared with model calculations, that describe the hydrogen transport as a function of the trap density. The comparison of the numerical simulation and the experimental data shows a good agreement over the whole range of plastic strain levels, leading to a trap density of 6.1.10 19 /d 3 . Together with the results of a previous study on the fracture toughness of FeE 690T in the presence of hydrogen the permeation data obtained in this work suggest that the observed influence of deformation rates on the fracture mechanism can be attributed to the reduced mobility of hydrogen atoms in the plastic zone. The assumption that the hydrogen transport during monotonic straining is controlled by diffusion was confirmed by investigations concerning the formation of surface films. Using a potentiodynamic method (cyclovoltammetry) a characterisation of the surface reactions involved in permeation experiments was performed. It was shown that the nature of the passive layers forming on the surface depends on the applied potential, affecting mainly the hydrogen absorption

  6. Texture Evolution in a Ti-Ta-Nb Alloy Processed by Severe Plastic Deformation

    Science.gov (United States)

    Cojocaru, Vasile-Danut; Raducanu, Doina; Gloriant, Thierry; Cinca, Ion

    2012-05-01

    Titanium alloys are extensively used in a variety of applications because of their good mechanical properties, high biocompatibility, and corrosion resistance. Recently, β-type Ti alloys containing Ta and Nb have received much attention because they feature not only high specific strength but also biocorrosion resistance, no allergic problems, and biocompatibility. A Ti-25Ta-25Nb β-type titanium alloy was subjected to severe plastic deformation (SPD) processing by accumulative roll bonding and investigated with the aim to observe the texture developed during SPD processing. Texture data expressed by pole figures, inverse pole figures, and orientation distribution functions for the (110), (200), and (211) β-Ti peaks were obtained by XRD investigations. The results showed that it is possible to obtain high-intensity share texture modes ({001}) and well-developed α and γ-fibers; the most important fiber is the α-fiber ({001} to {114} to {112} ). High-intensity texture along certain crystallographic directions represents a way to obtain materials with high anisotropic properties.

  7. New applications and novel processing of refractory metal alloys

    International Nuclear Information System (INIS)

    Briant, C.L.

    2001-01-01

    Refractory metals have often been limited in their application because of their propensity to oxidize and to undergo a loos of yield strength at elevated temperatures. However, recent developments in both processing and alloy composition have opened the possibility that these materials might be used in structural applications that were not considered possible in the past. At the same time, the use of refractory metals in the electronics industry is growing, particularly with the use of tantalum as a diffusion barrier for copper metallization. Finally, the application of grain boundary engineering to the problem of intergranular fracture in these materials may allow processes to be developed that will produce alloys with a greater resistance to fracture. (author)

  8. Microfabrication process for patterning metallic lithium encapsulated electrodes

    International Nuclear Information System (INIS)

    Oukassi, Sami; Dunoyer, Nicolas; Salot, Raphael; Martin, Steve

    2009-01-01

    This work presents recent achievements concerning thin film encapsulation of metallic lithium negative electrode. In the context of this study, the encapsulation stack includes polymer and dielectric layers combined in such way to optimize barrier performances of the whole structure towards oxygen and water vapor permeation. The first part of this work is dedicated to the description of the barrier stack architecture and properties. A second part presents the application of a microfabrication process to the metallic lithium negative electrode and barrier stack so as to have very small features (100 μm x 100 μm patterns). The microfabrication process includes several steps of photolithography and etching (dry and wet) blocks, which allows us to reach the target critical dimensions. These results show a method of patterning functional metallic lithium. It demonstrates the feasibility of energy sources miniaturization which is an important issue in the field of autonomous and wireless sensor networks.

  9. Corrosion processes of physical vapor deposition-coated metallic implants.

    Science.gov (United States)

    Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

    2009-01-01

    Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

  10. Dynamics of ultrathin metal films on amorphous substrates under fast thermal processing

    International Nuclear Information System (INIS)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2007-01-01

    A mathematical model is developed to analyze the growth/decay rate of surface perturbations of an ultrathin metal film on an amorphous substrate (SiO 2 ). The formulation combines the approach of Mullins [W. W. Mullins, J. Appl. Phys. 30, 77 (1959)] for bulk surfaces, in which curvature-driven mass transport and surface deformation can occur by surface/volume diffusion and evaporation-condensation processes, with that of Spencer et al. [B. J. Spencer, P. W. Voorhees, and S. H. Davis, Phys. Rev. Lett. 67, 26 (1991)] to describe solid-state transport in thin films under epitaxial strain. Modifications of the Mullins model to account for thin-film boundary conditions result in qualitatively different dispersion relationships especially in the limit as kh o o is the unperturbed film height. The model is applied to study the relative rate of solid-state mass transport as compared to that of liquid phase dewetting in a thin film subjected to a fast thermal pulse. Specifically, we have recently shown that multiple cycles of nanosecond (ns) pulsed laser melting and resolidification of ultrathin metal films on amorphous substrates can lead to the formation of various types of spatially ordered nanostructures [J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Phys. Rev. B 75, 235439 (2007)]. The pattern formation has been attributed to the dewetting of the thin film by a hydrodynamic instability. In such experiments the film is in the solid state during a substantial fraction of each thermal cycle. However, results of a linear stability analysis based on the aforementioned model suggest that solid-state mass transport has a negligible effect on morphological changes of the surface. Further, a qualitative analysis of the effect of thermoelastic stress, induced by the rapid temperature changes in the film-substrate bilayer, suggests that stress relaxation does not appreciably contribute to surface deformation. Hence, surface deformation caused by liquid

  11. Dynamics of ultrathin metal films on amorphous substrates under fast thermal processing

    Science.gov (United States)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2007-11-01

    A mathematical model is developed to analyze the growth/decay rate of surface perturbations of an ultrathin metal film on an amorphous substrate (SiO2). The formulation combines the approach of Mullins [W. W. Mullins, J. Appl. Phys. 30, 77 (1959)] for bulk surfaces, in which curvature-driven mass transport and surface deformation can occur by surface/volume diffusion and evaporation-condensation processes, with that of Spencer etal . [B. J. Spencer, P. W. Voorhees, and S. H. Davis, Phys. Rev. Lett. 67, 26 (1991)] to describe solid-state transport in thin films under epitaxial strain. Modifications of the Mullins model to account for thin-film boundary conditions result in qualitatively different dispersion relationships especially in the limit as kho≪1, where k is the wavenumber of the perturbation and ho is the unperturbed film height. The model is applied to study the relative rate of solid-state mass transport as compared to that of liquid phase dewetting in a thin film subjected to a fast thermal pulse. Specifically, we have recently shown that multiple cycles of nanosecond (ns) pulsed laser melting and resolidification of ultrathin metal films on amorphous substrates can lead to the formation of various types of spatially ordered nanostructures [J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Phys. Rev. B 75, 235439 (2007)]. The pattern formation has been attributed to the dewetting of the thin film by a hydrodynamic instability. In such experiments the film is in the solid state during a substantial fraction of each thermal cycle. However, results of a linear stability analysis based on the aforementioned model suggest that solid-state mass transport has a negligible effect on morphological changes of the surface. Further, a qualitative analysis of the effect of thermoelastic stress, induced by the rapid temperature changes in the film-substrate bilayer, suggests that stress relaxation does not appreciably contribute to surface

  12. Application of laser assisted cold spraying process for metal deposition

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-02-01

    Full Text Available Laser assisted cold spraying (LACS) process is a hybrid technique that uses laser and cold spray to deposit solid powders on metal substrates. For bonding to occur, the particle velocities must be supersonic which are achieved by entraining...

  13. Process of forming a sol-gel/metal hydride composite

    Science.gov (United States)

    Congdon, James W [Aiken, SC

    2009-03-17

    An external gelation process is described which produces granules of metal hydride particles contained within a sol-gel matrix. The resulting granules are dimensionally stable and are useful for applications such as hydrogen separation and hydrogen purification. An additional coating technique for strengthening the granules is also provided.

  14. Trace Metal Levels in Raw and Heat Processed Nigerian Staple ...

    African Journals Online (AJOL)

    The levels of some trace metals (Fe, Zn, Cu, Ni, Cd) were quantitatively determined in raw and heat processed staple food cultivars (yam, cassava, cocoyam and maize) from oil producing areas of part of the Niger Delta and compared with a non-oil producing area of Ebonyi State as control. The survey was conducted to ...

  15. Coagulation / flocculation process in the removal of trace metals ...

    African Journals Online (AJOL)

    Attempts were made in this study to examine the effectiveness of polymer addition to coagulation process during treatment of a beverage industrial wastewater to remove some of its trace metals content such as lead, cadmium, total iron, total chromium, nickel and zinc. Experiments were conducted using the standard Jar ...

  16. Continuous process for selective metal extraction with an ionic liquid

    NARCIS (Netherlands)

    Parmentier, D.; Paradis, S.; Metz, S.J.; Wiedmer, S.K.; Kroon, M.C.

    2016-01-01

    This work describes for the first time a continuous process for selective metal extraction with an ionic liquid (IL) at room temperature. The hydrophobic fatty acid based IL tetraoctylphosphonium oleate ([P8888][oleate]) was specifically chosen for its low viscosity and high selectivity towards

  17. Gas discharge processes in the standard and metal channel PMTs

    International Nuclear Information System (INIS)

    Morozov, V.A.; Morozova, N.V.

    2015-01-01

    The effect of the potential difference at the focusing chamber electrodes of the XP2020, FEU-85, FEU-87, and FEU-93 photomultipliers on the intensity of afterpulses resulting from gas discharge processes is investigated. The time distribution of the afterpulses in the metal channel PMTs - H6780 and R7600U-200 - is studied as well

  18. Electrochemical activity of heavy metal oxides in the process of ...

    Indian Academy of Sciences (India)

    Unknown

    2002-02-02

    Feb 2, 2002 ... Electrochemical activity of heavy metal oxides in the process of chloride induced .... decrease of pH value by MeOx, a synergism of acidic and chloride ... inhibitors and their influence on the physical properties of. Portland ...

  19. Impact of heavy metals on the oil products biodegradation process.

    Science.gov (United States)

    Zukauskaite, Audrone; Jakubauskaite, Viktorija; Belous, Olga; Ambrazaitiene, Dalia; Stasiskiene, Zaneta

    2008-12-01

    Oil products continue to be used as a principal source of energy. Wide-scale production, transport, global use and disposal of petroleum have made them major contaminants in prevalence and quantity in the environment. In accidental spills, actions are taken to remove or remediate or recover the contaminants immediately, especially if they occur in environmentally sensitive areas, for example, in coastal zones. Traditional methods to cope with oil spills are confined to physical containment. Biological methods can have an advantage over the physical-chemical treatment regimes in removing spills in situ as they offer biodegradation of oil fractions by the micro-organisms. Recently, biological methods have been known to play a significant role in bioremediation of oil-polluted coastal areas. Such systems are likely to be of significance in the effective management of sensitive coastal ecosystems chronically subjected to oil spillage. For this reason the aim of this paper is to present an impact of Mn, Cu, Co and Mo quantities on oil biodegradation effectiveness in coastal soil and to determine the relationship between metal concentrations and degradation of two oil products (black oil and diesel fuel). Soil was collected in the Baltic Sea coastal zone oil products degradation area (Klaipeda, Lithuania). The experiment consisted of two parts: study on the influence of micro-elements on the oil product biodegradation process; and analysis of the influence of metal concentration on the number of HDMs. The analysis performed and results obtained address the following areas: impact of metal on a population of hydrocarbon degrading micro-organisms, impact of metals on residual concentrations of oil products, influence of metals on the growth of micro-organisms, inter-relation of metal concentrations with degradation rates. Statistical analysis was made using ;Statgraphics plus' software. The influence of metals on the growth of micro-organisms, the biodegradation process

  20. Influence of the Strain History on TWIP Steel Deformation Mechanisms in the Deep-Drawing Process

    Science.gov (United States)

    Lapovok, R.; Timokhina, I.; Mester, A.-K.; Weiss, M.; Shekhter, A.

    2018-06-01

    A study of preferable deformation modes on strain path and strain level in a TWIP steel sheet was performed. Different strain paths were obtained by stretch forming of specimens with various shapes and tensile tests. TEM analysis was performed on samples cut from various locations in the deformed specimens, which had different strain paths and strain levels and the preferable deformation modes were identified. Stresses caused by various strain paths were considered and an analytical analysis performed to identify the preferable deformation modes for the case of single crystal. For a single crystal, in assumption of the absence of lattice rotation, the strain path and the level of accumulated equivalent strain define the preferable deformation mode. For a polycrystalline material, such analytical analysis is not possible due to the large number of grains and, therefore, numerical simulation was employed. For the polycrystalline material, the role of strain path diminishes due to the presence of a large number of grains with random orientations and the effect of accumulated strain becomes dominant. However, at small strains the strain path still defines the level of twinning activity. TEM analysis experimentally confirmed that various deformation modes lead to different deformation strengthening mechanisms.

  1. The formation of PSB-like shear bands in cyclically deformed ultrafine grained copper processed by ECAP

    Energy Technology Data Exchange (ETDEWEB)

    Wu, S.D.; Wang, Z.G.; Jiang, C.B.; Li, G.Y.; Alexandrov, I.V.; Valiev, R.Z

    2003-06-15

    Cyclic deformation was performed on ultrafine grained copper processed by ECAP. Shear bands (SBs) and adjacent microstructures were investigated using electron channeling contrast in scanning electron microscope. The possible formation mechanism of SB was discussed based on the characteristic distribution of defects introduced by ECAP.

  2. Influence of Compatibilizer and Processing Conditions on Morphology, Mechanical Properties, and Deformation Mechanism of PP/Clay Nano composite

    International Nuclear Information System (INIS)

    Akbari, B.; Bagheri, R.

    2012-01-01

    Polypropylene/montmorillonite nano composite was prepared by melt intercalation method using a twin-screw extruder with starve feeding system in this paper. The effects of compatibilizer, extruder rotor speed and feeding rate on properties of nano composite were investigated. Structure, tensile, and impact properties and deformation mechanism of the compounds were studied. For investigation of structure and deformation mechanisms, X-ray diffraction (XRD) and transmission optical microscopy (TOM) techniques were utilized, respectively. The results illustrate that introduction of the compatibilizer and also variation of the processing conditions affect structure and mechanical properties of nano composite.

  3. The obtained of concentrates containing precious metals for pyrometallurgical processing

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2014-10-01

    Full Text Available In the presented study the flotation process has been proposed as a method of enrichment of silver-bearing jewellery waste. This method, traditionally used for the enrichment of non-ferrous metal ores, is based on differences in wettability between individual minerals. Flotation concentrate, enriched with Ag, was subjected to further processing by the pyrometallurgical method in order to produce silver from these wastes.

  4. The obtained of concentrates containing precious metals for pyrometallurgical processing

    OpenAIRE

    Oleksiak, B.; Siwiec, G.; Blacha-Grzechnik, A.; Wieczorek, J.

    2014-01-01

    In the presented study the flotation process has been proposed as a method of enrichment of silver-bearing jewellery waste. This method, traditionally used for the enrichment of non-ferrous metal ores, is based on differences in wettability between individual minerals. Flotation concentrate, enriched with Ag, was subjected to further processing by the pyrometallurgical method in order to produce silver from these wastes.

  5. Plastic deformation of solids viewed as a self-excited wave process

    International Nuclear Information System (INIS)

    Zuev, L.B.; Danilov, V.I.

    1998-01-01

    A self-excited wave model of plastic flow in crystalline solids is proposed. Experimental data on plastic flow in single crystals and polycrystalline solids involving different mechanisms have been correlated. The main types of strain localization in the materials investigated have been established and correlated with the respective stages of plastic flow curves. The best observing conditions have been defined for the major types of autowaves emerging by plastic deformation. The synergetic concepts of self-organization are shown to apply to description of plastic deformation. Suggested is a self-excited wave model of plastic flow in materials with different mechanisms of deformation. (orig.)

  6. Synthesis and processing of composites by reactive metal penetration

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E.; Ewsuk, K.G. [Sandia National Labs., Albuquerque, NM (United States); Tomsia, A.P. [Pask Research and Engineering, Berkeley, CA (United States)] [and others

    1997-04-01

    Achieving better performance in commercial products and processes often is dependent on availability of new and improved materials. Ceramic-metal composites have advantages over more conventional materials because of their high stiffness-to-weight ratios, good fracture toughness, and because their electrical and thermal properties can be varied through control of their compositions and microstructures. However, ceramic composites will be more widely used only when their costs are competitive with other materials and when designers have more confidence in their reliability. Over the past four years reactive metal penetration has been shown to be a promising technique for making ceramic and metal-matrix composites to near-net-shape with control of both composition and microstructure. It appears that, with sufficient development, reactive metal penetration could be an economical process for manufacturing many of the advanced ceramic composites that are needed for light-weight structural and wear applications for transportation and energy conversion devices. Near-net-shape fabrication of parts is a significant advantage because costly and energy intensive grinding and machining operations are substantially reduced, and the waste generated from such finishing operations is minimized. The most promising compositions to date consist of Al and Al{sub 2}O{sub 3}; thus, these composites should be of particular interest to the aluminum industry. The goals of this ceramic-metal composite research and development program are: (1) to identify compositions favorable for making composites by reactive metal penetration; (2) to understand the mechanism(s) by which these composites are formed; (3) to control and optimize the process so that composites and composite coatings can be made economically; and (4) to apply R&D results to problems of interest to the aluminum industry.

  7. Microstructure and Texture in Surface Deformation Layer of Al-Zn-Mg-Cu Alloy Processed by Milling

    Directory of Open Access Journals (Sweden)

    CHEN Yanxia

    2017-12-01

    Full Text Available The microstructural and crystallographic features of the surface deformation layer in Al-Zn-Mg-Cu alloy induced by milling were investigated by means of transmission electron microscopy (TEM and precession electron diffraction (PED assisted nanoscale orientation mapping. The result shows that the surface deformation layer is composed by the top surface of equiaxed nanograins/ultrafine grains and the subsurface of lamellar nanograins/ultrafine grains surrounded by coarse grain boundary precipitates (GBPs. The recrystallized nanograins/ultrafine grains in the deformation layer show direct evidence that dynamic recrystallization plays an important role in grain refining process. The GBPs and grain interior precipitates (GIPs show a great difference in size and density with the matrix due to the thermally and mechanically induced precipitate redistribution. The crystallographic texture of the surface deformation layer is proved to be a mixture of approximate copper{112}, rotated cube{001} and F {111}. The severe shear deformation of the surface induced by milling is responsible for the texture evolution.

  8. Infiltration processing of metal matrix composites using coated ceramic particulates

    Science.gov (United States)

    Leon-Patino, Carlos Alberto

    2001-07-01

    A new process was developed to fabricate particulate metal matrix composites (MMCs). The process involves three steps: (1) modifying the particulate surface by metal coating, (2) forming a particulate porous compact; and (3) introducing metal into the channel network by vacuum infiltration. MMCs with different reinforcements, volume fractions, and sizes can be produced by this technique. Powders of alumina and silicon carbide were successfully coated with nickel and copper in preparation for infiltration with molten aluminum. Electroless Ni and Cu deposition was used since it enhances the wettability of the reinforcements for composite fabrication. While Cu deposits were polycrystalline, traces of phosphorous co-deposited from the electroless bath gave an amorphous Ni-P coating. The effect of metal coating on wetting behavior was evaluated at 800°C on plain and metal-coated ceramic plates using a sessile drop technique. The metallic films eliminated the non-wetting behavior of the uncoated ceramics, leading to equilibrium contact angles in the order of 12° and below 58° for Ni and Cu coated ceramics, respectively. The spreading data indicated that local diffusion at the triple junction was the governing mechanism of the wetting process. Precipitation of intermetallic phases in the drop/ceramic interface delayed the formation of Al4C3. Infiltration with molten Al showed that the coated-particulates are suitable as reinforcing materials for fabricating MMCs, giving porosity-free components with a homogeneously distributed reinforcing phase. The coating promoted easy metal flow through the preform, compared to the non-infiltration behavior of the uncoated counterparts. Liquid state diffusion kinetics due to temperature dependent viscosity forces controlled the infiltration process. Microstructural analysis indicated the formation of intermetallic phases such as CuAl 2, in the case of Cu coating, and Ni2Al3 and NiAl 3 when Ni-coated powders were infiltrated. The

  9. Deformation processed Al/Ca nano-filamentary composite conductors for HVDC applications

    Science.gov (United States)

    Czahor, C. F.; Anderson, I. E.; Riedemann, T. M.; Russell, A. M.

    2017-07-01

    Efficient long-distance power transmission is necessary as the world continues to implement renewable energy sources, often sited in remote areas. Light, strong, high-conductivity materials are desirable for this application to reduce both construction and operational costs. In this study an Al/Ca (11.5% vol.) composite with nano-filamentary reinforcement was produced by powder metallurgy then extruded, swaged, and wire drawn to a maximum true strain of 12.7. The tensile strength increased exponentially as the filament size was reduced to the sub-micron level. In an effort to improve the conductor’s ability to operate at elevated temperatures, the deformation-processed wires were heat-treated at 260°C to transform the Ca-reinforcing filaments to Al2Ca. Such a transformation raised the tensile strength by as much as 28%, and caused little change in ductility, while the electrical conductivity was reduced by only 1% to 3%. Al/Al2Ca composites are compared to existing conductor materials to show how implementation could affect installation and performance.

  10. The use of the analytic hierarchy process to aid decision making in acquired equinovarus deformity.

    Science.gov (United States)

    van Til, Janine A; Renzenbrink, Gerbert J; Dolan, James G; Ijzerman, Maarten J

    2008-03-01

    To increase the transparency of decision making about treatment in patients with equinovarus deformity poststroke. The analytic hierarchy process (AHP) was used as a structured methodology to study the subjective rationale behind choice of treatment. An 8-hour meeting at a centrally located rehabilitation center in The Netherlands, during which a patient video was shown to all participants (using a personal computer and a large screen) and the patient details were provided on paper. A panel of 10 health professionals from different backgrounds. Not applicable. The performance of the applicable treatments on outcome, impact, comfort, cosmetics, daily effort, and risks and side effects of treatment, as well as the relative importance of criteria in the choice of treatment. According to the model, soft-tissue surgery (.413) ranked first as the preferred treatment, followed by orthopedic footwear (.181), ankle-foot orthosis (.147), surface electrostimulation (.137), and finally implanted electrostimulation (.123). Outcome was the most influential consideration affecting treatment choice (.509), followed by risk and side effects (.194), comfort (.104), daily effort (.098), cosmetics (.065), and impact of treatment (.030). Soft-tissue surgery was judged best on outcome, daily effort, comfortable shoe wear, and cosmetically acceptable result and was thereby preferred as a treatment alternative by the panel in this study. In contrast, orthosis and orthopedic footwear are usually preferred in daily practice. The AHP method was found to be suitable methodology for eliciting subjective opinions and quantitatively comparing treatments in the absence of scientific evidence.

  11. Nuclear processes in deuterium/natural hydrogen-metal systems

    International Nuclear Information System (INIS)

    Zelensky, V.F.

    2013-01-01

    The survey presents the analysis of the phenomena taking place in deuterium - metal and natural hydrogen - metal systems under cold fusion experimental conditions. The cold fusion experiments have shown that the generation of heat and helium in the deuterium-metal system without emission of energetic gamma-quanta is the result of occurrence of a chain of chemical, physical and nuclear processes observed in the system, culminating in both the fusion of deuterium nuclei and the formation of a virtual, electron-modified excited 4He nucleus. The excitation energy of the helium nucleus is transferred to the matrix through emission of conversion electrons, and that, under appropriate conditions, provides a persistent synthesis of deuterium. The processes occurring in the deuterium/natural hydrogen - metal systems have come to be known as chemonuclear DD- and HD-fusion. The mechanism of stimulation of weak interaction reactions under chemonuclear deuterium fusion conditions by means of strong interaction reactions has been proposed. The results of numerous experiments discussed in the survey bear witness to the validity of chemonuclear fusion. From the facts discussed it is concluded that the chemonuclear deuterium fusion scenario as presented in this paper may serve as a basis for expansion of deeper research and development of this ecologically clean energy source. It is shown that the natural hydrogen-based system, containing 0.015% of deuterium, also has good prospects as an energy source. The chemonuclear fusion processes do not require going beyond the scope of traditional physics for their explanation

  12. Bilayer lift-off process for aluminum metallization

    Science.gov (United States)

    Wilson, Thomas E.; Korolev, Konstantin A.; Crow, Nathaniel A.

    2015-01-01

    Recently published reports in the literature for bilayer lift-off processes have described recipes for the patterning of metals that have recommended metal-ion-free developers, which do etch aluminum. We report the first measurement of the dissolution rate of a commercial lift-off resist (LOR) in a sodium-based buffered commercial developer that does not etch aluminum. We describe a reliable lift-off recipe that is safe for multiple process steps in patterning thin (recipe consists of an acid cleaning of the substrate, the bilayer (positive photoresist/LOR) deposition and development, the sputtering of the aluminum film along with a palladium capping layer and finally, the lift-off of the metal film by immersion in the LOR solvent. The insertion into the recipe of postexposure and sequential develop-bake-develop process steps are necessary for an acceptable undercut. Our recipe also eliminates any need for accompanying sonication during lift-off that could lead to delamination of the metal pattern from the substrate. Fine patterns were achieved for both 100-nm-thick granular aluminum/palladium bilayer bolometers and 500-nm-thick aluminum gratings with 6-μm lines and 4-μm spaces.

  13. Spectral BRDF measurements of metallic samples for laser processing applications

    International Nuclear Information System (INIS)

    Vitali, L; Fustinoni, D; Gramazio, P; Niro, A

    2015-01-01

    The spectral bidirectional reflectance distribution function (BRDF) of metals plays an important role in industrial processing involving laser-surface interaction. In particular, in laser metal machining, absorbance is strongly dependent on the radiation incidence angle as well as on finishing and contamination grade of the surface, and in turn it can considerably affect processing results. Very recently, laser radiation is also used to structure metallic surfaces, in order to produce many particular optical effects, ranging from a high level polishing to angular color shifting. Of course, full knowledge of the spectral BRDF of these structured layers makes it possible to infer reflectance or color for any irradiation and viewing angles. In this paper, we present Vis-NIR spectral BRDF measurements of laser-polished metallic, opaque, flat samples commonly employed in such applications. The resulting optical properties seem to be dependent on the atmospheric composition during the polishing process in addition to the roughness. The measurements are carried out with a Perkin Elmer Lambda 950 double-beam spectrophotometer, equipped with the Absolute Reflectance/Transmittance Analyzer (ARTA) motorized goniometer. (paper)

  14. Predicting deformation and stress as a function of additive manufacturing process parameters for Europa drill

    Data.gov (United States)

    National Aeronautics and Space Administration — We will combine part-level FEM model of residual stresses with phase-field transformation model to predict deformation and cracking due to thermal stresses from the...

  15. 10^3 Segment MEMS Deformable-Mirror Process Development, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Iris AO will extend its proven segmented MEMS deformable mirror architecture to large array sizes required for high-contrast astrophysical imagers. Current...

  16. Optimum stamping die structure based on analytical method of die deformation during draw process; Seikei katei no kanagata henkei kaiseki ni motozuku, press kanagata kozo no saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, T; Tamai, H [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    We measured an actual deformation and pressure distribution in draw process of bending cam, and analyzed deformation process of die structure, in order to eliminate adjusting work considering die deformation by stamping force. We studied die structure improvement with simulation based on analytical method. This report describes a sample of die structure improvement based on a simulation and actual measurement. 1 ref., 11 figs., 1 tab.

  17. Numerical simulation of deformation and failure processes of a complex technical object under impact loading

    Science.gov (United States)

    Kraus, E. I.; Shabalin, I. I.; Shabalin, T. I.

    2018-04-01

    The main points of development of numerical tools for simulation of deformation and failure of complex technical objects under nonstationary conditions of extreme loading are presented. The possibility of extending the dynamic method for construction of difference grids to the 3D case is shown. A 3D realization of discrete-continuum approach to the deformation and failure of complex technical objects is carried out. The efficiency of the existing software package for 3D modelling is shown.

  18. Some consistency requirements on thermophysicsal properties used in metal processing simulations

    International Nuclear Information System (INIS)

    Bertran, L.A.

    1992-01-01

    Stresses and deformations during metal processing are being simulated from room temperature to melting. This requires that thermophysical data be obtained at high temperature, an expensive task even when the sampling of elevated temperatures is quite sparse. Use of constitutive models with complex inelastic responses along with sparsely sampled data increases uncertainties as to physical meaning of simulation results. Identification of dependences among the physical parameters as a function of temperature offer increased confidence and lower experimental costs. In this paper examples for bilinear stress-strain materials are given (e.g., yield strain, the ratio of yield stress to Young's modulus, should be continuous where the coefficient of thermal expansion is continuous in T) and similar constraints are discussed for more complex constitutive responses

  19. Research on plant of metal fuel fabrication using casting process

    International Nuclear Information System (INIS)

    Senda, Yasuhide; Mori, Yukihide

    2003-12-01

    This document presents the plant concept of metal fuel fabrication system (38tHM/y) using casting process in electrolytic recycle, which based on recent studies of its equipment design and quality control system. And we estimate the cost of its construction and operation, including costs of maintenance, consumed hardware and management of waste. The content of this work is as follows. (1) Designing of fuel fabrication equipment: We make material flow diagrams of the fuel fabrication plant and rough designs of the injection casting furnace, demolder and inspection equipment. (2) Designing of resolution system of liquid waste, which comes from analytical process facility. Increased analytical items, we rearrange analytical process facility, estimate its chemicals and amount of waste. (3) Arrangement of equipments: We made a arrangement diagram of the metal fuel fabrication equipments in cells. (4) Estimation of cost data: We estimated cost to construct the facility and to operate it. (author)

  20. Advanced Wear Simulation for Bulk Metal Forming Processes

    Directory of Open Access Journals (Sweden)

    Behrens Bernd-Arno

    2016-01-01

    Full Text Available In the recent decades the finite element method has become an essential tool for the cost-efficient virtual process design in the metal forming sector in order to counter the constantly increasing quality standards, particularly from the automotive industry as well as intensified international competition in the forging industry. An optimized process design taking precise tool wear prediction into account is a way to increase the cost-efficiency of the bulk metal forming processes. The main objective of the work presented in this paper is a modelling algorithm, which allows predicting die wear with respect to a geometry update during the forming simulation. Changes in the contact area caused by geometry update lead to the different die wear distribution. It primarily concerns the die areas, which undergo high thermal and mechanical loads.

  1. Porosity Measurements and Analysis for Metal Additive Manufacturing Process Control.

    Science.gov (United States)

    Slotwinski, John A; Garboczi, Edward J; Hebenstreit, Keith M

    2014-01-01

    Additive manufacturing techniques can produce complex, high-value metal parts, with potential applications as critical metal components such as those found in aerospace engines and as customized biomedical implants. Material porosity in these parts is undesirable for aerospace parts - since porosity could lead to premature failure - and desirable for some biomedical implants - since surface-breaking pores allows for better integration with biological tissue. Changes in a part's porosity during an additive manufacturing build may also be an indication of an undesired change in the build process. Here, we present efforts to develop an ultrasonic sensor for monitoring changes in the porosity in metal parts during fabrication on a metal powder bed fusion system. The development of well-characterized reference samples, measurements of the porosity of these samples with multiple techniques, and correlation of ultrasonic measurements with the degree of porosity are presented. A proposed sensor design, measurement strategy, and future experimental plans on a metal powder bed fusion system are also presented.

  2. Relaxation processes and physical aging in metallic glasses

    Science.gov (United States)

    Ruta, B.; Pineda, E.; Evenson, Z.

    2017-12-01

    Since their discovery in the 1960s, metallic glasses have continuously attracted much interest across the physics and materials science communities. In the forefront are their unique properties, which hold the alluring promise of broad application in fields as diverse as medicine, environmental science and engineering. However, a major obstacle to their wide-spread commercial use is their inherent temporal instability arising from underlying relaxation processes that can dramatically alter their physical properties. The result is a physical aging process which can bring about degradation of mechanical properties, namely through embrittlement and catastrophic mechanical failure. Understanding and controlling the effects of aging will play a decisive role in our on-going endeavor to advance the use of metallic glasses as structural materials, as well as in the more general comprehension of out-of-equilibrium dynamics in complex systems. This review presents an overview of the current state of the art in the experimental advances probing physical aging and relaxation processes in metallic glasses. Similarities and differences between other hard and soft matter glasses are highlighted. The topic is discussed in a multiscale approach, first presenting the key features obtained in macroscopic studies, then connecting them to recent novel microscopic investigations. Particular emphasis is put on the occurrence of distinct relaxation processes beyond the main structural process in viscous metallic melts and their fate upon entering the glassy state, trying to disentangle results and formalisms employed by the different groups of the glass-science community. A microscopic viewpoint is presented, in which physical aging manifests itself in irreversible atomic-scale processes such as avalanches and intermittent dynamics, ascribed to the existence of a plethora of metastable glassy states across a complex energy landscape. Future experimental challenges and the comparison with

  3. Visualization and quantification of deformation processes controlling the mechanical response of alloys in aggressive environments

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Ian M. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering; Univ. of Illinois, Champaign, IL (United States)

    2017-01-05

    The overall objective of this program was to develop the technique of electron tomography for studies of defects and to couple it with real time dynamic experiments such that four-dimensional (time and three spatial dimensions) characterization of dislocation interactions with defects is feasible and apply it to discovery of the fundamental unit processes of dislocation-defect interactions in metallic systems. Strategies to overcome the restrictions normally associated with electron tomography and to make it practical within the constraints of conducting a dynamic experiment in the transmission electron microscope were developed. These methods were used to determine the mechanism controlling the transfer of slip across grain boundaries in FCC and HCP metals, dislocation precipitate interactions in Al alloys, and dislocation-dislocation interactions in HCP Ti. In addition, preliminary investigations of slip transfer across cube-on-cube and incoherent twin interfaces in a multi-layered system, thermal stability of grains in nanongrained Ni and Fe, and on corrosion of Fe films were conducted.

  4. MAPPING FLOW LOCALIZATION PROCESSES IN DEFORMATION OF IRRADIATED REACTOR STRUCTURAL ALLOYS - FINAL REPORT. Nuclear Energy Research Initiative Program No. MSF99-0072. Period: August 1999 through September 2002. (ORNL/TM-2003/63)

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, K.

    2003-09-26

    Metals that can sustain plastic deformation homogeneously throughout their bulk tend to be tough and malleable. Often, however, if a metal has been hardened it will no longer deform uniformly. Instead, the deformation occurs in narrow bands on a microscopic scale wherein stresses and strains become concentrated in localized zones. This strain localization degrades the mechanical properties of the metal by causing premature plastic instability failure or by inducing the formation of cracks. Irradiation with neutrons hardens a metal and makes it more prone to deformation by strain localization. Although this has been known since the earliest days of radiation damage studies, a full measure of the connection between neutron irradiation hardening and strain localization is wanting, particularly in commercial alloys used in the construction of nuclear reactors. Therefore, the goal of this project is to systematically map the extent of involvement of strain localization processes in plastic deformation of three reactor alloys that have been neutron irradiated. The deformation processes are to be identified and related to changes in the tensile properties of the alloys as functions of neutron fluence (dose) and degree of plastic strain. The intent is to define the role of strain localization in radiation embrittlement phenomena. The three test materials are a tempered bainitic A533B steel, representing reactor pressure vessel steel, an annealed 316 stainless steel and annealed Zircaloy-4 representing reactor internal components. These three alloys cover the range of crystal structures usually encountered in structural alloys, i.e. body-centered cubic (bcc), face-centered cubic (fcc), and close-packed hexagonal (cph), respectively. The experiments were conducted in three Phases, corresponding to the three years duration of the project. Phases 1 and 2 addressed irradiations and tensile tests made at near-ambient temperatures, and covered a wide range of neutron fluences

  5. Particle deformation during stirred media milling

    Science.gov (United States)

    Hamey, Rhye Garrett

    Production of high aspect ratio metal flakes is an important part of the paint and coating industry. The United States Army also uses high aspect ratio metal flakes of a specific dimension in obscurant clouds to attenuate infrared radiation. The most common method for their production is by milling a metal powder. Ductile metal particles are initially flattened in the process increasing the aspect ratio. As the process continues, coldwelding of metal flakes can take place increasing the particle size and decreasing the aspect ratio. Extended milling times may also result in fracture leading to a further decrease in the particle size and aspect ratio. Both the coldwelding of the particles and the breakage of the particles are ultimately detrimental to the materials performance. This study utilized characterization techniques, such as, light scattering and image analysis to determine the change in particle size as a function of milling time and parameters. This study proved that a fundamental relationship between the milling parameters and particle deformation could be established by using Hertz's theory to calculate the stress acting on the aluminum particles. The study also demonstrated a method by which milling efficiency could be calculated, based on the amount of energy required to cause particle deformation. The study found that the particle deformation process could be an energy efficient process at short milling times with milling efficiency as high as 80%. Finally, statistical design of experiment was used to obtain a model that related particle deformation to milling parameters, such as, rotation rate and milling media size.

  6. Parameter Identification of Piecewise Linear Plasticity Metal Models Used in Numerical Modeling of Structures Under Plastic Deformation and Failure

    Directory of Open Access Journals (Sweden)

    A. V. Shmeliov

    2016-01-01

    Full Text Available The article describes the models of metallic materials used in the calculation of deformation and destruction of engineering structures. The reliability of material models can adequately assess the strength characteristics of the designs of new technology in its designing and certification.The article deals with contingencies and true mechanical properties of materials and presents equations of their relationship. It notes that in the software systems mechanical characteristics of materials are given in the true sense.The paper considers the linear and exponential models of materials, their characteristics, and methods to implement them. It considers the models of Johnson-Cook Steinberg-Guinan, Zerilli-Armstrong, Cowper-Symonds, Gurson-Tvergaard that take into account the strain rate and temperature of the material. Describes their applications, advantages and disadvantages. Considers single- and multi-parameter criteria of materials fracture, the prospects for their use. Gives a rational justification for using a piecewise linear plasticity material model *MAT_PIECEWISE_LINEAR_PLASTICITY (024, LS-DYNA software package for the engineering industry, and presents its main parameters.A technique to identify parameters of piecewise linear plasticity metal material models has been developed. The technique consists of the stages, based on the equations of transition from the conventional stress and strain values to the true ones. Taking into consideration the stressstrain state in the neck of the sample is a distinctive feature of the technique.Tensile tests of the round material samples have been conducted. To test the developed technique in the software package ANSYS LS-DYNA PC have been made tensile sample modeling and results comparison to show high convergence.Further improvement of the technique can be achieved through the development of a statistical approach to the analysis of the results of a series of tests. This will allow a kind of

  7. The Chemophytostabilisation Process of Heavy Metal Polluted Soil.

    Science.gov (United States)

    Grobelak, Anna; Napora, Anna

    2015-01-01

    Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavy metals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavy metals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and

  8. The Chemophytostabilisation Process of Heavy Metal Polluted Soil.

    Directory of Open Access Journals (Sweden)

    Anna Grobelak

    Full Text Available Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavy metals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavy metals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry and inorganic amendments (lime, superphosphate, and potassium phosphate on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1. A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the

  9. Analysis of material flow in metal forming processes by using computer simulation and experiment with model material

    International Nuclear Information System (INIS)

    Kim, Heon Young; Kim, Dong Won

    1993-01-01

    The objective of the present study is to analyze material flow in the metal forming processes by using computer simulation and experiment with model material, plasticine. A UBET program is developed to analyze the bulk flow behaviour of various metal forming problems. The elemental strain-hardening effect is considered in an incremental manner and the element system is automatically regenerated at every deforming step in the program. The material flow behaviour in closed-die forging process with rib-web type cavity are analyzed by UBET and elastic-plastic finite element method, and verified by experiments with plasticine. There were good agreements between simulation and experiment. The effect of corner rounding on material flow behavior is investigated in the analysis of backward extrusion with square die. Flat punch indentation process is simulated by UBET, and the results are compared with that of elastic-plastic finite element method. (Author)

  10. Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing.

    Science.gov (United States)

    Arora, Harpreet Singh; Mridha, Sanghita; Grewal, Harpreet Singh; Singh, Harpreet; Hofmann, Douglas C; Mukherjee, Sundeep

    2014-06-01

    We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 μ m to 5 μ m) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites.

  11. Process, structure, property and applications of metallic glasses

    Directory of Open Access Journals (Sweden)

    B. Geetha Priyadarshini

    2016-07-01

    Full Text Available Metallic glasses (MGs are gaining immense technological significance due to their unique structure-property relationship with renewed interest in diverse field of applications including biomedical implants, commercial products, machinery parts, and micro-electro-mechanical systems (MEMS. Various processing routes have been adopted to fabricate MGs with short-range ordering which is believed to be the genesis of unique structure. Understanding the structure of these unique materials is a long-standing unsolved mystery. Unlike crystalline counterpart, the outstanding properties of metallic glasses owing to the absence of grain boundaries is reported to exhibit high hardness, excellent strength, high elastic strain, and anti-corrosion properties. The combination of these remarkable properties would significantly contribute to improvement of performance and reliability of these materials when incorporated as bio-implants. The nucleation and growth of metallic glasses is driven by thermodynamics and kinetics in non-equilibrium conditions. This comprehensive review article discusses the various attributes of metallic glasses with an aim to understand the fundamentals of relationship process-structure-property existing in such unique class of material.

  12. Different strategies for recovering metals from CARON process residue

    International Nuclear Information System (INIS)

    Cabrera, G.; Gomez, J.M.; Hernandez, I.; Coto, O.; Cantero, D.

    2011-01-01

    The capacity of Acidithiobacillus thiooxidans DMS 11478 to recover the heavy metals contained in the residue obtained from the CARON process has been evaluated. Different bioreactor configurations were studied: a two-stage batch system and two semi-continuous systems (stirred-tank reactor leaching and column leaching). In the two-stage system, 46.8% Co, 36.0% Mg, 26.3% Mn and 22.3% Ni were solubilised after 6 h of contact between the residue and the bacteria-free bioacid. The results obtained with the stirred-tank reactor and the column were similar: 50% of the Mg and Co and 40% of the Mn and Ni were solubilised after thirty one days. The operation in the column reactor allowed the solid-liquid ratio to be increased and the pH to be kept at low values (<1.0). Recirculation of the leachate in the column had a positive effect on metal removal; at sixty five days (optimum time) the solubilisation levels were as follows: 86% Co, 83% Mg, 72% Mn and Ni, 62% Fe and 23% Cr. The results corroborate the feasibility of the systems studied for the leaching of metals from CARON process residue and these methodologies can be considered viable for the recovery of valuable metals.

  13. Semi solid metal processing: The fraction solid dilemma

    International Nuclear Information System (INIS)

    Nafisi, S.; Emadi, D.; Ghomashchi, R.

    2009-01-01

    One of the most challenging aspects in semi solid metal (SSM) processing is to determine the actual volume fraction of the solid at the processing temperature. The fraction has great impact on the SSM slurry viscosity and the subsequent filling of the mold in the casting stage. Three methods, namely quantitative metallography, thermodynamic calculation, and thermal analysis are employed to investigate and clarify the contradictory open literature reports about the real value of the volume fraction of primary particles. It is reported that the discrepancies between the results obtained by different methods are caused mainly by variations in cooling rates and by coarsening of the primaries during the quenching process

  14. Semi solid metal processing: The fraction solid dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Nafisi, S. [EVRAZ Inc. NA 100 Armour Road, Regina, SK, S4P 3C7 (Canada)], E-mail: Shahrooz.Nafisi@evrazincna.com; Emadi, D. [CEPG, CanmetENERGY, Natural Resources Canada, Ottawa, ON, K1A 1M1 (Canada); Ghomashchi, R. [Advanced Materials and Processing Research Institute, Suite 122, A7-1390 Major MacKenzie, ON, L4S 0A1 (Canada)

    2009-05-15

    One of the most challenging aspects in semi solid metal (SSM) processing is to determine the actual volume fraction of the solid at the processing temperature. The fraction has great impact on the SSM slurry viscosity and the subsequent filling of the mold in the casting stage. Three methods, namely quantitative metallography, thermodynamic calculation, and thermal analysis are employed to investigate and clarify the contradictory open literature reports about the real value of the volume fraction of primary particles. It is reported that the discrepancies between the results obtained by different methods are caused mainly by variations in cooling rates and by coarsening of the primaries during the quenching process.

  15. SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

    Science.gov (United States)

    Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

    1962-08-14

    A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

  16. Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, S

    2003-09-23

    integration of forming processes and crash models. Computational analysis of vehicle-to-vehicle crashes between ULSAB and conventional car designs is reported in Section 3. The study involved vehicles of comparable weights and dimensions to assess the compatibility of the ULSAB with existing designs. Deformation and acceleration data for crashed vehicles were analyzed. Vehicle-modeling approaches have strong influence on computational results and the requirements for compatibility of models were identified for future research on vehicle-to-vehicle crash modeling.

  17. Post-Eruption Deformation Processes Measured Using ALOS-1 and UAVSAR InSAR at Pacaya Volcano, Guatemala

    Directory of Open Access Journals (Sweden)

    Lauren N. Schaefer

    2016-01-01

    Full Text Available Pacaya volcano is a persistently active basaltic cone complex located in the Central American Volcanic Arc in Guatemala. In May of 2010, violent Volcanic Explosivity Index-3 (VEI-3 eruptions caused significant topographic changes to the edifice, including a linear collapse feature 600 m long originating from the summit, the dispersion of ~20 cm of tephra and ash on the cone, the emplacement of a 5.4 km long lava flow, and ~3 m of co-eruptive movement of the southwest flank. For this study, Interferometric Synthetic Aperture Radar (InSAR images (interferograms processed from both spaceborne Advanced Land Observing Satellite-1 (ALOS-1 and aerial Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR data acquired between 31 May 2010 and 10 April 2014 were used to measure post-eruptive deformation events. Interferograms suggest three distinct deformation processes after the May 2010 eruptions, including: (1 subsidence of the area involved in the co-eruptive slope movement; (2 localized deformation near the summit; and (3 emplacement and subsequent subsidence of about a 5.4 km lava flow. The detection of several different geophysical signals emphasizes the utility of measuring volcanic deformation using remote sensing techniques with broad spatial coverage. Additionally, the high spatial resolution of UAVSAR has proven to be an excellent compliment to satellite data, particularly for constraining motion components. Measuring the rapid initiation and cessation of flank instability, followed by stabilization and subsequent influence on eruptive features, provides a rare glimpse into volcanic slope stability processes. Observing these and other deformation events contributes both to hazard assessment at Pacaya and to the study of the stability of stratovolcanoes.

  18. A metallic buried interconnect process for through-wafer interconnection

    International Nuclear Information System (INIS)

    Ji, Chang-Hyeon; Herrault, Florian; Allen, Mark G

    2008-01-01

    In this paper, we present the design, fabrication process and experimental results of electroplated metal interconnects buried at the bottom of deep silicon trenches with vertical sidewalls. A manual spray-coating process along with a unique trench-formation process has been developed for the electroplating of a metal interconnection structure at the bottom surface of the deep trenches. The silicon etch process combines the isotropic dry etch process and conventional Bosch process to fabricate a deep trench with angled top-side edges and vertical sidewalls. The resulting trench structure, in contrast to the trenches fabricated by wet anisotropic etching, enables spray-coated photoresist patterning with good sidewall and top-side edge coverage while maintaining the ability to form a high-density array of deep trenches without excessive widening of the trench opening. A photoresist spray-coating process was developed and optimized for the formation of electroplating mold at the bottom of 300 µm deep trenches having vertical sidewalls. A diluted positive tone photoresist with relatively high solid content and multiple coating with baking between coating steps has been experimentally proven to provide high quality sidewall and edge coverage. To validate the buried interconnect approach, a three-dimensional daisy chain structure having a buried interconnect as the bottom connector and traces on the wafer surface as the top conductor has been designed and fabricated

  19. Manufacturing process for the metal ceramic hybrid fuel cladding tube

    International Nuclear Information System (INIS)

    Jung, Yang Il; Kim, Sun Han; Park, Jeong Yong

    2012-01-01

    For application in LWRs with suppressed hydrogen release, a metal-ceramic hybrid cladding tube has been proposed. The cladding consists of an inner zirconium tube and outer SiC fiber matrix SiC ceramic composite. The inner zirconium allows the matrix to remain fully sealed even if the ceramic matrix cracks through. The outer SiC composite can increase the safety margin by taking the merits of the SiC itself. However, it is a challenging task to fabricate the metal-ceramic hybrid tube. Processes such as filament winding, matrix impregnation, and surface costing are additionally required for the existing Zr based fuel cladding tubes. In the current paper, the development of the manufacturing process will be introduced

  20. Biological removal of metal ions from aqueous process streams

    International Nuclear Information System (INIS)

    Shumate, S.E. II; Strandberg, G.W.; Parrott, J.R. Jr.

    1978-01-01

    Aqueous waste streams from nuclear fuel processing operations may contain trace quantities of heavy metals such as uranium. Conventional chemical and physical treatment may be ineffective or very expensive when uranium concentrations in the range of 10 to 100 g/m 3 must be reduced to 1 g/m 3 or less. The ability of some microorganisms to adsorb or complex dissolved heavy metals offers an alternative treatment method. Uranium uptake by Saccharomyces cerevisiae NRRL Y-2574 and a strain of Pseudomonas aeruginosa was examined to identify factors which might affect a process for the removal of uranium from wastewater streams. At uranium concentrations in the range of 10 to 500 g/m 3 , where the binding capacity of the biomass was not exceeded, temperature, pH, and initial uranium concentration were found to influence the rate of uranium uptake, but not the soluble uranium concentration at equilibrium. 6 figs

  1. Manufacturing process for the metal ceramic hybrid fuel cladding tube

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang Il; Kim, Sun Han; Park, Jeong Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    For application in LWRs with suppressed hydrogen release, a metal-ceramic hybrid cladding tube has been proposed. The cladding consists of an inner zirconium tube and outer SiC fiber matrix SiC ceramic composite. The inner zirconium allows the matrix to remain fully sealed even if the ceramic matrix cracks through. The outer SiC composite can increase the safety margin by taking the merits of the SiC itself. However, it is a challenging task to fabricate the metal-ceramic hybrid tube. Processes such as filament winding, matrix impregnation, and surface costing are additionally required for the existing Zr based fuel cladding tubes. In the current paper, the development of the manufacturing process will be introduced.

  2. An investigation of deformed microstructure and mechanical properties of Zircaloy-4 processed through multiaxial forging

    Energy Technology Data Exchange (ETDEWEB)

    Fuloria, Devasri; Nageswararao, P. [Department of Metallurgical and Materials Engineering & Centre of Nanotechnology, IIT Roorkee, Roorkee 247667 (India); Jayaganthan, R., E-mail: rjayafmt@iitr.ernet.in [Department of Metallurgical and Materials Engineering & Centre of Nanotechnology, IIT Roorkee, Roorkee 247667 (India); Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036 (India); Jha, S. [Nuclear Fuel Complex Limited, Hyderabad 501301 (India); Srivastava, D. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 40085 (India)

    2016-04-15

    In the present work, the mechanical behavior of Zircaloy-4 subjected to various deformation strains by multiaxial forging (MAF) at cryogenic temperature (CT) was investigated. The alloy was strained up to different number of cycles, viz., 6 cycles, 9 cycles, and 12 cycles at cumulative strains of 2.96, 4.44, and 5.91, respectively. The mechanical properties of the alloy were investigated by performing the universal tensile test and the Vickers hardness test. Both the test showed improvement in the ultimate tensile strength and hardness value by 51% and 26%, respectively, at the highest cumulative strain of 5.91. The electron backscattered diffraction (EBSD) measurement and transmission electron microscopy (TEM) were used for analyzing the deformed microstructure. The microstructures of the alloy underwent deformation at various cumulative strains/cycles showed grain refinement with the evolution of shear and twin bands that were highest for the alloy deformed at the highest number of cycles. The effective grain refinement was due to twins formation and their intersection, which led to the improvement in mechanical properties of the MAFed alloy, as observed in the present work. - Highlights: • Zircaloy-4 was subjected to MAF at cryogenic temperature. • Microstructural evolution was studied through EBSD and TEM. • Deformed microstructure was marked with various types of twinning and shear banding. • Twins formations are responsible for effective grain refinement and enhanced mechanical properties.

  3. Deformation behaviour of {gamma}+{alpha}{sub 2} Ti aluminide processed through reaction synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.K., E-mail: rohitkumar_gupta@vssc.gov.in [Vikram Sarabhai Space Centre, ISRO, Trivandrum, Kerala 695 022 (India); Pant, Bhanu [Vikram Sarabhai Space Centre, ISRO, Trivandrum, Kerala 695 022 (India); Kumar, Vinod [SAIL-RDCIS, Ranchi (India); Agarwala, Vijaya [Indian Institute of Technology, Roorkee 247 667 (India); Sinha, P.P. [Vikram Sarabhai Space Centre, ISRO, Trivandrum, Kerala 695 022 (India)

    2013-01-01

    {gamma}+{alpha}{sub 2} titanium aluminide alloys made through reaction synthesis have been used for deformation study. Hot isothermal compression test is carried out to study the deformation characteristics of the alloys using Gleeble thermomechanical simulator. Three alloys based on Ti48Al2Cr2Nb0.1B (at%) are tested at different temperatures and at different strain rates. True stress-true strain plots are analyzed along with analysis of tested specimens. Tested specimens are observed under optical and electron microscopes. Presence of various deformation morphologies and phases were confirmed. Microhardness evaluation and transmission electron microscopic examination are used to confirm the presence of different phases. It is found that dynamic recrystallization is mainly playing role in deformation of these alloys. Presence of dynamically recrystallized (DRX) grains and lamellar microstructures is confirmed at the intergranular area and inside the grains, respectively. A nucleation model is suggested for DRX and lamellar grain nucleation during deformation. Attempt has been made to quantify the presence of various phases through optical microscopy. Hot workability map is also suggested on the basis of microstructural and visual observation of compression tested specimens.

  4. Cadmium: The deformed metal

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, R L [Cadmium Association, London (UK)

    1979-03-01

    The paper, which is a somewhat abridged version of the introductory paper of the 2nd International Cadmium Conference in Cannes on February 6 to 8, 1979, outlines the present trends in production, reserves, consumption, world trade, prices, and cost. Due to the lack of statistics on the USSR and other socialist countries, the review is limited to the non-socialist world.

  5. Cadmium: The deformed metal

    International Nuclear Information System (INIS)

    Stubbs, R.L.

    1979-01-01

    The paper, which is a somewhat abridged version of the introductory paper of the 2nd International Cadmium Conference in Cannes on February 6 to 8, 1979, outlines the present trends in production, reserves, consumption, world trade, prices, and cost. Due to the lack of statistics on the USSR and other socialist countries, the review is limited to the non-socialist world. (orig./IHOE) [de

  6. New constraints on deformation processes in serpentinite from sub-micron Raman Spectroscopy and TEM

    Science.gov (United States)

    Smith, S. A. F.; Tarling, M.; Rooney, J. S.; Gordon, K. C.; Viti, C.

    2017-12-01

    Extensive work has been performed to characterize the mineralogical and mechanical properties of the various serpentine minerals (i.e. antigorite, lizardite, chrysotile, polyhedral and polygonal serpentine). However, correct identification of serpentine minerals is often difficult or impossible using conventional analytical techniques such as optical- and SEM-based microscopy, X-ray diffraction and infrared spectroscopy. Transmission Electron Microscopy (TEM) is the best analytical technique to identify the serpentine minerals, but TEM requires complex sample preparation and typically results in very small analysis areas. Sub-micron confocal Raman spectroscopy mapping of polished thin sections provides a quick and relatively inexpensive way of unambiguously distinguishing the main serpentine minerals within their in-situ microstructural context. The combination of high spatial resolution (with a diffraction-limited system, 366 nm), large-area coverage (up to hundreds of microns in each dimension) and ability to map directly on thin sections allows intricate fault rock textures to be imaged at a sample-scale, which can then form the target of more focused TEM work. The potential of sub-micron Raman Spectroscopy + TEM is illustrated by examining sub-micron-scale mineral intergrowths and deformation textures in scaly serpentinites (e.g. dissolution seams, mineral growth in pressure shadows), serpentinite crack-seal veins and polished fault slip surfaces from a serpentinite-bearing mélange in New Zealand. The microstructural information provided by these techniques has yielded new insights into coseismic dehydration and amorphization processes and the interplay between creep and localised rupture in serpentinite shear zones.

  7. Hot deformation and processing maps of K310 cold work tool steel

    International Nuclear Information System (INIS)

    Ezatpour, H.R.; Sajjadi, S.A.; Haddad-Sabzevar, M.; Ebrahimi, G.R.

    2012-01-01

    Highlights: ► The steady state stresses are related to strain rate and temperature. ► The study led to n DRX = 3.95 and Q DRX = 219.65 kJ/(mol K) and α = 1.2 × 10 −2 MPa −1 . ► The safe domain occurs in the region of 1000–1100 °C for a strain rate of 0.1 s −1 . - Abstract: Hot working response of cold work tool steel K310 was investigated by means of compression test at temperature range of 900–1100 °C. The equivalent strain rates used in these tests were 0.01, 0.1 and 1 s −1 , respectively in order to obtain the processing and stability maps of the studied material following the Dynamic Material Model. All the zones of flow instability were studied through scanning electron microscopy (SEM). The microstructure of the samples after deformation was then analyzed by light microscopy and the differences were compared together. The steady state stress obtained from the flow curves was related to strain rate (ε . ) and temperature (T) by means of the well known Zener–Holloman equation. A least square analysis of the data led to n = 3.95 and Q DRX = 219.65 kJ/mol and α = 1.2 × 10 −2 MPa −1 . Also, hardness results showed that by increasing strain from peak to steady state strain, hardness was decreased.

  8. Rheological Behaviour of a Bitumen Modified with Metal Oxides Obtained by Regeneration Processes

    Directory of Open Access Journals (Sweden)

    Tullio Giuffrè

    2018-02-01

    Full Text Available Nowadays, one important challenge is to demonstrate an innovative and integrated approach for the sustainable construction of roads considering the whole life cycle of the infrastructure. Road pavements with multiple asphalt layers generally undergo prolonged environmental exposure and the alternation between solar irradiation and low temperatures. As a result, relaxation or progressive removal of the material with a negative impact on the resistance to plastic deformation occur, also leading to the formation of slits and to dimensional variations, which are commonly defined as thermal cracking. This suggests the use of suitable bitumen modifiers. For these, important parameters are the optimal mixing time and mixing temperature, in order to reduce problems related to the stability of the bitumen. Therefore, the behaviour, upon changing the temperature, of bituminous mixtures containing (as fillers a series of metal oxides coming, as secondary products, from spent acid solutions regeneration processes, was investigated. This is intended in order to recover and reuse those otherwise dangerous wastes coming from several industrial (especially, metallurgical processes. The study was aimed at evaluating the properties of bituminous blends by performing rheological tests under dynamic shear regime. More specifically, five different bitumen matrices were prepared (70/100 bitumen and blends with metal oxides and/or SBS copolymer. Results showed that the addition of iron oxides leads to an increase of the softening point and the complex modulus. The increase is even more emphasized when SBS is added to the blend.

  9. Analysis of the influence of plastic deformations in fatigue and crack process by numerical simulation

    International Nuclear Information System (INIS)

    Rahimian, Mohammad.

    1981-06-01

    The aim of this work is to analyze, by numerical simulation the characteristics of the stresses and deformations at the bottom of cracks when plasticity is taken into account. This analysis is performed as from theoretical results laid down in the literature and makes it possible to understand the different solutions obtained from Hencky's deformation law or from the incremental theory. The role of plastic deformation is discussed in depth in the study of fatigue cracks. The problems linked to the fixed crack are studied in the first two chapters. The problems linked to the propagation of cracks are discussed in the following chapters. The fourth chapter is an application of the preceding results and knowledge to fatigue [fr

  10. Deformation twinning: Influence of strain rate

    Energy Technology Data Exchange (ETDEWEB)

    Gray, G.T. III

    1993-11-01

    Twins in most crystal structures, including advanced materials such as intermetallics, form more readily as the temperature of deformation is decreased or the rate of deformation is increased. Both parameters lead to the suppression of thermally-activated dislocation processes which can result in stresses high enough to nucleate and grow deformation twins. Under high-strain rate or shock-loading/impact conditions deformation twinning is observed to be promoted even in high stacking fault energy FCC metals and alloys, composites, and ordered intermetallics which normally do not readily deform via twinning. Under such conditions and in particular under the extreme loading rates typical of shock wave deformation the competition between slip and deformation twinning can be examined in detail. In this paper, examples of deformation twinning in the intermetallics TiAl, Ti-48Al-lV and Ni{sub 3}A as well in the cermet Al-B{sub 4}C as a function of strain rate will be presented. Discussion includes: (1) the microstructural and experimental variables influencing twin formation in these systems and twinning topics related to high-strain-rate loading, (2) the high velocity of twin formation, and (3) the influence of deformation twinning on the constitutive response of advanced materials.

  11. [INVITED] Evaluation of process observation features for laser metal welding

    Science.gov (United States)

    Tenner, Felix; Klämpfl, Florian; Nagulin, Konstantin Yu.; Schmidt, Michael

    2016-06-01

    In the present study we show how fast the fluid dynamics change when changing the laser power for different feed rates during laser metal welding. By the use of two high-speed cameras and a data acquisition system we conclude how fast we have to image the process to measure the fluid dynamics with a very high certainty. Our experiments show that not all process features which can be measured during laser welding do represent the process behavior similarly well. Despite the good visibility of the vapor plume the monitoring of its movement is less suitable as an input signal for a closed-loop control. The features measured inside the keyhole show a good correlation with changes of process parameters. Due to its low noise, the area of the keyhole opening is well suited as an input signal for a closed-loop control of the process.

  12. STUDY OF THE EFFECT OF PRELIMINARY PLASTIC DEFORMATION IN THE PROCESS OF DISSOLUTION DURING TEMPERING OF LOW-CARBON AND BORON-CONTAINING ALLOYS

    OpenAIRE

    M. Yu. Filonenko; S. B. Piliaieva

    2009-01-01

    In the paper the influence of preliminary deformation on disintegration of martensite in boron-containing and carbonic alloy is explored. It is shown that at the small degree of deformation (7 per cent) both in low-carbonic and boron-containing alloys the process of martensite disintegration takes place less intensively. The increase of degree of preliminary deformation in a boron-containing alloy is instrumental in more even distribution of boron-cementite particles appearing as a result of ...

  13. Strength and deformability of compressed concrete elements with various types of non-metallic fiber and rods reinforcement under static loading

    Science.gov (United States)

    Nevskii, A. V.; Baldin, I. V.; Kudyakov, K. L.

    2015-01-01

    Adoption of modern building materials based on non-metallic fibers and their application in concrete structures represent one of the important issues in construction industry. This paper presents results of investigation of several types of raw materials selected: basalt fiber, carbon fiber and composite fiber rods based on glass and carbon. Preliminary testing has shown the possibility of raw materials to be effectively used in compressed concrete elements. Experimental program to define strength and deformability of compressed concrete elements with non-metallic fiber reinforcement and rod composite reinforcement included design, manufacture and testing of several types of concrete samples with different types of fiber and longitudinal rod reinforcement. The samples were tested under compressive static load. The results demonstrated that fiber reinforcement of concrete allows increasing carrying capacity of compressed concrete elements and reducing their deformability. Using composite longitudinal reinforcement instead of steel longitudinal reinforcement in compressed concrete elements insignificantly influences bearing capacity. Combined use of composite rod reinforcement and fiber reinforcement in compressed concrete elements enables to achieve maximum strength and minimum deformability.

  14. Architectural design of heterogeneous metallic nanocrystals--principles and processes.

    Science.gov (United States)

    Yu, Yue; Zhang, Qingbo; Yao, Qiaofeng; Xie, Jianping; Lee, Jim Yang

    2014-12-16

    CONSPECTUS: Heterogeneous metal nanocrystals (HMNCs) are a natural extension of simple metal nanocrystals (NCs), but as a research topic, they have been much less explored until recently. HMNCs are formed by integrating metal NCs of different compositions into a common entity, similar to the way atoms are bonded to form molecules. HMNCs can be built to exhibit an unprecedented architectural diversity and complexity by programming the arrangement of the NC building blocks ("unit NCs"). The architectural engineering of HMNCs involves the design and fabrication of the architecture-determining elements (ADEs), i.e., unit NCs with precise control of shape and size, and their relative positions in the design. Similar to molecular engineering, where structural diversity is used to create more property variations for application explorations, the architectural engineering of HMNCs can similarly increase the utility of metal NCs by offering a suite of properties to support multifunctionality in applications. The architectural engineering of HMNCs calls for processes and operations that can execute the design. Some enabling technologies already exist in the form of classical micro- and macroscale fabrication techniques, such as masking and etching. These processes, when used singly or in combination, are fully capable of fabricating nanoscopic objects. What is needed is a detailed understanding of the engineering control of ADEs and the translation of these principles into actual processes. For simplicity of execution, these processes should be integrated into a common reaction system and yet retain independence of control. The key to architectural diversity is therefore the independent controllability of each ADE in the design blueprint. The right chemical tools must be applied under the right circumstances in order to achieve the desired outcome. In this Account, after a short illustration of the infinite possibility of combining different ADEs to create HMNC design

  15. Solidification in direct metal deposition by LENS processing

    Science.gov (United States)

    Hofmeister, William; Griffith, Michelle

    2001-09-01

    Thermal imaging and metallographic analysis were used to study Laser Engineered Net Shaping (LENS™) processing of 316 stainless steel and H13 tool steel. The cooling rates at the solid-liquid interface were measured over a range of conduction conditions. The length scale of the molten zone controls cooling rates during solidification in direct metal deposition. In LENS processing, the molten zone ranges from 0.5 mm in length to 1.5 mm, resulting in cooling rates at the solid-liquid interface ranging from 200 6,000 Ks-1.

  16. Carbon formation and metal dusting in advanced coal gasification processes

    Energy Technology Data Exchange (ETDEWEB)

    DeVan, J.H.; Tortorelli, P.F.; Judkins, R.R.; Wright, I.G.

    1997-02-01

    The product gases generated by coal gasification systems contain high concentrations of CO and, characteristically, have relatively high carbon activities. Accordingly, carbon deposition and metal dusting can potentially degrade the operation of such gasifier systems. Therefore, the product gas compositions of eight representative gasifier systems were examined with respect to the carbon activity of the gases at temperatures ranging from 480 to 1,090 C. Phase stability calculations indicated that Fe{sub 3}C is stable only under very limited thermodynamic conditions and with certain kinetic assumptions and that FeO and Fe{sub 0.877}S tend to form instead of the carbide. As formation of Fe{sub 3}C is a necessary step in the metal dusting of steels, there are numerous gasifier environments where this type of carbon-related degradation will not occur, particularly under conditions associated with higher oxygen and sulfur activities. These calculations also indicated that the removal of H{sub 2}S by a hot-gas cleanup system may have less effect on the formation of Fe{sub 3}C in air-blown gasifier environments, where the iron oxide phase can exist and is unaffected by the removal of sulfur, than in oxygen-blown systems, where iron sulfide provides the only potential barrier to Fe{sub 3}C formation. Use of carbon- and/or low-alloy steels dictates that the process gas composition be such that Fe{sub 3}C cannot form if the potential for metal dusting is to be eliminated. Alternatively, process modifications could include the reintroduction of hydrogen sulfide, cooling the gas to perhaps as low as 400 C and/or steam injection. If higher-alloy steels are used, a hydrogen sulfide-free gas may be processed without concern about carbon deposition and metal dusting.

  17. Characterization of hot deformation behavior and processing map of FGH4096–GH4133B dual alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanhui; Ning, Yongquan, E-mail: ningke521@163.com; Nan, Yang; Liang, Houquan; Li, Yuzhi; Zhao, Zhanglong

    2015-06-05

    Highlights: • Hot deformation behavior of dual superalloys FGH4096–GH4133B was investigated. • Power dissipation maps built at different strains exhibit a continuous dynamic course. • Processing map approach was adopted to optimize hot forging process for dual superalloys. • Microstructure evolution at different deformation temperature and strain rate of dual superalloys was researched. - Abstract: The dual superalloys FGH4096–GH4133B were joined by the electron beam welding. Isothermal compression tests were carried out on electron beam weldments FGH4096–GH4133B alloys at the temperatures of 1020–1140 °C (the nominal γ′-transus temperature is about 1080 °C) and strain rates of 0.001–1.0 s{sup −1} with the height reduction of 50%. The results showed that the true stress–true strain curves are greatly affected by deformation temperature and strain rate. There is an intrinsic and necessary connection between the flow stress and thermal–dynamic behavior, which can be indicated by the true stress–true strain curves. The power dissipation maps at different strains exhibit that true strain has a great effect on processing maps. Processing maps under different strains were constructed for evaluation of the flow instability regime and optimization of processing parameters. When the true strain is 0.69, the optimum processing condition is around 1090−1130 °C/0.1−1.0 s{sup −1} with the peak efficiency of 0.58. The dynamic recrystallization mechanism and microstructure evolution in the welding seam of the studied dual-alloys have been discussed. High temperature and low strain rate are instrumental to dynamic recrystallization. The size of dynamically recrystallized grain decreased with the increase of strain rate and increased with the increase of deformation temperature. Based on the established combine processing map and microstructures, hot deformation process should be carried out under the condition of 1100−1120 °C/0.3−1.0 s

  18. Characterization of hot deformation behavior and processing map of FGH4096–GH4133B dual alloys

    International Nuclear Information System (INIS)

    Liu, Yanhui; Ning, Yongquan; Nan, Yang; Liang, Houquan; Li, Yuzhi; Zhao, Zhanglong

    2015-01-01

    Highlights: • Hot deformation behavior of dual superalloys FGH4096–GH4133B was investigated. • Power dissipation maps built at different strains exhibit a continuous dynamic course. • Processing map approach was adopted to optimize hot forging process for dual superalloys. • Microstructure evolution at different deformation temperature and strain rate of dual superalloys was researched. - Abstract: The dual superalloys FGH4096–GH4133B were joined by the electron beam welding. Isothermal compression tests were carried out on electron beam weldments FGH4096–GH4133B alloys at the temperatures of 1020–1140 °C (the nominal γ′-transus temperature is about 1080 °C) and strain rates of 0.001–1.0 s −1 with the height reduction of 50%. The results showed that the true stress–true strain curves are greatly affected by deformation temperature and strain rate. There is an intrinsic and necessary connection between the flow stress and thermal–dynamic behavior, which can be indicated by the true stress–true strain curves. The power dissipation maps at different strains exhibit that true strain has a great effect on processing maps. Processing maps under different strains were constructed for evaluation of the flow instability regime and optimization of processing parameters. When the true strain is 0.69, the optimum processing condition is around 1090−1130 °C/0.1−1.0 s −1 with the peak efficiency of 0.58. The dynamic recrystallization mechanism and microstructure evolution in the welding seam of the studied dual-alloys have been discussed. High temperature and low strain rate are instrumental to dynamic recrystallization. The size of dynamically recrystallized grain decreased with the increase of strain rate and increased with the increase of deformation temperature. Based on the established combine processing map and microstructures, hot deformation process should be carried out under the condition of 1100−1120 °C/0.3−1.0 s −1 with

  19. Finite element modelling of shot peening process: Prediction of the compressive residual stresses, the plastic deformations and the surface integrity

    International Nuclear Information System (INIS)

    Frija, M.; Hassine, T.; Fathallah, R.; Bouraoui, C.; Dogui, A.

    2006-01-01

    This paper presents a numerical simulation of the shot peening process using finite element method. The majority of the controlling parameters of the process have been taken into account. The shot peening loading has been characterised by using energy equivalence between the dynamic impact and a static indentation of a peening shot in the treated surface. The behaviour of the subjected material is supposed to be elastic plastic with damage. An integrated law of the damage proposed by Lemaitre and Chaboche has been used. The proposed model leads to obtain the residual stress, the plastic deformation profiles and the surface damage. An application on a shot peened Ni-based super alloy Waspaloy has been carried out. The comparison of the residual stresses, obtained by X-ray diffraction method and by finite element calculation, shows a good correlation. The in-depth profile of the plastic deformations and the superficial damage values are in good agreement with the experimental observations

  20. Process of technology management in SMEs of the metal processing industry – the case study investigation

    Directory of Open Access Journals (Sweden)

    Krawczyk-Dembicka Elżbieta

    2017-03-01

    Full Text Available The main purpose of this work is to identify the factors that influence the process of technology management in the sector of small- and medium-sized enterprises of the metal processing industry, considering the shape and course required to achieve modern operation conditions by enterprises in the market.

  1. A novel deformation mechanism for superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Muto, H.; Sakai, M. (Toyohashi Univ. of Technology (Japan). Dept. of Materials Science)

    1999-01-01

    Uniaxial compressive creep tests with strain value up to -0.1 for a [beta]-spodumene glass ceramic are conducted at 1060 C. From the observation of microstructural changes between before and after the creep deformations, it is shown that the grain-boundary sliding takes place via cooperative movement of groups of grains rather than individual grains under the large-scale-deformation. The deformation process and the surface technique used in this work are not only applicable to explain the deformation and flow of two-phase ceramics but also the superplastic deformation. (orig.) 12 refs.

  2. Nanoscale lamellae in an oxide dispersion strengthened steel processed by dynamic plastic deformation

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Mishin, Oleg; Tao, N. R.

    2014-01-01

    The microstructure of an oxide dispersion strengthened ferritic PM2000 steel with a strong initial (100) texture has been investigated after compression by dynamic plastic deformation (DPD) at room temperature to a strain of 2.1. Measurements using electron backscatter diffraction and transmission...

  3. Through-Thickness Variations of Deformed and Annealed Microstructures in ECAE-Processed Copper

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bowen, Jacob R.

    2009-01-01

    in the deformed sample follows the distribution of strain imposed by ECAE, where lower strain is imparted to the material that passes through the outer die corner. Also, the macroscopic distribution of recrystallized grains as a function of depth in the billet is found to be in correspondence to the applied...

  4. Developments in Processing by Severe Plastic Deformation at the 3rd Pan American Materials Congress

    Science.gov (United States)

    Figueiredo, Roberto B.; Kawasaki, Megumi; Langdon, Terence G.

    2017-10-01

    The 3rd Pan American Materials Congress in San Diego, California, February 26-March 2, 2017, provided an opportunity to bring together many participants working in the field of severe plastic deformation. This article provides a brief review of these activities.

  5. Evaluation of material's state during deformation process by means of thermographic measurement

    Czech Academy of Sciences Publication Activity Database

    Žďárský, M.; Valach, Jaroslav; Kytýř, D.

    2012-01-01

    Roč. 17, č. 10 (2012), s. 102-107 ISSN 1435-4934. [Quantitative infrared thermotheraphy /11./. Naples, 11.06.2012-14.06.2012] R&D Projects: GA ČR(CZ) GA103/09/2101 Institutional support: RVO:68378297 Keywords : thermography * ductile crack * plastic deformation Subject RIV: JL - Materials Fatigue, Friction Mechanics www.ndt.net/?id=13389

  6. Process for producing metal oxide kernels and kernels so obtained

    International Nuclear Information System (INIS)

    Lelievre, Bernard; Feugier, Andre.

    1974-01-01

    The process desbribed is for producing fissile or fertile metal oxide kernels used in the fabrication of fuels for high temperature nuclear reactors. This process consists in adding to an aqueous solution of at least one metallic salt, particularly actinide nitrates, at least one chemical compound capable of releasing ammonia, in dispersing drop by drop the solution thus obtained into a hot organic phase to gel the drops and transform them into solid particles. These particles are then washed, dried and treated to turn them into oxide kernels. The organic phase used for the gel reaction is formed of a mixture composed of two organic liquids, one acting as solvent and the other being a product capable of extracting the anions from the metallic salt of the drop at the time of gelling. Preferably an amine is used as product capable of extracting the anions. Additionally, an alcohol that causes a part dehydration of the drops can be employed as solvent, thus helping to increase the resistance of the particles [fr

  7. Sustainability assessment of shielded metal arc welding (SMAW) process

    Science.gov (United States)

    Alkahla, Ibrahim; Pervaiz, Salman

    2017-09-01

    Shielded metal arc welding (SMAW) process is one of the most commonly employed material joining processes utilized in the various industrial sectors such as marine, ship-building, automotive, aerospace, construction and petrochemicals etc. The increasing pressure on manufacturing sector wants the welding process to be sustainable in nature. The SMAW process incorporates several types of inputs and output streams. The sustainability concerns associated with SMAW process are linked with the various input and output streams such as electrical energy requirement, input material consumptions, slag formation, fumes emission and hazardous working conditions associated with the human health and occupational safety. To enhance the environmental performance of the SMAW welding process, there is a need to characterize the sustainability for the SMAW process under the broad framework of sustainability. Most of the available literature focuses on the technical and economic aspects of the welding process, however the environmental and social aspects are rarely addressed. The study reviews SMAW process with respect to the triple bottom line (economic, environmental and social) sustainability approach. Finally, the study concluded recommendations towards achieving economical and sustainable SMAW welding process.

  8. Peculiarities of metal welding process modelling for the Arctic

    Science.gov (United States)

    Lagunov, Alexey; Fofanov, Andrey; Losunov, Anton

    2017-09-01

    M etal being rather tough has been used in the Arctic for a long time. In severe weather conditions metal construction is subject to strong corrosion and erosion. These processes affect the welds particular strongly. Violation of weld integrity leads to the different industrial accidents. Therefore, the welding quality is given such a strong focus. M ost high-quality welding is obtained if welding zone is provided with gas what eliminates the influence of oxygen on the process. But in this case it is very difficult to find the right concentration, gas pressure, direction of the jet. Study of the welding process using video and photography is expensive, in terms of money and time. Mathematical modelling of welding process using the program FlowVision enables to solve this issue at less cost. It's essential that obtained results qualitatively conform to the experimental ones and can be used in real application.

  9. The effect of coarse second-phase particles on the rate of grain refinement during severe deformation processing

    DEFF Research Database (Denmark)

    Apps, P.J.; Bowen, Jacob R.; Prangnell, P.B.

    2003-01-01

    The effect of second-phase particles on the rate of grain refinement during severe deformation processing has been investigated, by comparing the microstructure evolution in an AA8079 aluminium alloy, containing 2.5 vol.% of ~2 μm particles, with that in a high purity, single-phase, Al-0.13% Mg a...... by an effective strain of only five in the particle-containing alloy, compared to ten in the single-phase material. The mechanisms that contribute to this acceleration of the grain refinement process are discussed.......The effect of second-phase particles on the rate of grain refinement during severe deformation processing has been investigated, by comparing the microstructure evolution in an AA8079 aluminium alloy, containing 2.5 vol.% of ~2 μm particles, with that in a high purity, single-phase, Al-0.13% Mg...... alloy, deformed identically by ECAE to an effective strain of ten. The materials were analysed by high-resolution EBSD orientation mapping, which revealed that grain refinement occurred at a dramatically higher rate in the particle-containing alloy. A submicron grain structure could be achieved...

  10. Discontinuity Detection in the Shield Metal Arc Welding Process.

    Science.gov (United States)

    Cocota, José Alberto Naves; Garcia, Gabriel Carvalho; da Costa, Adilson Rodrigues; de Lima, Milton Sérgio Fernandes; Rocha, Filipe Augusto Santos; Freitas, Gustavo Medeiros

    2017-05-10

    This work proposes a new methodology for the detection of discontinuities in the weld bead applied in Shielded Metal Arc Welding (SMAW) processes. The detection system is based on two sensors-a microphone and piezoelectric-that acquire acoustic emissions generated during the welding. The feature vectors extracted from the sensor dataset are used to construct classifier models. The approaches based on Artificial Neural Network (ANN) and Support Vector Machine (SVM) classifiers are able to identify with a high accuracy the three proposed weld bead classes: desirable weld bead, shrinkage cavity and burn through discontinuities. Experimental results illustrate the system's high accuracy, greater than 90% for each class. A novel Hierarchical Support Vector Machine (HSVM) structure is proposed to make feasible the use of this system in industrial environments. This approach presented 96.6% overall accuracy. Given the simplicity of the equipment involved, this system can be applied in the metal transformation industries.

  11. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, S.G.T.

    1994-12-06

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

  12. High-energy X-ray measurements of structural anisotropy and excess free volume in a homogenously deformed Zr-based metallic glass

    International Nuclear Information System (INIS)

    Ott, R.T.; Kramer, M.J.; Besser, M.F.; Sordelet, D.J.

    2006-01-01

    We have used high-energy X-ray scattering to measure the structural anisotropy and excess free volume in a homogeneously deformed Zr-based metallic glass alloy. The scattering results show that bond length anisotropy is present in the samples following isothermal tensile creep deformation. The average atomic bond length in the direction parallel to the tensile loading axis is larger than that in the direction normal to the loading axis. The magnitude of the bond length anisotropy is found to be dependent on the gradient of macroscopic plastic strain along the gauge length. Furthermore, the scattering results show that the excess free volume also increases with increasing macroscopic plastic strain. Results from differential scanning calorimetry analysis of free volume variations along the gauge length of the creep samples are consistent with results from the X-ray scattering experiments

  13. Parameters in selective laser melting for processing metallic powders

    Science.gov (United States)

    Kurzynowski, Tomasz; Chlebus, Edward; Kuźnicka, Bogumiła; Reiner, Jacek

    2012-03-01

    The paper presents results of studies on Selective Laser Melting. SLM is an additive manufacturing technology which may be used to process almost all metallic materials in the form of powder. Types of energy emission sources, mainly fiber lasers and/or Nd:YAG laser with similar characteristics and the wavelength of 1,06 - 1,08 microns, are provided primarily for processing metallic powder materials with high absorption of laser radiation. The paper presents results of selected variable parameters (laser power, scanning time, scanning strategy) and fixed parameters such as the protective atmosphere (argon, nitrogen, helium), temperature, type and shape of the powder material. The thematic scope is very broad, so the work was focused on optimizing the process of selective laser micrometallurgy for producing fully dense parts. The density is closely linked with other two conditions: discontinuity of the microstructure (microcracks) and stability (repeatability) of the process. Materials used for the research were stainless steel 316L (AISI), tool steel H13 (AISI), and titanium alloy Ti6Al7Nb (ISO 5832-11). Studies were performed with a scanning electron microscope, a light microscopes, a confocal microscope and a μCT scanner.

  14. Fabrication of metal matrix composite by semi-solid powder processing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yufeng [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    Various metal matrix composites (MMCs) are widely used in the automotive, aerospace and electrical industries due to their capability and flexibility in improving the mechanical, thermal and electrical properties of a component. However, current manufacturing technologies may suffer from insufficient process stability and reliability and inadequate economic efficiency and may not be able to satisfy the increasing demands placed on MMCs. Semi-solid powder processing (SPP), a technology that combines traditional powder metallurgy and semi-solid forming methods, has potential to produce MMCs with low cost and high efficiency. In this work, the analytical study and experimental investigation of SPP on the fabrication of MMCs were explored. An analytical model was developed to understand the deformation mechanism of the powder compact in the semi-solid state. The densification behavior of the Al6061 and SiC powder mixtures was investigated with different liquid fractions and SiC volume fractions. The limits of SPP were analyzed in terms of reinforcement phase loading and its impact on the composite microstructure. To explore adoption of new materials, carbon nanotube (CNT) was investigated as a reinforcing material in aluminum matrix using SPP. The process was successfully modeled for the mono-phase powder (Al6061) compaction and the density and density distribution were predicted. The deformation mechanism at low and high liquid fractions was discussed. In addition, the compaction behavior of the ceramic-metal powder mixture was understood, and the SiC loading limit was identified by parametric study. For the fabrication of CNT reinforced Al6061 composite, the mechanical alloying of Al6061-CNT powders was first investigated. A mathematical model was developed to predict the CNT length change during the mechanical alloying process. The effects of mechanical alloying time and processing temperature during SPP were studied on the mechanical, microstructural and

  15. Design and Fabrication of a Large-Stroke Deformable Mirror Using a Gear-Shape Ionic-Conductive Polymer Metal Composite

    Directory of Open Access Journals (Sweden)

    Guo-Dung John Su

    2012-08-01

    Full Text Available Conventional camera modules with image sensors manipulate the focus or zoom by moving lenses. Although motors, such as voice-coil motors, can move the lens sets precisely, large volume, high power consumption, and long moving time are critical issues for motor-type camera modules. A deformable mirror (DM provides a good opportunity to improve these issues. The DM is a reflective type optical component which can alter the optical power to focus the lights on the two dimensional optical image sensors. It can make the camera system operate rapidly. Ionic polymer metal composite (IPMC is a promising electro-actuated polymer material that can be used in micromachining devices because of its large deformation with low actuation voltage. We developed a convenient simulation model based on Young’s modulus and Poisson’s ratio. We divided an ion exchange polymer, also known as Nafion®, into two virtual layers in the simulation model: one was expansive and the other was contractive, caused by opposite constant surface forces on each surface of the elements. Therefore, the deformation for different IPMC shapes can be described more easily. A standard experiment of voltage vs. tip displacement was used to verify the proposed modeling. Finally, a gear shaped IPMC actuator was designed and tested. Optical power of the IPMC deformable mirror is experimentally demonstrated to be 17 diopters with two volts. The needed voltage was about two orders lower than conventional silicon deformable mirrors and about one order lower than the liquid lens.

  16. Deformation behavior of commercial Mg-Al-Zn-Mn type alloys under a hydrostatic extrusion process at elevated temperatures

    International Nuclear Information System (INIS)

    Yoon, Duk Jae; Lee, Sang Mok; Lim, Seong Joo; Kim, Eung Zu

    2010-01-01

    This paper presents the deformation behavior of commercial Mg-Al-Zn-Mn type alloys during hydrostatic extrusion process at elevated temperatures. In the current study commercial Mg-Al-Zn-Mn type alloys with different Al contents were subjected to hydrostatic extrusion process at a range of temperatures and at ram speeds of 4.5, 10 and 17 mm/sec. Under the hydrostatic condition at 518K, the alloy with Al contents of 2.9 wt% was successfully extruded at all applied speeds. The alloys with Al content of 5.89 and 7.86 wt% were successful up to 10mm/sec, and finally extrusion of alloy with Al content 8.46wt% was successful only at 4.5 mm/sec. These results show that the deformation limit in the Mg alloys in terms of extrusion speed greatly extended to higher value in the proximity of lower Al content. It is presumed that deformation becomes harder as Al content increases because of strengthening mechanism by solute drag to increase of supersaturated Mg 17 Al 12 precipitates. Also, microstructures of cast and extruded Mg alloys were compared. Defect-wide microstructure of cast alloy completely evolved into dense and homogeneous microstructure with equiaxed grains

  17. Demonstration of pyrometallurgical processing for metal fuel and HLW

    International Nuclear Information System (INIS)

    Tadafumi, Koyama; Kensuke, Kinoshita; Takatoshi, Hizikata; Tadashi, Inoue; Ougier, M.; Rikard, Malmbeck; Glatz, J.P.; Lothar, Koch

    2001-01-01

    CRIEPI and JRC-ITU have started a joint study on pyrometallurgical processing to demonstrate the capability of this type of process for separating actinide elements from spent fuel and HLW. The equipment dedicated for this experiments has been developed and installed in JRC-ITU. The stainless steel box equipped with tele-manipulators is operated under pure Ar atmosphere, and prepared for later installation in a hot cell. Experiments on pyro-processing of un-irradiated U-Pu-Zr metal alloy fuel by molten salt electrorefining has been carried out. Recovery of U and Pu from this type alloy fuel was first demonstrated with using solid iron cathode and liquid Cd cathode, respectively. (author)

  18. Process Optimization for Valuable Metal Recovery from Dental Amalgam Residues

    Directory of Open Access Journals (Sweden)

    C.M. Parra–Mesa

    2009-07-01

    Full Text Available In this paper, the methodology used for optimizing leaching in a semi pilot plant is presented. This leaching process was applied to recover value metals from dental amalgam residues. 23 factorial design was used to characterize the process during the first stage and in the second one, a central compound rotational design was used for modeling copper percentage dissolved, a function of the nitric acid concentration, leaching time and temperature. This model explained the 81% of the response variability, which is considered satisfactory given the complexity of the process kinetics and, furthermore, it allowed the definition of the operation conditions for better copper recovery, which this was of 99.15%, at a temperature of 55°C, a concentration of 30% by weight and a time of 26 hours.

  19. Investigation of the yield process by deformation luminescence of X-ray irradiated KCl:Ca2+

    International Nuclear Information System (INIS)

    Nakamura, S.; Ida, K.; Ohgaku, T.

    2011-01-01

    It is found that deformation luminescence gives us information about the microscopic yield process of X-ray irradiated KCl:Ca 2+ . The stress-strain curve has a macroscopic yield point. But we find that luminescence appears to start before the macroscopic yield. This means that dislocation begin to move before the macroscopic yield because deformation luminescence is attributed to radiation-induced dislocation motion. The beginning of luminescence is considered to be the microscopic yield. Investigating the dependence of microscopic yield stress on strain rate and impurity concentration gives us additional information. The activation volume obtained from the dependence of microscopic yield stress on strain rate is comparable to the value estimated from the concentration of impurity. Then the dislocation starts to move overcoming impurity-vacancy dipoles as obstacles to dislocation motion. The dislocation density starts to increase at the microscopic yield point and then sharply increases to the macroscopic yield.

  20. Investigation of deformation at a centrifugal compressor rotor in process of interference on shaft

    Science.gov (United States)

    Shamim, M. R.; Berezhnoi, D. V.

    2016-11-01

    In this paper, according to the finite element method, we had implemented “master- slave” method of contact interaction in elastic deformable bodies, with consider of the friction in the contact zone. We had compiled the orientation of solving extremum problems with inequality restrictions, projection algorithm, which called “the closest point projection algorithm”. Finally, an example, had brought to show the calculation of the rotor nozzle centrifugal compressor on the shaft with interference.

  1. Superior metallic alloys through rapid solidification processing (RSP) by design

    Energy Technology Data Exchange (ETDEWEB)

    Flinn, J.E. [Idaho National Engineering Laboratory, Idaho Falls, ID (United States)

    1995-05-01

    Rapid solidification processing using powder atomization methods and the control of minor elements such as oxygen, nitrogen, and carbon can provide metallic alloys with superior properties and performance compared to conventionally processing alloys. Previous studies on nickel- and iron-base superalloys have provided the baseline information to properly couple RSP with alloy composition, and, therefore, enable alloys to be designed for performance improvements. The RSP approach produces powders, which need to be consolidated into suitable monolithic forms. This normally involves canning, consolidation, and decanning of the powders. Canning/decanning is expensive and raises the fabrication cost significantly above that of conventional, ingot metallurgy production methods. The cost differential can be offset by the superior performance of the RSP metallic alloys. However, without the performance database, it is difficult to convince potential users to adopt the RSP approach. Spray casting of the atomized molten droplets into suitable preforms for subsequent fabrication can be cost competitive with conventional processing. If the fine and stable microstructural features observed for the RSP approach are preserved during spray casing, a cost competitive product can be obtained that has superior properties and performance that cannot be obtained by conventional methods.

  2. Processing of Refractory Metal Alloys for JOYO Irradiations

    International Nuclear Information System (INIS)

    RF Luther; ME Petrichek

    2006-01-01

    This is a summary of the refractory metal processing experienced by candidate Prometheus materiats as they were fabricated into specimens destined for testing within the JOYO test reactor, ex-reactor testing at Oak Ridge National Laboratory (ORNL), or testing within the NRPCT. The processing is described for each alloy from the point of inception to the point where processing was terminated due to the cancellation of Naval Reactor's involvement in the Prometheus Project. The alloys included three tantalum-base alloys (T-111, Ta-10W, and ASTAR-811C), a niobium-base alloy, (FS-85), and two molybdenum-rhenium alloys, one containing 44.5 w/o rhenium, and the other 47.5 w/o rhenium. Each of these alloys was either a primary candidate or back-up candidate for cladding and structural applications within the space reactor. Their production was intended to serve as a forerunner for large scale production ingots that were to be procured from commercial refractory metal vendors such as Wah Chang

  3. Regulable process for sawage electrochemical treatment from heavy metals

    International Nuclear Information System (INIS)

    Covaliov, V.; Covaliova, O.

    2004-01-01

    The invention relates to a process for sewage treatment and may be used in the protection for metal working, in particular, for electroplating. The disperse magnetic particle are obtaining in the comminution of the sintered spheric particle into a magnetilique faction block at the electrolyser at the outlet from the electrolyzer it is determined the suspension magnetization value concentration of the solid phase and the redox potential of the values it is automatically regulated the feed of magnetic particles and the current intensity correspondingly

  4. PM - processing for manufacturing of metals with cellular structures

    International Nuclear Information System (INIS)

    Strobl, S.; Danninger, H.

    2001-01-01

    In this review the major Processes about manufacturing of metals with cellular structure are described - based on powder metallurgy, chemical deposition and some other methods (without melting techniques). It can be shown that during the last decade many interesting innovations led to new production methods to design cellular materials. Some of them are used nowadays in industry. Also characterization and properties become more important and have therefore been carried out carefully, because of their strong influence on the functions and applications of such materials. (author)

  5. Metal matrix composite fabrication processes for high performance aerospace structures

    Science.gov (United States)

    Ponzi, C.

    A survey is conducted of extant methods of metal matrix composite (MMC) production in order to serve as a basis for prospective MMC users' selection of a matrix/reinforcement combination, cost-effective primary fabrication methods, and secondary fabrication techniques for the achievement of desired performance levels. Attention is given to the illustrative cases of structural fittings, control-surface connecting rods, hypersonic aircraft air inlet ramps, helicopter swash plates, and turbine rotor disks. Methods for technical and cost analysis modeling useful in process optimization are noted.

  6. VOLATILE CHLORIDE PROCESS FOR THE RECOVERY OF METAL VALUES

    Science.gov (United States)

    Hanley, W.R.

    1959-01-01

    A process is presented for recovering uranium, iron, and aluminum from centain shale type ores which contain uranium in minute quantities. The ore is heated wiih a chlorinating agent. such as chlorine, to form a volatilized stream of metal chlorides. The chloride stream is then passed through granular alumina which preferentially absorbs the volatile uranium chloride and from which the uranium may later be recovered. The remaining volatilized chlorides, chiefly those of iron and aluminum, are further treated to recover chlorine gas for recycle, and to recover ferric oxide and aluminum oxide as valuable by-products.

  7. Instrumented anvil-on-rod impact experiments for validating constitutive strength model for simulating transient dynamic deformation response of metals

    International Nuclear Information System (INIS)

    Martin, M.; Shen, T.; Thadhani, N.N.

    2008-01-01

    Instrumented anvil-on-rod impact experiments were performed to access the applicability of this approach for validating a constitutive strength model for dynamic, transient-state deformation and elastic-plastic wave interactions in vanadium, 21-6-9 stainless steel, titanium, and Ti-6Al-4V. In addition to soft-catching the impacted rod-shaped samples, their transient deformation states were captured by high-speed imaging, and velocity interferometry was used to record the sample back (free) surface velocity and monitor elastic-plastic wave interactions. Simulations utilizing AUTODYN-2D hydrocode with Steinberg-Guinan constitutive equation were used to generate simulated free surface velocity traces and final/transient deformation profiles for comparisons with experiments. The simulations were observed to under-predict the radial strain for bcc vanadium and fcc steel, but over-predict the radial strain for hcp titanium and Ti-6Al-4V. The correlations illustrate the applicability of the instrumented anvil-on-rod impact test as a method for providing robust model validation based on the entire deformation event, and not just the final deformed state

  8. Oxide dispersion strengthened ferritic alloys. 14/20% chromium: effects of processing on deformation texture, recrystallization and tensile properties

    International Nuclear Information System (INIS)

    Regle, H.

    1994-01-01

    The ferritic oxide dispersion strengthened alloys are promising candidates for high temperature application materials, in particular for long life core components of advanced nuclear reactors. The aim of this work is to control the microstructure, in order to optimise the mechanical properties. The two ferritic alloys examined here, MA956 and MA957, are obtained by Mechanical Alloying techniques. They are characterised by quite anisotropic microstructure and mechanical properties. We have investigated the influence of hot and cold working processes (hot extrusion, swaging and cold-drawing) and recrystallization heat treatments on deformation textures, microstructures and tensile properties. The aim was to control the size of the grains and their anisotropic shape, using recrystallization heat treatments. After consolidation and hot extrusion, as-received materials present a extremely fine microstructure with elongated grains and a very strong (110) deformation texture with single-crystal character. At that stage of processing, recrystallization temperature are very high (1450 degrees C for MA957 alloy and 1350 degrees C for MA956 alloy) and materials develop millimetric recrystallized grains. Additional hot extrusion induce a fibre texture. Cold-drawing maintains a fibre texture, but the intensity decreases with increasing cold-work level. For both materials, the decrease of texture intensities correspond to a decrease of the recrystallization temperatures (from 1350 degrees C for a low cold-work level to 750 degrees C for 60 % cold-deformation, case of MA956 alloy) and a refinement of the grain size (from a millimetric size to less than an hundred of micrometer). Swaging develop a cyclic component where the intensity increases with increasing deformation in this case, the recrystallization temperature remains always very high and the millimetric grain size is slightly modified, even though cold-work level increases. Technologically, cold-drawing is the only way

  9. Effect on deformation process of adding a copper core to multifilament MgB2 superconducting wire

    DEFF Research Database (Denmark)

    Hancock, Michael Halloway; Bay, Niels

    2007-01-01

    Using the PIT method, multifilament wire with different packing strategies has been manufactured. In all, three types of wire have been investigated, a 19-filament configuration using ex-situ powder in an Fe-matrix and two 8-filament configurations in an Fe-matrix applying a copper core, one using....... This finding is supported by numerical simulations of the deformation process which indicate that tensile stresses are. concentrated around the middle of the wire during the drawing process. As such, strategic packing of the multifilament configuration can reduce the need for annealing during the mechanical...

  10. The role of chemical processes and brittle deformation during shear zone formation and its potential geophysical implications

    Science.gov (United States)

    Goncalves, Philippe; Leydier, Thomas; Mahan, Kevin; Albaric, Julie; Trap, Pierre; Marquer, Didier

    2017-04-01

    Ductile shear zones in the middle and lower continental crust are the locus of interactions between mechanical and chemical processes. Chemical processes encompass metamorphic reactions, fluid-rock interactions, fluid flow and chemical mass-transfer. Studying these processes at the grain scale, and even the atom scale, on exposed inactive shear zones can give insights into large-scale geodynamics phenomena (e.g. crustal growth and mountain building through the reconstruction of P-T-t-D-Ɛ evolutionary paths. However, other major issues in earth sciences can be tackled through these studies as well. For instance, the mechanism of fluid flow and mass transfer in the deep crust where permeability should be small and transient is still largely debated. Studying exhumed inactive shear zones can also help to interpret several new geophysical observations like (1) the origin of tremor and very low frequency earthquakes observed in the ductile middle and lower crust, (2) mechanisms for generating slow slip events and (3) the physical origin of puzzling crustal anisotropy observed in major active crustal shear zones. In this contribution, we present a collection of data (deformation, petrology, geochemistry, microtexture) obtained on various shear zones from the Alps that were active within the viscous regime (T > 450°C). Our observations show that the development of a shear zone, from its nucleation to its growth and propagation, is not only governed by ductile deformation coeval with reactions but also involves brittle deformation. Although brittle deformation is a very short-lived phenomenon, our petrological and textural observations show that brittle failure is also associated with fluid flow, mass transfer, metasomatic reactions and recrystallization. We speculate that the fluids and the associated mineralogical changes involved during this brittle failure in the ductile crust might play a role in earthquake / tremor triggering below the brittle - ductile transition

  11. A Fundamental Study of Stretch-Drawing Process of Sheet Metals : Single and Double Operations

    Science.gov (United States)

    Gotoh, Manabu; Kim, Young-soo; Yamashita, Minoru

    1998-05-01

    Fundamental and informative data of axisymmetric stretch-drawing of several sheet metals with thichness of 0.7 1.0 mm are presented especially for single and double operations. Very small radius is applied to the die-profile (or -shoulder) in all operations to induce wall-thinning by the effect of bending-under-tension, from which the name `stretch-drawing' comes. It is clearly demonstrated that deeper cups could be formed by the single and double stretch-drawings from smaller cirlcular blanks due to such wall-thinning action than in the usual deep-drawing of larger blanks. From this fact, it is emphasized that the deep-drawability of a sheet metal is not evaluated simply by the conventional LDR (=limiting drawing ratio), but the depth of the drawn cup should also be taken into account. Many experimental data about various metals and thicknesses given in this paper offer a valueable information on this process for more general use which recommends to replace the conventional deep-drawing process by the stretch-drawing process both for single and double operations. In the single stretch-drawing, it is also confirmed that a deeper cup can be produced by raising the blank-holding force at later stage of operation. Fracturing is found to occur at the middle section of the wall part or at the die-profile other than at the punch profile common in the usual deep-drawing process. Numerical simulation of the single stretch-drawing process is also performed by use of DYNA-3D code to confirm that a satisfactory prediction especially in the depth of the drawn-cup can be done at least in a practical sense, although this kind of numerical analysis is very difficult because of the severity or localization of deformation around the die profile. The drawn cup of SUS304 among others fractures in a couple of weeks after the operation due to the residual circumferential tensile stress, whereas that of SUS304L does not. In the double stretch-drawing, it is confirmed that very deeper

  12. Cleaning Process Development for Metallic Additively Manufactured Parts

    Science.gov (United States)

    Tramel, Terri L.; Welker, Roger; Lowery, Niki; Mitchell, Mark

    2014-01-01

    Additive Manufacturing of metallic components for aerospace applications offers many advantages over traditional manufacturing techniques. As a new technology, many aspects of its widespread utilization remain open to investigation. Among these are the cleaning processes that can be used for post finishing of parts and measurements to verify effectiveness of the cleaning processes. Many cleaning and drying processes and measurement methods that have been used for parts manufactured using conventional techniques are candidates that may be considered for cleaning and verification of additively manufactured parts. Among these are vapor degreasing, ultrasonic immersion and spray cleaning, followed by hot air drying, vacuum baking and solvent displacement drying. Differences in porosity, density, and surface finish of additively manufactured versus conventionally manufactured parts may introduce new considerations in the selection of cleaning and drying processes or the method used to verify their effectiveness. This presentation will review the relative strengths and weaknesses of different candidate cleaning and drying processes as they may apply to additively manufactured metal parts for aerospace applications. An ultrasonic cleaning technique for exploring the cleanability of parts will be presented along with an example using additively manufactured Inconel 718 test specimens to illustrate its use. The data analysis shows that this ultrasonic cleaning approach results in a well-behaved ultrasonic cleaning/extraction behavior. That is, it does not show signs of accelerated cavitation erosion of the base material, which was later confirmed by neutron imaging. In addition, the analysis indicated that complete cleaning would be achieved by ultrasonic immersion cleaning at approximately 5 minutes, which was verified by subsequent cleaning of additional parts.

  13. Deformation During Friction Stir Welding

    Science.gov (United States)

    White, Henry J.

    2002-01-01

    Friction Stir Welding (FSW) is a solid state welding process that exhibits characteristics similar to traditional metal cutting processes. The plastic deformation that occurs during friction stir welding is due to the superposition of three flow fields: a primary rotation of a radially symmetric solid plug of metal surrounding the pin tool, a secondary uniform translation, and a tertiary ring vortex flow (smoke rings) surrounding the tool. If the metal sticks to the tool, the plug surface extends down into the metal from the outer edge of the tool shoulder, decreases in diameter like a funnel, and closes up beneath the pin. Since its invention, ten years have gone by and still very little is known about the physics of the friction stir welding process. In this experiment, an H13 steel weld tool (shoulder diameter, 0.797 in; pin diameter, 0.312 in; and pin length, 0.2506 in) was used to weld three 0.255 in thick plates. The deformation behavior during friction stir welding was investigated by metallographically preparing a plan view sections of the weldment and taking Vickers hardness test in the key-hole region.

  14. Novel Chemical Process for Producing Chrome Coated Metal

    Directory of Open Access Journals (Sweden)

    Christopher Pelar

    2018-01-01

    Full Text Available This work demonstrates that a version of the Reduction Expansion Synthesis (RES process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM. SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

  15. Novel Chemical Process for Producing Chrome Coated Metal.

    Science.gov (United States)

    Pelar, Christopher; Greenaway, Karima; Zea, Hugo; Wu, Chun-Hsien; Luhrs, Claudia C; Phillips, Jonathan

    2018-01-05

    This work demonstrates that a version of the Reduction Expansion Synthesis (RES) process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM). SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

  16. Process model for carbothermic production of silicon metal

    Energy Technology Data Exchange (ETDEWEB)

    Andresen, B.

    1995-09-12

    This thesis discusses an advanced dynamical two-dimensional cylinder symmetric model for the high temperature part of the carbothermic silicon metal process, and its computer encoding. The situation close to that which is believed to exist around one of three electrodes in full-scale industrial furnaces is modelled. This area comprises a gas filled cavity surrounding the lower tip of the electrode, the metal pool underneath and the lower parts of the materials above. The most important phenomena included are: Heterogeneous chemical reactions taking place in the high-temperature zone (above 1860 {sup o}C), Evaporation and condensation of silicon, Transport of materials by dripping, Turbulent or laminar fluid flow, DC electric arcs, Heat transport by convection, conduction and radiation. The results from the calculations, such as production rates, gas- and temperature distributions, furnace- and particle geometries, fluid flow fields etc, are presented graphically. In its present state the model is a prototype. The process is very complex, and the calculations are time consuming. The governing equations are coded into a Fortran 77 computer code applying the commercial 3D code FLUENT as a basis. 64 refs., 110 figs., 11 tabs.

  17. High-coercivity ultrafine-grained anisotropic Nd–Fe–B magnets processed by hot deformation and the Nd–Cu grain boundary diffusion process

    International Nuclear Information System (INIS)

    Sepehri-Amin, H.; Ohkubo, T.; Nagashima, S.; Yano, M.; Shoji, T.; Kato, A.; Schrefl, T.; Hono, K.

    2013-01-01

    The grain boundary diffusion process using an Nd 70 Cu 30 eutectic alloy has been applied to hot-deformed anisotropic Nd–Fe–B magnets, resulting in a substantial enhancement of coercivity, from 1.5 T to 2.3 T, at the expense of remanence. Scanning electron microscopy showed that the areal fraction of an Nd-rich intergranular phase increased from 10% to 37%. The intergranular phase of the hot-deformed magnet initially contained ∼55 at.% ferromagnetic element, while it diminished to an undetectable level after the process. Microscale eutectic solidification of Nd/NdCu as well as a fine lamellae structure of Nd 70 (Co,Cu) 30 /Nd were observed in the intergranular phase. Micromagnetic simulations indicated that the reduction of the magnetization in the intergranular phases leads to the enhancement of coercivity in agreement with the experimental observation

  18. Hot deformation behaviors and processing maps of B{sub 4}C/Al6061 neutron absorber composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yu-Li [School of Materials Science and Engineering, Taiyuan University Of Technology, Taiyuan 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Wen-Xian, E-mail: Wangwenxian@tyut.edu.cn [School of Materials Science and Engineering, Taiyuan University Of Technology, Taiyuan 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); Zhou, Jun [School of Materials Science and Engineering, Taiyuan University Of Technology, Taiyuan 030024 (China); Department of Mechanical Engineering, Pennsylvania State University Erie, The Behrend College, Erie, PA 16563 (United States); Chen, Hong-Sheng [School of Materials Science and Engineering, Taiyuan University Of Technology, Taiyuan 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China)

    2017-02-15

    In this study, the hot deformation behaviors of 30 wt.% B{sub 4}C/Al6061 neutron absorber composites (NACs) have been investigated by conducting isothermal compression tests at temperatures ranging from 653 K to 803 K and strain rates from 0.01 to 10 s{sup −1}. It was found that, during hot compression, the B{sub 4}C/Al6061 NACs exhibited a steady flow characteristic which can be expressed by the Zener-Hollomon parameter as a hyperbolic-sine function of flow stress. High average activation energy (185.62 kJ/mol) of B{sub 4}C/Al6061 NACs is noted in current study owing to the high content of B{sub 4}C particle. The optimum hot working conditions for B{sub 4}C/Al6061 NACs are found to be 760–803 K/0.01–0.05 s{sup −1} based on processing map and microstructure evolution. Typical material instabilities are thought to be attributed to void formation, adiabatic shear bands (ASB), particle debonding, and matrix cracking. Finally, the effect of the plastic deformation zones (PDZs) on the microstructure evolution in this 30 wt.% B{sub 4}C/Al6061 composite is found to be very important. - Highlights: •The hot deformation behavior of the 30 wt.% B{sub 4}C/Al6061 NACs was first analyzed. •The 3D efficiency map and the instability map are developed. •The optimum hot working conditions were identified and validated by SEM and TEM. •The hot deformation schematic diagram of 30 wt.% B{sub 4}C/Al6061 NACs is developed.

  19. Deformation style and controlling geodynamic processes at the eastern Guadalquivir foreland basin (Southern Spain)

    Science.gov (United States)

    Marín-Lechado, C.; Pedrera, A.; Peláez, J. A.; Ruiz-Constán, A.; González-Ramón, A.; Henares, J.

    2017-06-01

    The tectonic structure of the Guadalquivir foreland basin becomes complex eastward evolving from a single depocenter to a compartmented basin. The deformation pattern within the eastern Guadalquivir foreland basin has been characterized by combining seismic reflection profiles, boreholes, and structural field data to output a 3-D model. High-dipping NNE-SSW to NE-SW trending normal and reverse fault arrays deform the Variscan basement of the basin. These faults generally affect Tortonian sediments, which show syntectonic features sealed by the latest Miocene units. Curved and S-shaped fault traces are abundant and caused by the linkage of nearby fault segments during lateral fault propagation. Preexisting faults were reactivated either as normal or reverse faults depending on their position within the foreland. At Tortonian time, reverse faults deformed the basin forebulge, while normal faults predominated within the backbulge. Along-strike variation of the Betic foreland basin geometry is supported by an increasing mechanical coupling of the two plates (Alborán Domain and Variscan basement) toward the eastern part of the cordillera. Thus, subduction would have progressed in the western Betics, while it would have failed in the eastern one. There, the initially subducted Iberian paleomargin (Nevado-Filábride Complex) was incorporated into the upper plate promoting the transmission of collision-related compressional stresses into the foreland since the middle Miocene. Nowadays, compression is still active and produces low-magnitude earthquakes likely linked to NNE-SSW to NE-SW preexiting faults reactivated with reverse oblique-slip kinematics. Seismicity is mostly concentrated around fault tips that are frequently curved in overstepping zones.

  20. Surface deformation induced by magmatic processes at Pacaya Volcano, Guatemala revealed by InSAR

    Science.gov (United States)

    Wnuk, K.; Wauthier, C.

    2017-09-01

    Pacaya Volcano, Guatemala is a continuously active, basaltic volcano with an unstable western flank. Despite continuous activity since 1961, a lack of high temporal resolution geodetic surveying has prevented detailed modeling of Pacaya's underlying magmatic plumbing system. A new, temporally dense dataset of Interferometric Synthetic Aperture Radar (InSAR) RADARSAT-2 images, spanning December 2012 to March 2014, show magmatic deformation before and during major eruptions in January and March 2014. Inversion of InSAR surface displacements using simple analytical forward models suggest that three magma bodies are responsible for the observed deformation: (1) a 4 km deep spherical reservoir located northwest of the summit, (2) a 0.4 km deep spherical source located directly west of the summit, and (3) a shallow dike below the summit. Periods of heightened volcanic activity are instigated by magma pulses at depth, resulting in rapid inflation of the edifice. We observe an intrusion cycle at Pacaya that consists of deflation of one or both magma reservoirs followed by dike intrusion. Intrusion volumes are proportional to reservoir volume loss and do not always result in an eruption. Periods of increased activity culminate with larger dike-fed eruptions. Large eruptions are followed by inter-eruptive periods marked by a decrease in crater explosions and a lack of detected deformation. Co-eruptive flank motion appears to have initiated a new stage of volcanic rifting at Pacaya defined by repeated NW-SE oriented dike intrusions. This creates a positive feedback relationship whereby magmatic forcing from eruptive dike intrusions induce flank motion.