WorldWideScience

Sample records for alloy sheet metal

  1. Experiments on sheet metal shearing

    OpenAIRE

    Gustafsson, Emil

    2013-01-01

    Within the sheet metal industry, different shear cutting technologies are commonly used in several processing steps, e.g. in cut to length lines, slitting lines, end cropping etc. Shearing has speed and cost advantages over competing cutting methods like laser and plasma cutting, but involves large forces on the equipment and large strains in the sheet material.Numerical models to predict forces and sheared edge geometry for different sheet metal grades and different shear parameter set-ups a...

  2. Lubricant Test Methods for Sheet Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

    2008-01-01

    appearing in different sheet forming operations such as stretch forming, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production. Application of the tests for evaluating new lubricants before introducing them in production has......Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...... oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions...

  3. Perforation of metal sheets

    DEFF Research Database (Denmark)

    Steenstrup, Jens Erik

    simulation is focused on the sheet deformation. However, the effect on the tool and press is included. The process model is based on the upper bound analysis in order to predict the force progress and hole characteristics etc. Parameter analyses are divided into two groups, simulation and experimental tests......The main purposes of this project are:1. Development of a dynamic model for the piercing and performation process2. Analyses of the main parameters3. Establishing demands for process improvements4. Expansion of the existing parameter limitsThe literature survey describes the process influence...

  4. Ductile transplutonium metal alloys

    Science.gov (United States)

    Conner, William V.

    1983-01-01

    Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as sources of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

  5. Research on Al-alloy sheet forming formability during warm/hot sheet hydroforming based on elliptical warm bulging test

    Science.gov (United States)

    Cai, Gaoshen; Wu, Chuanyu; Gao, Zepu; Lang, Lihui; Alexandrov, Sergei

    2018-05-01

    An elliptical warm/hot sheet bulging test under different temperatures and pressure rates was carried out to predict Al-alloy sheet forming limit during warm/hot sheet hydroforming. Using relevant formulas of ultimate strain to calculate and dispose experimental data, forming limit curves (FLCS) in tension-tension state of strain (TTSS) area are obtained. Combining with the basic experimental data obtained by uniaxial tensile test under the equivalent condition with bulging test, complete forming limit diagrams (FLDS) of Al-alloy are established. Using a quadratic polynomial curve fitting method, material constants of fitting function are calculated and a prediction model equation for sheet metal forming limit is established, by which the corresponding forming limit curves in TTSS area can be obtained. The bulging test and fitting results indicated that the sheet metal FLCS obtained were very accurate. Also, the model equation can be used to instruct warm/hot sheet bulging test.

  6. Study of laser bending of a preloaded Titanium alloy sheet

    Directory of Open Access Journals (Sweden)

    Wang Xiufeng

    2014-01-01

    Full Text Available Laser bending of sheet metals with preload offers some attractive characteristics/merits, comparing to laser free bending without prestressing on the metals. The study reported in this paper was focused on a Titanium alloy which finds widespread applications in aerospace manufacturing. FE simulation of laser bending with prestressing on the Titanium alloy sheet was conducted for the analysis of the bending process and experiment carried out to verify the model and the result. It was shown that the simulation result is close to that measured in the experiment. Based on the computed result, the load-displacement curve was analysed and transmission efficiency of the elastic energy defined to evaluate the bending effect. These enhanced understanding of the mechanism of laser bending with a preload. A method for the optimization on technological parameters was further proposed. Referring to the deformation targeted, the preload value was determined through the FE simulation. The result showed that, on the premise that the specimen surface can be prevented from damaging, transmission efficiency of the elastic energy could reach to the maximum value through adjusting technological parameters of the laser system and deformation accuracy of the specimen could also be improved through this approach. The work presented in this paper may find its application in the manufacture of Titanium alloy sheets with a more cost-effective and a more precise way.

  7. AI applications in sheet metal forming

    CERN Document Server

    Hussein, Hussein

    2017-01-01

    This book comprises chapters on research work done around the globe in the area of artificial intelligence (AI) applications in sheet metal forming. The first chapter offers an introduction to various AI techniques and sheet metal forming, while subsequent chapters describe traditional procedures/methods used in various sheet metal forming processes, and focus on the automation of those processes by means of AI techniques, such as KBS, ANN, GA, CBR, etc. Feature recognition and the manufacturability assessment of sheet metal parts, process planning, strip-layout design, selecting the type and size of die components, die modeling, and predicting die life are some of the most important aspects of sheet metal work. Traditionally, these activities are highly experience-based, tedious and time consuming. In response, researchers in several countries have applied various AI techniques to automate these activities, which are covered in this book. This book will be useful for engineers working in sheet metal industri...

  8. Automobile sheet metal part production with incremental sheet forming

    Directory of Open Access Journals (Sweden)

    İsmail DURGUN

    2016-02-01

    Full Text Available Nowadays, effect of global warming is increasing drastically so it leads to increased interest on energy efficiency and sustainable production methods. As a result of adverse conditions, national and international project platforms, OEMs (Original Equipment Manufacturers, SMEs (Small and Mid-size Manufacturers perform many studies or improve existing methodologies in scope of advanced manufacturing techniques. In this study, advanced manufacturing and sustainable production method "Incremental Sheet Metal Forming (ISF" was used for sheet metal forming process. A vehicle fender was manufactured with or without die by using different toolpath strategies and die sets. At the end of the study, Results have been investigated under the influence of method and parameters used.Keywords: Template incremental sheet metal, Metal forming

  9. Heated Hydro-Mechanical Deep Drawing of Magnesium Sheet Metal

    Science.gov (United States)

    Kurz, Gerrit

    In order to reduce fuel consumption efforts have been made to decrease the weight of automobile constructions by increasing the use of lightweight materials. In this field of application magnesium alloys are important because of their low density. A promising alternative to large surfaced and thin die casting parts has been found in construction parts that are manufactured by sheet metal forming of magnesium. Magnesium alloys show a limited formability at room temperature. A considerable improvement of formability can be achieved by heating the material. Formability increases above a temperature of approximately T = 225 °C.

  10. Advanced friction modeling for sheet metal forming

    NARCIS (Netherlands)

    Hol, J.; Cid Alfaro, M.V.; de Rooij, Matthias B.; Meinders, Vincent T.

    2012-01-01

    The Coulomb friction model is frequently used for sheet metal forming simulations. This model incorporates a constant coefficient of friction and does not take the influence of important parameters such as contact pressure or deformation of the sheet material into account. This article presents a

  11. Advanced friction modeling in sheet metal forming

    NARCIS (Netherlands)

    Hol, J.; Cid Alfaro, M.V.; Meinders, Vincent T.; Huetink, Han

    2011-01-01

    The Coulomb friction model is frequently used for sheet metal forming simulations. This model incorporates a constant coefficient of friction and does not take the influence of important parameters such as contact pressure or deformation of the sheet material into account. This article presents a

  12. Rare earth metal alloy magnets

    International Nuclear Information System (INIS)

    Harris, I.R.; Evans, J.M.; Nyholm, P.S.

    1979-01-01

    This invention relates to rare earth metal alloy magnets and to methods for their production. The technique is based on the fact that rare earth metal alloys (for e.g. cerium or yttrium) which have been crumbled to form a powder by hydride formation and decomposition can be used for the fabrication of magnets without the disadvantages inherent in alloy particle size reduction by mechanical milling. (UK)

  13. Effect of material flow on joint strength in activation spot joining of Al alloy and steel sheets

    International Nuclear Information System (INIS)

    Watanabe, Goro; Yogo, Yasuhiro; Takao, Hisaaki

    2014-01-01

    A new joining method for dissimilar metal sheets was developed where a rotated consumable rod of Al alloy is pressed onto an Al alloy sheet at the part overlapped with a mild steel sheet. The metal flow in the joining region is increased by the through-hole in the Al sheet and consumable Al rod. The rod creates the joint interface and pads out of the thinly joined parts through pressing. This produces a higher joint strength than that of conventional friction stir spot welding. Measurements of the joint interface showed the presence of a 5-10 nm thick amorphous layer consisting of Al and Mg oxides

  14. A System of Test Methods for Sheet Metal Forming Tribology

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

    2007-01-01

    Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...... oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions...... appearing in different sheet forming operations such as stamping, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production....

  15. Trapping of point defects and segregation at the free surfaces of a metal sheet under irradiation

    International Nuclear Information System (INIS)

    Sarce, Alicia

    2003-01-01

    The migration of irradiation produced vacancies and interstitials to the free surfaces of a sheet of thickness d (pure metal and binary alloys AB of hcp structure) is calculated. For alloys, the irradiation temperature when no segregation exists (critical temperature) is obtained. The anisotropy of the diffusion of point defects in the hcp lattice is explicitly included in the calculations. (author)

  16. 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 ...

  17. Multiscale friction modeling for sheet metal forming

    NARCIS (Netherlands)

    Hol, J.; Cid Alfaro, M.V.; de Rooij, Matthias B.; Meinders, Vincent T.; Felder, Eric; Montmitonnet, Pierre

    2010-01-01

    The most often used friction model for sheet metal forming simulations is the relative simple Coulomb friction model. This paper presents a more advanced friction model for large scale forming simulations based on the surface change on the micro-scale. The surface texture of a material changes when

  18. Constitutive Modeling for Sheet Metal Forming

    International Nuclear Information System (INIS)

    Barlat, Frederic

    2005-01-01

    This paper reviews aspects of the plastic behaviour common in sheet metals. Macroscopic and microscopic phenomena occurring during plastic deformation are described succinctly. Constitutive models of plasticity suitable for applications to forming, are discussed in a very broad manner. Approaches to plastic anisotropy are described in a somewhat more detailed manner

  19. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  20. Assembly for testing weldability of sheet metal

    International Nuclear Information System (INIS)

    David, S.A.; Woodhouse, J.J.

    1985-01-01

    A test assembly for determining the weldability of sheet metal includes a base having a flat side surface with an annular groove in the side surface, a counterbore being formed in the outer wall of the groove and the surface portion of the base circumscribed by the inner wall of the groove being substantially coplanar with the bottom of the counterbore, a test disk of sheet metal the periphery of which is positioned in the counterbore and the outer surface of which is coplanar with one side of the base, and a clamp ring overlying the side surface of the base and the edge portion of the test disk and a plurality of clamp screws which extend through the clamp ring for holding the periphery of the test disk against the bottom of the counterbore

  1. Plastic Deformation Characteristics Of AZ31 Magnesium Alloy Sheets At Elevated Temperature

    International Nuclear Information System (INIS)

    Park, Jingee; Lee, Jongshin; You, Bongsun; Choi, Seogou; Kim, Youngsuk

    2007-01-01

    Using lightweight materials is the emerging need in order to reduce the vehicle's energy consumption and pollutant emissions. Being a lightweight material, magnesium alloys are increasingly employed in the fabrication of automotive and electronic parts. Presently, magnesium alloys used in automotive and electronic parts are mainly processed by die casting. The die casting technology allows the manufacturing of parts with complex geometry. However, the mechanical properties of these parts often do not meet the requirements concerning the mechanical properties (e.g. endurance strength and ductility). A promising alternative can be forming process. The parts manufactured by forming could have fine-grained structure without porosity and improved mechanical properties such as endurance strength and ductility. Because magnesium alloy has low formability resulted form its small slip system at room temperature it is usually formed at elevated temperature. Due to a rapid increase of usage of magnesium sheets in automotive and electronic industry it is necessary to assure database for sheet metal formability and plastic yielding properties in order to optimize its usage. Especially, plastic yielding criterion is a critical property to predict plastic deformation of sheet metal parts in optimizing process using CAE simulation. Von-Mises yield criterion generally well predicts plastic deformation of steel sheets and Hill'1979 yield criterion predicts plastic deformation of aluminum sheets. In this study, using biaxial tensile test machine yield loci of AZ31 magnesium alloy sheet were obtained at elevated temperature. The yield loci ensured experimentally were compared with the theoretical predictions based on the Von-Mises, Hill, Logan-Hosford, and Barlat model

  2. Sheet-bulk metal forming – forming of functional components from sheet metals

    Directory of Open Access Journals (Sweden)

    Merklein Marion

    2015-01-01

    Full Text Available The paper gives an overview on the application of sheet-bulk metal forming operations in both scientific and industrial environment. Beginning with the need for an innovative forming technology, the definition of this new process class is introduced. The rising challenges of the application of bulk metal forming operations on sheet metals are presented and the demand on a holistic investigation of this topic is motivated. With the help of examples from established production processes, the latest state of technology and the lack on fundamental knowledge is shown. Furthermore, perspectives regarding new research topics within sheet-bulk metal forming are presented. These focus on processing strategies to improve the quality of functional components by the application of process-adapted semi-finished products as well as the local adaption of the tribological system.

  3. Formability of Annealed Ni-Ti Shape Memory Alloy Sheet

    Science.gov (United States)

    Fann, K. J.; Su, J. Y.; Chang, C. H.

    2018-03-01

    Ni-Ti shape memory alloy has two specific properties, superelasiticity and shape memory effect, and thus is widely applied in diverse industries. To extend its application, this study attempts to investigate the strength and cold formability of its sheet blank, which is annealed at various temperatures, by hardness test and by Erichsen-like cupping test. As a result, the higher the annealing temperature, the lower the hardness, the lower the maximum punch load as the sheet blank fractured, and the lower the Erichsen-like index or the lower the formability. In general, the Ni-Ti sheet after annealing has an Erichsen-like index between 8 mm and 9 mm. This study has also confirmed via DSC that the Ni-Ti shape memory alloy possesses the austenitic phase and shows the superelasticity at room temperature.

  4. Pseudo-creep in Shape Memory Alloy Wires and Sheets

    Science.gov (United States)

    Russalian, V. R.; Bhattacharyya, A.

    2017-10-01

    Interruption of loading during reorientation and isothermal pseudoelasticity in shape memory alloys with a strain arrest ( i.e., holding strain constant) results in a time-dependent evolution in stress or with a stress arrest ( i.e., holding stress constant) results in a time-dependent evolution in strain. This phenomenon, which we term as pseudo-creep, is similar to what was reported in the literature three decades ago for some traditional metallic materials undergoing plastic deformation. In a previous communication, we reported strain arrest of isothermal pseudoelastic loading, isothermal pseudoelastic unloading, and reorientation in NiTi wires as well as a rate-independent phase diagram. In this paper, we provide experimental results of the pseudo-creep phenomenon during stress arrest of isothermal pseudoelasticity and reorientation in NiTi wires as well as strain arrest of isothermal pseudoelasticity and reorientation in NiTi sheets. Stress arrest in NiTi wires accompanied by strain accumulation or recovery is studied using the technique of multi-video extensometry. The experimental results were used to estimate the amount of mechanical energy needed to evolve the wire from one microstructural state to another during isothermal pseudoelastic deformation and the difference in energies between the initial and the final rest state between which the aforementioned evolution has occurred.

  5. Laser surface alloying of aluminium-transition metal alloys

    International Nuclear Information System (INIS)

    Almeida, A.; Vilar, R.

    1998-01-01

    Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM) alloys. Cr and Mo are particularly interesting alloying elements to produce stable high-strength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO 2 laser . This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloy, over the last years. (Author) 16 refs

  6. 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

  7. Damage Prediction in Sheet Metal Forming

    International Nuclear Information System (INIS)

    Saanouni, Khemais; Badreddine, Houssem

    2007-01-01

    Ductile (or plastic) damage often occurs during sheet metal forming processes due to the large plastic flow localization. Accordingly, it is crucial for numerical tools, used in the simulation of that processes, to use fully coupled constitutive equations accounting for both hardening and damage. This can be used in both cases, namely to overcome the damage initiation during some sheet metal forming processes as deep drawing, ... or to enhance the damage initiation and growth as in sheet metal cutting. In this paper, a fully coupled constitutive equations accounting for combined isotropic and kinematic hardening as well as the ductile damage is implemented into the general purpose Finite Element code for metal forming simulation. First, the fully coupled anisotropic constitutive equations in the framework of Continuum Damage Mechanics are presented. Attention is paid to the strong coupling between the main mechanical fields as elasto-viscoplasticity, mixed hardening, ductile isotropic damage and contact with friction. The anisotropy of the plastic flow is taken into account using various kinds of quadratic or non quadratic yield criteria in the framework of non associative finite plasticity theory with two types of normality rules. The associated numerical aspects concerning both the local integration of the coupled constitutive equations as well as the (global) equilibrium integration schemes are presented. The local integration is outlined thanks to the Newton iterative scheme applied to a reduced system of 2 equations. For the global resolution of the initial and boundary value problem, the classical dynamic explicit (DE) scheme with an adaptive time step control is used. The numerical implementation of the damage is made in such a manner that calculations can be executed with or without damage effect, i.e. fully coupled or uncoupled calculations. For the 2D processes an advanced adaptive meshing procedure is used in order to enhance the numerical solution and

  8. Mechanical characterization and constitutive modeling of Mg alloy sheets

    International Nuclear Information System (INIS)

    Mekonen, M. Nebebe; Steglich, D.; Bohlen, J.; Letzig, D.; Mosler, J.

    2012-01-01

    Highlights: ► Material characterization of the Mg alloys AZ31 and ZE10 at elevated temperatures. ► Distortion of the yield locus does not depend on the strain rate. ► Novel constitutive model suitable for the analysis of sheet forming of magnesium. ► Strain-dependent r-values are included within the model. ► The model is thermodynamically consistent and accounts for distortional hardening. - Abstract: In this paper, an experimental mechanical characterization of the magnesium alloys ZE10 and AZ31 is performed and a suitable constitutive model is established. The mechanical characterization is based on uniaxial tensile tests. In order to avoid poor formability at room temperature, the tests were conducted at elevated temperature (200 °C). The uniaxial tensile tests reveal sufficient ductility allowing sheet forming processes at this temperature. The differences in yield stresses and plastic strain ratios (r-values) confirm the anisotropic response of the materials under study. The constitutive model is established so that the characteristic mechanical features observed in magnesium alloys such as anisotropy and compression-tension asymmetry can be accommodated. This model is thermodynamically consistent, incorporates rate effect, is formulated based on finite strain plasticity theory and is applicable in sheet forming simulations of magnesium alloys. More precisely, a model originally proposed by Cazacu and Barlat in 2004 and later modified to account for the evolution of the material anisotropy is rewritten in a thermodynamically consistent framework. The calibrated constitutive model is shown to capture the characteristic mechanical features observed in magnesium alloy sheets.

  9. Tribo-systems for Sheet Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels

    2009-01-01

    The present paper gives an overview of more than 10 years work by the author’s research group through participation in national as well as international framework programmes on developing and testing environmentally friendly lubricants and tool materials and coatings inhibiting galling. Partners ......’s research group has especially been involved in the development of a system of tribo-tests for sheet metal forming and in testing and modelling of friction and limits of lubrication of new, environmentally friendly lubricants and tool materials....

  10. Cold Forming of Ni-Ti Shape Memory Alloy Sheet

    Science.gov (United States)

    Fann, Kaung-Jau; Su, Jhe-Yung

    2018-03-01

    Ni-Ti shape memory alloy has two specific properties, superelasiticity and shape memory effect, and thus is widely applied in diverse industries. To extend its further application, this study attempts to investigate the feasibility of cold forming its sheet blank especially under a bi-axial tensile stress state. Not only experiments but also a Finite Element Analysis (FEA) with DEFORM 2D was conducted in this study. The material data for FEA was accomplished by the tensile test. An Erichsen-like cupping test was performed as well to determine the process parameter for experiment setup. As a result of the study, the Ni-Ti shape memory alloy sheet has a low formability for cold forming and shows a relative large springback after releasing the forming load.

  11. Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes.

    Science.gov (United States)

    Zhou, Du; Yuan, Xi; Gao, Haoxiang; Wang, Ailing; Liu, Jun; El Fakir, Omer; Politis, Denis J; Wang, Liliang; Lin, Jianguo

    2016-12-13

    The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques. This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

  12. Formability of porous tantalum sheet-metal

    International Nuclear Information System (INIS)

    Nebosky, Paul S; Schmid, Steven R; Pasang, Timotius

    2009-01-01

    Over the past ten years, a novel cellular solid, Trabecular Metal T M , has been developed for use in the orthopaedics industry as an ingrowth scaffold. Manufactured using chemical vapour deposition (CVD) on top of a graphite foam substrate, this material has a regular matrix of interconnecting pores, high strength, and high porosity. Manufacturing difficulties encourage the application of bending, stamping and forming technologies to increase CVD reactor throughput and reduce material wastes. In this study, the bending and forming behaviour of Trabecular Metal T M was evaluated using a novel camera-based system for measuring surface strains, since the conventional approach of printing or etching gridded patterns was not feasible. A forming limit diagram was obtained using specially fabricated 1.65 mm thick sheets. A springback coefficient was measured and modeled using effective hexagonal cell arrangements.

  13. Stiffness management of sheet metal parts using laser metal deposition

    Science.gov (United States)

    Bambach, Markus; Sviridov, Alexander; Weisheit, Andreas

    2017-10-01

    Tailored blanks are established solutions for the production of load-adapted sheet metal components. In the course of the individualization of production, such semi-finished products are gaining importance. In addition to tailored welded blanks and tailored rolled blanks, patchwork blanks have been developed which allow a local increase in sheet thickness by welding, gluing or soldering patches onto sheet metal blanks. Patchwork blanks, however, have several limitations, on the one hand, the limited freedom of design in the production of patchwork blanks and, on the other hand, the fact that there is no optimum material bonding with the substrate. The increasing production of derivative and special vehicles on the basis of standard vehicles, prototype production and the functionalization of components require solutions with which semi-finished products and sheet metal components can be provided flexibly with local thickenings or functional elements with a firm metallurgical bond to the substrate. An alternative to tailored and patchwork blanks is, therefore, a free-form reinforcement applied by additive manufacturing via laser metal deposition (LMD). By combining metal forming and additive manufacturing, stiffness can be adapted to the loads based on standard components in a material-efficient manner and without the need to redesign the forming tools. This paper details a study of the potential of stiffness management by LMD using a demonstrator part. Sizing optimization is performed and part distortion is taken into account to find an optimal design for the cladding. A maximum stiffness increase of 167% is feasible with only 4.7% additional mass. Avoiding part distortion leads to a pareto-optimal design which achieves 95% more stiffness with 6% added mass.

  14. Filler metal alloy for welding cast nickel aluminide alloys

    Science.gov (United States)

    Santella, M.L.; Sikka, V.K.

    1998-03-10

    A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

  15. Characterization of zinc alloy by sheet bulging test with analytical models and digital image correlation

    Science.gov (United States)

    Vitu, L.; Laforge, N.; Malécot, P.; Boudeau, N.; Manov, S.; Milesi, M.

    2018-05-01

    Zinc alloys are used in a wide range of application such as electronics, automotive and building construction. Their various shapes are generally obtained by metal forming operation such as stamping. Therefore, it is important to characterize the material with adequate characterization tests. Sheet Bulging Test (SBT) is well recognized in the metal forming community. Different theoretical models of the literature for the evaluation of thickness and radius of the deformed sheet in SBT have been studied in order to get the hardening curve of different materials. These theoretical models present the advantage that the experimental procedure is very simple. But Koç et al. showed their limitation, since the combination of thickness and radius evaluations depend on the material. As Zinc alloys are strongly anisotropic with a special crystalline structure, a procedure is adopted for characterizing the hardening curve of a Zinc alloy. The anisotropy is first studied with tensile test, and SBT with elliptical dies is also investigated. Parallel to this, Digital Image Correlation (DIC) measures are carried out. The results obtained from theoretical models and DIC measures are compared. Measures done on post-mortem specimens complete the comparisons. Finally, DIC measures give better results and the resulting hardening curve of the studied zinc alloy is provided.

  16. Stretch strength of Al-Li alloy sheet

    Energy Technology Data Exchange (ETDEWEB)

    Sato, K.; Sawa, Y.; Yokoyama, T.; Fujimoto, S. [Science Univ. of Tokyo (Japan). Dept. of Mech. Eng.; Sakamoto, T. [Kobe Steel Works, Tokyo (Japan)

    1998-07-01

    Stretch test on Al-Li alloy sheet was carried out in stretch rate of 0.01 to 0.2 mm/sec. The limiting stretch depth was measured in various conditions and the following results were obtained. (1) Stretch rate does not affect the limiting stretch depth of Al-Li alloy. (2) The limiting stretch depth is increased with increase of the profile radius. (3) Strain hardening exponent(n-value) and r-value of Lankford do not affect the limiting stretch depth. (4) Rapture pattern in stretch test of Al is {alpha} type rapture and that of Al-Li alloy is straight line type rapture. (orig.) 4 refs.

  17. Numerical modelling in friction lap joining of aluminium alloy and carbon-fiber-reinforced-plastic sheets

    Science.gov (United States)

    Das, A.; Bang, H. S.; Bang, H. S.

    2018-05-01

    Multi-material combinations of aluminium alloy and carbon-fiber-reinforced-plastics (CFRP) have gained attention in automotive and aerospace industries to enhance fuel efficiency and strength-to-weight ratio of components. Various limitations of laser beam welding, adhesive bonding and mechanical fasteners make these processes inefficient to join metal and CFRP sheets. Friction lap joining is an alternative choice for the same. Comprehensive studies in friction lap joining of aluminium to CFRP sheets are essential and scare in the literature. The present work reports a combined theoretical and experimental study in joining of AA5052 and CFRP sheets using friction lap joining process. A three-dimensional finite element based heat transfer model is developed to compute the temperature fields and thermal cycles. The computed results are validated extensively with the corresponding experimentally measured results.

  18. Liquid metal corrosion considerations in alloy development

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.

    1984-01-01

    Liquid metal corrosion can be an important consideration in developing alloys for fusion and fast breeder reactors and other applications. Because of the many different forms of liquid metal corrosion (dissolution, alloying, carbon transfer, etc.), alloy optimization based on corrosion resistance depends on a number of factors such as the application temperatures, the particular liquid metal, and the level and nature of impurities in the liquid and solid metals. The present paper reviews the various forms of corrosion by lithium, lead, and sodium and indicates how such corrosion reactions can influence the alloy development process

  19. Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal

    Directory of Open Access Journals (Sweden)

    A. Nikitin

    2017-01-01

    Full Text Available Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT® in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals.

  20. An introduction to surface alloying of metals

    CERN Document Server

    Hosmani, Santosh S; Goyal, Rajendra Kumar

    2014-01-01

    An Introduction to Surface Alloying of Metals aims to serve as a primer to the basic aspects of surface alloying of metals. The book serves to elucidate fundamentals of surface modification and their engineering applications. The book starts with basics of surface alloying and goes on to cover key surface alloying methods, such as carburizing, nitriding, chromizing, duplex treatment, and the characterization of surface layers. The book will prove useful to students at both the undergraduate and graduate levels, as also to researchers and practitioners looking for a quick introduction to surface alloying.

  1. Explosive force of primacord grid forms large sheet metal parts

    Science.gov (United States)

    1966-01-01

    Primacord which is woven through fish netting in a grid pattern is used for explosive forming of large sheet metal parts. The explosive force generated by the primacord detonation is uniformly distributed over the entire surface of the sheet metal workpiece.

  2. Formability analysis of sheet metals by cruciform testing

    Science.gov (United States)

    Güler, B.; Alkan, K.; Efe, M.

    2017-09-01

    Cruciform biaxial tests are increasingly becoming popular for testing the formability of sheet metals as they achieve frictionless, in-plane, multi-axial stress states with a single sample geometry. However, premature fracture of the samples during testing prevents large strain deformation necessary for the formability analysis. In this work, we introduce a miniature cruciform sample design (few mm test region) and a test setup to achieve centre fracture and large uniform strains. With its excellent surface finish and optimized geometry, the sample deforms with diagonal strain bands intersecting at the test region. These bands prevent local necking and concentrate the strains at the sample centre. Imaging and strain analysis during testing confirm the uniform strain distributions and the centre fracture are possible for various strain paths ranging from plane-strain to equibiaxial tension. Moreover, the sample deforms without deviating from the predetermined strain ratio at all test conditions, allowing formability analysis under large strains. We demonstrate these features of the cruciform test for three sample materials: Aluminium 6061-T6 alloy, DC-04 steel and Magnesium AZ31 alloy, and investigate their formability at both the millimetre scale and the microstructure scale.

  3. Metals and alloys for Arctic use

    Energy Technology Data Exchange (ETDEWEB)

    Thurston, R C.A. [ed.

    1976-01-01

    The northlands of Canada can be regarded as a vast, but not inexhaustible, storehouse of mineral, oil and gas reserves. At the same time, this area is a delicate ecology that can easily be irreversibly damaged. It is vitally important that industrial activity associated with these reserves should proceed with a maximum of safety and a minimum risk of pollution, with optimum utilization of materials. In order to facilitate these objectives, appropriate technical information is required on the characteristics of available engineering metals and alloys with respect to service in Arctic and sub-Arctic environments. The body of this monograph consists of data sheets on irons and steels, aluminum, magnesium, titanium, copper, lead, tin, nickel and zinc alloys. Background information is given on the general characteristics of the various alloy systems, their advantages and disadvantages, on typical engineering applications, and on potential problem areas. Human difficulties associated with low temperature will exert some measure of control over the available construction periods, and may influence the techniques and materials used. A second important factor is the general inaccessibility of the northern regions. The designer must pay attention to reliability, ease of maintenance and ease of transportation. A premium is placed on the lightness and compactness of equipment, and may emphasize low density or high strength materials. Easy installation and removal is advantageous, due to the temporary nature of many operations, and the limited local labor available. Pollution avoidance must be considered, and aspects such as scrap recovery value and rate of degradation are important. In cases with little recovery value, corrosion resistance may be a disadvantage rather than an advantage. 238 refs., 7 figs., 26 tabs.

  4. 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.

  5. Development of Metallic Sensory Alloys

    Science.gov (United States)

    Wallace Terryl A.; Newman, John A.; Horne, Michael R.; Messick, Peter L.

    2010-01-01

    Existing nondestructive evaluation (NDE) technologies are inherently limited by the physical response of the structural material being inspected and are therefore not generally effective at the identification of small discontinuities, making the detection of incipient damage extremely difficult. One innovative solution to this problem is to enhance or complement the NDE signature of structural materials to dramatically improve the ability of existing NDE tools to detect damage. To address this need, a multifunctional metallic material has been developed that can be used in structural applications. The material is processed to contain second phase sensory particles that significantly improve the NDE response, enhancing the ability of conventional NDE techniques to detect incipient damage both during and after flight. Ferromagnetic shape-memory alloys (FSMAs) are an ideal material for these sensory particles as they undergo a uniform and repeatable change in both magnetic properties and crystallographic structure (martensitic transformation) when subjected to strain and/or temperature changes which can be detected using conventional NDE techniques. In this study, the use of a ferromagnetic shape memory alloy (FSMA) as the sensory particles was investigated.

  6. Vibrational entropies in metallic alloys

    Science.gov (United States)

    Ozolins, Vidvuds; Asta, Mark; Wolverton, Christopher

    2000-03-01

    Recently, it has been recognized that vibrational entropy can have significant effects on the phase stability of metallic alloys. Using density functional linear response calculations and molecular dynamics simulations we study three representative cases: (i) phase diagram of Al-rich Al-Sc alloys, (ii) stability of precipitate phases in CuAl_2, and (iii) phonon dynamics in bcc Zr. We find large vibrational entropy effects in all cases. In the Al-Sc system, vibrations increase the solid solubility of Sc in Al by decreasing the stability of the L12 (Al_3Sc) phase. This leads to a nearly ten-fold increase in the solid solubility of Sc in Al at T=800 K. In the Cu-Al system, our calculations predict that the tetragonal Laves phase of CuAl2 has 0.35 kB/atom higher vibrational entropy than the cubic CaF_2-type phase (the latter is predicted to be the T=0 K ground state of CuAl_2). This entropy difference causes a structural transformation in CuAl2 precipitates from the fluorite to the tetragonal Laves phase around T=500 K. Finally, we analyze the highly unusual dynamics of anharmonically stabilized bcc Zr, finding large diffuse-scattering intensity streaks between the bcc Bragg peaks.

  7. Method and apparatus for determining weldability of thin sheet metal

    Science.gov (United States)

    Goodwin, Gene M.; Hudson, Joseph D.

    1988-01-01

    A fixture is provided for testing thin sheet metal specimens to evaluate hot-cracking sensitivity for determining metal weldability on a heat-to-heat basis or through varying welding parameters. A test specimen is stressed in a first direction with a load selectively adjustable over a wide range and then a weldment is passed along over the specimen in a direction transverse to the direction of strain to evaluate the hot-cracking characteristics of the sheet metal which are indicative of the weldability of the metal. The fixture provides evaluations of hot-cracking sensitivity for determining metal weldability in a highly reproducible manner with minimum human error.

  8. Weldability of molybdenum and its alloy sheet, 1

    International Nuclear Information System (INIS)

    Matsuda, Fukuhisa; Ushio, Masao; Nakata, Kazuhiro; Edo, Yoshiaki

    1979-01-01

    Basic weldability of electron-beam melted pure molybdenum has been examined in electron-beam welding in high vacuum and GTA welding in pure and air mixed argon atmospheres by paying attention to weld defects such as hot cracking and porosity in weld metal and also mechanical properties of welded joint in comparison with conventional TZM alloys. The main conclusions obtained were as follows; (1) The weld metals of electron-beam melted pure molybdenum with electron-beam and GTA weldings in pure and air mixed argon atmosphere up to about 1% were almost porosity free. However, large amount of oxygen content of 200 ppm in powder-metallurgy TZM alloy made very porous weld bead in electron-beam welding in high vacuum. Therefore, oxygen content in base metal should be lowered to the minimum, that is, less than 10 ppm, especially in electron-beam welding in high vacuum. (2) Hot cracking occurred in the weld metal of GTA welding when air content in argon atmosphere exceeded about 0.6% for electron-beam melted pure molybdenum and powder metallurgy TZM alloy. In less than 0.26% air, no hot cracking were observed in this experiment. Moreover, in electron-beam welding, no hot cracking was observed in weld metals for both materials. In order to prevent the formation of hot cracking, the purity of welding atmosphere should be kept as high as possible. (3) Joint efficiency of the welded joint of electron-beam melted pure molybdenum with electron-beam welding was 50 to 60% to base metal at room temperature and 500 0 C and almost 100% at 1000 0 C. Those of GTA welds in pure and 0.13% air mixed argon atmospheres were fairly lower than those in electron-beam welding for each testing temperature. (author)

  9. Influence of inorganic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.

    2009-01-01

    Surface contaminants as a result of thermo-mechanical processing of magnesium alloys, e.g. sheet rolling, can have a negative effect on the corrosion resistance of magnesium alloys. Especially contaminants such as Fe, Ni and Cu, left on the surface of magnesium alloys result in the formation...... of micro-galvanic couples and can therefore increase corrosion attack on these alloys. Due to this influence they should be removed to obtain good corrosion resistance. In this study, the effect of inorganic acid pickling on the corrosion behaviour of a commercial AZ31 magnesium alloy sheet...... cleaning the AZ31 sheet. However, to obtain reasonable corrosion resistance at least 5 mu m of the surface of AZ31 magnesium alloy sheet have to be removed....

  10. Zr-based conversion layer on Zn-Al-Mg alloy coated steel sheets: insights into the formation mechanism

    International Nuclear Information System (INIS)

    Lostak, Thomas; Maljusch, Artjom; Klink, Björn; Krebs, Stefan; Kimpel, Matthias; Flock, Jörg; Schulz, Stephan; Schuhmann, Wolfgang

    2014-01-01

    Zr-based conversion layers are considered as environmentally friendly alternatives replacing trication phosphatation in the automotive industry. Based on excellent electronic barrier properties they provide an effective corrosion protection of the metallic substrate. In this work, thin protective layers were grown on novel Zn-Al-Mg alloy coated steel sheets by increasing the local pH-value at the sample surface leading to deposition of a Zr-based conversion layer. For this purpose Zn-Al-Mg alloy (ZM) coated steel sheets were treated in an aqueous model conversion solution containing well-defined amounts of hexafluorozirconic acid (H 2 ZrF 6 ) and characterized after different immersion times with SKPFM and field emission SEM (FE-SEM)/EDX techniques. A deposition mechanism of Zr-based conversion coatings on microstructural heterogeneous Zn-Al-Mg alloy surfaces was proposed

  11. Working with Design: A Package for Sheet Metal

    Science.gov (United States)

    Fiebich, Paul D.

    1974-01-01

    The author describes a design approach used to study sheet metal layout in junior high and high school mechanical drafting courses. Students observe packaging in stores, study package construction, and design and produce their own packages. (EA)

  12. Limit State of Trapezoidal Metal Sheets Exposed to Concentrated Load

    OpenAIRE

    Kateřina Jurdová

    2013-01-01

    In most industrial compounds are used trapezoidal metal sheets like a roof decks. These trapezoidal metal sheets are exposed by concentrated loads, usually by service loads arise from installation of air distribution, sanitary distribution, sprinkler system or wiring installation. In objects of public facilities (like shopping centre, tennis hall, etc.) they can be used for hanging advertising posters etc, too. These systems work as “building kit”. These anchoring systems are represented by c...

  13. 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

  14. Laser Indirect Shock Welding of Fine Wire to Metal Sheet.

    Science.gov (United States)

    Wang, Xiao; Huang, Tao; Luo, Yapeng; Liu, Huixia

    2017-09-12

    The purpose of this paper is to present an advanced method for welding fine wire to metal sheet, namely laser indirect shock welding (LISW). This process uses silica gel as driver sheet to accelerate the metal sheet toward the wire to obtain metallurgical bonding. A series of experiments were implemented to validate the welding ability of Al sheet/Cu wire and Al sheet/Ag wire. It was found that the use of a driver sheet can maintain high surface quality of the metal sheet. With the increase of laser pulse energy, the bonding area of the sheet/wire increased and the welding interfaces were nearly flat. Energy dispersive spectroscopy (EDS) results show that the intermetallic phases were absent and a short element diffusion layer which would limit the formation of the intermetallic phases emerging at the welding interface. A tensile shear test was used to measure the mechanical strength of the welding joints. The influence of laser pulse energy on the tensile failure modes was investigated, and two failure modes, including interfacial failure and failure through the wire, were observed. The nanoindentation test results indicate that as the distance to the welding interface decreased, the microhardness increased due to the plastic deformation becoming more violent.

  15. Noble metal alloys for metal-ceramic restorations.

    Science.gov (United States)

    Anusavice, K J

    1985-10-01

    A review of the comparative characteristics and properties of noble metal alloys used for metal-ceramic restorations has been presented. Selection of an alloy for one's practice should be based on long-term clinical data, physical properties, esthetic potential, and laboratory data on metal-ceramic bond strength and thermal compatibility with commercial dental porcelains. Although gold-based alloys, such as the Au-Pt-Pd, Au-Pd-Ag, and Au-Pd classes, may appear to be costly compared with the palladium-based alloys, they have clearly established their clinical integrity and acceptability over an extended period of time. Other than the relatively low sag resistance of the high gold-low silver content alloys and the potential thermal incompatibility with some commercial porcelain products, few clinical failures have been observed. The palladium-based alloys are less costly than the gold-based alloys. Palladium-silver alloys require extra precautions to minimize porcelain discoloration. Palladium-copper and palladium-cobalt alloys may also cause porcelain discoloration, as copper and cobalt are used as colorants in glasses. The palladium-cobalt alloys are least susceptible to high-temperature creep compared with all classes of noble metals. Nevertheless, insufficient clinical data exist to advocate the general use of the palladium-copper and palladium-cobalt alloys at the present time. One should base the selection and use of these alloys in part on their ability to meet the requirements of the ADA Acceptance Program. A list of acceptable or provisionally acceptable alloys is available from the American Dental Association and is published annually in the Journal of the American Dental Association. Dentists have the legal and ethical responsibility for selection of alloys used for cast restorations. This responsibility should not be delegated to the dental laboratory technician. It is advisable to discuss the criteria for selection of an alloy with the technician and the

  16. Heat transfer modeling in asymmetrical sheet rolling of aluminium alloys with ultra high shear strain

    Directory of Open Access Journals (Sweden)

    Pesin Alexander

    2016-01-01

    Full Text Available Asymmetrical sheet rolling is a method of severe plastic deformation (SPD for production of aluminium alloys with UFG structure. Prediction of sheet temperature during SPD is important. The temperature of sheet is changed due to the conversion of mechanical work into heat through sliding on contact surfaces and high shear strain. Paper presents the results of FEM simulation of the effect of contact friction, rolling speed and rolls speed ratio on the heating of aluminium sheets during asymmetrical rolling.

  17. 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.

  18. Improving resistance welding of aluminum sheets by addition of metal powder

    DEFF Research Database (Denmark)

    Al Naimi, Ihsan K.; Al-Saadi, Moneer H.; Daws, Kasim M.

    2015-01-01

    . The improvement obtained is shown to be due to the development of a secondary bond in the joint beside the weld nugget increasing the total weld area. The application of powder additive is especially feasible, when using welding machines with insufficient current capacity for producing the required nugget size......In order to ensure good quality joints between aluminum sheets by resistance spot welding, a new approach involving the addition of metal powder to the faying surfaces before resistance heating is proposed. Three different metal powders (pure aluminum and two powders corresponding to the alloys AA....... In such cases the best results are obtained with pure aluminum powder....

  19. The elasto plastic fracture mechanics in ductile metal sheets

    International Nuclear Information System (INIS)

    Khan, M.A.; Malik, M.N.; Naeem, A.; Haq, A.U.; Atkins, A.G.

    1999-01-01

    The crack initiation of propagation in ductile metal sheets are caused by various micro and macro changes taking place due to material properties, applied loads, shape of the indenter (tool geometry) and the environmental conditions. These microstructural failures are directly related to the atomic bonding, crystal lattices, grain boundary status, material flaws in matrix, inhomogeneities and anisotropy in the metal sheets. The Elasto-Plastic related energy based equations are applied to these Rigid Plastic materials to determine the onset of fracture in metal forming. The combined stress and strain criterion of a critical plastic work per unit volume is no more considered as a universal ductile fracture criterion, rather a critical plastic work per unit volume dependence on all sort of stresses (hydrostatic) are the required features for the sheet metal failure (fracture). In this present study, crack initiation and propagation are related empirically with fracture toughness and the application of the theory in industry to save energy. (author)

  20. Single sheet metal oxides and hydroxides

    DEFF Research Database (Denmark)

    Huang, Lizhi

    The synthesis of layered double hydroxides (LDHs) provides a relatively easy and traditional way to build versatile chemical compounds with a rough control of the bulk structure. The delamination of LDHs to form their single host layers (2D nanosheets) and the capability to reassemble them offer......) Delamination of the LDHs structure (oxGRC12) with the formation of single sheet iron (hydr)oxide (SSI). (3) Assembly of the new 2D nanosheets layer by layer to achieve desired functionalities....

  1. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

    Full Text Available Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM alloys. Cr and Mo are particularly interesting alloying elements to produce stable highstrength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO2 laser. This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloys, over the last years.

    En el presente trabajo se estudia la aleación superficial mediante láser de aluminio con metales de transición. El cromo y el molibdeno son particularmente interesantes porque producen aleaciones de alta resistencia y por el bajo coeficiente de difusión y solución sólida en aluminio. Para producir estas aleaciones se ha seguido un procedimiento desarrollado en dos partes. En primer lugar, el material se alea usando una baja velocidad de procesado y en segundo lugar la estructura se modifica mediante un refinamiento posterior. Este procedimiento se ha empleado en la producción de aleaciones Al-Cr, Al-Mo y Al-Nb mediante aleación con láser de CO2 de polvos de Cr, Mo o Nb en aluminio y la aleación 7175. Este trabajo es una revisión del desarrollado en el Instituto Superior Técnico de Lisboa en los últimos años.

  2. Electrochemical Impedance Spectroscopy Of Metal Alloys

    Science.gov (United States)

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  3. Surface energy of metal alloy nanoparticles

    Science.gov (United States)

    Takrori, Fahed M.; Ayyad, Ahmed

    2017-04-01

    The measurement of surface energy of alloy nanoparticles experimentally is still a challenge therefore theoretical work is necessary to estimate its value. In continuation of our previous work on the calculation of the surface energy of pure metallic nanoparticles we have extended our work to calculate the surface energy of different alloy systems, namely, Co-Ni, Au-Cu, Cu-Al, Cu-Mg and Mo-Cs binary alloys. It is shown that the surface energy of metallic binary alloy decreases with decreasing particle size approaching relatively small values at small sizes. When both metals in the alloy obey the Hume-Rothery rules, the difference in the surface energy is small at the macroscopic as well as in the nano-scale. However when the alloy deviated from these rules the difference in surface energy is large in the macroscopic and in the nano scales. Interestingly when solid solution formation is not possible at the macroscopic scale according to the Hume-Rothery rules, it is shown it may form at the nano-scale. To our knowledge these findings here are presented for the first time and is challenging from fundamental as well as technological point of views.

  4. Characteristics of Resistance Spot Welded Ti6Al4V Titanium Alloy Sheets

    Directory of Open Access Journals (Sweden)

    Xinge Zhang

    2017-10-01

    Full Text Available Ti6Al4V titanium alloy is applied extensively in the aviation, aerospace, jet engine, and marine industries owing to its strength-to-weight ratio, excellent high-temperature properties and corrosion resistance. In order to extend the application range, investigations on welding characteristics of Ti6Al4V alloy using more welding methods are required. In the present study, Ti6Al4V alloy sheets were joined using resistance spot welding, and the weld nugget formation, mechanical properties (including tensile strength and hardness, and microstructure features of the resistance spot-welded joints were analyzed and evaluated. The visible indentations on the weld nugget surfaces caused by the electrode force and the surface expulsion were severe due to the high welding current. The weld nugget width at the sheets’ faying surface was mainly affected by the welding current and welding time, and the welded joint height at weld nugget center was chiefly associated with electrode force. The maximum tensile load of welded joint was up to 14.3 kN in the pullout failure mode. The hardness of the weld nugget was the highest because of the coarse acicular α′ structure, and the hardness of the heat-affected zone increased in comparison to the base metal due to the transformation of the β phase to some fine acicular α′ phase.

  5. Warm Hydroforming of Lightweight Metal Sheets

    International Nuclear Information System (INIS)

    Aginagalde, A.; Orus, A.; Esnaola, J. A.; Torca, I.; Galdos, L.; Garcia, C.

    2007-01-01

    Hydroforming is well known in steel applications for automotive industry, where complicated shapes can be get with high strength to weight ratios. Nevertheless, the poor formability of light alloys at room temperature has limited the application of hydroforming technology for aluminum and magnesium parts. Increasing the temperature of these materials allows substantially greater elongation without fracture. Warm forming strategy is applied in conventional processes, such as rolling and forging, in order to get complex shapes, but still rare in hydroforming technology. This is the technical base of this research project: the development of the hydroforming process at warm working temperatures. The main tasks of the initial phases of the research were the material characterization, and the heated fluid and tooling system design and set up for warm hydroforming of lightweight alloys. Once these goals were accomplished the present paper shows the obtained results. The uniaxial tensile deformation of 5754H111, 6082-T6, 6082-O and AZ31B at the temperature range of 25 deg. C - 250 deg. C is presented as the output of the material characterization task. Both the system features and the results obtained for a bulge test geometry carried out with a warm hydroforming system are also presented. The selected alloys show an improvement in formability at the studied temperature range under both uniaxial and biaxial state of stress

  6. 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

  7. Phase stability of transition metals and alloys

    International Nuclear Information System (INIS)

    Hixson, R.S.; Schiferl, D.; Wills, J.M.; Hill, M.A.

    1997-01-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project was focused on resolving unexplained differences in calculated and measured phase transition pressures in transition metals. Part of the approach was to do new, higher accuracy calculations of transmission pressures for group 4B and group 6B metals. Theory indicates that the transition pressures for these baseline metals should change if alloyed with a d-electron donor metal, and calculations done using the Local Density Approximation (LDA) and the Virtual Crystal Approximation (VCA) indicate that this is true. Alloy systems were calculated for Ti, Zr and Hf based alloys with various solute concentrations. The second part of the program was to do new Diamond Anvil Cell (DAC) measurements to experimentally verify calculational results. Alloys were prepared for these systems with grain size suitable for Diamond Anvil Cell experiments. Experiments were done on pure Ti as well as Ti-V and Ti-Ta alloys. Measuring unambiguous transition pressures for these systems proved difficult, but a new technique developed yielded good results

  8. Texture and structure of VT-19 alloy thin sheets and their welded joints

    International Nuclear Information System (INIS)

    Ehgiz, I.V.; Babarehko, A.A.; Khorev, M.A.

    1986-01-01

    The phase content and texture of VT-19 alloys in all zones of welded joints (weld, a heat affected zone a base metal) after different heat treatments and the effect of the latter on mechanical properties of the welded joint are studied. It is characteristic of a 2.5 mm sheet of the VT-19 alloy rolled in the β → α phase transformation temperature range the development of β-phase plane deformation textures with (001), (112), (111) orientations in the rolling plane that compose 56% of the β-phase material volume. In this case a texture of univariant phase transformation of the above β-phase components { 1120 } - { 1122 } - { 1124 }, as well as that of α-phase plane deformation } 1014 } - { 1015 } are formed in the α-phase. Hardening with subsequent ageing of the rolled sheet leads to increasing the fraction of textured material in the β-phase up to 95% with expanding the volume with the (111) orientation, but as a whole the β-phase texture type remains the same. The α-phase texture type corresponds to the univariant β → α phase transformation, the material having the α-phase texture accounts for 70%. In the weld zone the and axes with orientation spreading to 20 deg are the β-phase crystallization axes in the trans verse direction. The textured material accounts for ∼ 70%. The same texture is observed along the normal to the sheet plane. The α-phase texture after hardening and ageing corresponds to the univariant phase transformation of the above-mentionedβ-phase orientations, the material volume with the α-phase texture is ∼80%

  9. Development of Weldable Superplastic Forming Aluminum Alloy Sheet Final Report CRADA No. TC-1086-95

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sun, T. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-11-01

    Numerous applications could exist for superplastic formable, weldable aluminum alloys in the automotive, aerospace, architectural, and construction industries. In this project, LLNL and Kaiser worked with the Institute for Metals Superplasticity Problems to develop and evaluate weldable superplastic alloys.

  10. 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.

  11. 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

  12. A theoretical study on pure bending of hexagonal close-packed metal sheet

    Science.gov (United States)

    Mehrabi, Hamed; Yang, Chunhui

    2018-05-01

    Hexagonal close-packed (HCP) metals have quite different mechanical behaviours in comparison to conventional cubic metals such as steels and aluminum alloys [1, 2]. They exhibit a significant tension-compression asymmetry in initial yielding and subsequent plastic hardening. The reason for this unique behaviour can be attributed to their limited symmetric crystal structure, which leads to twining deformation [3-5]. This unique behaviour strongly influences sheet metal forming of such metals, especially for roll forming, in which the bending is dominant. Hence, it is crucial to represent constitutive relations of HCP metals for accurate estimation of bending moment-curvature behaviours. In this paper, an analytical model for asymmetric elastoplastic pure bending with an application of Cazacu-Barlat asymmetric yield function [6] is presented. This yield function considers the asymmetrical tension-compression behaviour of HCP metals by using second and third invariants of the stress deviator tensor and a specified constant, which can be expressed in terms of uniaxial yield stresses in tension and compression. As a case study, the analytical model is applied to predict the moment-curvature behaviours of AZ31B magnesium alloy sheets under uniaxial loading condition. Furthermore, the analytical model is implemented as a user-defined material through the UMAT interface in Abaqus [7, 8] for conducting pure bending simulations. The results show that the analytical model can reasonably capture the asymmetric tension-compression behaviour of the magnesium alloy. The predicted moment-curvature behaviour has good agreement with the experimental results. Furthermore, numerical results show a better accuracy by the application of the Cazacu-Barlat yield function than those using the von-Mises yield function, which are more conservative than analytical results.

  13. An Improvement of the Anisotropy and Formability Predictions of Aluminum Alloy Sheets

    Science.gov (United States)

    Banabic, D.; Comsa, D. S.; Jurco, P.; Wagner, S.; Vos, M.

    2004-06-01

    The paper presents an yield criterion for orthotropic sheet metals and its implementation in a theoretical model in order to calculate the Forming Limit Curves. The proposed yield criterion has been validated for two aluminum alloys: AA3103-0 and AA5182-0, respectively. The biaxial tensile test of cross specimens has been used for the determination of the experimental yield locus. The new yield criterion has been implemented in the Marciniak-Kuczynski model for the calculus of limit strains. The calculated Forming Limit Curves have been compared with the experimental ones, determined by frictionless test: bulge test, plane strain test and uniaxial tensile test. The predicted Forming Limit Curves using the new yield criterion are in good agreement with the experimental ones.

  14. Theoretical studies of metallic alloys

    International Nuclear Information System (INIS)

    Faulkner, J.S.; Wille, L.T.

    1991-07-01

    A new method to predict and understand the structure and phase stability of solid-solution alloys from a knowledge only of the atomic numbers of the constituent atoms is being developed. The coherent potential approximation will be used to obtain the electronic contribution to the energy and the Monte Carlo method of statistical mechanics will be used for the thermodynamic part of the calculation. An improved coherent potential approximation will be developed by combining the standard approach with the quadratic KKR (QKKR) band theory method. This will make it easier to predict the properties of alloys from first principles. The QKKR method will be developed further

  15. TEM of nanostructured metals and alloys

    International Nuclear Information System (INIS)

    Karnthaler, H.P.; Waitz, T.; Rentenberger, C.; Mingler, B.

    2004-01-01

    Nanostructuring has been used to improve the mechanical properties of bulk metals and alloys. Transmission electron microscopy (TEM) including atomic resolution is therefore appropriate to study these nanostructures; four examples are given as follows. (1) The early stages of precipitation at RT were investigated in an Al-Mg-Si alloy. By high resolution TEM it is shown that the precipitates lie on (0 0 1) planes having an ordered structure. (2) In Co alloys the fronts of martensitic phase transformations were analysed showing that the transformation strains are very small thus causing no surface relief. (3) Re-ordering and recrystallization were studied by in situ TEM of an Ni 3 Al alloy being nanocrystalline after severe plastic deformation. (4) In NiTi severe plastic deformation is leading to the formation of amorphous shear bands. From the TEM analysis it is concluded that the amorphization is caused by plastic shear instability starting in the shear bands

  16. Observations on Mode I ductile tearing in sheet metals

    DEFF Research Database (Denmark)

    El-Naaman, Salim Abdallah; Nielsen, Kim Lau

    2013-01-01

    Cracked ductile sheet metals, subject to Mode I tearing, have been observed to display a variety of fracture surface morphologies depending on the material properties, and a range of studies on the fracture surface appearance have been published in the literature. Whereas classical fractures...

  17. A Collaborative Design Curriculum for Reviving Sheet Metal Handicraft

    Science.gov (United States)

    Chan, Patrick K. C.

    2015-01-01

    Galvanised sheet metal was a popular and important material for producing handmade home utensils in Hong Kong from the 1930s onwards. It was gradually replaced by new materials like stainless steel and plastic because similar goods made with these are cheaper, more standardised, more durable and of much better quality. The handicrafts behind sheet…

  18. Testing of environmentally friendly lubricants for sheet metal forming

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

    2005-01-01

    the authors have especially been involved in the development of a system of test methods for sheet metal forming and in testing of friction and limits of lubrication of new, environmentally friendly lubricants. An overview of the developed tests is presented together with selected results....

  19. Tooling solutions for sheet metal forming and punching of lean duplex stainless steel

    DEFF Research Database (Denmark)

    Wadman, Boel; Madsen, Erik; Bay, Niels

    2012-01-01

    .4509 and lean duplex EN1.4162 in a production designed for austenitic stainless steels, such as EN1.4301 and 1.4401. The result is a guideline that summarizes how stainless material properties may affect tool degradation, and suggests tool solutions for reduced production disturbances and tool maintenance cost.......For producers of advanced stainless components the choice of stainless material influences not only the product properties, but also the tooling solution for sheet metal stamping. This work describes how forming and punching tools will be affected when introducing the stainless alloys ferritic EN1...

  20. Fatigue Characteristics of Selected Light Metal Alloys

    Directory of Open Access Journals (Sweden)

    Cieśla M.

    2016-03-01

    Full Text Available The paper addresses results of fatigue testing of light metal alloys used in the automotive as well as aerospace and aviation industries, among others. The material subject to testing comprised hot-worked rods made of the AZ31 alloy, the Ti-6Al-4V two-phase titanium alloy and the 2017A (T451 aluminium alloy. Both low- and high-cycle fatigue tests were conducted at room temperature on the cycle asymmetry ratio of R=-1. The low-cycle fatigue tests were performed using the MTS-810 machine on two levels of total strain, i.e.Δεc= 1.0% and 1.2%. The high-cycle fatigue tests, on the other hand, were performed using a machine from VEB Werkstoffprufmaschinen-Leipzig under conditions of rotary bending. Based on the results thus obtained, one could develop fatigue life characteristics of the materials examined (expressed as the number of cycles until failure of sample Nf as well as characteristics of cyclic material strain σa=f(N under the conditions of low-cycle fatigue testing. The Ti-6Al-4V titanium alloy was found to be characterised by the highest value of fatigue life Nf, both in lowand high-cycle tests. The lowest fatigue life, on the other hand, was established for the aluminium alloys examined. Under the high-cycle fatigue tests, the life of the 2017A aluminium and the AZ31 magnesium alloy studied was determined by the value of stress amplitude σa. With the stress exceeding 150 MPa, it was the aluminium alloy which displayed higher fatigue life, whereas the magnesium alloy proved better on lower stress.

  1. Joining of Aluminium Alloy Sheets by Rectangular Mechanical Clinching

    International Nuclear Information System (INIS)

    Abe, Y.; Mori, K.; Kato, T.

    2011-01-01

    A mechanical clinching has the advantage of low running costs. However, the joint strength is not high. To improve the maximum load of the joined sheets by a mechanical clinching, square and rectangular mechanical clinching were introduced. In the mechanical clinching, the two sheets are mechanically joined by forming an interlock between the lower and upper sheets by the punch and die. The joined length with the interlock was increased by the rectangular punch and die. The deforming behaviours of the sheets in the mechanical clinching were investigated, and then the interlock in the sheets had distribution in the circumference of the projection. Although the interlocks were formed in both projection side and diagonal, the interlock in the diagonal was smaller because of the long contact length between the lower sheet and the die cavity surface. The maximum load of the joined sheets by the rectangular mechanical clinching was two times larger than the load by the round mechanical clinching.

  2. 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.

  3. Process Simulation of Aluminium Sheet Metal Deep Drawing at Elevated Temperatures

    International Nuclear Information System (INIS)

    Winklhofer, Johannes; Trattnig, Gernot; Lind, Christoph; Sommitsch, Christof; Feuerhuber, Hannes

    2010-01-01

    Lightweight design is essential for an economic and environmentally friendly vehicle. Aluminium sheet metal is well known for its ability to improve the strength to weight ratio of lightweight structures. One disadvantage of aluminium is that it is less formable than steel. Therefore complex part geometries can only be realized by expensive multi-step production processes. One method for overcoming this disadvantage is deep drawing at elevated temperatures. In this way the formability of aluminium sheet metal can be improved significantly, and the number of necessary production steps can thereby be reduced. This paper introduces deep drawing of aluminium sheet metal at elevated temperatures, a corresponding simulation method, a characteristic process and its optimization. The temperature and strain rate dependent material properties of a 5xxx series alloy and their modelling are discussed. A three dimensional thermomechanically coupled finite element deep drawing simulation model and its validation are presented. Based on the validated simulation model an optimised process strategy regarding formability, time and cost is introduced.

  4. Forming Limits in Sheet Metal Forming for Non-Proportional Loading Conditions - Experimental and Theoretical Approach

    International Nuclear Information System (INIS)

    Ofenheimer, Aldo; Buchmayr, Bruno; Kolleck, Ralf; Merklein, Marion

    2005-01-01

    The influence of strain paths (loading history) on material formability is well known in sheet forming processes. Sophisticated experimental methods are used to determine the entire shape of strain paths of forming limits for aluminum AA6016-T4 alloy. Forming limits for sheet metal in as-received condition as well as for different pre-deformation are presented. A theoretical approach based on Arrieux's intrinsic Forming Limit Stress Curve (FLSC) concept is employed to numerically predict the influence of loading history on forming severity. The detailed experimental strain paths are used in the theoretical study instead of any linear or bilinear simplified loading histories to demonstrate the predictive quality of forming limits in the state of stress

  5. Overlay metallic-cermet alloy coating systems

    International Nuclear Information System (INIS)

    Gedwill, M.A.; Glasgow, T.K.; Levine, S.R.

    1982-01-01

    A substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use is coated with a base coating of an oxide dispersed, metallic alloy (cermet). A top coating of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then deposited on the base coating. A heat treatment is used to improve the bonding. The base coating serves as an inhibitor to interdiffusion between the protective top coating and the substrate. Otherwise, the protective top coating would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures

  6. Overlay metallic-cermet alloy coating systems

    Science.gov (United States)

    Gedwill, M. A.; Levine, S. R.; Glasgow, T. K. (Inventor)

    1984-01-01

    A substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use is coated with a base coating of an oxide dispersed, metallic alloy (cermet). A top coating of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then deposited on the base coating. A heat treatment is used to improve the bonding. The base coating serves as an inhibitor to interdiffusion between the protective top coating and the substrate. Otherwise, the protective top coating would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures.

  7. Thermal expansion: Metallic elements and alloys. [Handbook

    Science.gov (United States)

    Touloukian, Y. S.; Kirby, R. K.; Taylor, R. E.; Desai, P. D.

    1975-01-01

    The introductory sections of the work are devoted to the theory of thermal expansion of solids and to methods for the measurement of the linear thermal expansion of solids (X-ray methods, high speed methods, interferometry, push-rod dilatometry, etc.). The bulk of the work is devoted to numerical data on the thermal linear expansion of all the metallic elements, a large number of intermetallics, and a large number of binary alloy systems and multiple alloy systems. A comprehensive bibliography is provided along with an index to the materials examined.

  8. Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

    International Nuclear Information System (INIS)

    Braun, R.; Dalle Donne, C.; Staniek, G.

    2000-01-01

    Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β '' (Mg 2 Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

  9. Stable carbides in transition metal alloys

    International Nuclear Information System (INIS)

    Piotrkowski, R.

    1991-01-01

    In the present work different techniques were employed for the identification of stable carbides in two sets of transition metal alloys of wide technological application: a set of three high alloy M2 type steels in which W and/or Mo were total or partially replaced by Nb, and a Zr-2.5 Nb alloy. The M2 steel is a high speed steel worldwide used and the Zr-2.5 Nb alloy is the base material for the pressure tubes in the CANDU type nuclear reactors. The stability of carbide was studied in the frame of Goldschmidt's theory of interstitial alloys. The identification of stable carbides in steels was performed by determining their metallic composition with an energy analyzer attached to the scanning electron microscope (SEM). By these means typical carbides of the M2 steel, MC and M 6 C, were found. Moreover, the spatial and size distribution of carbide particles were determined after different heat treatments, and both microstructure and microhardness were correlated with the appearance of the secondary hardening phenomenon. In the Zr-Nb alloy a study of the α and β phases present after different heat treatments was performed with optical and SEM metallographic techniques, with the guide of Abriata and Bolcich phase diagram. The α-β interphase boundaries were characterized as short circuits for diffusion with radiotracer techniques and applying Fisher-Bondy-Martin model. The precipitation of carbides was promoted by heat treatments that produced first the C diffusion into the samples at high temperatures (β phase), and then the precipitation of carbide particles at lower temperature (α phase or (α+β)) two phase field. The precipitated carbides were identified as (Zr, Nb)C 1-x with SEM, electron microprobe and X-ray diffraction techniques. (Author) [es

  10. Semi-solid twin-roll casting process of magnesium alloy sheets

    International Nuclear Information System (INIS)

    Watari, H.; Davey, K.; Rasgado, M.T. Alonso; Haga, T.; Koga, N.

    2004-01-01

    An experimental approach has been performed to ascertain the effectiveness of semi-solid strip casting using a horizontal twin roll caster. The demand for light-weight products with high strength has grown recently due to the rapid development of automobile and aircraft technology. One key to such development has been utilization of magnesium alloys, which can potentially reduce the total product weight. However, the problems of utilizing magnesium alloys are still mainly related to high manufacturing cost. One of the solutions to this problem is to develop magnesium casting-rolling technology in order to produce magnesium sheet products at competitive cost for commercial applications. In this experiment, magnesium alloy AZ31B was used to ascertain the effectiveness of semi-solid roll strip casting for producing magnesium alloy sheets. The temperature of the molten magnesium, and the roll speeds of the upper and lower rolls, (which could be changed independently), were varied to find an appropriate manufacturing condition. Rolling and heat treatment conditions were changed to examine which condition would be appropriate for producing wrought magnesium alloys with good formability. Microscopic observation of the crystals of the manufactured wrought magnesium alloys was performed. It has been found that a limiting drawing ratio of 2.7 was possible in a warm deep drawing test of the cast magnesium alloy sheets after being hot rolled

  11. Production of an Amorphous Fe_<75>Si_<10>B_<15> Sheet by a Metallic Mold Casting Method and its Properties

    OpenAIRE

    Inoue, Akihisa; Yamamoto, Hirokazu; Saito, Takanobu; Masumoto, Tsuyosi

    1993-01-01

    The application of a metallic mold casting method to an Fe_Si_B_ alloy with the largest glass-forming ability in (Fe, Co, Ni)-Si-B system was found to cause the formation of a mostly single amorphous phase in a sheet form with a thickness of 0.1 mm. No distinct difference in thermal stability (crystallization temperature and heat of crystallization), hardness, Curie temperature and magnetization is detected between the as-cast sheet and the melt-spun amorphous ribbon with a thickness of 0.02 ...

  12. 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

  13. Effect of Intermediate Annealing on Microstructure and Property of 5182 Aluminum Alloy Sheet for Automobile

    Directory of Open Access Journals (Sweden)

    WANG Yu

    2016-09-01

    Full Text Available Effect of intermediate annealing on the microstructure and properties of 5182 aluminum alloy sheet with full annealed state (5182-O was investigated by means of optical microscope, scanning electron microscope and universal testing machine. The results indicate that compared with 5182-O sheet without intermediate annealing, 5182-O sheet with intermediate annealing possesses too fine grain size, intermetallic compounds not broken enough, larger size intermetallic particles, less dispersed phase. Yield strength and ultimate tensile strength, work hardening exponent and normal anisotropy of plastic strain ratio decrease but planner anisotropy of plastic strain ratio increases. The mechanical properties and forming ability of 5182-O aluminum alloy sheet and its microstructure are not improved significantly after intermediate annealing.

  14. Material characterization and finite element simulations of aluminum alloy sheets during non-isothermal forming process

    Science.gov (United States)

    Zhang, Nan

    evolving yield stresses and Lankford coefficients (r-value) at various temperatures with specimens in 0°, 45° and 90° to the rolling direction. Besides, thermally-activated deformation mechanisms, dynamic strain ageing and dislocation climb, are identified to control the material deformation at the ambient-to-warm temperature range. For biaxial loading condition, the hydraulic bulge test has been performed and the evaluated effective stress-strain curve is found to be identical to that from uniaxial tests. A new piece-wised temperature-dependent phenomenological constitutive model has been developed to describe and predict the evolving stress-strain curves within the experimental condition. The power-law model is chosen for temperature ranges from 25° to 100° where negative strain rate sensitivity is observed. At elevated temperatures, a new model has been developed and expressed as the product of two power-law models. This proposed model has been proved to be capable of capturing both strain hardening and thermal softening behaviors of material, even for perfect plasticity with large strain conditions. To account for the directionality of the material properties in sheet metal, Yld2000-2d, which has been proved to be one of the most accurate and efficient yield functions for aluminum alloys in numerical analysis, is selected as the anisotropic yield function in this work. Eight parameters in Yld2000-2d have been determined and calibrated using the experimental results from uniaxial and biaxial testing of AA5182-O. Moreover, those eight parameters are fitted in to the temperature-dependent functions, hence the evolution of yield surface is predictable in response to the temperature changes. It is noticed that the material carries more anisotropy at ambient temperatures and tends to approach the isotropic behavior when the temperature elevated to 300°. The strain-based and stress-based forming limit diagrams (FLD) of AA5182-O at various temperatures have been

  15. Effects of organic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.

    2010-01-01

    mu m of the contaminated surface was required to reach corrosion rates less than 1 mm/year in salt spray condition. Among the three organic acids examined, acetic acid is the best choice. Oxalic acid can be an alternative while citric acid is not suitable for cleaning AZ31 sheet, because......Organic acids were used to clean AZ31 magnesium alloy sheet and the effect of the cleaning processes on the surface condition and corrosion performance of the alloy was investigated. Organic acid cleanings reduced the surface impurities and enhanced the corrosion resistance. Removal of at least 4...

  16. Electromagnetic confinement and movement of thin sheets of molten metal

    Science.gov (United States)

    Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

    1990-01-01

    An apparatus capable of producing a combination of magnetic fields that can retain a metal in liquid form in a region having a smooth vertical boundary including a levitation magnet that produces low frequency magnetic field traveling waves to retain the metal and a stabilization magnet that produces a high frequency magnetic field to produce a smooth vertical boundary. As particularly adapted to the casting of solid metal sheets, a metal in liquid form can be continuously fed into one end of the confinement region produced by the levitation and stabilization magnets and removed in solid form from the other end of confinement region. An additional magnet may be included for support at the edges of the confinement region where eddy currents loop.

  17. Cast bulk metallic glass alloys: prospects as wear materials

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Dogan, Omer N.; Shiflet, Gary J. (Dept. of Materials Science and Engineering, University of Virginia, Charlottesville, VA)

    2005-01-01

    Bulk metallic glasses are single phase materials with unusual physical and mechanical properties. One intriguing area of possible use is as a wear material. Usually, pure metals and single phase dilute alloys do not perform well in tribological conditions. When the metal or alloy is lightweight, it is usually soft leading to galling in sliding situations. For the harder metals and alloys, their density is usually high, so there is an energy penalty when using these materials in wear situations. However, bulk metallic glasses at the same density are usually harder than corresponding metals and dilute single phase alloys, and so could offer better wear resistance. This work will discuss preliminary wear results for metallic glasses with densities in the range of 4.5 to 7.9 g/cc. The wear behavior of these materials will be compared to similar metals and alloys.

  18. Development of Rolling Schedules for AZ31 Magnesium Alloy Sheets

    Science.gov (United States)

    2015-06-01

    Materials 2 2.2 Hot Rolling 3 2.2 Sample Characterization: Microstructure and Tensile Properties 3 3. Rolling Experiments 5 3.1 High-Temperature...material systems for protective and structural applications, especially in ground vehicles. Magnesium (Mg), due to its low density (~25% that of steel ...applications, wrought Mg is difficult to produce in thin sheets because of its inherently low ductility . As a result, Mg sheet is often produced at

  19. 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

  20. STUDY THE EFFECTS OF PRESTRAINS IN UNIAXIAL TENSION ON THE FORMING LIMIT DIAGRAM OF ALUMINUM ALLOY SHEETS(2024 T3

    Directory of Open Access Journals (Sweden)

    Waleed J. Ali

    2015-02-01

    Full Text Available           The strain path for sheet metal may be changed during forming , this may be affect the forming limit curve (FLC . In this work the FLC before and after prestraining was determined for aluminum alloy (2024 T3 to study the effect of this type of prestraining and in different values on the FLC. This alloy was chosen because it is used widely , specially in aircraft structures .It was shown that the using of uniaxial tension prestrain affects the FLC . The major strain in right side is increased with the increasing in the prestrain , while in the left side the effect is small .

  1. RAPID FREEFORM SHEET METAL FORMING: TECHNOLOGY DEVELOPMENT AND SYSTEM VERIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Kiridena, Vijitha [Ford Scientific Research Lab., Dearborn, MI (United States); Verma, Ravi [Boeing Research and Technology (BR& T), Seattle, WA (United States); Gutowski, Timothy [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Roth, John [Pennsylvania State Univ., University Park, PA (United States)

    2018-03-31

    The objective of this project is to develop a transformational RApid Freeform sheet metal Forming Technology (RAFFT) in an industrial environment, which has the potential to increase manufacturing energy efficiency up to ten times, at a fraction of the cost of conventional technologies. The RAFFT technology is a flexible and energy-efficient process that eliminates the need for having geometry-specific forming dies. The innovation lies in the idea of using the energy resource at the local deformation area which provides greater formability, process control, and process flexibility relative to traditional methods. Double-Sided Incremental Forming (DSIF), the core technology in RAFFT, is a new concept for sheet metal forming. A blank sheet is clamped around its periphery and gradually deformed into a complex 3D freeform part by two strategically aligned stylus-type tools that follow a pre-described toolpath. The two tools, one on each side of the blank, can form a part with sharp features for both concave and convex shapes. Since deformation happens locally, the forming force at any instant is significantly decreased when compared to traditional methods. The key advantages of DSIF are its high process flexibility, high energy-efficiency, low capital investment, and the elimination of the need for massive amounts of die casting and machining. Additionally, the enhanced formability and process flexibility of DSIF can open up design spaces and result in greater weight savings.

  2. Surface studies of liquid metals and alloys

    International Nuclear Information System (INIS)

    Bastasz, Robert

    2003-01-01

    Liquid metals and alloys have been proposed for use in nuclear fusion reactors to serve as replaceable plasma-facing surfaces that remove particles and heat from reacting plasmas. Several materials are being considered for this purpose including lithium, gallium, and tin as well as some of the alloys made from these elements. In order to better understand the properties of liquid surfaces, the technique of low-energy ion scattering was used to examine the surface composition of several of these materials in vacuum as a function of temperature. Oxygen is found to rapidly segregate to the surface of several metallic liquids. The segregation process can be interpreted using a simple thermodynamic model based on Gibbs theory. In the case of an alloy of Sn and Li, Li also segregates to the liquid surface. This provides a means to produce a surface enriched in Li, which is more plasma compatible than Sn, without the need to handle large quantities of liquid Li. (author)

  3. Research on Computer Integrated Manufacturing of Sheet Metal Parts for Lithium Battery

    Directory of Open Access Journals (Sweden)

    Pan Wei-Min

    2016-01-01

    Full Text Available Lithium battery has been widely used as the main driving force of the new energy vehicle in recent years. Sheet metal parts are formed by means of pressure forming techniques with the characteristics of light weight, small size and high structural strength. The sheet metal forming has higher productivity and material utilization than the mechanical cutting, therefore sheet metal parts are widely used in many fields, such as modern automotive industry, aviation, aerospace, machine tools, instruments and household appliances. In this paper, taking a complex lithium battery box as an example, the integrated manufacturing of sheet metal parts is studied, and the digital integrated design and manufacturing process system is proposed. The technology is studied such as sheet metal design, unfolding, sheet nesting and laser cutting, CNC turret punch stamping programming, CNC bending etc. The feasibility of the method is verified through the examples of products and the integrated manufacturing of sheet metal box is completed.

  4. Evaluation of creep and relaxation data for hastelloy alloy x sheet

    International Nuclear Information System (INIS)

    Booker, M.K.

    1979-02-01

    Hastelloy alloy X has been a successful high-temperature structural material for more than two decades. Recently, Hastelloy alloy X sheet has been selected as a prime structural material for the proposed Brayton Isotope Power System (BIPS). The material also sees extensive application in the High-Temperature Gas-Cooled Reactor (HTGR). Design of these systems requires a detailed consideration of the high-temperature creep properties of this material. Therefore, available creep, creep-rupture, and relaxation data for Hastelloy alloy X were collected and analyzed to yield mathematical representations of the behavior for design use

  5. Mass transport in non crystalline metallic alloys

    International Nuclear Information System (INIS)

    Limoge, Y.

    1986-08-01

    In order to improve our understanding of mass transport in non crystalline metallic alloys we have developed indirect studies of diffusion based on electron irradiation and hydrostatic pressure effects upon crystallization. In a first part we present the models of crystallization which are used, then we give the experimental results. The main point is the first experimental measurement of the activation volume for diffusion in a metallic glass: the value of which is roughly one atomic volume. We show also recent quantitative results concerning radiation enhanced diffusion in metallic glasses (FeNi) 8 (PB) 2 and Ni 6 Nb 4 . In a last part we discuss the atomic model needed to explain our results

  6. Metal-ceramic alloys in dentistry: a review.

    Science.gov (United States)

    Roberts, Howard W; Berzins, David W; Moore, B Keith; Charlton, David G

    2009-02-01

    The purpose of this article is to review basic information about the alloys used for fabricating metal-ceramic restorations in dentistry. Their compositions, properties, advantages, and disadvantages are presented and compared. In addition to reviewing traditional noble-metal and base-metal metal-ceramic alloys, titanium and gold composite alloys are also discussed. A broad search of the published literature was performed using Medline to identify pertinent current articles on metal-ceramic alloys as well as articles providing a historical background about the development of these alloys. Textbooks, the internet, and manufacturers' literature were also used to supplement this information. The review discusses traditional as well as more recently-developed alloys and technologies used in dentistry for fabricating metal-ceramic restorations. Clear advantages and disadvantages for these alloy types are provided and discussed as well as the role that compositional variations have on the alloys' performance. This information should enable clinicians and technicians to easily identify the important physical properties of each type and their primary clinical indications. A number of alloys and metals are available for metal-ceramic use in dentistry. Each has its advantages and disadvantages, primarily based on its specific composition. Continuing research and development are resulting in the production of new technologies and products, giving clinicians even more choices in designing and fabricating metal-ceramic restorations.

  7. Metal dusting of low alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Grabke, H.J. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)); Bracho-Troconis, C.B. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)); Mueller-Lorenz, E.M. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany))

    1994-04-01

    The metal dusting of two low alloy steels was investigated at 475 C in flowing CO-H[sub 2]-H[sub 2]O mixtures at atmospheric pressure with a[sub C] > 1. The reaction sequence comprises: (1) oversaturation with C, formation of cementite and its decomposition to metal particles and carbon, and (2) additional carbon deposition on the metal particles from the atmosphere. The metal wastage rate r[sub 1] was determined by analysis of the corrosion product after exposures, this rate is constant with time and virtually independent of the environment. The carbon deposition from the atmosphere was determined by thermogravimetry, its rate r[sub 2] increases linearly with time, which can be explained by the catalytic action of the metal particles - periodic changes are superposed. The rate of carbon deposition r[sub 2] is proportional to the carbon activity in the atmosphere. The metal dusting could not be suppressed by increasing the oxygen activity or preoxidation, even if magnetite should be stable. Addition of H[sub 2]S, however, effectively suppresses the attack. (orig.)

  8. Hydrogen storage alloys for nickel/metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Kuriyama, Nobuhiro; Sakai, Tetsuo; Myamura, Hiroshi; Tanaka, Hideaki; Ishikawa, Hiroshi; Uehara, Itsuki [Osaka National Research Inst. (Japan)

    1996-06-01

    Efforts to improve performance of metal hydride electrodes such as substitution of alloy components, heat treatment, and surface treatment intended to change surface and bulk structure of hydrogen storage alloys, mainly LaNi{sub 5} based alloys, are reviewed. The importance of control of morphology is emphasized. (author)

  9. Testing of Lubricant Performance in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Friis, Kasper Leth

    2008-01-01

    Increasing focus on environmental issues in industrial production has urged a number of sheet metal forming companies to look for new tribo-systems in order to substitute hazardous lubricants such as chlorinated paraffin oils. The problems are especially pronounced, when forming tribologically...... of the lubricant film causing pick-up of work piece material on the tool surface and scoring of subsequent work piece surfaces. The present paper gives an overview of more than 10 years work by the authors’ research group through participation in national as well as international framework programmes on developing...

  10. Variation simulation for compliant sheet metal assemblies with applications

    Science.gov (United States)

    Long, Yufeng

    Sheet metals are widely used in discrete products, such as automobiles, aircraft, furniture and electronics appliances, due to their good manufacturability and low cost. A typical automotive body assembly consists of more than 300 parts welded together in more than 200 assembly fixture stations. Such an assembly system is usually quite complex, and takes a long time to develop. As the automotive customer demands products of increasing quality in a shorter time, engineers in automotive industry turn to computer-aided engineering (CAE) tools for help. Computers are an invaluable resource for engineers, not only to simplify and automate the design process, but also to share design specifications with manufacturing groups so that production systems can be tooled up quickly and efficiently. Therefore, it is beneficial to develop computerized simulation and evaluation tools for development of automotive body assembly systems. It is a well-known fact that assembly architectures (joints, fixtures, and assembly lines) have a profound impact on dimensional quality of compliant sheet metal assemblies. To evaluate sheet metal assembly architectures, a special dimensional analysis tool need be developed for predicting dimensional variation of the assembly. Then, the corresponding systematic tools can be established to help engineers select the assembly architectures. In this dissertation, a unified variation model is developed to predict variation in compliant sheet metal assemblies by considering fixture-induced rigid-body motion, deformation and springback. Based on the unified variation model, variation propagation models in multiple assembly stations with various configurations are established. To evaluate the dimensional capability of assembly architectures, quantitative indices are proposed based on the sensitivity matrix, which are independent of the variation level of the process. Examples are given to demonstrate their applications in selecting robust assembly

  11. Multi-objective optimization under uncertainty for sheet metal forming

    Directory of Open Access Journals (Sweden)

    Lafon Pascal

    2016-01-01

    Full Text Available Aleatory uncertainties in material properties, blank thickness and friction condition are inherent and irreducible variabilities in sheet metal forming. Optimal design configurations, which are obtained by conventional design optimization methods, are not always able to meet the desired targets due to the effect of uncertainties. This paper proposes a multi-objective robust design optimization that aims to tackle this problem. Results obtained on a U shape draw bending benchmark show that spring-back effect can be controlled by optimizing process parameters.

  12. Optimization of resistance spot welding on the assembly of refractory alloy 50Mo-50Re thin sheet

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jianhui [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States); Jiang, Xiuping [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States); Zeng, Qiang [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States); Zhai, Tongguang [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)]. E-mail: tzhai0@engr.uky.edu; Leonhardt, Todd [Rhenium Alloys Inc., Elyria, OH 44036 (United States); Farrell, John [Semicon Associates, 695 Laco Drive, Lexington, KY 40510 (United States); Umstead, Williams [Semicon Associates, 695 Laco Drive, Lexington, KY 40510 (United States); Effgen, Michael P. [Semicon Associates, 695 Laco Drive, Lexington, KY 40510 (United States)

    2007-07-01

    Resistance spot welding (RSW) was employed to pre-join refractory alloy 50Mo-50Re (wt%) sheet with a 0.127 mm gage. Five important welding parameters (hold time, electrode, ramp time, weld current and electrode force) were adjusted in an attempt to optimize the welding quality. It was found that increasing the hold time from 50 ms to 999 ms improved the weld strength. Use of rod-shaped electrodes produced symmetric nugget and enhanced the weld strength. Use of a ramp time of 8 ms minimized electrode sticking and molten metal expulsion. The weld strength continuously increased with increasing the weld current up to 1100 A, but the probabilities of occurrence of electrode sticking and molten metal expulsion were also increased. Electrode force was increased from 4.44 N to 17.8 N, in order to reduce the inconsistency of the welding quality. Welding defects including porosities, columnar grains and composition segregation were also studied.

  13. Manufacture of a four-sheet complex component from different titanium alloys by superplastic forming

    Science.gov (United States)

    Allazadeh, M. R.; Zuelli, N.

    2017-10-01

    A superplastic forming (SPF) technology process was deployed to form a complex component with eight-pocket from a four-sheet sandwich panel sheetstock. Six sheetstock packs were composed of two core sheets made of Ti-6Al-4V or Ti-5Al-4Cr-4Mo-2Sn-2Zr titanium alloy and two skin sheets made of Ti-6Al-4V or Ti-6Al-2Sn-4Zr-2Mo titanium alloy in three different combinations. The sheets were welded with two subsequent welding patterns over the core and skin sheets to meet the required component's details. The applied welding methods were intermittent and continuous resistance seam welding for bonding the core sheets to each other and the skin sheets over the core panel, respectively. The final component configuration was predicted based on the die drawings and finite element method (FEM) simulations for the sandwich panels. An SPF system set-up with two inlet gas pipe feeding facilitated the trials to deliver two pressure-time load cycles acting simultaneously which were extracted from FEM analysis for specific forming temperature and strain rate. The SPF pressure-time cycles were optimized via GOM scanning and visually inspecting some sections of the packs in order to assess the levels of core panel formation during the inflation process of the sheetstock. Two sets of GOM scan results were compared via GOM software to inspect the surface and internal features of the inflated multisheet packs. The results highlighted the capability of the tested SPF process to form complex components from a flat multisheet pack made of different titanium alloys.

  14. Numerical Prediction of Springback Shape of Severely Bent Sheet Metal

    International Nuclear Information System (INIS)

    Iwata, Noritoshi; Murata, Atsunobu; Yogo, Yasuhiro; Tsutamori, Hideo; Niihara, Masatomo; Ishikura, Hiroshi; Umezu, Yasuyoshi

    2007-01-01

    In the sheet metal forming simulation, the shell element widely used is assumed as a plane stress state based on the Mindlin-Reissner theory. Numerical prediction with the conventional shell element is not accurate when the bending radius is small compared to the sheet thickness. The main reason is because the strain and stress formulation of the conventional shell element does not fit the actual phenomenon. In order to predict precisely the springback of a bent sheet with a severe bend, a measurement method for through-thickness strain has been proposed. The strain was formulated based on measurement results and calculation results from solid element. Through-thickness stress distribution was formulated based on the equilibrium. The proposed shell element based on the formulations was newly introduced into the FEM code. The accuracy of this method's prediction of the springback shape of two bent processes has been confirmed. As a result, it was found that the springback shape even in severe bending can be predicted with high accuracy. Moreover, the calculation time in the proposed shell element is about twice that in the conventional shell element, and has been shortened to about 1/20 compared to a solid element

  15. Studies in Cup Drawing Behavior of Polymer Laminated Sheet Metal

    Science.gov (United States)

    Elnagmi, M.; Jain, M.; Bruhis, M.; Nielsen, K.

    2011-08-01

    Axisymmetric deep drawing behavior of a polymer laminated sheet metal (PLSM) is investigated using an axisymmetric cup drawing test. PLSMs are of interest as a replacement for painted finishes for automotive applications as they have the potential to achieve good quality long lasting and aesthetically appealing surfaces on stamped parts. However, there is limited understanding of PLSMs in automotive deep drawing situations to produce complex 3-D parts. The tests are carried out using well-controlled, laboratory-based, dual-action, servo-hydraulic forming presses under blank-holder force and punch displacement control conditions. An optical strain mapping system is used to measure the surface strains (and to construct 3D strain maps) from the film side of the deformed samples for a range of forming conditions. Deep drawing characteristics such as punch load versus punch displacement traces, strain distribution along the cup profile, flange wrinkling and fracture characteristics are experimentally assessed for stainless steel-plastic film laminated sheet materials. Also the effect of lamination pressure on wrinkling and delamination is investigated for a decorative pressure sensitive adhesive film affixed to the stainless steel sheet.

  16. Radiation blistering in metals and alloys

    International Nuclear Information System (INIS)

    Das, S.K.; Kaminsky, M.

    1975-01-01

    Radiation blistering in solids has been identified as a process leading to damage and erosion of irradiated surfaces. Some of the major parameters governing the blistering process in metals and some metallic alloys are the type of projectile and its energy, total dose, dose rate, target temperature, channeling condition of the projectile, orientation of the irradiated surface plane, and target material and its microstructure. Experimental results and models proposed for blister formation and rupture are reviewed. The blistering phenomenon is important as an erosion process in applications such as fusion reactor technology (plasma-wall interactions) and accelerator technology (erosion of components and targets). A description of methods for the reduction of surface erosion caused by blistering is included

  17. Prediction of formability of aluminum alloy 5454 sheet

    International Nuclear Information System (INIS)

    Kim, Chan Il; Yang, Seung Han; Kim, Young Suk

    2012-01-01

    In the automobile industry, reducing the weight is the most important objective for reducing air pollution and improving the fuel efficiency. For this reason, the application of aluminum sheets is increasing. When the sheets are applied to the automobile, using inappropriate variables for the material, product design, and press processing can generate tearing, wrinkling, and spring back problems, which are the main types of failure in the manufacturing process. Therefore, it is necessary to reduce these failures by harmonizing the many variables and strictly managing the processes. In this research, we study the theoretical plasticity instability of Al5454 and obtain the forming limit diagram (FLD) using MATLAB. Moreover, we compare the theoretical FLD with an experimental FLD obtained from a stretching test

  18. Electrodeposition of platinum metals and alloys from chloride melts

    Directory of Open Access Journals (Sweden)

    Saltykova N.A.

    2003-01-01

    Full Text Available The structure of platinum metals and their alloys deposited by the electrolysis of chloride melts have been investigated. The cathodic deposits were both in the form of compact layers and dendrites. All the alloys of platinum metals obtained are solid solutions in the whole range of composition. Depending on the experimental conditions the layers had columnar, stratum and spiral (dissipative structures. The stratum and dissipative structures were observed in the case of alloys only.

  19. Formability models for warm sheet metal forming analysis

    Science.gov (United States)

    Jiang, Sen

    Several closed form models for the prediction of strain space sheet metal formability as a function of temperature and strain rate are proposed. The proposed models require only failure strain information from the uniaxial tension test at an elevated temperature setting and failure strain information from the traditionally defined strain space forming limit diagram at room temperature, thereby featuring the advantage of offering a full forming limit description without having to carry out expensive experimental studies for multiple modes of deformation under the elevated temperature. The Power law, Voce, and Johnson-Cook hardening models are considered along with the yield criterions of Hill's 48 and Logan-Hosford yield criteria. Acceptable correlations between the theory and experiment are reported for all the models under a plane strain condition. Among all the proposed models, the model featuring Johnson-Cook hardening model and Logan-Hosford yield behavior (LHJC model) was shown to best correlate with experiment. The sensitivity of the model with respect to various forming parameters is discussed. This work is significant to those aiming to incorporate closed-form formability models directly into numerical simulation programs for the purpose of design and analysis of products manufactured through the warm sheet metal forming process. An improvement based upon Swift's diffuse necking theory, is suggested in order to enhance the reliability of the model for biaxial stretch conditions. Theory relating to this improvement is provided in Appendix B.

  20. Application of Six Sigma Robust Optimization in Sheet Metal Forming

    International Nuclear Information System (INIS)

    Li, Y.Q.; Cui, Z.S.; Ruan, X.Y.; Zhang, D.J.

    2005-01-01

    Numerical simulation technology and optimization method have been applied in sheet metal forming process to improve design quality and shorten design cycle. While the existence of fluctuation in design variables or operation condition has great influence on the quality. In addition to that, iterative solution in numerical simulation and optimization usually take huge computational time or endure expensive experiment cost In order to eliminate effect of perturbations in design and improve design efficiency, a CAE-based six sigma robust design method is developed in this paper. In the six sigma procedure for sheet metal forming, statistical technology and dual response surface approximate model as well as algorithm of 'Design for Six Sigma (DFSS)' are integrated together to perform reliability optimization and robust improvement. A deep drawing process of a rectangular cup is taken as an example to illustrate the method. The optimization solutions show that the proposed optimization procedure not only improves significantly the reliability and robustness of the forming quality, but also increases optimization efficiency with approximate model

  1. Damage percolation during stretch flange forming of aluminum alloy sheet

    Science.gov (United States)

    Chen, Zengtao; Worswick, Michael J.; Keith Pilkey, A.; Lloyd, David J.

    2005-12-01

    A multi-scale finite element (FE)-damage percolation model was employed to simulate stretch flange forming of aluminum alloys AA5182 and AA5754. Material softening and strain gradients were captured using a Gurson-based FE model. FE results were then fed into the so-called damage percolation code, from which the damage development was modelled within measured microstructures. The formability of the stretch flange samples was predicted based upon the onset of catastrophic failure triggered by profuse void coalescence within the measured second-phase particle field. Damage development is quantified in terms of crack and void areal fractions, and compared to metallographic results obtained from interrupted stretch flange specimens. Parametric study is conducted on the effect of void nucleation strain in the prediction of formability of stretch flanges to "calibrate" proper nucleation strains for both alloys.

  2. A new constitutive model for prediction of springback in sheet metal forming

    International Nuclear Information System (INIS)

    Appiah, E.; Jain, M.

    2004-01-01

    With advances in computer capabilities, cost of sheet metal forming has being reducing mainly due to the reduction of trial and error approaches. At the moment, a complete process can be simulated on computer and appropriate forming conditions optimized before actual industrial forming process is carried out. While formability predictions have improved, the problem of springback exhibited by most metal, including aluminum alloy AA6111-T4, after forming persist and often leads to significant part fit-up problems during assembly. There are a number of factors that affect springback and perhaps the most significant one is constitutive equation. In this paper springback predicted by six advanced kinematic models are evaluated. In addition an improved constitutive kinematic model is presented. It is shown that by adding stress correction term (SCT) to Armstrong-Frederick model a relatively simple and yet accurate stress prediction could be obtained. The SCT was developed with the assumption that the yield surface remains convex, yield center depends on translation, size and shape variations of the yield surface. The model is implemented in a commercial finite element code (ABAQUS/Standard) via its user material interface (UMAT). Numerical simulations of U-bending were performed using automotive aluminum sheet material (AA6111-T4). It was noted that springback has inverse relationship with residual stress

  3. Connection of crystallographic texture with anisotropy of yield strength of titanium alloy sheets

    International Nuclear Information System (INIS)

    Serebryannyj, V.N.; Koknaev, R.G.

    1983-01-01

    Using the programs developed in FORTRAN-4 algorithmic language for the ES-1022 computer the contribution of crystallographic texture to the anisotropy of yield strength in the sheet plane for warm-rolled sheets of α-titanium alloys VT1 and VT5-1, is evaluated. It is established, that experimental and calculation data for the sheet of VT1-0 agree satisfactorily in the angle range phi 40 deg the value anti M (phi) exceeds the experimental values σsub(0.2)(phi./σsub(0.2)(0). The results obtained for the sheet of the VT5-1 alloy show, that calculation and experimental data agree well for narrow angles (phi <= 60 deg) and at wider angles the values anti M(phi) exceed the values σsub(0.2)(phi)/σsub(0.2)(0). Calculation and experimental curves for the VT5-1 alloy on the whole agree better than for the VT1-0 one

  4. NUMISHEET 2016: 10th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes

    International Nuclear Information System (INIS)

    2016-01-01

    The NUMISHEET conference series have been established as a world-class forum through which new intellectual ideas and technologies in the area of sheet metal forming simulation are exchanged. Previous NUMISHEET conferences have given enormous contributions to industry and academia in what regards the development of new methods and ideas for the numerical simulation of sheet metal forming processes. Previous NUMISHEET conferences were held in: Zurich (Switzerland, 1991), Isehara (Japan, 1993), Dearborn (USA, 1996), Besancon (France, 1999), Jeju Island (South Korea, 2002), Detroit (USA, 2005), Interlaken (Switzerland, 2008), Seoul (South Korea, 2011) and Melbourne (Australia, 2014). The NUMISHEET 2016 conference will be held in Bristol, UK. It features technical, keynote and plenary sessions and mini-symposiums in diverse sheet metal forming areas including the recently introduced incremental sheet forming and electromagnetic forming, as well as new prominent numerical methods such as IsoGeometric Analysis and meshless methods for sheet analysis. NUMISHEET 2016 will have eight academic plenary lectures delivered by worldwide recognised experts in the areas of sheet metal forming, material modelling and numerical methods in general. Also, NUMISHEET 2016 will have three industrial plenary lectures which will be addressed by three different companies with strong businesses in sheet metal forming processes: AutoForm, Crown Technology and Jaguar Land Rover. One of the most distinguishing features of NUMISHEET conference series is the industrial benchmark sessions, during which numerical simulations of industrial sheet formed parts are compared with experimental results from the industry. The benchmark sessions provide an extraordinary opportunity for networking, for the exchange of technologies related to sheet metal forming and for the numerical validation of sheet metal forming codes/software. Three benchmark studies have been organised in NUMISHEET 2016: BM1) &apos

  5. New technique for producing the alloys based on transition metals

    International Nuclear Information System (INIS)

    Dolukhanyan, S.K.; Aleksanyan, A.G.; Shekhtman, V.Sh.; Mantashyan, A.A.; Mayilyan, D.G.; Ter-Galstyan, O.P.

    2007-01-01

    In principle new technique was elaborated for obtaining the alloys of refractory metals by their hydrides compacting and following dehydrogenation. The elaborated technique is described. The conditions of alloys formation from different hydrides of appropriate metals was investigated in detail. The influence of the process parameters such as: chemical peculiarities, composition of source hydrides, phase transformation during dehydrogenation, etc. on the alloys formation were established. The binary and tertiary alloys of α and ω phases: Ti 0 .8Zr 0 .8; Ti 0 .66Zr 0 .33; Ti 0 .3Zr 0 .8; Ti 0 .2Zr 0 .8; Ti 0 .8Hf 0 .2; Ti 0 .6Hf 0 .4Ti 0 .66Zr 0 .23Hf 0 .11; etc were recieved. Using elaborated special hydride cycle, an earlier unknown effective process for formation of alloys of transition metals was realized. The dependence of final alloy structure on the composition of initial mixture and hydrogen content in source hydrides was established

  6. Crystal Plasticity Finite Element Analysis of Loading-Unloading Behaviour in Magnesium Alloy Sheet

    International Nuclear Information System (INIS)

    Hama, Takayuki; Fujimoto, Hitoshi; Takuda, Hirohiko

    2010-01-01

    Magnesium alloy sheets exhibit strong inelastic response during unloading. In this study crystal plasticity finite element analysis of loading-unloading behaviour during uniaxial tension in a rolled magnesium alloy sheet was carried out, and the mechanism of this inelastic response was examined in detail in terms of macroscopic and mesoscopic deformations. The unloading behaviour obtained by the simulation was in good agreement with the experiment in terms of variation with stress of instantaneous tangent modulus during unloading. Variations of activities of each family of slip systems during the deformation showed that the activation of basal slip systems is the largest during unloading, and the slip direction during unloading is opposite from during loading. These results indicated that one of the factors of the inelastic behaviour during unloading is the fact that the basal slip systems are easily activated during unloading because of their low strengths.

  7. Design of multi materials combining crystalline and amorphous metallic alloys

    International Nuclear Information System (INIS)

    Volland, A.; Ragani, J.; Liu, Y.; Gravier, S.; Suéry, M.; Blandin, J.J.

    2012-01-01

    Highlights: ► Elaboration of multi materials associating metallic glasses and conventional crystalline alloys by co-deformation performed at temperatures close to the glass transition temperature of the metallic glasses. ► Elaboration of filamentary metal matrix composites with a core in metallic glass by co extrusion. ► Sandwich structures produced by co-pressing. ► Detection of atomic diffusion from the glass to the crystalline alloys during the processes. ► Good interfaces between the metallic glasses and the crystalline alloys, as confirmed by mechanical characterisation. - Abstract: Multi materials, associating zirconium based bulk metallic glasses and crystalline metallic alloys like magnesium alloys or copper are elaborated by co-deformation processing performed in the supercooled liquid regions (SLR) of the bulk metallic glasses. Two processes are investigated: co-extrusion and co-pressing. In the first case, filamentary composites with various designs can be produced whereas in the second case sandwich structures are obtained. The experimental window (temperature, time) in which processing can be carried out is directly related to the crystallisation resistance of the glass which requires getting information about the crystallisation conditions in the selected metallic glasses. Thermoforming windows are identified for the studied BMGs by thermal analysis and compression tests in their SLR. The mechanical properties of the produced multi materials are investigated thanks to specifically developed mechanical devices and the interfaces between the amorphous and the crystalline alloys are characterised.

  8. TSCA Chemical Data Reporting Fact Sheet: Reporting Manufactured Chemical Substances from Metal Mining and Related Activities

    Science.gov (United States)

    This fact sheet provides guidance on the Chemical Data Reporting (CDR) rule requirements related to the reporting of mined metals, intermediates, and byproducts manufactured during metal mining and related activities.

  9. Large patternable metal nanoparticle sheets by photo/e-beam lithography

    Science.gov (United States)

    Saito, Noboru; Wang, Pangpang; Okamoto, Koichi; Ryuzaki, Sou; Tamada, Kaoru

    2017-10-01

    Techniques for micro/nano-scale patterning of large metal nanoparticle sheets can potentially be used to realize high-performance photoelectronic devices because the sheets provide greatly enhanced electrical fields around the nanoparticles due to localized surface plasmon resonances. However, no single metal nanoparticle sheet currently exists with sufficient durability for conventional lithographical processes. Here, we report large photo and/or e-beam lithographic patternable metal nanoparticle sheets with improved durability by incorporating molecular cross-linked structures between nanoparticles. The cross-linked structures were easily formed by a one-step chemical reaction; immersing a single nanoparticle sheet consisting of core metals, to which capping molecules ionically bond, in a dithiol ethanol solution. The ligand exchange reaction processes were discussed in detail, and we demonstrated 20 μm wide line and space patterns, and a 170 nm wide line of the silver nanoparticle sheets.

  10. Ultrasonic measurement of through-thickness stress gradients in textured sheet metals

    International Nuclear Information System (INIS)

    Man Chising; Li Jianbo; Fan Xingyan; Lu Weiyang

    2000-01-01

    The objective of this investigation is to explore the possibility of using the dispersion of high-frequency Rayleigh waves for the evaluation of through-thickness stress gradients at the surface of metal sheets. We consider an orthorhombic sheet of cubic metal with through-thickness inhomogeneities in stress and texture, and adopt a coordinate system under which the rolling (RD), transverse (TD), and normal direction (ND) of the sheet are taken as the 1-, 2-, and 3-direction, respectively. We restrict our attention to the special case where only the stress components T 11 (x 3 ) and T 22 (x 3 ) in the sheet are nonzero, and consider only Rayleigh waves of sufficiently high frequency for which the sheet can be taken as the half-space x 3 ≥0. For Rayleigh waves of two different frequencies (with wave numbers k 1 and k k 2 respectively) propagating on the same wave path along either RD or TD, we appeal to an analysis of J. Li and Man to obtain a high-frequency asymptotic formula which gives the relative change in time-of-flight Δt/t 0 as (1/k 1 -1/k 2 ) times a linear combination of the derivatives T 11 ' (0), T 22 ' (0), W 4m0 ' (0)(m=0,2,4) and W 6m0 (0)(m=0,2,4,6) at the surface are ascertained and the material constants in the acoustoelastic consitutive equation of this polycrystal are known. An experiment was performed on an AA7075-T651 aluminum alloy beam, in which Δt/t 0 was measured for various values of T 11 (0) and T 11 ' (0) produced by beam bending (with (T 22 ≡0). The relevant texture coefficients of the beam were measured by X-ray diffraction. To obtain specific predictions from the aforementioned symptotic formula, we replace the material constants of the sample by their counterparts predicted for polycrystalline (pure) aluminum by the Man-Paroni model. The predictions and Δt/t 0 are then compared with the experimental results

  11. Investigation of americium-241 metal alloys for target applications

    International Nuclear Information System (INIS)

    Conner, W.V.; Rockwell International Corp., Golden, CO

    1982-01-01

    Several 241 Am metal alloys have been investigated for possible use in the Lawrence Livermore National Laboratory Radiochemical Diagnostic Tracer Program. Several properties were desired for an alloy to be useful for tracer program applications. A suitable alloy would have a fairly high density, be ductile, homogeneous and easy to prepare. Alloys investigated have included uranium-americium, aluminium-americium, and cerium-americium. Uranium-americium alloys with the desired properties proved to be difficult to prepare, and work with this alloy was discontinued. Aluminium-americium alloys were much easier to prepare, but the alloy consisted of an aluminium-americium intermetallic compound (AmAl 4 ) in an aluminum matrix. This alloy could be cast and formed into shapes, but the low density of aluminum, and other problems, made the alloy unsuitable for the intended application. Americium metal was found to have a high solid solubility in cerium and alloys prepared from these two elements exhibited all of the properties desired for the tracer program application. Cerium-americium alloys containing up to 34 wt% americium have been prepared using both co-melting and co-reduction techniques. The latter technique involves co-reduction of cerium tetrafluoride and americium tetrafluoride with calcium metal in a sealed reduction vessel. Casting techniques have been developed for preparing up to eight 2.2 cm (0.87 in) diameter disks in a single casting, and cerium-americium metal alloy disks containing from 10 to 25 wt% 241 Am have been prepared using these techniques. (orig.)

  12. A study on corrosion resistance of electrodeposited Zn-base alloy steel sheet

    International Nuclear Information System (INIS)

    Park, Hyun Soon

    1986-01-01

    Effects of electrodeposits of Zn-Ni or Zn-Co alloy with small amounts of Mo or W in sulphate bath on the corrosion resistance of plated steel sheet were studied. 1) The electrodeposition of Zn-Ni and Zn-Co alloy shows both anomalous codeposition behavior. The grade of anomalous codeposition of Zn-Co alloy rises with adding Mo or W in bath. 2) The Ni content in Zn-Ni deposits increases with decreasing cathode current density and with increasing bath temperature. 3) In case of electroplating of Zn-Co, the increase of cathodic current density of bath bring on increasing of the Co content, but on decreasing of the Mo content in deposits. And rising bath temperature increases both Co and Mo deposits. 4) The corrosion resistance of the Zn-Ni electrodeposited steel sheet is shown a maximum at the Ni content of 10-17%. The structure of Zn-Ni of these composition range was finegrained γ-phase. 5) The corrosion resistance of the Zn-Co electrodeposited steel sheet is improved with increasing Co content. The corrosion resistance of the Zn-Co-Mo or Zn-Co-W deposits electroplated by proper plating conditions was improved much more than that of Zn-Co deposits. (Author)

  13. Multi-scale contact modeling of coated steels for sheet metal forming applications

    NARCIS (Netherlands)

    Shisode, Meghshyam; Hazrati Marangalou, Javad; Mishra, Tanmaya; De Rooij, Matthijn; Van Den Boogaard, Ton; Bay, Niels; Nielsen, Chris V.

    2018-01-01

    Friction in sheet metal forming is a local phenomenon which depends on continuously evolving contact conditions during the forming process. This is mainly influenced by local contact pressure, surface textures of the sheet metal as well as the forming tool surface profile and material behavior. The

  14. Application of Multivariate Adaptive Regression Splines to Sheet Metal Bending Process for Springback Compensation

    Directory of Open Access Journals (Sweden)

    Dilan Rasim Aşkın

    2016-01-01

    Full Text Available An intelligent regression technique is applied for sheet metal bending processes to improve bending performance. This study is a part of another extensive study, automated sheet bending assistance for press brakes. Data related to material properties of sheet metal is collected in an online manner and fed to an intelligent system for determining the most accurate punch displacement without any offline iteration or calibration. The overall system aims to reduce the production time while increasing the performance of press brakes.

  15. Stamping of Thin-Walled Structural Components with Magnesium Alloy AZ31 Sheets

    International Nuclear Information System (INIS)

    Chen, F.-K.; Chang, C.-K.

    2005-01-01

    In the present study, the stamping process for manufacturing cell phone cases with magnesium alloy AZ31 sheets was studied using both the experimental approach and the finite element analysis. In order to determine the proper forming temperature and set up a fracture criterion, tensile tests and forming limit tests were first conducted to obtain the mechanical behaviors of AZ31 sheets at various elevated temperatures. The mechanical properties of Z31 sheets obtained from the experiments were then adopted in the finite element analysis to investigate the effects of the process parameters on the formability of the stamping process of cell phone cases. The finite element simulation results revealed that both the fracture and wrinkle defects could not be eliminated at the same time by adjusting blank-holder force or blank size. A drawbead design was then performed using the finite element simulations to determine the size and the location of drawbead required to suppress the wrinkle defect. An optimum stamping process, including die geometry, forming temperature, and blank dimension, was then determined for manufacturing the cell phone cases. The finite element analysis was validated by the good agreement between the simulation results and the experimental data. It confirms that the cell phone cases can be produced with magnesium alloy AZ31 sheet by the stamping process at elevated temperatures

  16. Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-07-15

    A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets.

  17. Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

    International Nuclear Information System (INIS)

    Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y.

    2014-01-01

    A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets

  18. Springback of aluminum alloy brazing sheet in warm forming

    Science.gov (United States)

    Han, Kyu Bin; George, Ryan; Kurukuri, Srihari; Worswick, Michael J.; Winkler, Sooky

    2017-10-01

    The use of aluminum is increasing in the automotive industry due to its high strength-to-weight ratio, recyclability and corrosion resistance. However, aluminum is prone to significant springback due to its low elastic modulus coupled with its high strength. In this paper, a warm forming process is studied to improve the springback characteristics of 0.2 mm thick brazing sheet with an AA3003 core and AA4045 clad. Warm forming decreases springback by lowering the flow stress. The parts formed have complex features and geometries that are representative of automotive heat exchangers. The key objective is to utilize warm forming to control the springback to improve the part flatness which enables the use of harder temper material with improved strength. The experiments are performed by using heated dies at several different temperatures up to 350 °C and the blanks are pre-heated in the dies. The measured springback showed a reduction in curvature and improved flatness after forming at higher temperatures, particularly for the harder temper material conditions.

  19. 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...

  20. Increasing the Robustness of the Sheet Metal Forming Simulation by the Prediction of the Forming Limit Band

    Science.gov (United States)

    Banabic, D.; Vos, M.; Paraianu, L.; Jurco, P.

    2007-05-01

    The experimental research on the formability of metal sheets has shown that there is a significant dispersion of the limit strains in an area delimited by two curves: a lower curve (LFLC) and an upper one (UFLC). The region between the two curves defines the so-called Forming Limit Band (FLB). So far, this forming band has only been determined experimentally. In this paper the authors suggested a method to predict the Forming Limit Band. The proposed method is illustrated on the AA6111-T43 aluminium alloy.

  1. Increasing the Robustness of the Sheet Metal Forming Simulation by the Prediction of the Forming Limit Band

    International Nuclear Information System (INIS)

    Banabic, D.; Paraianu, L.; Vos, M.; Jurco, P.

    2007-01-01

    The experimental research on the formability of metal sheets has shown that there is a significant dispersion of the limit strains in an area delimited by two curves: a lower curve (LFLC) and an upper one (UFLC). The region between the two curves defines the so-called Forming Limit Band (FLB). So far, this forming band has only been determined experimentally. In this paper the authors suggested a method to predict the Forming Limit Band. The proposed method is illustrated on the AA6111-T43 aluminium alloy

  2. Gamma rays shielding parameters for white metal alloys

    Science.gov (United States)

    Kaur, Taranjot; Sharma, Jeewan; Singh, Tejbir

    2018-05-01

    In the present study, an attempt has been made to check the feasibility of white metal alloys as gamma rays shielding materials. Different combinations of cadmium, lead, tin and zinc were used to prepare quaternary alloys Pb60Sn20ZnxCd20-x (where x = 5, 10, 15) using melt quench technique. These alloys were also known as white metal alloys because of its shining appearance. The density of prepared alloys has been measured using Archimedes Principle. Gamma rays shielding parameters viz. mass attenuation coefficient (µm), effective atomic number (Zeff), electron density (Nel), Mean free path (mfp), Half value layer (HVL) and Tenth value layer (TVL) has been evaluated for these alloys in the wide energy range from 1 keV to 100 GeV. The WinXCom software has been used for obtaining mass attenuation coefficient values for the prepared alloys in the given energy range. The effective atomic number (Zeff) has been assigned to prepared alloys using atomic to electronic cross section ratio method. Further, the variation of various shielding parameters with photon energy has been investigated for the prepared white metal alloys.

  3. Ductile fracture surface morphology of amorphous metallic alloys

    NARCIS (Netherlands)

    Miskuf, J; Csach, K; Ocelik, [No Value; Bengus, VZ; Tabachnikova, ED; Duhaj, P; Ocelik, Vaclav

    1999-01-01

    Fracture surfaces of ductile failure of two types bulk amorphous metallic alloys were studied using quantitative and qualitative fractographic analysis. The observed fractographic behaviour of ductile failure in comparison with the ductile failure of amorphous alloy ribbons shows signs of the same

  4. Metal induced crystallization of silicon germanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gjukic, M.

    2007-05-15

    In the framework of this thesis the applicability of the aluminium-induced layer exchange on binary silicon germanium alloys was studied. It is here for the first time shown that polycrstalline silicon-germanium layers can be fabricated over the whole composition range by the aluminium-induced layer exchange. The experimental results prove thet the resulting material exhibits a polycrystalline character with typocal grain sizes of 10-100 {mu}m. Raman measurements confirm that the structural properties of the resulting layers are because of the large crystallites more comparable with monocrystalline than with nano- or microcrystalline silicon-germanium. The alloy ratio of the polycrystalline layer correspondes to the chemical composition of the amorphous starting layer. The polycrystalline silicon-germanium layers possess in the range of the interband transitions a reflection spectrum, as it is otherwise only known from monocrystalline reference layers. The improvement of the absorption in the photovoltaically relevant spectral range aimed by the application of silicon-germanium could be also proved by absorption measurments. Strongly correlated with the structural properties of the polycrystalline layers and the electronic band structure resulting from this are beside the optical properties also the electrical properties of the material, especially the charge-carrier mobility and the doping concentration. For binary silicon-germanium layers the hole concentration of about 2 x 10{sup 18} cm{sup -3} for pure silicon increrases to about 5 x 10{sup 20} cm{sub -3} for pure germanium. Temperature-resolved measurements were applied in order to detect doping levels respectively semiconductor-metal transitions. In the last part of the thesis the hydrogen passivation of polycrystalline thin silicon-germanium layers, which were fabricated by means of aluminium-induced layer exchange, is treated.

  5. Radiation effects on metals, alloys and cement

    International Nuclear Information System (INIS)

    Lucki, G.; Sciani, V.

    1988-12-01

    High - energy particle irradiation of materials brings as a consequence changes in their atomic structures that alter the electrical, magnetic and mechanical properties which are the most important characteristics for practical applications of metals and alloys. A review is made on experimental results of in-pile (IEA-RI reactor) and CV-28 cyclotron irradiated materials. Resistivity measurements on CuPd and FeNi alloys showed different behaviour during fast neutron irradiation. While CuPd had almost coincidental relaxation curves, FeNi presented a distinguishable short and long-range ordering with the critical order-disorder temperature at 515 0 C. Vacancy supersaturation curves of FeNiSi (49-49-2 at %), FeNiCr (49-95-49, 95-0,1 at. %), FeNiMo (50-50 at.% + 50 ppm) and pure FeNi (50-50 at.%), determined by means of the Magnetic After Effect are presented as an effective pre-selection method of nuclear materials before the destructive stage of void formation and swelling. A displacement of damage peak from 480 to 500 and 570 0 C was detected on pure AISI 321 stainless steel and with 0,05 wt.% and 0,10 wt.% of Nb additions by means of resistivity and micro-hardness. Ultrasound techniques applied to fast neutron irradiated portland cement paste (fluence 7,2 x 10 18 n/cm 2 ) showed a 24% decrease in its dynamic elasticity modulus. Helium diffusion on Au, Ag and Al foils irradiated in cyclotron was studied, suggesting a vacancy mechanism for single He atom diffusion. Embrittlement by Alpha particle implantation in cyclotron to simulate in-pile (n,α) reaction-was measured by high temperature creep on AISI 316 stainles steel. (author) [pt

  6. Coefficient of electrical transport vacuum arc for metals and alloys

    International Nuclear Information System (INIS)

    Markov, G.V.; Ehjzner, B.A.

    1998-01-01

    In this article the authors propose formulas for estimation coefficient of electrical transport vacuum arc for metals and alloys. They also represent results of analysis principal physical processes which take place in cathode spot vacuum arc

  7. The solubility of metals in Pb-17Li liquid alloy

    International Nuclear Information System (INIS)

    Borgstedt, H.U.; Feuerstein, H.

    1992-01-01

    The solubility data of iron in the eutectic alloy Pb-17Li which were evaluated from corrosion tests in a turbulent flow of the molten alloy are discussed in the frame of solubilities of the transition metals in liquid lead. It is shown that the solubility of iron in the alloy is close to that in lead. This is also the fact for several other alloying elements of steels. A comparison of all known data shows that they are in agreement with generally shown trends for the solubility of the transition metals in low melting metals. These trends indicate comparably high solubilities of nickel and manganese in the liquid metals, lower saturation concentration of vanadium, chromium, iron, and cobalt, and extremely low solubility of molybdenum. (orig.)

  8. Ion-beam modification of properties of metals and alloys

    International Nuclear Information System (INIS)

    Khodasevich, V.V.; Uglov, V.V.; Ponaryadov, V.V.; Zhukova, S.I.

    2002-01-01

    Physical fundaments for ion-beam modification and plasma-vacuum synthesis of new types of coatings and compounds in technically important metals and alloys were development as well as corresponding installation and technologies were created. (authors)

  9. Non-contact sheet forming using lasers applied to a high strength aluminum alloy

    Directory of Open Access Journals (Sweden)

    Rafael Humberto Mota Siqueira

    2016-07-01

    Full Text Available Laser beam forming (LBF is a contactless mechanical process accomplished by the introduction of thermal stresses on the surface of a material using a laser in order to induce plastic deformation. In this work, LBF was performed on 1.6 mm thick sheets of a high strength aluminum alloy, AA6013-T4 class by using a defocused continuous Yb-fiber laser beam of 0.6 mm in diameter on the sheet top surface. The laser power and process speed were varied from 200 W to 2000 W and from 3 to 30 mm/s, respectively. For these experimental conditions, the bending angle of the sheet ranged from 0.1° to 2.5° per run. In the highest bending angle condition, 1000 W and 30 mm/s, the depth of remelted pool was 0.6 mm and the microstructure near the plate bottom surface remained unaltered. For the whole set of experimental conditions, the hardness remained constant at approximately 100 HV, which is similar to the base material. In order to verify the applicability of the method, some previously T-welded sheets were straightened. The method was efficient in correcting the distortion of the sheets with a bending angle up to 5°.

  10. Review on progressive microforming of bulk metal parts directly using sheet metals (Keynote Paper

    Directory of Open Access Journals (Sweden)

    Fu M.W.

    2015-01-01

    Full Text Available Due to the ubiquitous trend of product miniaturization, energy saving and weight reduction, micro/meso-scale parts have been widely used in many industrial clusters. Micromanufacturing processes for production of such micro/meso-scale parts are thus critically needed. Microforming, as one of these micro manufacturing processes, is a promising process and thus got many explorations and researches. Compared with the research on size effect affected deformation behaviours, less attention has been paid to the process development for mass production of micro-parts. The product quality and fabrication productivity of micro-parts depend on the involved process chain. To address the difficulty in handling and transporting of the micro-sized workpiece, development of a progressive microforming process for directly fabricating bulk micro-parts using sheet metals seems quite promising as it avoids or facilitates billet handling, transportation, positioning, and ejection in the process chain. In this paper, an intensive review on the latest development of progressive microforming technologies is presented. First of all, the paper summarizes the characteristic of progressive microforming directly using sheet metal. The size effect-affected deformation behaviour and the dimensional accuracy, deformation load, ductile fracture, and the surface finish of the microformed parts by progressive microforming using sheet metals are then presented. Finally, some research issues from the implementation of mass production perspective are also discussed.

  11. Evaluation of biocidal efficacy of copper alloy coatings in comparison with solid metal surfaces: generation of organic copper phosphate nanoflowers.

    Science.gov (United States)

    Gutierrez, H; Portman, T; Pershin, V; Ringuette, M

    2013-03-01

    To analyse the biocidal efficacy of thermal sprayed copper surfaces. Copper alloy sheet metals containing >60% copper have been shown to exhibit potent biocidal activity. Surface biocidal activity was assessed by epifluorescence microscopy. After 2-h exposure at 20 °C in phosphate-buffered saline (PBS), contact killing of Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis by brass sheet metal and phosphor bronze was 3-4-times higher than that by stainless steel. SEM observations revealed that the surface membranes of both bacterial strains were slightly more irregular when exposed to brass sheet metal than stainless steel. However, when exposed to phosphor bronze coating, E. coli were 3-4 times larger with irregular membrane morphology. In addition, the majority of the cells were associated with spherical carbon-copper-phosphate crystalline nanostructures characteristic of nanoflowers. The membranes of many of the S. epidermidis exhibited blebbing, and a small subset was also associated with nanoflowers. Our data indicate that increasing the surface roughness of copper alloys had a pronounced impact on the membrane integrity of Gram-positive and, to a lesser degree, Gram-negative bacteria. In the presence of PBS, carbon-copper-phosphate-containing nanoflowers were formed, likely nucleated by components derived from killed bacteria. The intimate association of the bacteria with the nanoflowers and phosphor bronze coating likely contributed to their nonreversible adhesion. Thermal spraying of copper alloys provides a strategy for the rapid coating of three-dimensional organic and inorganic surfaces with biocidal copper alloys. Our study demonstrates that the macroscale surface roughness generated by the thermal spray process enhances the biocidal activity of copper alloys compared with the nanoscale surface roughness of copper sheet metals. Moreover, the coating surface topography provides conditions for the rapid formation of organic copper

  12. Method for estimating the lattice thermal conductivity of metallic alloys

    International Nuclear Information System (INIS)

    Yarbrough, D.W.; Williams, R.K.

    1978-08-01

    A method is described for calculating the lattice thermal conductivity of alloys as a function of temperature and composition for temperatures above theta/sub D//2 using readily available information about the atomic species present in the alloy. The calculation takes into account phonon interactions with point defects, electrons and other phonons. Comparisons between experimental thermal conductivities (resistivities) and calculated values are discussed for binary alloys of semiconductors, alkali halides and metals. A discussion of the theoretical background is followed by sufficient numerical work to facilitate the calculation of lattice thermal conductivity of an alloy for which no conductivity data exist

  13. Many-Body Potentials For Binary Immiscible liquid Metal Alloys

    International Nuclear Information System (INIS)

    Karaguelle, H.

    2004-01-01

    The modified analytic embedded atom method (MAEAM) type many- body potentials have been constructed for three binary liquid immiscible alloy systems: Al-Pb, Ag-Ni, Ag- Cu. The MAEAM potential functions are fitted to both solid and liquid state properties for only liquid pure metals which consist the immiscible alloy. In order to test the reliability of the constructed MAEAM effective potentials, partial structure factors and pair distribution functions of these binary liquid metal alloys have been calculated using the thermodynamically self-consistent variational modified hypernetted chain (VMHNC) theory of liquids. A good agreement with the available experimental data for structure has

  14. Determination of hydrogen in metals and alloys

    International Nuclear Information System (INIS)

    Sayi, Y.S.; Ramanjaneyulu, P.S.; Ramakumar, K.L.

    2008-01-01

    Hydrogen will be invariably present in all materials. Its presence in excess is harmful and sometimes calamitous. Hydrogen embrittlement can occur quite readily in most high strength materials, irrespective of their composition or structure. It is therefore essential to maintain low levels of hydrogen. To know the amount of hydrogen present in the materials, it is essential to determine it with high degree of precision and accuracy. It is required to give the uncertainty associated with the measurement to increase the confidence on measurements. Several methodologies are available for the determination of hydrogen. It its isotope, deuterium, also co-exists it becomes all the more difficult to determine these individually. Hot vacuum extraction cum quadrupole mass spectrometry (HVE-QMS) developed in our laboratory to determine hydrogen and deuterium is routinely employed for the determination of hydrogen and deuterium in metals and alloys. The present paper deals in detail about our experiences with HVE-QMS and estimation of uncertainty associated in this methodology. (author)

  15. Defect accumulation behaviour in hcp metals and alloys

    International Nuclear Information System (INIS)

    Woo, C.H.

    2000-01-01

    The effects of displacement damage on the physical and mechanical properties of metals and alloys, caused by the bombardment of energetic particles, have been investigated for several decades. Besides the obvious technical and industrial implications, an important motive of such investigations is to understand the factors that differentiate the response of different metals under different irradiation conditions. Recently, much interest is shown in the possible effects of the crystal lattice structure on variations in the damage accumulation behaviour of metals and alloys. In this paper we focus on the case of metals and alloys that crystallize in the hexagonal close pack (hcp) structure, and describe recent understanding of the damage production, accumulation and its consequences in these metals

  16. Standard specification for tantalum and tantalum alloy plate, sheet, and strip. ASTM standard

    International Nuclear Information System (INIS)

    1998-09-01

    This specification is under the jurisdiction of ASTM Committee B-10 on Reactive and Refractory Metals and Alloys and is the direct responsibility of Subcommittee B10.03 on Niobium and Tantalum. Current edition approved May 10, 1998 and published September 1998. Originally published as B 708-82. Last previous edition was B 708-92

  17. Mechanical properties of sheet metal components with local reinforcement produced by additive manufacturing

    Science.gov (United States)

    Ünsal, Ismail; Hama-Saleh, R.; Sviridov, Alexander; Bambach, Markus; Weisheit, A.; Schleifenbaum, J. H.

    2018-05-01

    New technological challenges like electro-mobility pose an increasing demand for cost-efficient processes for the production of product variants. This demand opens the possibility to combine established die-based manufacturing methods and innovative, dieless technologies like additive manufacturing [1, 2]. In this context, additive manufacturing technologies allow for the weight-efficient local reinforcement of parts before and after forming, enabling manufacturers to produce product variants from series parts [3]. Previous work by the authors shows that the optimal shape of the reinforcing structure can be determined using sizing optimization. Sheet metal parts can then be reinforced using laser metal deposition. The material used is a pearlite-reduced, micro-alloyed steel (ZE 630). The aim of this paper is to determine the effect of the additive manufacturing process on the material behavior and the mechanical properties of the base material and the resulting composite material. The parameters of the AM process are optimized to reach similar material properties in the base material and the build-up volume. A metallographic analysis of the parts is presented, where the additive layers, the base material and also the bonding between the additive layers and the base material are analyzed. The paper shows the feasibility of the approach and details the resulting mechanical properties and performance.

  18. 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.

  19. Numerical investigation of blanking for metal polymer sandwich sheets

    Directory of Open Access Journals (Sweden)

    Gutknecht Florian

    2016-01-01

    Full Text Available Metal polymer sandwich sheets consist of materials with drastically different mechanical properties. Due to this fact and because of high local gradients in the cutting zone during the blanking process, traditional process strategies and empirical knowledge are difficult to apply. A finite-element simulation of the shear cutting process is used to predict the necessary force and the geometry of the cutting surface. A fully-coupled ductile damage model is used for the description of the material behaviour. This model considers the influence of shear and compression-dominated stress states on the initiation of damage. Experimental tensile and compression test data is used for the identification of material parameters. The results of the blanking simulation are compared with experimental data. Furthermore, the evolution of the stress state is analysed to gain understanding of the underlying physics. Finally this model enables the prediction of core compression and other quantities such as the acting stresses and corresponding triaxilities, which provide valuable information for the development of analytical models.

  20. Advanced Gradient Based Optimization Techniques Applied on Sheet Metal Forming

    International Nuclear Information System (INIS)

    Endelt, Benny; Nielsen, Karl Brian

    2005-01-01

    The computational-costs for finite element simulations of general sheet metal forming processes are considerable, especially measured in time. In combination with optimization, the performance of the optimization algorithm is crucial for the overall performance of the system, i.e. the optimization algorithm should gain as much information about the system in each iteration as possible. Least-square formulation of the object function is widely applied for solution of inverse problems, due to the superior performance of this formulation.In this work focus will be on small problems which are defined as problems with less than 1000 design parameters; as the majority of real life optimization and inverse problems, represented in literature, can be characterized as small problems, typically with less than 20 design parameters.We will show that the least square formulation is well suited for two classes of inverse problems; identification of constitutive parameters and process optimization.The scalability and robustness of the approach are illustrated through a number of process optimizations and inverse material characterization problems; tube hydro forming, two step hydro forming, flexible aluminum tubes, inverse identification of material parameters

  1. Towards Industrial Application of Damage Models for Sheet Metal Forming

    Science.gov (United States)

    Doig, M.; Roll, K.

    2011-05-01

    Due to global warming and financial situation the demand to reduce the CO2-emission and the production costs leads to the permanent development of new materials. In the automotive industry the occupant safety is an additional condition. Bringing these arguments together the preferable approach for lightweight design of car components, especially for body-in-white, is the use of modern steels. Such steel grades, also called advanced high strength steels (AHSS), exhibit a high strength as well as a high formability. Not only their material behavior but also the damage behavior of AHSS is different compared to the performances of standard steels. Conventional methods for the damage prediction in the industry like the forming limit curve (FLC) are not reliable for AHSS. Physically based damage models are often used in crash and bulk forming simulations. The still open question is the industrial application of these models for sheet metal forming. This paper evaluates the Gurson-Tvergaard-Needleman (GTN) model and the model of Lemaitre within commercial codes with a goal of industrial application.

  2. Thermophysical Property Measurements of Silicon-Transition Metal Alloys

    Science.gov (United States)

    Banish, R. Michael; Erwin, William R.; Sansoucie, Michael P.; Lee, Jonghyun; Gave, Matthew A.

    2014-01-01

    Metals and metallic alloys often have high melting temperatures and highly reactive liquids. Processing reactive liquids in containers can result in significant contamination and limited undercooling. This is particularly true for molten silicon and it alloys. Silicon is commonly termed "the universal solvent". The viscosity, surface tension, and density of several silicon-transition metal alloys were determined using the Electrostatic Levitator system at the Marshall Space Flight Center. The temperature dependence of the viscosity followed an Arrhenius dependence, and the surface tension followed a linear temperature dependence. The density of the melts, including the undercooled region, showed a linear behavior as well. Viscosity and surface tension values were obtain for several of the alloys in the undercooled region.

  3. Tool Monitoring and Electronic Event Logging for Sheet Metal Forming Processes

    Directory of Open Access Journals (Sweden)

    Gerd Heiserich

    2010-06-01

    Full Text Available This contribution describes some innovative solutions regarding sensor systems for tool monitoring in the sheet metal industry. Autonomous and tamper-proof sensors, which are integrated in the forming tools, can detect and count the strokes carried out by a sheet metal forming press. Furthermore, an electronic event logger for documentary purposes and quality control was developed. Based on this technical solution, new business models such as leasing of sheet metal forming tools can be established for cooperation among enterprises. These models allow usage-based billing for the contractors, taking the effectively produced number of parts into account.

  4. Friction and lubrication modelling in sheet metal forming: Influence of lubrication amount, tool roughness and sheet coating on product quality

    Science.gov (United States)

    Hol, J.; Wiebenga, J. H.; Carleer, B.

    2017-09-01

    In the stamping of automotive parts, friction and lubrication play a key role in achieving high quality products. In the development process of new automotive parts, it is therefore crucial to accurately account for these effects in sheet metal forming simulations. This paper presents a selection of results considering friction and lubrication modelling in sheet metal forming simulations of a front fender product. For varying lubrication conditions, the front fender can either show wrinkling or fractures. The front fender is modelled using different lubrication amounts, tool roughness’s and sheet coatings to show the strong influence of friction on both part quality and the overall production stability. For this purpose, the TriboForm software is used in combination with the AutoForm software. The results demonstrate that the TriboForm software enables the simulation of friction behaviour for varying lubrication conditions, i.e. resulting in a generally applicable approach for friction characterization under industrial sheet metal forming process conditions.

  5. A technology to improve formability for aluminum alloy thin-wall corrugated sheet component hydroforming

    Directory of Open Access Journals (Sweden)

    Lang Lihui

    2015-01-01

    Full Text Available The explosively forming projectile (EFP had been traditional adopted for the aluminum thin-walled corrugated sheet, whose deformation range is large but the formability is poor, and this process usually has problems of poor surface quality, long manufacturing cycle and high cost. The active hydroforming process was suggested to solve these issues during EFP. A new technology named as blank bulging by turning the upside down active hydroforming technology was proposed to overcome difficulties in non-uniform thickness distribution and cracking failure of corrugated sheet during the conventional hydroforming process. Both numerical simulations and experiments were conducted for this new technology. The result show that the deformation capacity of aluminum alloys can be improved effectively, and the more uniform distribution of wall thickness was obtained by this new method. It is conducted that the new method is universal for thin-walled, shallow drawing parts with complex section.

  6. Punchless Drawing of Magnesium Alloy Sheet under Cold Condition and its Computation

    International Nuclear Information System (INIS)

    Yamashita, Minoru; Hattori, Toshio; Sato, Joji

    2011-01-01

    The punchless drawing with Maslennikov's technique was applied to the circular cup drawing of magnesium alloy AZ31B sheet under cold condition. The elastic rubber ring was used instead of the 'hard' punch, where the compressed ring dragged the sheet inward the die cavity. Attainable circumferential strain of the blank was increased by this technique with repetitive drawing operation. Thickness of the rubber pad affected little the attainable strain. The shape appearance became better when a harder rubber was used. The cup forming by single drawing operation was also tested using a small die shoulder radius. The LDR of 1.250 was obtained with the straight cup wall. Further, the computation of the punchless drawing was also conducted for the single drawing operation. The computed deformation pattern was well consistent with the corresponding experimental result.

  7. Semi-quantitative evaluation of texture components and anisotropy of the yield strength in 2524 T3 alloy sheets

    International Nuclear Information System (INIS)

    Shen, Fanghua; Yi, Danqing; Wang, Bin; Liu, Huiqun; Jiang, Yong; Tang, Cong; Jiang, Bo

    2016-01-01

    Decreasing the anisotropy of 2524 alloys is a key factor for their use in applications such as high-performance inertial components or space robots. Studying the interaction between sheet textures and anisotropy is a key factor to overcome this problem. In this study, the semi-quantitative approach to estimate the relation between texture and in-plane anisotropy (IPA) of yield strength has been developed. The intensity ratio between Cube and Brass texture components (F CGB ) was used as an effective variable for this purpose. This approach has been tested in 2524 T3 aluminum alloy sheets, which were investigated using X-Ray diffraction, scanning electron microscopy, optical microscopy and tensile tests. The results show that F CGB decreased with an increase in cold reduction. The 2524 T3 sheet, dominated by Cube texture grains, possesses the lowest in-plane anisotropy for the yield strength of all texture components investigated. The alloy sheet dominated by Brass texture exhibits the highest anisotropy, while the Goss texture-led sheets fall in between them. These results agree with the trends seen in the factor F CGB , suggesting that is suited to evaluate the anisotropy of yield strength in 2524 T3 alloy sheets semi-quantitatively.

  8. Semi-quantitative evaluation of texture components and anisotropy of the yield strength in 2524 T3 alloy sheets

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Fanghua [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Yi, Danqing, E-mail: yioffice@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Light Alloy Research Institute, Central South University, Changsha, Hunan 410083 (China); National Collaborative Innovation Center of Advanced Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083 (China); Wang, Bin; Liu, Huiqun; Jiang, Yong; Tang, Cong; Jiang, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2016-10-15

    Decreasing the anisotropy of 2524 alloys is a key factor for their use in applications such as high-performance inertial components or space robots. Studying the interaction between sheet textures and anisotropy is a key factor to overcome this problem. In this study, the semi-quantitative approach to estimate the relation between texture and in-plane anisotropy (IPA) of yield strength has been developed. The intensity ratio between Cube and Brass texture components (F{sub CGB}) was used as an effective variable for this purpose. This approach has been tested in 2524 T3 aluminum alloy sheets, which were investigated using X-Ray diffraction, scanning electron microscopy, optical microscopy and tensile tests. The results show that F{sub CGB} decreased with an increase in cold reduction. The 2524 T3 sheet, dominated by Cube texture grains, possesses the lowest in-plane anisotropy for the yield strength of all texture components investigated. The alloy sheet dominated by Brass texture exhibits the highest anisotropy, while the Goss texture-led sheets fall in between them. These results agree with the trends seen in the factor F{sub CGB}, suggesting that is suited to evaluate the anisotropy of yield strength in 2524 T3 alloy sheets semi-quantitatively.

  9. Chitosan coatings crosslinked with genipin for corrosion protection of AZ31 magnesium alloy sheets.

    Science.gov (United States)

    de Y Pozzo, Ludmila; da Conceição, Thiago F; Spinelli, Almir; Scharnagl, Nico; Pires, Alfredo T N

    2018-02-01

    In this study, coatings of chitosan crosslinked with genipin were prepared on sheets of AZ31 magnesium alloy and their corrosion protection properties were characterized by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The coatings were also characterized by means of FTIR and XPS. It was observed that the crosslinking process decreases the corrosion current and shifts the corrosion potential of the alloy to less negative values. The EIS analysis demonstrated that the crosslinking process increases the maximum impedance after short and long exposure times. The superior performance of the crosslinked coatings is related to a lower degree of swelling, as observed in the swelling tests carried out on free-standing films. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Modeling and optimization of kerf taper and surface roughness in laser cutting of titanium alloy sheet

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Arun Kumar; Dubey, Avanish Kumar [Motilal Nehru National Institute of Technology Allahabad, Uttar Pradesh (India)

    2013-07-15

    Laser cutting of titanium and its alloys is difficult due to it's poor thermal conductivity and chemical reactivity at elevated temperatures. But demand of these materials in different advanced industries such as aircraft, automobile and space research, require accurate geometry with high surface quality. The present research investigates the laser cutting process behavior of titanium alloy sheet (Ti-6Al-4V) with the aim to improve geometrical accuracy and surface quality by minimizing the kerf taper and surface roughness. The data obtained from L{sub 27} orthogonal array experiments have been used for developing neural network (NN) based models of kerf taper and surface roughness. A hybrid approach of neural network and genetic algorithm has been proposed and applied for the optimization of different quality characteristics. The optimization results show considerable improvements in both the quality characteristics. The results predicted by NN models are well in agreement with the experimental data.

  11. Failure analysis of fusion clad alloy system AA3003/AA6xxx sheet under bending

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y., E-mail: shiyh@mcmaster.ca [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Jin, H. [Novelis Global Technology Center, P.O. Box 8400, Kingston, Ontario, Canada K7L 5L9 (Canada); Wu, P.D. [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Lloyd, D.J. [Aluminum Materials Consultants, 106 Nicholsons Point Road, Bath, Ontario, Canada K0H 1G0 (Canada); Embury, D. [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

    2014-07-29

    An ingot of AA6xxx Al–Si–Mg–Cu alloy clad with AA3003 Al–Mn alloy was co-cast by Fusion technology. Bending tests and numerical modeling were performed to investigate the potential for sub-surface cracking for this laminate system. To simulate particle-induced crack initiation and growth, both random and stringer particles have been selected to mimic the particle distribution in the tested samples. The morphology of cracking in the model was similar to that observed in clad sheet tested in the Cantilever bend test. The crack initiated in the core close to the clad-core interface where the strain in the core is highest, between particles or near particles and propagates along local shear bands in the core, while the clad layer experiences extreme thinning before failure.

  12. Effect of Hydraulic Pressure on Warm Hydro Mechanical Deep Drawing of Magnesium Alloy Sheet

    Science.gov (United States)

    Liu, Wei; Wu, Linzhi; Yuan, Shijian

    The uniaxial tensile test and hydraulic bulging test of AZ31 magnesium alloy sheets were applied to study the influence of temperature on the material properties and obtain the forming limit curves at different temperatures. Numerical simulations of warm hydro mechanical deep drawing were carried out to investigate the effect of hydraulic pressure on the formability of a cylindrical cup, and the simplified hydraulic pressure profiles were used to simulate the loading procedure of hydraulic pressure. The optimal hydraulic pressure at different temperatures were given and verified by experimental studies at temperature 100°C and 170V.

  13. Experimental and FE simulation validation of sheet thickness optimization in superplastic forming of Al alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kumaresan, G.; Jothilingam, A. [Anna University, Chennai (India)

    2016-07-15

    Superplasticity is the ability of a polycrystalline materials to exhibit very large elongations without necking prior to failure. In this paper, the superplastic forming potential of fine grained 7075 aluminium alloy was studied. The process parameters like pressure, forming time and initial sheet thickness were selected, using the design of experiments technique. The same condition of formation process was attempted in the finite element simulation using ABAQUS software. The deviation of the thickness distribution between the simulation and experiment was made and the variation lies within 8%.

  14. Numerical models for the prediction of failure for multilayer fusion Al-alloy sheets

    International Nuclear Information System (INIS)

    Gorji, Maysam; Berisha, Bekim; Hora, Pavel; Timm, Jürgen

    2013-01-01

    Initiation and propagation of cracks in monolithic and multi-layer aluminum alloys, called “Fusion”, is investigated. 2D plane strain finite element simulations are performed to model deformation due to bending and to predict failure. For this purpose, fracture strains are measured based on microscopic pictures of Nakajima specimens. In addition to, micro-structure of materials is taken into account by introducing a random grain distribution over the sheet thickness as well as a random distribution of the measured yield curve. It is shown that the performed experiments and the introduced FE-Model are appropriate methods to highlight the advantages of the Fusion material, especially for bending processes

  15. Local Chemical Reactivity of a Metal Alloy Surface

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Scheffler, Matthias

    1995-01-01

    The chemical reactivity of a metal alloy surface is studied by density functional theory investigating the interaction of H2 with NiAl(110). The energy barrier for H2 dissociation is largely different over the Al and Ni sites without, however, reflecting the barriers over the single component metal...

  16. Early stage crystallization kinetics in metallic glass-forming alloys

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, Dmitri V.

    2014-01-01

    Highlights: • Heterogeneous nucleation may precede the homogeneous one in an alloy. • High kinetic constants and the nucleation rate at the initial stage. • Metallic glasses have heterogeneous nucleation sites which saturate later. -- Abstract: The crystallization kinetics and structural changes of a few metallic glassy alloys were monitored using X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Microstructural observations were used to estimate the nucleation and growth rates. A clear comparison of the differences in the crystallization kinetics in the metallic glassy samples is observed at the early and later crystallization stages

  17. Mechanisms of diffusional phase transformations in metals and alloys

    CERN Document Server

    Aaronson, Hubert I; Lee, Jong K

    2010-01-01

    Developed by the late metallurgy professor and master experimentalist Hubert I. Aaronson, this collection of lecture notes details the fundamental principles of phase transformations in metals and alloys upon which steel and other metals industries are based. Mechanisms of Diffusional Phase Transformations in Metals and Alloys is devoted to solid-solid phase transformations in which elementary atomic processes are diffusional jumps, and these processes occur in a series of so-called nucleation and growth through interface migration. Instead of relying strictly on a pedagogical approach, it doc

  18. Interfacial delamination in polymer coated metal sheet : a numerical-experimental study

    NARCIS (Netherlands)

    van den Bosch, M.

    2007-01-01

    An increasing amount of products are nowadays made of polymer coated metal sheet. Polymer coated metal has several advantages compared to traditionally Sn (tin) coated metal, such as costs savings and a more environmental friendly production process. Beverage and food cans are formed by draw-redraw

  19. PHYSICAL BASES OF SYSTEMS CREATION FOR MAGNETIC-IMPULSIVE ATTRACTION OF THIN-WALLED SHEET METALS

    Directory of Open Access Journals (Sweden)

    Y. Batygin

    2009-01-01

    Full Text Available The work is dedicated to the physical base of systems creating for the thin-walled sheet metals magnetic pulse attraction. Some practical realization models of the author’s suggestions are represented.

  20. An expert system for process planning of sheet metal parts produced ...

    Indian Academy of Sciences (India)

    Sachin Salunkhe

    set of production rules and frames for process planning of axisymmetric deep ... parameters for design of stamping die for manufacturing of circular cup with ..... proper sequence of operations to manufacture sheet metal part correctly and ...

  1. 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...

  2. Properties of cemented carbides alloyed by metal melt treatment

    International Nuclear Information System (INIS)

    Lisovsky, A.F.

    2001-01-01

    The paper presents the results of investigations into the influence of alloying elements introduced by metal melt treatment (MMT-process) on properties of WC-Co and WC-Ni cemented carbides. Transition metals of the IV - VIll groups (Ti, Zr, Ta, Cr, Re, Ni) and silicon were used as alloying elements. It is shown that the MMT-process allows cemented carbides to be produced whose physico-mechanical properties (bending strength, fracture toughness, total deformation, total work of deformation and fatigue fracture toughness) are superior to those of cemented carbides produced following a traditional powder metallurgy (PM) process. The main mechanism and peculiarities of the influence of alloying elements added by the MMT-process on properties of cemented carbides have been first established. The effect of alloying elements on structure and substructure of phases has been analyzed. (author)

  3. Application of YAG Laser TIG Arc Hybrid Welding to Thin AZ31B Magnesium Alloy Sheet

    Science.gov (United States)

    Kim, Taewon; Kim, Jongcheol; Hasegawa, Yu; Suga, Yasuo

    A magnesium alloy is said to be an ecological material with high ability of recycling and lightweight property. Especially, magnesium alloys are in great demand on account of outstanding material property as a structural material. Under these circumstances, research and development of welding process to join magnesium alloy plates are of great significance for wide industrial application of magnesium. In order to use it as a structure material, the welding technology is very important. TIG arc welding process is the most ordinary process to weld magnesium alloy plates. However, since the heat source by the arc welding process affects the magnesium alloy plates, HAZ of welded joint becomes wide and large distortion often occurs. On the other hand, a laser welding process that has small diameter of heat source seems to be one of the possible means to weld magnesium alloy in view of the qualitative improvement. However, the low boiling point of magnesium generates some weld defects, including porosity and solidification cracking. Furthermore, precise edge preparation is very important in butt-welding by the laser welding process, due to the small laser beam diameter. Laser/arc hybrid welding process that combines the laser beam and the arc is an effective welding process in which these two heat sources influence and assist each other. Using the hybrid welding, a synegistic effect is achievable and the disadvantages of the respective processes can be compensated. In this study, YAG laser/TIG arc hybrid welding of thin magnesium alloy (AZ31B) sheets was investigated. First of all, the effect of the irradiation point and the focal position of laser beam on the quality of a weld were discussed in hybrid welding. Then, it was confirmed that a sound weld bead with sufficient penetration is obtained using appropriate welding conditions. Furthermore, it was made clear that the heat absorption efficiency is improved with the hybrid welding process. Finally, the tensile tests

  4. Ferromagnetism and spin glass ordering in transition metal alloys (invited)

    Science.gov (United States)

    Crane, S.; Carnegie, D. W., Jr.; Claus, H.

    1982-03-01

    Magnetic properties of transition metal alloys near the percolation threshold are often complicated by metallurgical effects. Alloys like AuFe, VFe, CuNi, RhNi, and PdNi are in general not random solid solutions but have various degrees of atomic clustering or short-range order (SRO), depending on the heat treatment. First, it is shown how the magnetic ordering temperature of these alloys varies with the degree of clustering or SRO. Second, by systematically changing this degree of clustering or SRO, important information can be obtained about the magnetic phase diagram. In all these alloys below the percolation limit, the onset of ferromagnetic order is probably preceded by a spin glass-type ordering. However, details of the magnetic phase diagram near the critical point can be quite different alloy systems.

  5. Determination of the Number of Fixture Locating Points for Sheet Metal By Grey Model

    Directory of Open Access Journals (Sweden)

    Yang Bo

    2017-01-01

    Full Text Available In the process of the traditional fixture design for sheet metal part based on the "N-2-1" locating principle, the number of fixture locating points is determined by trial and error or the experience of the designer. To that end, a new design method based on grey theory is proposed to determine the number of sheet metal fixture locating points in this paper. Firstly, the training sample set is generated by Latin hypercube sampling (LHS and finite element analysis (FEA. Secondly, the GM(1, 1 grey model is constructed based on the established training sample set to approximate the mapping relationship between the number of fixture locating points and the concerned sheet metal maximum deformation. Thirdly, the final number of fixture locating points for sheet metal can be inversely calculated under the allowable maximum deformation. Finally, a sheet metal case is conducted and the results indicate that the proposed approach is effective and efficient in determining the number of fixture locating points for sheet metal.

  6. Probabilistic Design in a Sheet Metal Stamping Process under Failure Analysis

    International Nuclear Information System (INIS)

    Buranathiti, Thaweepat; Cao, Jian; Chen, Wei; Xia, Z. Cedric

    2005-01-01

    Sheet metal stamping processes have been widely implemented in many industries due to its repeatability and productivity. In general, the simulations for a sheet metal forming process involve nonlinearity, complex material behavior and tool-material interaction. Instabilities in terms of tearing and wrinkling are major concerns in many sheet metal stamping processes. In this work, a sheet metal stamping process of a mild steel for a wheelhouse used in automobile industry is studied by using an explicit nonlinear finite element code and incorporating failure analysis (tearing and wrinkling) and design under uncertainty. Margins of tearing and wrinkling are quantitatively defined via stress-based criteria for system-level design. The forming process utilizes drawbeads instead of using the blank holder force to restrain the blank. The main parameters of interest in this work are friction conditions, drawbead configurations, sheet metal properties, and numerical errors. A robust design model is created to conduct a probabilistic design, which is made possible for this complex engineering process via an efficient uncertainty propagation technique. The method called the weighted three-point-based method estimates the statistical characteristics (mean and variance) of the responses of interest (margins of failures), and provide a systematic approach in designing a sheet metal forming process under the framework of design under uncertainty

  7. Charge transfers in complex transition metal alloys (Ti2Fe)

    International Nuclear Information System (INIS)

    Abramovici, G.

    1998-01-01

    We introduce a new non-orthogonal tight-binding model, for complex alloys, in which electronic structure is characterized by charge transfers. We give the analytic calculation of a charge transfer, in which overlapping two-center terms are rigorously taken into account. Then, we apply numerically this result to an approximant phase of a quasicrystal of Ti 2 Fe alloy. This model is more particularly adapted to transition metals, and gives realistic densities of states. (orig.)

  8. The energetics of ordered intermetallic alloys (of the transition metals)

    International Nuclear Information System (INIS)

    Watson, R.E.; Weinert, M.; Davenport, J.W.; Fernando, G.W.; Bennett, L.H.

    1992-01-01

    The atomically ordered phases in ordered transition metal alloys are discussed. This chapter is divided into: physical parameters controlling phase stability (Hume-Rothery, structural maps, Miedema Hamiltonian), wave functions ampersand band theory, comment on entropy terms, cohesive energies (electron promotion energies, Hund's rule on orbital effects), structural energies/stabilities of elemental solids, total energies and atomic positions, charge transfer (Au alloys, charge tailing), heats of formation of ordered compounds

  9. Microstructural and magnetic properties study of Fe–P rolled sheet alloys

    International Nuclear Information System (INIS)

    Jafari, S.; Beitollahi, A.; EftekhariYekta, B.; Kanada, Keiu; Ohkubo, T.; Gopalan, R.; Herzer, Giselher; Hono, K.

    2014-01-01

    In the work presented here, the soft magnetic properties of Fe 1−x P x (x=0.36, 0.7, 1.1 at%) rolled sheet alloys were investigated. In this respect, the as-rolled sheets were subjected to a two steps annealing processes; the first one between 800 and 1000 °C for 1 h referred as first stage annealing and the second one at lower temperatures (500 and 600 °C) for 30 min, referred as second step annealing. BH tracer measurements at 50 Hz showed that for all of the phosphorous containing alloys, in general, the magnitude of coercivity decreased by applying these two annealing steps compared to those of as-rolled samples. For all of the studied samples, the B 50 values measured at 50 Hz were in the range of 1.6–1.7 tesla (T). Samples having highest amount of phosphorous (1.1 at%) exhibited lower eddy current loss compared to the rest of the specimens due to the increased electrical resistivity. Besides, microstructural studies revealed that the prepared samples were free from Fe 3 P phase precipitation and the average grain size increased (∼three times) with increasing the phosphorous content giving rise to the decrease of hysteresis losses. Further, amongst the whole prepared samples, the alloy containing 1.1 at% P showed the lowest hysteresis loss (6.99 W/kg), eddy current loss (9.25 W/kg) as well as the highest magnetic induction (1.7 T) at 5000 A/M (B 50 ). - Highlights: • We have studied magnetic properties and microstructure of Fe 1−x P x rolled sheet alloys. • Increasing phosphorous content increases the B 50 from 1.65 to 1.70 T. • Increasing phosphorous content causes the decline of the eddy current loss. • The grain size increases about 3 times with increasing phosphorous concentration. • The hysteresis loss decreases with increasing the phosphorous content (88%)

  10. Microstructural and magnetic properties study of Fe–P rolled sheet alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, S. [Center of Excellence for Ceramics in Energy and Environment, School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Beitollahi, A., E-mail: beitolla@iust.ac.ir [Center of Excellence for Ceramics in Energy and Environment, School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); EftekhariYekta, B. [Center of Excellence for Ceramics in Energy and Environment, School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Kanada, Keiu [Toyota Motor Corporation, Aichi Prefecture, Toyota (Japan); Ohkubo, T.; Gopalan, R. [Magnetic Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Herzer, Giselher [Vacuumschmelze GmBH, D-63450 Hanau (Germany); Hono, K. [Magnetic Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan)

    2014-05-01

    In the work presented here, the soft magnetic properties of Fe{sub 1−x}P{sub x} (x=0.36, 0.7, 1.1 at%) rolled sheet alloys were investigated. In this respect, the as-rolled sheets were subjected to a two steps annealing processes; the first one between 800 and 1000 °C for 1 h referred as first stage annealing and the second one at lower temperatures (500 and 600 °C) for 30 min, referred as second step annealing. BH tracer measurements at 50 Hz showed that for all of the phosphorous containing alloys, in general, the magnitude of coercivity decreased by applying these two annealing steps compared to those of as-rolled samples. For all of the studied samples, the B{sub 50} values measured at 50 Hz were in the range of 1.6–1.7 tesla (T). Samples having highest amount of phosphorous (1.1 at%) exhibited lower eddy current loss compared to the rest of the specimens due to the increased electrical resistivity. Besides, microstructural studies revealed that the prepared samples were free from Fe{sub 3}P phase precipitation and the average grain size increased (∼three times) with increasing the phosphorous content giving rise to the decrease of hysteresis losses. Further, amongst the whole prepared samples, the alloy containing 1.1 at% P showed the lowest hysteresis loss (6.99 W/kg), eddy current loss (9.25 W/kg) as well as the highest magnetic induction (1.7 T) at 5000 A/M (B{sub 50}). - Highlights: • We have studied magnetic properties and microstructure of Fe{sub 1−x}P{sub x} rolled sheet alloys. • Increasing phosphorous content increases the B{sub 50} from 1.65 to 1.70 T. • Increasing phosphorous content causes the decline of the eddy current loss. • The grain size increases about 3 times with increasing phosphorous concentration. • The hysteresis loss decreases with increasing the phosphorous content (88%)

  11. The Effect of Grinding and Polishing Procedure of Tool Steels in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Lindvall, F.; Bergström, J.; Krakhmalev, P.

    2010-01-01

    The surface finish of tools in sheet metal forming has a large influence on the performance of the forming tool. Galling, concern of wear in sheet metal forming, is a severe form of adhesive wear where sheet material is transferred on to the tool surface. By polishing the tools to a fine surface ...... 40 and Vanadis 6 and up to ten different grinding and polishing treatments were tested against AISI 316 stainless steel. The tests showed that an optimum surface preparation might be found at the transition between abrasive and adhesive wear....

  12. Elaboration of the technology of forming a conical product of sheet metal

    Directory of Open Access Journals (Sweden)

    W. Matysiak

    2010-01-01

    Full Text Available The work presents a general knowledge about spinning draw pieces of sheets, one of multi-operational processes of spinning a sheet metal conical product without machining. The objective of the work was to elaborate both the technology of forming conical products of sheet metal and execution of technological tests as well as to determine the technological parameters for the process of spinning a conical insert. As a result of the investigations, the products with improved mechanical properties, stricter execution tolerance and low roughness have been obtained. The series of 200 prototype conical inserts for the shipbuilding industry have been made.

  13. Room temperature creep in metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Deibler, Lisa Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials Characterization and Performance

    2014-09-01

    Time dependent deformation in the form of creep and stress relaxation is not often considered a factor when designing structural alloy parts for use at room temperature. However, creep and stress relaxation do occur at room temperature (0.09-0.21 Tm for alloys in this report) in structural alloys. This report will summarize the available literature on room temperature creep, present creep data collected on various structural alloys, and finally compare the acquired data to equations used in the literature to model creep behavior. Based on evidence from the literature and fitting of various equations, the mechanism which causes room temperature creep is found to include dislocation generation as well as exhaustion.

  14. Phase distribution studies in metallic alloy SIMFUEL

    International Nuclear Information System (INIS)

    Kolay, S.; Basu, M.; Kaity, S.; Das, D.

    2014-01-01

    Utilization of U-Pu based alloy fuel in the three stage nuclear power generation program in India is one of the important mandate due to shorter doubling time for breeding of the fissile isotopes ( 239 Pu and 233 U) to be used in Th based driver fuel in the 3rd stage. Reported information shows successful performance of fuel with porous alloy matrix in achieving 10-15 atom % burn-up. The porosity and microstructure of this alloy are strongly dependent on the composition and phases of the fission products incorporated in the matrix. The porosity influences the extent of fuel swelling and fission gas release, which affects the performance and integrity of the fuel. This study addresses to these issues taking the base alloy U-10wt% Zr

  15. Experimental investigation of the degree of weakening in structural notch area of 7075-T6 aluminum alloy sheet welded with the RFSSW method

    Directory of Open Access Journals (Sweden)

    Kubit Andrzej

    2017-01-01

    Full Text Available The paper presents the methodology of the research determining the degree of weakening of the welded sheet obtained by the refill friction stir spot welding (RFSSW method. The considered weakness is the effect of a structural notch resulting from penetration by the tool. RFSSW technology is a relatively new method of joining metals, which can successfully provide an alternative to resistance welding or riveting - traditionally used methods of joining thin-walled structures in the aerospace and automotive industries. The study presented in the paper focuses on the overlapping of sheet metal with 7075-T6 aluminum alloy combined in the configuration: 1.6 mm top sheet and 0.8 mm bottom sheet. Joints were assembled following the following process parameters: Welding time 1.5 s, the tool plunge depth in the range of 1.5 ÷ 1.9 mm, and the spindle speed of 2600 rpm. The analysis of the microstructure of joints revealed that along the edge of the tool path a structural notch is formed, the size and shape of which depend on the parameters applied. The paper describes the study consisting in punching the welded area along the formed notch in the upper sheet. The punching process was performed on a universal testing machine and the punching force was measured during the test. Based on the force value, the degree of sheet weakening in the notched area was determined. The smallest weakening was observed in joints made with the smallest tool depth, i.e. 1.5 mm, whereas the biggest weakening was obtained for tool depth of 1.9 mm. The load applied to the joints was equal to 5290N and 7585N respectively.

  16. Electrical resistivity of liquid noble metal alloys

    International Nuclear Information System (INIS)

    Anis Alam, M.; Tomak, M.

    1983-08-01

    Calculations of the dependence of the electrical resistivity in liquid Ag-Au, Cu-Ag, Cu-Au binary alloys on composition are reported. The structure of the binary alloy is described as a hard sphere system. A one-parameter local pseudopotential, which incorporates s-d hybridization effects phenomenologically, is employed in the resistivity calculation. A reasonable agreement with experimental trends is observed in cases where experimental information is available. (author)

  17. Magnetic properties of metals and alloys

    International Nuclear Information System (INIS)

    Lyuborskij, F.E.; Livingston, D.D.; Chin, Zh.I.

    1987-01-01

    The nature of magnetic properties of materials and their dependence on the composition and the material structure are described. Properties and application of such materials as the alloys of the Fe-Ni-Co, Fe-Cr-Co, Co-rare earth, Fe-Si, Ni-Se system are considered. Application outlook for amorphous alloys of the (Fe, Ni, Co) 80 (metalloid) 20 type is shown. Methods for magnetic property measurement are pointed out

  18. Feature Size Effect on Formability of Multilayer Metal Composite Sheets under Microscale Laser Flexible Forming

    Directory of Open Access Journals (Sweden)

    Huixia Liu

    2017-07-01

    Full Text Available Multilayer metal composite sheets possess superior properties to monolithic metal sheets, and formability is different from monolithic metal sheets. In this research, the feature size effect on formability of multilayer metal composite sheets under microscale laser flexible forming was studied by experiment. Two-layer copper/nickel composite sheets were selected as experimental materials. Five types of micro molds with different diameters were utilized. The formability of materials was evaluated by forming depth, thickness thinning, surface quality, and micro-hardness distribution. The research results showed that the formability of two-layer copper/nickel composite sheets was strongly influenced by feature size. With feature size increasing, the effect of layer stacking sequence on forming depth, thickness thinning ratio, and surface roughness became increasingly larger. However, the normalized forming depth, thickness thinning ratio, surface roughness, and micro-hardness of the formed components under the same layer stacking sequence first increased and then decreased with increasing feature size. The deformation behavior of copper/nickel composite sheets was determined by the external layer. The deformation extent was larger when the copper layer was set as the external layer.

  19. Fundamentals of radiation materials science metals and alloys

    CERN Document Server

    Was, Gary S

    2017-01-01

    The revised second edition of this established text offers readers a significantly expanded introduction to the effects of radiation on metals and alloys. It describes the various processes that occur when energetic particles strike a solid, inducing changes to the physical and mechanical properties of the material. Specifically it covers particle interaction with the metals and alloys used in nuclear reactor cores and hence subject to intense radiation fields. It describes the basics of particle-atom interaction for a range of particle types, the amount and spatial extent of the resulting radiation damage, the physical effects of irradiation and the changes in mechanical behavior of irradiated metals and alloys. Updated throughout, some major enhancements for the new edition include improved treatment of low- and intermediate-energy elastic collisions and stopping power, expanded sections on molecular dynamics and kinetic Monte Carlo methodologies describing collision cascade evolution, new treatment of t...

  20. Processing and microstructure of Nb-1 percent Zr-0.1 percent C alloy sheet

    Science.gov (United States)

    Uz, Mehmet; Titran, Robert H.

    1992-01-01

    A systematic study was carried out to evaluate the effects of processing on the microstructure of Nb-1 wt. pct. Zr-0.1 wt. pct. C alloy sheet. The samples were fabricated by cold rolling different sheet bars that were single-, double- or triple-extruded at 1900 K. Heat treatment consisted on one- or two-step annealing of different samples at temperatures ranging from 1350 to 1850 K. The assessment of the effects of processing on microstructure involved characterization of the precipitates including the type, crystal structure, chemistry and distribution within the material as well as an examination of the grain structure. A combination of various analytical and metallographic techniques were used on both the sheet samples and the residue extracted from them. The results show that the relatively coarse orthorhombic Nb2C carbides in the as-rolled samples transformed to rather fine cubic monocarbides of Nb and Zr with varying Zr/Nb ratios upon subsequent heat treatment. The relative amount of the cubic carbides and the Zr/Nb ratio increased with increasing number of extrusions prior to cold rolling. Furthermore, the size and the aspect ratio of the grains appear to be strong functions of the processing history of the material. These and other results obtained will be presented with the emphasis on a possible relationship between processing and microstructure.

  1. Corrosion-electrochemical and mechanical properties of aluminium-berylium alloys alloyed by rare-earth metals

    International Nuclear Information System (INIS)

    Safarov, A.M.; Odinaev, Kh.E.; Shukroev, M.Sh.; Saidov, R.Kh.

    1997-01-01

    In order to study influence of rare earth metals on corrosion-electrochemical and mechanical properties of aluminium-berylium alloys the alloys contain 1 mass % beryllium and different amount of rare earth metals were obtained.-electrochemical and mechanical properties of aluminium-berylium alloys. The electrochemical characteristics of obtained alloys, including stationary potential, potentials of passivation beginning and full passivation, potentials of pitting formation and re passivation were defined.

  2. Hydrogen as a New Alloying Element in Metals

    International Nuclear Information System (INIS)

    Shapovalov, Vladimir

    1999-01-01

    Hydrogen was regarded as a harmful impurity in many alloys and particularly in steels where it gives rise to a specific type of embrittlement and forms various discontinuities like flakes and blowholes. For this reason, the researcher efforts were mainly focused on eliminating hydrogen's negative impacts and explaining its uncommonly high diffusivity in condensed phases. Meanwhile, positive characteristics of hydrogen as an alloying element remained unknown for quite a long time. Initial reports in this field did not appear before the early 1970s. Data on new phase diagrams are given for metal-hydrogen systems where the metal may or may not form hydrides. Various kinds of hydrogen impact on structure formation in solidification, melting and solid-solid transformations are covered. Special attention is given to the most popular alloys based on iron, aluminum, copper, nickel, magnesium and titanium. Detailed is what is called gas-eutectic reaction resulting in a special type of gas-solid structure named gasarite. Properties and applications of gasars - gasaritic porous materials - are dealt with. Various versions of solid-state alloying with hydrogen are discussed that change physical properties and fabrication characteristics of metals. Details are given on a unique phenomenon of anomalous spontaneous deformation due to combination of hydrogen environment and polymorphic transformation. All currently known versions of alloying with hydrogen are categorized for both hydride-forming and non-hydrid forming metals

  3. Production and properties of light-metal base amorphous alloys

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Masumoto, Tsuyoshi

    1993-01-01

    Light-metal base alloys with high specific strength and good corrosion resistance were produced through amorphization of Al and Mg-based alloys. The amorphous phase is formed in rapidly solidified Al-TM-Ln and Mg-TM-Ln (TM=transition metal, Ln=lanthanide metal) alloys. The highest tensile strength (σ f ) reaches 1,330 MPa for the Al base and 830 MPa for the Mg base. Furthermore, the Mg-based alloys have a large glass-forming capacity which enables to produce an amorphous phase by a metallic mold casting method. The extrusion of the Al-based amorphous powders at temperatures above crystallization temperature caused the formation of high strength materials with finely mixed structure consisting of dispersed intermetallic compounds in an Al matrix. The highest values of σ f and fatigue limit are as high as 940 and 313 MPa, respectively, at room temperature and 520 and 165 MPa at 473 K. The extruded Al-Ni-Mm alloy has already been used as machine parts and subsequent further development as practical materials is expected by taking these advantages

  4. Metallic ion release from biocompatible cobalt-based alloy

    Directory of Open Access Journals (Sweden)

    Dimić Ivana D.

    2014-01-01

    Full Text Available Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5. After a certain immersion period (1, 3 and 6 weeks the concentrations of released ions were determined using Inductively Coupled Plasma - Mass Spectrophotometer (ICP-MS. The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy. [Projekat Ministarstva nauke Republike Srbije, br. III 46010 i br. ON 174004

  5. Forming characteristics of artificial aging Al-Mg-Si-Cu sheet alloys

    Science.gov (United States)

    Klos, Artur; Kellner, Sven; Wortberg, Daniel; Walter, Philipp; Bassi, Corrado; Merklein, Marion

    2017-10-01

    AA6111 is a commonly used aluminum alloy for body-in-white (BIW) components with good bake-hardening response, high strength and excellent formability. For industrial applications various process strategies are considered to reach strength of about 250 MPa in the final body part with that type of alloy. The purpose of this paper is to discuss recent process strategies of high-strength AA6111 sheets to evaluate the forming characteristics, precipitation kinetics dissolution and mechanical properties in the final condition. The forming behavior is investigated by four potential process chains after single-stage or multi-stage heat treatment including T4 (pre-aged at > 80 °C after quenching), T61 (T4 + artificial aged at 120-150 °C for 10-18 h), T6 (T4 + artificial aged at 180-220°C up to 12 h) and PFHT (T4 + post form heat treatment at 205°C for 30 min). The experimental input for characterization of the formability consists of tensile tests, bending tests and drawing tests. Differential Scanning Calorimetry (DSC) is used, to correlate the forming behavior with the precipitation distribution in the advanced stages of aging. The study shows that the forming behavior is strongly dependent on the condition the alloy.

  6. Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

    International Nuclear Information System (INIS)

    Sheng, Z.Q.; Shivpuri, R.

    2005-01-01

    Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments

  7. Elementary characterization of Ti metal alloys used in implant dentistry

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Catarina A. M. P.; Paschuk, Sergei A.; Rocha, Anna S. S.; Corrêa, Janine Nicolosi [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Deniak, Valeriy [Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, PR (Brazil); Camargo, Liliane [Universidade Paranaense, Umuarama, PR (Brazil); Assis, J.T, E-mail: cata-montenegro@bol.com.br, E-mail: spaschuk@gmail.com, E-mail: denyak@gmail.com, E-mail: lili_camargo2@hotmail.com, E-mail: joaquim@iprj.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil)

    2017-07-01

    The main goal of present work is analytical characterization of standard dental implants broadly used by Brazilian dentists. An ideal biological alloy for dental implants must have very high biocompatibility, which means that such material should not provoke any serious adverse tissue response. Dental implants are generally marketed as commercially pure titanium (TiCP) due to their excellent mechanical and physical properties. However, sometimes other alloys are employed and consequently it is essential to study the chemical elements present in those alloys that could bring prejudice for the health. Present work investigated TiCP metal alloys used for dental implant manufacturing and evaluated the presence of elements. For alloy characterization and identification of elements it was used EDXRF technique. This method allows to perform the qualitative and quantitative analysis of the materials using the spectra of the characteristic X-rays emitted by the elements present in the metal samples. The experimental setup was based on two X- ray tubes, Mini X model with Ag and Au targets and X-123SDD detector (AMPTEK) and a 0.5 mm Cu collimator, developed due to specific sample geometrical and topography characteristics. Obtained results showed that implant alloys are not exactly TiCP but were manufactured using Ti-Al-V alloy, which contained Fe, Ni, Cu and Zn. The presence of such metals as Al and V in all studied samples shows very clear that studied implants were not manufactured from TiCP alloy. Moreover, according to the American Society for Testing and Materials (ASTM), these elements should not be present in TiCP. (author)

  8. Elementary characterization of Ti metal alloys used in implant dentistry

    International Nuclear Information System (INIS)

    Torres, Catarina A. M. P.; Paschuk, Sergei A.; Rocha, Anna S. S.; Corrêa, Janine Nicolosi; Deniak, Valeriy; Camargo, Liliane; Assis, J.T

    2017-01-01

    The main goal of present work is analytical characterization of standard dental implants broadly used by Brazilian dentists. An ideal biological alloy for dental implants must have very high biocompatibility, which means that such material should not provoke any serious adverse tissue response. Dental implants are generally marketed as commercially pure titanium (TiCP) due to their excellent mechanical and physical properties. However, sometimes other alloys are employed and consequently it is essential to study the chemical elements present in those alloys that could bring prejudice for the health. Present work investigated TiCP metal alloys used for dental implant manufacturing and evaluated the presence of elements. For alloy characterization and identification of elements it was used EDXRF technique. This method allows to perform the qualitative and quantitative analysis of the materials using the spectra of the characteristic X-rays emitted by the elements present in the metal samples. The experimental setup was based on two X- ray tubes, Mini X model with Ag and Au targets and X-123SDD detector (AMPTEK) and a 0.5 mm Cu collimator, developed due to specific sample geometrical and topography characteristics. Obtained results showed that implant alloys are not exactly TiCP but were manufactured using Ti-Al-V alloy, which contained Fe, Ni, Cu and Zn. The presence of such metals as Al and V in all studied samples shows very clear that studied implants were not manufactured from TiCP alloy. Moreover, according to the American Society for Testing and Materials (ASTM), these elements should not be present in TiCP. (author)

  9. Enhanced mechanical properties of ARB-processed aluminum alloy 6061 sheets by subsequent asymmetric cryorolling and ageing

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hailiang, E-mail: hailiang@uow.edu.au [State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083 (China); School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Su, Lihong; Lu, Cheng; Tieu, Kiet [School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Li, Huijun, E-mail: huijun@uow.edu.au [School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Li, Jintao; Godbole, Ajit [School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Kong, Charlie [Electron Microscope Unit, University of New South Wales, Sydney, NSW 2052 (Australia)

    2016-09-30

    Grain size and precipitations affect the strength and ductility of ultrafine-grained materials. In this study, aluminum alloy 6061 sheets were fabricated using the accumulative roll bonding (ARB) technique. The ARB-processed sheets were subsequently subjected to cryorolling and asymmetric cryorolling. The sheets were further aged at 100 °C for 48 h. Mechanical tests show that a combination of asymmetric cryorolling and ageing results in significant improvement in both the ductility and the strength of the ARB-processed sheets. The microstructures of the sheets at different stages of the process were also analyzed using optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction in order to correlate the mechanical properties with the microstructure.

  10. Enhanced mechanical properties of ARB-processed aluminum alloy 6061 sheets by subsequent asymmetric cryorolling and ageing

    International Nuclear Information System (INIS)

    Yu, Hailiang; Su, Lihong; Lu, Cheng; Tieu, Kiet; Li, Huijun; Li, Jintao; Godbole, Ajit; Kong, Charlie

    2016-01-01

    Grain size and precipitations affect the strength and ductility of ultrafine-grained materials. In this study, aluminum alloy 6061 sheets were fabricated using the accumulative roll bonding (ARB) technique. The ARB-processed sheets were subsequently subjected to cryorolling and asymmetric cryorolling. The sheets were further aged at 100 °C for 48 h. Mechanical tests show that a combination of asymmetric cryorolling and ageing results in significant improvement in both the ductility and the strength of the ARB-processed sheets. The microstructures of the sheets at different stages of the process were also analyzed using optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction in order to correlate the mechanical properties with the microstructure.

  11. Electromagnetic Characterization Of Metallic Sensory Alloy

    Science.gov (United States)

    Wincheski, Russell A.; Simpson, John; Wallace, Terryl A.; Newman, John A.; Leser, Paul; Lahue, Rob

    2012-01-01

    Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

  12. A Novel 3D Printer to Support Additive Manufacturing of Gradient Metal Alloy Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Gradient metal alloy structures possess multi-functional properties that conventional monolithic metal counterparts do not have. Such structures can potentially...

  13. A Novel 3D Printer to Support Additive Manufacturing of Gradient Metal Alloy Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gradient metal alloy structures possess multi-functional properties that conventional monolithic metal counterparts do not have. Such structures can potentially...

  14. 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

  15. Rolling induced size effects in elastic–viscoplastic sheet metals

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2015-01-01

    sheet rolling, where a non-homogeneous material deformation takes place between the rollers. Large strain gradients develop where the rollers first come in contact with the sheet, and a higher order plasticity model is employed to illustrate their influence at small scales. The study reveals...... presented revolves around the rolling induced effect of visco-plasticity (ranging hot and cold rolling) in combination with strain gradient hardening – including both dissipative and energetic contributions. To bring out first order effects on rolling at small scale, the modeling efforts are limited to flat...

  16. Warm Deep Drawing of Rectangular Parts of AZ31 Magnesium Alloy Sheet Adopting Variable Blank Holder Force

    International Nuclear Information System (INIS)

    Peng Yinghong; Chang Qunfeng; Li Dayong; Zeng Xiaoqin

    2007-01-01

    AZ31 magnesium alloy sheet with good shape and formability is fabricated by warm cross rolling. Uniaxial tensile tests are conducted using a Gleeble 3500 thermal - mechanical simulator, and the mechanical properties of AZ31 magnesium alloy sheet are analyzed. A warm deep drawing process of square part is also simulated by the finite element method. The influences of blank holder force on the formability are numerically investigated. A double-action hydraulic press that can realize adjustable blank holder forces is developed and its working principle and control system are introduced. Some warm deep drawing experiments of square parts of AZ31 magnesium alloy sheet are also performed. Different variation schemes of the blank holder force with the stroke of the punch are tested, and the experiment results are compared. Results show that the suitable blank holder force variation scheme is a ladder curve with the punch stroke. Adopting the variable blank holder force technique can improve 13.2% of the drawing depth of square parts of AZ31 magnesium alloy sheet

  17. Strengthening of metallic alloys with nanometer-size oxide dispersions

    Science.gov (United States)

    Flinn, John E.; Kelly, Thomas F.

    1999-01-01

    Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains.

  18. Metastability and thermophysical properties of metallic bulk glass forming alloys

    International Nuclear Information System (INIS)

    Wunderlich, R.K.; Fecht, H.J.

    1998-01-01

    The absence of crystallization over a wide time/temperature window can be used to produce bulk metallic glass by relatively slow cooling of the melt. For a number of alloys, including several multicomponent Zr-based alloys, the relevant thermodynamic and thermomechanical properties of the metastable glassy and undercooled liquid states have been measured below and above the glass transition temperature. These measurements include specific heat, viscosity, volume, and elastic properties as a function of temperature. As a result, it becomes obvious that the maximum undercooling for these alloys is given by an isentropic condition before an enthalpic or isochoric instability is reached. Alternatively, these glasses can also be produced by mechanical alloying, thus replacing the thermal disorder by static disorder and resulting in the same thermodynamic glass state. During heating through the undercooled liquid, a nanoscale phase separation occurs for most glasses as a precursor of crystallization

  19. Molybdenum-A Key Component of Metal Alloys

    Science.gov (United States)

    Kropschot, S.J.

    2010-01-01

    Molybdenum, whose chemical symbol is Mo, was first recognized as an element in 1778. Until that time, the mineral molybdenite-the most important source of molybdenum-was believed to be a lead mineral because of its metallic gray color, greasy feel, and softness. In the late 19th century, French metallurgists discovered that molybdenum, when alloyed (mixed) with steel in small quantities, creates a substance that is remarkably tougher than steel alone and is highly resistant to heat. The alloy was found to be ideal for making tools and armor plate. Today, the most common use of molybdenum is as an alloying agent in stainless steel, alloy steels, and superalloys to enhance hardness, strength, and resistance to corrosion.

  20. Strengthening of metallic alloys with nanometer-size oxide dispersions

    Science.gov (United States)

    Flinn, J.E.; Kelly, T.F.

    1999-06-01

    Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains. 20 figs.

  1. Atmospheric corrosion of metals in tropics and subtropic. 2. Corrosion resistance of different metals and alloys

    International Nuclear Information System (INIS)

    Strekalov, P.V.

    1993-01-01

    Data from 169 sources concerning corrosion of different metals, alloys and means of protection, obtained for a 30-year period (up to 1987) in different continent including Europe (Bulgaria, Spain, Italy, France, USSR); America (USA, Panama, Cuba, Venezuela, Brasil, Argentine); Africa (Nigeria, SAR); Australia, New Zeland, Papua-Newguinea, Philippines, are systemized. Actual results of full-scal atmospheric testings of iron, zinc, copper, cadmium, aluminium, tin, lead, carbon, low-alloys. Stainless steels, cast irons, halvanic coatings, copper, aluminium, nickel, titanium, magnesium alloys are presented. Data on the fracture rate can be used for creating the data base in banks on atmospheric resistance of metal materials

  2. Amorphous Metallic Alloys: Pathways for Enhanced Wear and Corrosion Resistance

    Science.gov (United States)

    Aditya, Ayyagari; Felix Wu, H.; Arora, Harpreet; Mukherjee, Sundeep

    2017-11-01

    Amorphous metallic alloys are widely used in bulk form and as coatings for their desirable corrosion and wear behavior. Nevertheless, the effects of heat treatment and thermal cycling on these surface properties are not well understood. In this study, the corrosion and wear behavior of two Zr-based bulk metallic glasses were evaluated in as-cast and thermally relaxed states. Significant improvement in wear rate, friction coefficient, and corrosion penetration rate was seen for both alloys after thermal relaxation. A fully amorphous structure was retained with thermal relaxation below the glass transition. There was an increase in surface hardness and elastic modulus for both alloys after relaxation. The improvement in surface properties was explained based on annihilation of free volume.

  3. Diffusion and surface alloying of gradient nanostructured metals

    Directory of Open Access Journals (Sweden)

    Zhenbo Wang

    2017-03-01

    Full Text Available Gradient nanostructures (GNSs have been optimized in recent years for desired performance. The diffusion behavior in GNS metals is crucial for understanding the diffusion mechanism and relative characteristics of different interfaces that provide fundamental understanding for advancing the traditional surface alloying processes. In this paper, atomic diffusion, reactive diffusion, and surface alloying processes are reviewed for various metals with a preformed GNS surface layer. We emphasize the promoted atomic diffusion and reactive diffusion in the GNS surface layer that are related to a higher interfacial energy state with respect to those in relaxed coarse-grained samples. Accordingly, different surface alloying processes, such as nitriding and chromizing, have been modified significantly, and some diffusion-related properties have been enhanced. Finally, the perspectives on current research in this field are discussed.

  4. Wetting of refractory metals with copper base alloys

    International Nuclear Information System (INIS)

    Anikeev, E.F.; Kostikov, V.I.; Chepelenko, V.N.; Batov, V.M.

    1978-01-01

    The effect is studied of phosphorus upon the wetting of molybdenum, niobium and tantalum by an alloy of the system copper-silver (10%) as a function of contact time and phosphorus concentration. Experiments have been conducted in vacuum of 5x10 -4 mm Hg at 900 deg C. It is established that the introduction of phosphorus into a copper-silver alloy improves the wetting of molybdenum, niobium and tantalum. Formation of intermetallic compounds on the alloy-refractory metal interface can be avoided by adjusting the time of contact of the solder with molybdenum, niobium and tantalum. As a solder with 2.9% phosphorus spreads well over copper, it is suggested to use said solder for brazing copper and the investigated refractory metals in items intended for service at temperatures of up to 600 deg C

  5. Hydrogen formation in metals and alloys during fusion reactor operation

    International Nuclear Information System (INIS)

    Zimin, S.; Takatsu, Hideyuki; Mori, Seiji

    1994-08-01

    The results of neutron transport calculations of the hydrogen formation based on the JENDL gas-production cross section file are discussed for some metals and alloys, namely 51 V, Cr, Fe, Ni, Mo, austenitic stainless steel (Ti modified 316SS:PCA), ferritic steel (Fe-8Cr-2W:F82H) and the vanadium-base alloy (V-5Cr-5Ti). Impact of the steel fraction in steel/water homogeneous blanket/shield compositions on the hydrogen formation rate in above-mentioned metals and alloys is discussed both for the hydrogen formation in the first wall and the blanket/shield components. The results obtained for the first wall are compared with those for the helium formation obtained at JAERI by the same calculational conditions. Hydrogen formation rates at the first wall having 51 V, Cr, Fe, Ni and Mo are larger than those of helium by 3-8 times. (author)

  6. Efficient implicit FEM simulation of sheet metal forming

    NARCIS (Netherlands)

    van den Boogaard, Antonius H.; Meinders, Vincent T.; Huetink, Han

    2003-01-01

    For the simulation of industrial sheet forming processes, the time discretisation is one of the important factors that determine the accuracy and efficiency of the algorithm. For relatively small models, the implicit time integration method is preferred, because of its inherent equilibrium check.

  7. Fatigue damage assessment of recycled metals and alloys | Ayensu ...

    African Journals Online (AJOL)

    Cyclic fatigue tests were conducted on recycled polycrystalline metals and alloys at room and elevated tempera-ures to determine the fatigue strength, endurance limit and endurance ratio. Annealed and polished stainless steel (Fe-18Cr-8Ni), mild steel (Fe-0.25Cr), aluminium (Al), alpha-brass (Cu-30 % Zn) and copper ...

  8. Charge transfer in chromium-transition metal alloys

    International Nuclear Information System (INIS)

    Kulakowski, K.; Maksymowicz, A.

    1984-07-01

    The average T-matrix approximation is applied for calculations of charge transfer of 3d-electrons in transition metal alloys. The role of concentration, long-range and short-range atomic order is investigated. The results are in reasonable agreement with experimental data. (author)

  9. Electronic structure of metallic alloys through Auger and photoemission spectroscopy

    International Nuclear Information System (INIS)

    Kleiman, G.G.; Rogers, J.D.; Sundaram, V.S.

    1981-01-01

    A review is presented of experimental results of electron spectroscopy studies for various series of transition metal alloys as well as a model for their interpretation which leads to the possibility for the first time to determine independently relative variations in the dipole barrier and Fermi energy contributions to the work function. (L.C.) [pt

  10. Nitrogen annealing of zirconium or titanium metals and their alloys

    International Nuclear Information System (INIS)

    Eucken, C.M.

    1982-01-01

    A method is described of continuously nitrogen annealing zirconium and titanium metals and their alloys at temperatures at from 525 0 to 875 0 C for from 1/2 minute to 15 minutes. The examples include the annealing of Zircaloy-4. (U.K.)

  11. A kinematic hardening constitutive model for the uniaxial cyclic stress-strain response of magnesium sheet alloys at room temperature

    Science.gov (United States)

    He, Zhitao; Chen, Wufan; Wang, Fenghua; Feng, Miaolin

    2017-11-01

    A kinematic hardening constitutive model is presented, in which a modified form of von Mises yield function is adopted, and the initial asymmetric tension and compression yield stresses of magnesium (Mg) alloys at room temperature (RT) are considered. The hardening behavior was classified into slip, twinning, and untwinning deformation modes, and these were described by two forms of back stress to capture the mechanical response of Mg sheet alloys under cyclic loading tests at RT. Experimental values were obtained for AZ31B-O and AZ31B sheet alloys under both tension-compression-tension (T-C-T) and compression-tension (C-T) loadings to calibrate the parameters of back stresses in the proposed model. The predicted parameters of back stresses in the twinning and untwinning modes were expressed as a cubic polynomial. The predicted curves based on these parameters showed good agreement with the tests.

  12. INDUCTION HEATING OF NON-MAGNETIC SHEET METALS IN THE FIELD OF A FLAT CIRCULAR MULTITURN SOLENOID

    Directory of Open Access Journals (Sweden)

    Y. Batygin

    2016-06-01

    Full Text Available The theoretical analysis of electromagnetic processes in the system for induction heating presented by a flat circular multiturn solenoid positioned above a plane of thin sheet non-magnetic metal has been conducted. The calculated dependences for the current induced in a metal sheet blank and ratio of transformation determined have been obtained. The maximal value of the transformation ratio with regard to spreading the eddy-currents over the whole area of the sheet metal has been determined.

  13. In-situ stress analysis with X-Ray diffraction for yield locus characterization of sheet metals

    Energy Technology Data Exchange (ETDEWEB)

    Güner, A.; Tekkaya, A. E. [Institute of Forming Technology and Lightweight Construction, TU Dortmund University, Baroper Str. 301, 44227 Dortmund (Germany); Zillmann, B.; Lampke, T. [Institute of Materials Science and Engineering, Chemnitz University of Technology, Erfenschlager Strasse 73 D-09125 Chemnitz (Germany)

    2013-12-16

    A main problem in the field of sheet metal characterization is the inhomogeneous plastic deformation in the gauge regions of specimens which causes the analytically calculated stresses to differ from the sought state of stress acting in the middle of the gauge region. To overcome this problem, application of X-Ray diffraction is analyzed. For that purpose a mobile X-ray diffractometer and an optical strain measurement system are mounted on a universal tensile testing machine. This enables the recording of the whole strain and stress history of a material point. The method is applied to uniaxial tension tests, plane strain tension tests and shear tests to characterize the interstitial free steel alloy DC06. The applicability of the concepts of stress factors is verified by uniaxial tension tests. The experimentally obtained values are compared with the theoretical values calculated with crystal elasticity models utilizing the orientation distribution functions (ODF). The relaxation problem is addressed which shows itself as drops in the stress values with the strain kept at a constant level. This drop is analyzed with elasto-viscoplastic material models to correct the measured stresses. Results show that the XRD is applicable to measure the stresses in sheet metals with preferred orientation. The obtained yield locus is expressed with the Yld2000–2D material model and an industry oriented workpiece is analyzed numerically. The comparison of the strain distribution on the workpiece verifies the identified material parameters.

  14. Assessing the formability of metallic sheets by means of localized and diffuse necking models

    Science.gov (United States)

    Comşa, Dan-Sorin; Lǎzǎrescu, Lucian; Banabic, Dorel

    2016-10-01

    The main objective of the paper consists in elaborating a unified framework that allows the theoretical assessment of sheet metal formability. Hill's localized necking model and the Extended Maximum Force Criterion proposed by Mattiasson, Sigvant, and Larsson have been selected for this purpose. Both models are thoroughly described together with their solution procedures. A comparison of the theoretical predictions with experimental data referring to the formability of a DP600 steel sheet is also presented by the authors.

  15. Effect of Heating Rate on Grain Structure and Superplasticity of 7B04 Aluminum Alloy Sheets

    Directory of Open Access Journals (Sweden)

    CHEN Min

    2017-03-01

    Full Text Available Fine-grained 7B04 aluminum alloy sheets were manufactured through thermo-mechanical treatment. The effects of anneal heating rate on grain structure and superplasticity were investigated using electron back scattering diffraction(EBSD and high temperature tensile test. The results show that at the heating rate of 5.0×10-3K/s, the average grain sizes along the rolling direction(RD and normal direction(ND are 28.2μm and 13.9μm respectively, the nucleation rate is 1/1000. With the increase of heating rate, the average grain size decreases, and the nucleation rate increases. When the heating rate increases to 30.0K/s, the average grain sizes along the RD and ND decrease respectively to 9.9μm and 5.1μm, and the nucleation rate increases to 1/80. Besides, with the increase of heating rate, the elongation of sheets also increases. The elongation of the specimens increases from 100% to 730% under the deforming condition of 773K/8×10-4s-1.

  16. A numerical simulation of thermodynamic processes for cryogenic metal forming of aluminum sheets and comparison with experimental results

    International Nuclear Information System (INIS)

    Reichl, Ch.; Schneider, R.; Hohenauer, W.; Grabner, F.; Grant, R.J.

    2017-01-01

    Highlights: • Thermodynamic processes for cryogenic sheet metal forming tools were examined. • Static and transient temperature field simulations are evaluated on a Nakajima tool. • Differently arranged cooling loops lead to homogeneous temperature distribution. • Scaling of the geometry leads to significantly increased heat transfer times. • The temperature management of complex forming tools can be developed numerically. - Abstract: Forming at cryogenic temperatures provides a significant improvement in formability of aluminum sheets. This offers the potential for light, complex and highly integrated one-piece components to be produced out of aluminum alloys at sub-zero temperatures. This would allow weight reduction, environmental conservation and cost reduction of a car body to give one example in the automotive industry. For temperature supported processes special forming tools and cooling strategies are required to be able to reach and maintain process stability. Time dependent numerical simulations of the thermodynamic processes of cryogenic sheet metal forming covering all aspects of heat transfer through conduction, convection and radiation play a vital role in the design and development of future tools and are presented for several geometries. Cooling (and heating) strategies (including selection of the number of cooling loops and their relative positioning) in a Nakajima testing tool were evaluated using computational fluid dynamics. These simulations were performed with static and transient solvers to demonstrate the extraction of tool surface temperature distributions on different forming tool geometries. Comparisons of predicted temperature characteristics of an aluminum sheet and experimentally determined temperature distributions were made. The temperature distribution of the surface of an aluminum sheet could be predicted with high accuracy. Further, the influence of the tool size on the parameters temperature transfer times and

  17. Development and pilot production of three ingot-source beryllium sheet metal parts

    International Nuclear Information System (INIS)

    Floyd, D.R.

    1975-01-01

    Results of an extensive development program aimed at making three, separate, structural components from beryllium, using sheet-metal fabrication methods, are presented. Ingot-source beryllium sheet at thicknesses of 0.100, 0.125, and 0.170 inch is formed in a fully-recrystallized and in a partially-recrystallized condition. The tensile yield strength is 26,000 psi after full recrystallization. After partial recrystallization, tensile yield strength is between 35,000 and 45,000 psi, depending upon sheet thickness, heat treat temperature, and time at temperature. The high yield strength is retained in the parts after forming. (U.S.)

  18. Process for continuous production of metallic uranium and uranium alloys

    Science.gov (United States)

    Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

    1995-01-01

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

  19. Process for continuous production of metallic uranium and uranium alloys

    Science.gov (United States)

    Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

    1995-06-06

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

  20. Deformation and fracture of thin sheet aluminum-lithium alloys: The effect of cryogenic temperatures

    Science.gov (United States)

    Wagner, John A.; Gangloff, Richard P.

    1990-01-01

    The objective is to characterize the fracture behavior and to define the fracture mechanisms for new Al-Li-Cu alloys, with emphasis on the role of indium additions and cryogenic temperatures. Three alloys were investigated in rolled product form: 2090 baseline and 2090 + indium produced by Reynolds Metals, and commercial AA 2090-T81 produced by Alcoa. The experimental 2090 + In alloy exhibited increases in hardness and ultimate strength, but no change in tensile yield strength, compared to the baseline 2090 composition in the unstretched T6 condition. The reason for this behavior is not understood. Based on hardness and preliminary Kahn Tear fracture experiments, a nominally peak-aged condition was employed for detailed fracture studies. Crack initiation and growth fracture toughness were examined as a function of stress state and microstructure using J(delta a) methods applied to precracked compact tension specimens in the LT orientation. To date, J(delta a) experiments have been limited to 23 C. Alcoa 2090-T81 exhibited the highest toughness regardless of stress state. Fracture was accompanied by extensive delamination associated with high angle grain boundaries normal to the fatigue precrack surface and progressed microscopically by a transgranular shear mechanism. In contrast the two peak-aged Reynolds alloys had lower toughness and fracture was intersubgranular without substantial delamination. The influences of cryogenic temperature, microstructure, boundary precipitate structure, and deformation mode in governing the competing fracture mechanisms will be determined in future experiments. Results contribute to the development of predictive micromechanical models for fracture modes in Al-Li alloys, and to fracture resistant materials.

  1. Development of Multi-Scale Finite Element Analysis Codes for High Formability Sheet Metal Generation

    International Nuclear Information System (INIS)

    Nnakamachi, Eiji; Kuramae, Hiroyuki; Ngoc Tam, Nguyen; Nakamura, Yasunori; Sakamoto, Hidetoshi; Morimoto, Hideo

    2007-01-01

    In this study, the dynamic- and static-explicit multi-scale finite element (F.E.) codes are developed by employing the homogenization method, the crystalplasticity constitutive equation and SEM-EBSD measurement based polycrystal model. These can predict the crystal morphological change and the hardening evolution at the micro level, and the macroscopic plastic anisotropy evolution. These codes are applied to analyze the asymmetrical rolling process, which is introduced to control the crystal texture of the sheet metal for generating a high formability sheet metal. These codes can predict the yield surface and the sheet formability by analyzing the strain path dependent yield, the simple sheet forming process, such as the limit dome height test and the cylindrical deep drawing problems. It shows that the shear dominant rolling process, such as the asymmetric rolling, generates ''high formability'' textures and eventually the high formability sheet. The texture evolution and the high formability of the newly generated sheet metal experimentally were confirmed by the SEM-EBSD measurement and LDH test. It is concluded that these explicit type crystallographic homogenized multi-scale F.E. code could be a comprehensive tool to predict the plastic induced texture evolution, anisotropy and formability by the rolling process and the limit dome height test analyses

  2. Computational dynamics of laser alloyed metallic materials for improved corrosion performance: computational dynamics of laser alloyed metallic materials

    CSIR Research Space (South Africa)

    Fatoba, OS

    2016-04-01

    Full Text Available Laser alloying is a material processing method which utilizes the high power density available from defocused laser beam to melt both metal coatings and a part of the underlying substrate. Since melting occur solitary at the surface, large...

  3. Rapid Prototyping by Single Point Incremental Forming of Sheet Metal

    DEFF Research Database (Denmark)

    Skjødt, Martin

    2008-01-01

    . The process is incremental forming since plastic deformation takes place in a small local zone underneath the forming tool, i.e. the sheet is formed as a summation of the movement of the local plastic zone. The process is slow and therefore only suited for prototypes or small batch production. On the other...... in the plastic zone. Using these it is demonstrated that the growth rate of accumulated damage in SPIF is small compared to conventional sheet forming processes. This combined with an explanation why necking is suppressed is a new theory stating that SPIF is limited by fracture and not necking. The theory...... SPIF. A multi stage strategy is presented which allows forming of a cup with vertical sides in about half of the depth. It is demonstrated that this results in strain paths which are far from straight, but strains are still limited by a straight fracture line in the principal strain space. The multi...

  4. A NEW TREND IN MAGNETIC-PULSE METAL WORKING ASSOCIATED WITH THIN-WALLED SHEET METAL ATTRACTION. HISTORY AND DEVELOPMENT PROSPECTS

    Directory of Open Access Journals (Sweden)

    A.V. Gnatov

    2013-04-01

    Full Text Available Within the scope of this article, a summary is presented on the main world achievements of the new trend in magnetic-pulse metal working associated with attraction of specified sheet metal sections in vehicle production and repair. The importance of the new trend has been justified, its basic sources disclosed. Alternative straightening methods for damaged sheet metals are given.

  5. 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.

  6. COST 507: Thermophysical properties of light metal alloys. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jaroma-Weiland, G; Brandt, R; Neuer, G

    1994-02-15

    The thermophysical properties of Al-, Mg- and Ti-based light metal alloys have been studied by reviewing the literature published so far, evaluating the empirical results and by empirical investigations. The properties to the covered in the literature research are: thermal conductivity, thermal diffusivity, specific heat capacity, thermal expansion and electrical resistivity. The data have been stored in the factual data base THERSYST together with the results of experimental measurements supplied from participants of the COST 507-action (Group D). Altogether 1325 data-sets referring to 146 alloys have been stored. They have been uniformly represented and critically analyzed by means of the THERSYST program moduli. These numerical data cover a number of systems with variing chemical composition and thermal treatment. Partly large discrepancies especially of the thermal conductivity have been found for similar alloys. The problem of experimental uncertainities has been studied in detail by investigation of AA-8090 alloy (Al-2.5Li-1.1Cu). The thermophysical properties of monolithic alloy KS1275 (AlSi12CuNi) and metal matrix composite (KS1275 reinforced with Al2O3 short fibre) have been determined experimentally. (orig.)

  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. Keyhole shapes during laser welding of thin metal sheets

    International Nuclear Information System (INIS)

    Aalderink, B J; Lange, D F de; Aarts, R G K M; Meijer, J

    2007-01-01

    Camera observations of the full penetration keyhole laser welding process show that the keyhole shape is elongated under certain welding conditions. Under these unfavourable circumstances, the welding process is susceptible to holes in the weld bead. Existing models of the pressure balance at the keyhole wall cannot explain this keyhole elongation. In this paper a new model is presented, accounting for the doubly curved shape of the keyhole wall. In this model, the surface tension pressure has one term that tends to close the keyhole and another term that tries to open it. Model calculations show that when the keyhole diameter is of the same order as the sheet thickness, the latter part can become dominant, causing the keyhole to elongate. Experiments on thin aluminium (AA5182) and mild steel (DC04) sheets verify these model calculations. As the keyhole radius depends on the radius of the focused laser spot, it was found for both materials that the ratio of the spot radius and the sheet thickness must be above a critical value to prevent keyhole elongation. These critical radii are 0.25 for AA5182 and 0.4 for DC04, respectively. Furthermore, differences in appearance of the weld bead between the circular and the elongated keyhole welds could be explained by this model

  9. Influence of part orientation on the geometric accuracy in robot-based incremental sheet metal forming

    Science.gov (United States)

    Störkle, Denis Daniel; Seim, Patrick; Thyssen, Lars; Kuhlenkötter, Bernd

    2016-10-01

    This article describes new developments in an incremental, robot-based sheet metal forming process (`Roboforming') for the production of sheet metal components for small lot sizes and prototypes. The dieless kinematic-based generation of the shape is implemented by means of two industrial robots, which are interconnected to a cooperating robot system. Compared to other incremental sheet metal forming (ISF) machines, this system offers high geometrical form flexibility without the need of any part-dependent tools. The industrial application of ISF is still limited by certain constraints, e.g. the low geometrical accuracy. Responding to these constraints, the authors present the influence of the part orientation and the forming sequence on the geometric accuracy. Their influence is illustrated with the help of various experimental results shown and interpreted within this article.

  10. Development of parallel benchmark code by sheet metal forming simulator 'ITAS'

    International Nuclear Information System (INIS)

    Watanabe, Hiroshi; Suzuki, Shintaro; Minami, Kazuo

    1999-03-01

    This report describes the development of parallel benchmark code by sheet metal forming simulator 'ITAS'. ITAS is a nonlinear elasto-plastic analysis program by the finite element method for the purpose of the simulation of sheet metal forming. ITAS adopts the dynamic analysis method that computes displacement of sheet metal at every time unit and utilizes the implicit method with the direct linear equation solver. Therefore the simulator is very robust. However, it requires a lot of computational time and memory capacity. In the development of the parallel benchmark code, we designed the code by MPI programming to reduce the computational time. In numerical experiments on the five kinds of parallel super computers at CCSE JAERI, i.e., SP2, SR2201, SX-4, T94 and VPP300, good performances are observed. The result will be shown to the public through WWW so that the benchmark results may become a guideline of research and development of the parallel program. (author)

  11. Surface segregation energies in transition-metal alloys

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt; Nørskov, Jens Kehlet

    1999-01-01

    We present a database of 24 x 24 surface segregation energies of single transition metal impurities in transition-metal hosts obtained by a Green's-function linear-muffin-tin-orbitals method in conjunction with the coherent potential and atomic sphere approximations including a multipole correction...... to the electrostatic potential and energy. We use the database to establish the major factors which govern surface segregation in transition metal alloys. We find that the calculated trends are well described by Friedel's rectangular state density model and that the few but significant deviations from the simple...

  12. Bulk metallic glasses and high entropy alloys for reprocessing applications

    International Nuclear Information System (INIS)

    Kamachi Mudali, U.; Jayaraj, J.

    2016-01-01

    Recent breakthroughs in materials engineering have generated complex alloys that retain a glassy state in bulk form (bulk metallic glasses or BMGs) via ingot casting. High corrosion resistance is expected for BMGs (amorphous) as they are free from defects associated with the crystalline state such as grain boundaries, dislocations and stacking faults. Compared with conventional alloys containing one or two principal elements, the recently developed HEAs are usually composed of five or more elements with equimolar or near equimolar elemental fractions, which forms single solid solution phase. These HEAs exhibit excellent microstructural stability with better mechanical, wear and corrosion resistance properties as they are essentially single phase. Reprocessing of spent fuel from the fast breeder reactor involves the use of high concentration of (11.5 M) nitric acid under boiling conditions for the dissolution of the fuel. Conventional AISI type 304LSS and nitric acid grade 304L stainless steel would undergo inter-granular corrosion under these conditions and cannot be used for the fabrication of dissolver vessel. Currently titanium is used and zirconium alloys are proposed for future dissolver applications. Thus searching for newer materials with higher corrosion resistance suggests metallic glasses and HEAs for critical components of the dissolver application. Several Zr-based glassy alloys with different microstructural states and Ni-Nb based glassy alloys and TiZrHfNbTa HEA were cast and characterized for microstructure and corrosion resistance in nitric acid medium. From these studies, factors such as the corrosive environment (nitric acid, chloride and fluoride), and the presence of passivating elements in the alloy were emphasized for better corrosion resistance of BMGs and HEA. Attempts were also made to prepare coatings of Zr-and Ni-based glassy alloys on 304LSS by laser based deposition technique and their corrosion properties were evaluated. (author)

  13. Alloy with metallic glass and quasi-crystalline properties

    Science.gov (United States)

    Xing, Li-Qian; Hufnagel, Todd C.; Ramesh, Kaliat T.

    2004-02-17

    An alloy is described that is capable of forming a metallic glass at moderate cooling rates and exhibits large plastic flow at ambient temperature. Preferably, the alloy has a composition of (Zr, Hf).sub.a Ta.sub.b Ti.sub.c Cu.sub.d Ni.sub.e Al.sub.f, where the composition ranges (in atomic percent) are 45.ltoreq.a.ltoreq.70, 3.ltoreq.b.ltoreq.7.5, 0.ltoreq.c.ltoreq.4, 3.ltoreq.b+c.ltoreq.10, 10.ltoreq.d.ltoreq.30, 0.ltoreq.e.ltoreq.20, 10.ltoreq.d+e.ltoreq.35, and 5.ltoreq.f.ltoreq.15. The alloy may be cast into a bulk solid with disordered atomic-scale structure, i.e., a metallic glass, by a variety of techniques including copper mold die casting and planar flow casting. The as-cast amorphous solid has good ductility while retaining all of the characteristic features of known metallic glasses, including a distinct glass transition, a supercooled liquid region, and an absence of long-range atomic order. The alloy may be used to form a composite structure including quasi-crystals embedded in an amorphous matrix. Such a composite quasi-crystalline structure has much higher mechanical strength than a crystalline structure.

  14. Coating with overlay metallic-cermet alloy systems

    Science.gov (United States)

    Gedwill, M. A.; Levine, S. R.; Glasgow, T. K. (Inventor)

    1984-01-01

    A base layer of an oxide dispersed, metallic alloy (cermet) is arc plasma sprayed onto a substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use. A top layer of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then arc plasma sprayed onto the base layer. A heat treatment is used to improve the bonding. The base layer serves as an inhibitor to interdiffusion between the protective top layer and the substrate. Otherwise, the 10 protective top layer would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures.

  15. Modification of amorphous metal alloys and nanocrystals by radiation

    International Nuclear Information System (INIS)

    Holkova, D.; Sitek, J.

    2017-01-01

    The paper deals with radiation damage and modification of amorphous metal alloys by neutron irradiation and electrons. Initial experiments were focused on electron irradiation, with various amorphous precursors as well as nanocrystalline alloys: Fe_8_1Nb_7B_1_2, (Fe_3Ni_1)_8_1Nb_7B_1_2, (Fe_3Ni_1)_8_1Nb_7B_1_2 and NANOMET Fe_8_1_._6B_9_._6Si_4_._8P_3Cu_1 being selected for the irradiated objects. The experimental part summarizes the previous results obtained by Moessbauer spectroscopy as well as XRD. (authors)

  16. Research on NC laser combined cutting optimization model of sheet metal parts

    Science.gov (United States)

    Wu, Z. Y.; Zhang, Y. L.; Li, L.; Wu, L. H.; Liu, N. B.

    2017-09-01

    The optimization problem for NC laser combined cutting of sheet metal parts was taken as the research object in this paper. The problem included two contents: combined packing optimization and combined cutting path optimization. In the problem of combined packing optimization, the method of “genetic algorithm + gravity center NFP + geometric transformation” was used to optimize the packing of sheet metal parts. In the problem of combined cutting path optimization, the mathematical model of cutting path optimization was established based on the parts cutting constraint rules of internal contour priority and cross cutting. The model played an important role in the optimization calculation of NC laser combined cutting.

  17. Multiscale model of metal alloy oxidation at grain boundaries

    International Nuclear Information System (INIS)

    Sushko, Maria L.; Alexandrov, Vitaly; Schreiber, Daniel K.; Rosso, Kevin M.; Bruemmer, Stephen M.

    2015-01-01

    High temperature intergranular oxidation and corrosion of metal alloys is one of the primary causes of materials degradation in nuclear systems. In order to gain insights into grain boundary oxidation processes, a mesoscale metal alloy oxidation model is established by combining quantum Density Functional Theory (DFT) and mesoscopic Poisson-Nernst-Planck/classical DFT with predictions focused on Ni alloyed with either Cr or Al. Analysis of species and fluxes at steady-state conditions indicates that the oxidation process involves vacancy-mediated transport of Ni and the minor alloying element to the oxidation front and the formation of stable metal oxides. The simulations further demonstrate that the mechanism of oxidation for Ni-5Cr and Ni-4Al is qualitatively different. Intergranular oxidation of Ni-5Cr involves the selective oxidation of the minor element and not matrix Ni, due to slower diffusion of Ni relative to Cr in the alloy and due to the significantly smaller energy gain upon the formation of nickel oxide compared to that of Cr 2 O 3 . This essentially one-component oxidation process results in continuous oxide formation and a monotonic Cr vacancy distribution ahead of the oxidation front, peaking at alloy/oxide interface. In contrast, Ni and Al are both oxidized in Ni-4Al forming a mixed spinel NiAl 2 O 4 . Different diffusivities of Ni and Al give rise to a complex elemental distribution in the vicinity of the oxidation front. Slower diffusing Ni accumulates in the oxide and metal within 3 nm of the interface, while Al penetrates deeper into the oxide phase. Ni and Al are both depleted from the region 3–10 nm ahead of the oxidation front creating voids. The oxide microstructure is also different. Cr 2 O 3 has a plate-like structure with 1.2–1.7 nm wide pores running along the grain boundary, while NiAl 2 O 4 has 1.5 nm wide pores in the direction parallel to the grain boundary and 0.6 nm pores in the perpendicular direction providing an additional

  18. Fracture assessment for a dissimilar metal weld of low alloy steel and Ni-base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Takuya, E-mail: takuya4.ogawa@toshiba.co.jp [Toshiba Corporation Power Systems Company, Power and Industrial Systems Research and Development Center, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8523 (Japan); Itatani, Masao; Saito, Toshiyuki; Hayashi, Takahiro; Narazaki, Chihiro; Tsuchihashi, Kentaro [Toshiba Corporation Power Systems Company, Power and Industrial Systems Research and Development Center, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8523 (Japan)

    2012-02-15

    Recently, instances of SCC in Ni-base alloy weld metal of light water reactor components have been reported. Despite the possibility of propagation of SCC crack to the fusion line between low alloy steel (LAS) of pressure vessel and Ni-base alloy of internal structure, a fracture assessment method of dissimilar metal welded joint has not been established. The objective of this study is to investigate a fracture mode of dissimilar metal weld of LAS and Ni-base alloy for development of a fracture assessment method for dissimilar metal weld. Fracture tests were conducted using two types of dissimilar metal weld test plates with semi-elliptical surface crack. In one of the test plates, the fusion line lies around the surface points of the surface crack and the crack tips at the surface points have intruded into LAS. Material ahead of the crack tip at the deepest point is Ni-base alloy. In the other, the fusion line lies around the deepest point of the surface crack and the crack tip at the deepest point has intruded into LAS. Material ahead of the crack tip at the deepest point is LAS. The results of fracture tests using the former type of test plate reveal that the collapse load considering the proportion of ligament area of each material gives a good estimation for fracture load. That is, fracture assessment based on plastic collapse mode is applicable to the former type of test plate. It is also understood that a fracture assessment method based on the elastic-plastic fracture mode is suitable for the latter type of test plate.

  19. Optimizing the Parameters in Heat Treatment for Achieving High Hardness and Efficient Bending of Thin BS 2014 Aluminium Alloy Sheets

    Directory of Open Access Journals (Sweden)

    Abirami Priyadarshini B.

    2016-05-01

    Full Text Available The present work targets in setting a standard heat treatment procedure for obtaining high hardness values of the order of 80 HRB in BS 2014 aluminium alloy sheets of 2mm thick commonly used in aerospace industries. A hardness range of 60HRB to 72HRB is possible in low thickness sheets as stated in the standard BS EN 485-2:2013. Experiments were performed to achieve higher hardness values by controlling the heat treatment temperatures thereby understanding the ageing mechanism of the Al-Cu alloy to a wider extent. The validated process sequence in turn resulted in complications where bending of the sheets resulted in cracking. Further investigation was performed and it was found that the BS 2014 alloy has to be bent within two hours of solution annealing in order to have an efficient bending. The results showed that the natural ageing is so rapid in this alloy, which strengthens the material so quickly by the formation of CuAl2 precipitates, thereby, demanding the bending procedure to be performed before the growth of precipitates becomes dominant.

  20. Possibility of surface carburization of refractory metals of electric spark alloying

    International Nuclear Information System (INIS)

    Verkhoturov, A.D.; Isaeva, L.P.; Timofeeva, I.I.; Tsyban', V.A.

    1981-01-01

    The paper is concerned with a study in the alloying layer formation under electric spark alloying of refractory (Ti, Zr, Nb, Mo, W, Co, Fe) metals with graphite in argon and in air using the EhFI-46A installation. It is shown that in electric spark alloying with graphite there appear certain specific conditions for the alloying layer formation manifested in the cathode mass decrease during treatment. In this case an alloying layer consisting of carbides, oxides of the corresponding metals and material of the base is formed on the metal surface. The best carburization conditions in the process of electric spark alloying are realized for group 4 metals when treating them in ''soft'' regime, specific time of alloying being 1-3 min/sm 2 and for group 5 and 6 metals - in ''rigid'' regime of treatment and specific time of alloying 3-5 min/cm 2 [ru

  1. Three dimensional atom probe study of Ni-base alloy/low alloy steel dissimilar metal weld interfaces

    International Nuclear Information System (INIS)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun

    2012-01-01

    Three dimensional atom probe tomography (3D APT) is applied to characterize the dissimilar metal joint which was welded between the Ni-based alloy, Alloy 690 and the low alloy steel, A533 Gr. B, with Alloy 152 filler metal. While there is some difficulty in preparing the specimen for the analysis, the 3D APT has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multicomponent metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. In this study, the procedure for 3D APT specimen preparation was established, and those for dissimilar metal weld interface were prepared near the fusion boundary by a focused ion beam. The result of the analysis in this study showed the precipitation of chromium carbides near the fusion boundary between A533 Gr. B and Alloy 152.

  2. Three dimensional atom probe study of Ni-base alloy/low alloy steel dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-08-15

    Three dimensional atom probe tomography (3D APT) is applied to characterize the dissimilar metal joint which was welded between the Ni-based alloy, Alloy 690 and the low alloy steel, A533 Gr. B, with Alloy 152 filler metal. While there is some difficulty in preparing the specimen for the analysis, the 3D APT has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multicomponent metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. In this study, the procedure for 3D APT specimen preparation was established, and those for dissimilar metal weld interface were prepared near the fusion boundary by a focused ion beam. The result of the analysis in this study showed the precipitation of chromium carbides near the fusion boundary between A533 Gr. B and Alloy 152.

  3. Detection of defects in formed sheet metal using medial axis transformation

    Science.gov (United States)

    Murmu, Naresh C.; Velgan, Roman

    2003-05-01

    In the metal forming processes, the sheet metals are often prone to various defects such as thinning, dents, wrinkles etc. In the present manufacturing environments with ever increasing demand of higher quality, detecting the defects of formed sheet metal using an effective and objective inspection system is the foremost norm to remain competitive in market. The defect detection using optical techniques aspire to satisfy its needs to be non-contact and fast. However, the main difficulties to achieve this goal remain essentially on the development of efficient evaluation technique and accurate interpretation of extracted data. The defect like thinning is detected by evaluating the deviations of the thickness in the formed sheet metal against its nominal value. The present evaluation procedure for determination of thickness applied on the measurements data is not without deficiency. To improve this procedure, a new evaluation approach based on medial axis transformation is proposed here. The formed sheet metals are digitized using fringe projection systems in different orientations, and afterwards registered into one coordinate frame. The medial axis transformation (MAT) is applied on the point clouds, generating the point clouds of MAT. This data is further processed and medial surface is determined. The thinning defect is detected by evaluating local wall thickness and other defects like wrinkles are determined using the shape recognition on the medial surface. The applied algorithm is simple, fast and robust.

  4. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed; Goumri-Said, Souraya

    2014-01-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

  5. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed

    2014-09-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young\\'s modulus, and Poisson\\'s ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

  6. Enhancement of tensile ductility and stretch formability of AZ31 magnesium alloy sheet processed by cross-wavy bending

    International Nuclear Information System (INIS)

    Huo, Qinghuan; Yang, Xuyue; Sun, Huan; Li, Bin; Qin, Jia; Wang, Jun; Ma, Jijun

    2013-01-01

    Highlights: •The AZ31 Mg alloy sheet is deformed to 4 passes at 673 K by cross-wavy bending. •A fine-grained microstructure and a weak and random texture are achieved. •Different softening mechanisms significantly affect the microstructure evolution. •The tensile ductility and stretch formability enhance dramatically. -- Abstract: The microstructure and texture evolution in the sheets of AZ31 magnesium alloy was studied by means of cross-wavy bending for 4 passes at 673 K. The bended samples were examined by optical microscopy and electron backscatter diffraction analysis. Finite element analysis suggested an inhomogeneous deformation at each pass. Following cross-wavy bending, a fine-grained microstructure with an average grain size of ∼8 μm and a weak and random basal texture were achieved. Accumulative effective strain was almost equal in the whole sheet at the end. Different work softening mechanisms significantly affected the evolution of the microstructure. Dynamic recovery played an important role during the first three bending passes whereas, in contrast, dynamic recrystallization dominated the evident grain refinement during the last pass. The tensile ductility and stretch formability of the 4-pass sheet at room temperature were distinctly enhanced compared to the initial sheet (1.55 and 2 times larger, respectively). These prominent increases were mainly attributed to texture randomizing rather than texture weakening alone

  7. Weld Growth Mechanisms and Failure Behavior of Three-Sheet Resistance Spot Welds Made of 5052 Aluminum Alloy

    Science.gov (United States)

    Li, Yang; Yan, Fuyu; Luo, Zhen; Chao, Y. J.; Ao, Sansan; Cui, Xuetuan

    2015-06-01

    This paper investigates the weld nugget formation in three-sheet aluminum alloy resistance spot welding. The nugget formation process in three equal thickness sheets and three unequal thickness sheets of 5052 aluminum alloy were studied. The results showed that the nugget was initially formed at the workpiece/workpiece interfaces (i.e., both upper interface and lower interface). The two small nuggets then grew along the radial direction and axial direction (welding direction) as the welding time increased. Eventually, the two nuggets fused into one large nugget. During the welding process, the Peltier effect between the Cu-Al caused the shift of the nugget in the welding direction. In addition, the mechanical strength and fracture mode of the weld nuggets at the upper and lower interfaces were also studied using tensile shear specimen configuration. Three failure modes were identified, namely interfacial, mixed, and pullout. The critical welding time and critical nugget diameter corresponding to the transitions of these modes were investigated. Finally, an empirical failure load formula for three-sheet weld similar to two-sheet spot weld was developed.

  8. Texture and mechanical properties of Al-0.5Mg-1.0Si-0.5Cu alloy sheets manufactured via a cross rolling method

    Science.gov (United States)

    Jeon, Jae-Yeol; Son, Hyeon-Taek; Woo, Kee-Do; Lee, Kwang-Jin

    2012-04-01

    The relationship between the texture and mechanical properties of 6xxx aluminum alloy sheets processed via cross rolling was investigated. The microstructures of the conventional rolled and cross rolled sheets after annealing were analyzed using optical micrographs (OM). The texture distribution across the thickness in the Al-Mg-Si-Cu alloy, conventional rolled sheets, and cross rolled sheets both before and after annealing was investigated via X-ray texture measurements. The texture was analyzed in three layers from the surface to the center of the sheet. The β-fiber texture of the conventional rolled sheet was typical of the texture obtained using aluminumoll ring. After annealing, the typical β-fiber orientations were changed to recrystallization textures: cube{001} and normal direction (ND)-rotated cubes. However, the texture of the cross rolled sheet was composed of an asymmetrical, rolling direction (RD)-rotated cubes. After annealing, the asymmetrical orientations in the cross rolled sheet were changed to a randomized texture. The average R-value of the annealed cross rolled sheets was higher than that of the conventional rolled sheets. The limit dome height (LDH) test results demonstrated that cross rolling is effective in improving the formability of the Al-Mg-Si-Cu alloy sheets.

  9. Radiation embrittlement of metals and alloys

    International Nuclear Information System (INIS)

    Wechsler, M.S.

    1975-01-01

    Three types of radiation embrittlement are identified: (1) radiation embrittlement in nominally ductile metals, (2) radiation embrittlement in metals that undergo a ductile-brittle transition, and (3) high-temperature grain boundary embrittlement. This paper deals with type (1) and, more briefly, type (2) radiation embrittlement. Radiation embrittlement in nominally ductile metals is characterized by the premature onset of plastic instability, which causes a sharp decrease in the macroscopic plastic strain that the material can sustain before necking (uniform strain) and breaking (fracture strain). Dislocation channeling seems to be largely responsible and experimental results are reviewed. The origin of dislocation channeling is discussed. Irradiated metals that exhibit a ductile-brittle transition show an increase in the transition temperature but the nature of the transition (shear to cleavage fracture) does not appear to be greatly altered. A key factor is the temperature dependence of yielding and how it is affected upon irradiation. Impurities exert an influence on the stability of radiation-produced defect clusters and thus can alter the amount of radiation embrittlement experienced upon irradiation at somewhat elevated temperatures. In general, radiation embrittlement appears to stem mostly from changes in plastic properties (particularly in the trend toward more dynamic and inhomogeneous plastic deformation) rather than from changes in the inherent fracture process. 63 references, 10 figures

  10. Characterization of the deformation texture after tensile test and cold rolling of a Ti-6Al-4V sheet alloy

    International Nuclear Information System (INIS)

    Mehdi, B; Badji, R; Azzeddine, H; Alili, B; Bradai, D; Ji, V

    2015-01-01

    The deformation texture after cold rolling and tensile test of an industrial Ti-6Al-4V sheet alloy was studied using X-ray diffraction. The alloy was subjected to a cold rolling to different thickness reductions (from 20% to 60%) and then tensile tests have been carried out along three directions relatively to the rolling direction (0°, 45° and 90°). The experimental results were compared to the existing literature and discussed in terms of active plastic deformation mechanisms. (paper)

  11. Influence of the Aluminium Alloy Type on Defects Formation in Friction Stir Lap Welding of Thin Sheets

    Directory of Open Access Journals (Sweden)

    M. I. Costa

    Full Text Available Abstract The weldability in Friction Stir Lap Welding (FSLW of heat and non-heat treatable aluminium alloys, the AA6082-T6 and the AA5754-H22 aluminium alloys, respectively, are compared. For both alloys, welds were produced in very thin sheets, using the same welding parameters and procedures, and strong differences in welds morphology were found. The strength of the welds was evaluated by performing tensile-shear tests under monotonic and cyclic loading conditions. As-welded and heat-treated samples of the AA6082- T6 were tested. It was found that the heat-treatable alloy is more sensitive to defects formation, in lap welding, than the non-heat-treatable alloy. The presence of defects has a strong influence on the monotonic and fatigue behaviour of the welds. In spite of this, for very high-applied stresses, the heat-treatable alloy welds perform better in fatigue than the non-heat-treatable alloy welds.

  12. Discontinuous structural phase transition of liquid metal and alloys (2)

    International Nuclear Information System (INIS)

    Wang, Li; Liu, Jiantong

    2004-01-01

    The diameter (d f ) of diffusion fluid cluster before and after phase transition has been calculated in terms of the paper ''Discontinuous structural phase transition of liquid metal and alloy (1)'' Physics Letters. A 326 (2004) 429-435, to verify quantitatively the discontinuity of structural phase transition; the phenomena of thermal contraction and thermal expansion during the phase transition, together with the evolution model of discontinuous structural phase transition are also discussed in this Letter to explore further the nature of structural transition; In addition, based on the viscosity experimental result mentioned in paper [Y. Waseda, The Structure of Non-Crystalline Materials--Liquids and Amorphous Solids, McGraw-Hill, New York, 1980], we present an approach to draw an embryo of the liquid-liquid (L-L) phase diagram for binary alloys above liquidus in the paper, expecting to guide metallurgy process so as to improve the properties of alloys. The idea that controls amorphous structure and its properties by means of the L-L phase diagram for alloys and by the rapid cooling technique to form the amorphous alloy has been brought forward in the end

  13. Stretchable and bendable carbon nanotube on PDMS super-lyophobic sheet for liquid metal manipulation

    International Nuclear Information System (INIS)

    Kim, Daeyoung; Jung, Daewoong; Yoo, Jun Hyeon; Lee, Gil S; Lee, Jeong-Bong; Lee, Yunho; Choi, Wonjae; Yoo, Koangki

    2014-01-01

    We report a vertically-aligned carbon nanotube (CNT) forest on polydimethylsiloxane (PDMS) sheet as a novel widely stretchable and bendable anti-wetting super-lyophobic surface for naturally oxidized gallium-based liquid metals. The vertically-aligned CNT has inherent chemical inertness and a hierarchical texture combining micro/nanoscale roughness; these two characters render the developed sheet as a super-lyophobic substrate against gallium-based liquid metals. The vertically-aligned CNT forest was first grown on Si substrate and then transferred onto a PDMS sheet by imprinting. It was found that the transferred CNT on the PDMS sheet maintained its vertically-aligned nature as well as hierarchical micro/nano surface morphology. It was found that the static contact angles of the gallium-based liquid metal droplet on the CNT on Si and on the CNT on PDMS were both greater than 155° and the contact angle hysteresis on the CNT on Si was 4° and that on the transferred CNT on PDMS was 19°. These measurement results showed that the surface retains a super-lyophobic property before and after the CNT transfer onto PDMS. We tested the CNT on PDMS sheet for its mechanical flexibility using stretching (50% and 100%) and bending (curvature of 0.1 and 0.4 mm −1 ). We carried out a bouncing test and a rolling test on the stretched/bent CNT on the PDMS sheet and the results confirmed that the flexible sheet maintains anti-wetting characteristics under bending or stretching conditions. (paper)

  14. Structural models for amorphous transition metal binary alloys

    International Nuclear Information System (INIS)

    Ching, W.Y.; Lin, C.C.

    1976-01-01

    A dense random packing of 445 hard spheres with two different diameters in a concentration ratio of 3 : 1 was hand-built to simulate the structure of amorphous transition metal-metalloid alloys. By introducing appropriate pair potentials of the Lennard-Jones type, the structure is dynamically relaxed by minimizing the total energy. The radial distribution functions (RDF) for amorphous Fe 0 . 75 P 0 . 25 , Ni 0 . 75 P 0 . 25 , Co 0 . 75 P 0 . 25 are obtained and compared with the experimental data. The calculated RDF's are resolved into their partial components. The results indicate that such dynamically constructed models are capable of accounting for some subtle features in the RDF of amorphous transition metal-metalloid alloys

  15. Thermal plasma synthesis of transition metal nitrides and alloys

    International Nuclear Information System (INIS)

    Ronsheim, P.; Christensen, A.N.; Mazza, A.

    1981-01-01

    Applications of arc plasma processing to high-temperature chemistry of Group V nitrides and Si and Ge alloys are studied. The transition metal nitrides 4f-VN, 4f-NbN, and 4f-TaN are directly synthesized in a dc argon-nitrogen plasma from powders of the metals. A large excess of N 2 is required to form stoichiometric 4f-VN, while the Nb and Ta can only be synthesized with a substoichiometric N content. In a dc argon plasma the alloys V 3 Si, VSi 2 , NbSi 2 , NbGe 2 , Cr 3 Si, and Mo 3 Si are obtained from powder mixtures of the corresponding elements. The compounds are identified by x-ray diffraction patterns and particle shape and size are studied by electron microscopy

  16. Computer controlled experimental device for investigations of tribological influences in sheet metal forming

    Directory of Open Access Journals (Sweden)

    Milan Djordjevic

    2012-05-01

    Full Text Available Sheet metal forming, especially deep drawing process, is influenced by many factors. Blank holding force and drawbead displacement are two of them that can be controlled during the forming process. For this purpose, electro-hydraulic computerized sheet-metal strip sliding device has been constructed. Basic characteristic of this device is realization of variable contact pressure and drawbead height as functions of time or stripe displacement. There are both, pressure and drawbead, ten linear and nonlinear functions. Additional features consist of the ability to measure drawing force, contact pressure, drawbead displacement etc. Presented in the paper are the device overview and the first results of steel sheet stripe sliding over rounded  drawbead.

  17. COMPUTER CONTROLLED EXPERIMENTAL DEVICE FOR INVESTIGATIONS OF TRIBOLOGICAL INFLUENCES IN SHEET METAL FORMING

    Directory of Open Access Journals (Sweden)

    Tomislav Vujinović

    2012-05-01

    Full Text Available Sheet metal forming, especially deep drawing process is influenced by many factors. Blank holding force and drawbead displacement are two of them that can be controlled during the forming process.For this purpose, an electro-hydraulic computerized sheet-metal strip sliding device has been constructed. The basic characteristic of this device is realization of variable contact pressure and drawbead height as functions of time or stripe displacement. There are both, pressure and drawbead, ten linear and nonlinear functions. Additional features consist of the ability to measure drawing force, contact pressure, drawbead displacement etc.The device overview and first results of steel sheet stripe sliding over rounded drawbead are presented in the paper.

  18. 48 CFR 53.301-1427 - Standard Form 1427, Inventory Schedule A-Construction Sheet (Metals in Mill Product Form).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Standard Form 1427, Inventory Schedule A-Construction Sheet (Metals in Mill Product Form). 53.301-1427 Section 53.301-1427... Illustrations of Forms 53.301-1427 Standard Form 1427, Inventory Schedule A—Construction Sheet (Metals in Mill...

  19. Impulse Hydroforming Method for Very Thin Sheets from Metallic or Hybrid Materials

    OpenAIRE

    Beerwald, C.; Beerwald, M.; Dirksen, U.; Henselek, A.

    2010-01-01

    Forming of very thin metallic and hybrid material foils is a demanding task in several application areas as for example in food or pharmaceutical packaging industries. Narrow forming limits of very thin sheet metals as well as minor process reliability due to necessary exact tool manufacturing (small punch-die clearance), both, causes abiding interest in new and innovative forming processes. In this contribution a new method using high pressure pulses will be introduced to form small geometry...

  20. Lithium Adsorption on Graphene: From Isolated Adatoms to Metallic Sheets.

    Science.gov (United States)

    Garay-Tapia, A M; Romero, Aldo H; Barone, Veronica

    2012-03-13

    We have studied Li adsorption on graphene for Li concentrations ranging from about 1% to 50% by means of density functional theory calculations. At low adsorbant densities, we observe a strong ionic interaction characterized by a substantial charge transfer from the adatoms to the substrate. In this low concentration regime, the electronic density around the Li adatoms is well localized and does not contribute to the electronic behavior in the vicinity of the Fermi level. For larger concentrations, we observe the formation of a chemically bound Li layer characterized by a stronger binding energy as well as a significant density of states above the Fermi level coming from both graphene and the two-dimensional Li sheet.

  1. Eliminating Heavy Metals from Water with NanoSheet Minerals as Adsorbents

    Directory of Open Access Journals (Sweden)

    Shaoxian Song

    2017-12-01

    Full Text Available Heavy metals usually referred to those with atomic weights ranging from 63.5 to 200.6. Because of natural-mineral dissolution and human activities such as mining, pesticides, fertilizer, metal planting and batteries manufacture, etc., these heavy metals, including zinc, copper, mercury, lead, cadmium and chromium have been excessively released into water courses, like underground water, lake and river, etc. The ingestion of the heavy metals-contaminated water would raise serious health problems to human beings even at a low concentration. For instance, lead can bring human beings about barrier to the normal function of kidney, liver and reproductive system, while zinc can cause stomach cramps, skin irritations, vomiting and anemia. Mercury is a horrible neurotoxin that may result in damages to the central nervous system, dysfunction of pulmonary and kidney, chest and dyspnea. Chromium (VI has been proved can cause many diseases ranging from general skin irritation to severe lung carcinoma. Accordingly, the World Health Organization announced the maximum contaminant levels (MCL for the heavy metals in drinking water. There are numerous processes for eliminating heavy metals from water in order to provide citizens safe drinking water, including precipitation, adsorption, ion exchange, membrane separation and biological treatment, etc. Adsorption is considered as a potential process for deeply removing heavy metals, in which the selection of adsorbents plays a predominant role. Nano-sheet minerals as the adsorbents are currently the hottest researches in the field. They are obtained from layered minerals, such as montmorillonite, graphite and molybdenite, through the processing of intercalation, electrochemical and mechanical exfoliation, etc. Nano-sheet minerals are featured by their large specific surface area, relatively low costs and active adsorbing sites, leading to be effective and potential adsorbents for heavy metals removal from water

  2. Magnetic properties of fcc Ni-based transition metal alloy

    Czech Academy of Sciences Publication Activity Database

    Kudrnovský, Josef; Drchal, Václav

    2009-01-01

    Roč. 100, č. 9 (2009), s. 1193-1196 ISSN 1862-5282 R&D Projects: GA MŠk OC 150; GA AV ČR IAA100100616 Institutional research plan: CEZ:AV0Z10100520 Keywords : transition metal alloys * Ni-based * pair exchange interactions * Curie temperatures * renormalized RPA Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.862, year: 2009

  3. Formation of amorphous metal alloys by chemical vapor deposition

    Science.gov (United States)

    Mullendore, A.W.

    1988-03-18

    Amorphous alloys are deposited by a process of thermal dissociation of mixtures of organometallic compounds and metalloid hydrides,e.g., transition metal carbonyl, such as nickel carbonyl and diborane. Various sizes and shapes of deposits can be achieved, including near-net-shape free standing articles, multilayer deposits, and the like. Manipulation or absence of a magnetic field affects the nature and the structure of the deposit. 1 fig.

  4. On the unit rupture work of metals and alloys

    International Nuclear Information System (INIS)

    Verkhoturov, A.D.; Kovalenko, V.S.; Dyatel, V.P.

    1980-01-01

    Studied is the effect of the nature of the treated material treatment regimes on their unit rupture work at laser treatment in the regime of quasistationary evaporation. It is shown that the unit rupture work changes its values depending on the treatment regimes, coincidences between experimental and calculation values of unit rupture work are not being observed, especially for refractory metals of the 6th group and for solid alloys. Established are optimum regimes for determination of stable values of unit rupture work

  5. Semiquantitative activation analysis in metallic alloys submitted to irregular irradiation

    International Nuclear Information System (INIS)

    Veissid, N.; Lucki, G.

    1979-01-01

    An analytic semiquantitative method using neutron activation was developed to determine the impurities and verify the composition of metallic alloys. By the radioactive transformation law, the number of atoms of each element present in the sample is determined measuring the activity in a multichannel. Two samples were analysed: a) Sample of nominal compositions FeNiCr (49,95-49,95 - 0,1% at). b) Sample of nominal composition NiCr (80,20% at). (Author) [pt

  6. Finite-element solidification modelling of metals and binary alloys

    International Nuclear Information System (INIS)

    Mathew, P.M.

    1986-12-01

    In the Canadian Nuclear Fuel Waste Management Program, cast metals and alloys are being evaluated for their ability to support a metallic fuel waste container shell under disposal vault conditions and to determine their performance as an additional barrier to radionuclide release. These materials would be cast to fill residual free space inside the container and allowed to solidify without major voids. To model their solidification characteristics following casting, a finite-element model, FAXMOD-3, was adopted. Input parameters were modified to account for the latent heat of fusion of the metals and alloys considered. This report describes the development of the solidification model and its theoretical verification. To model the solidification of pure metals and alloys that melt at a distinct temperature, the latent heat of fusion was incorporated as a double-ramp function in the specific heat-temperature relationship, within an interval of +- 1 K around the solidification temperature. Comparison of calculated results for lead, tin and lead-tin eutectic melts, unidirectionally cooled with and without superheat, showed good agreement with an alternative technique called the integral profile method. To model the solidification of alloys that melt over a temperature interval, the fraction of solid in the solid-liquid region, as calculated from the Scheil equation, was used to determine the fraction of latent heat to be liberated over a temperature interval within the solid-liquid zone. Comparison of calculated results for unidirectionally cooled aluminum-4 wt.% copper melt, with and without superheat, showed good agreement with alternative finite-difference techniques

  7. Effect of material scatter on the plastic behavior and stretchability in sheet metal forming

    NARCIS (Netherlands)

    Wiebenga, J.H.; Atzema, E.H.; Atzema, E.H.; An, Y.G.; Vegter, H.; van den Boogaard, Antonius H.

    2014-01-01

    Robust design of forming processes is gaining attention throughout the industry. To analyze the robustness of a sheet metal forming process using Finite Element (FE) simulations, an accurate input in terms of parameter scatter is required. This paper presents a pragmatic, accurate and economic

  8. Testing and modelling of industrial tribo-systems for sheet metal forming

    DEFF Research Database (Denmark)

    Friis, Kasper Leth; Nielsen, Peter Søe; Bay, Niels

    2008-01-01

    Galling is a well-known problem in sheet metal forming of tribological difficult materials such as stainless steel. In this work new, environmentally friendly lubricants and wear resistant tool materials are tested in a laboratory environment using a strip reduction test as well as in a real...

  9. Numerical modelling of microscopic lubricant flow in sheet metal forming. Application to plane strip drawing

    DEFF Research Database (Denmark)

    Carretta, Y.; Boman, R.; Bech, Jakob Ilsted

    2017-01-01

    This paper presents a numerical investigation of microscopic lubricant flows from the cavities to the plateaus of the surface roughness of metal sheets during forming processes. This phenomenon, called micro-plasto-hydrodynamic (MPH) lubrication, was observed experimentally in various situations...

  10. EXPERIMENTAL TESTING OF DRAW-BEAD RESTRAINING FORCE IN SHEET METAL FORMING

    Institute of Scientific and Technical Information of China (English)

    J.H. Yang; J. Chen; D.N. He; X. Y. Ruan

    2003-01-01

    Due to complexities of draw-bead restraining force calculated according to theory anddepending on sheet metal forming properties experiment testing system, a simplifiedmethod to calculate draw-bead restraining force is put forward by experimental methodin cup-shaped drawing process. The experimental results were compared with numer-ical results and proved agreement. It shows the method is effective.

  11. An expert system for process planning of sheet metal parts produced

    Indian Academy of Sciences (India)

    Process planning of sheet metal part is an important activity in the design of compound die. Traditional methods of carrying out this task are manual, tedious, time-consuming, error-prone and experiencebased. This paper describes the research work involved in the development of an expert system for process planning of ...

  12. Friction modelling in sheet metal forming simulations: application and validation on an U-Bend product

    NARCIS (Netherlands)

    Sigvant, Mats; Hol, Johan; Chezan, Toni; van den Boogaard, Ton; Hora, P.

    2015-01-01

    The accuracy of sheet metal forming simulations strongly depends on, amongst others, friction modelling. The industrial standard is to use the Coulomb friction model with a constant coefficient of friction. However, it is known that the true friction conditions are dependent on the tribology system,

  13. Designing a logistic control system : dealing with changes in Fokker's sheet metal unit

    NARCIS (Netherlands)

    Gomes, Javier

    2008-01-01

    The following report presents the results of the Logistics Design Project carried out at the sheet metal unit of Stork-Fokker AESP, from October 2007 to March 2008. Stork Fokker AESP designs, develops and produces advanced structures and electrical systems for the aerospace and defense industry. The

  14. 75 FR 15741 - Sheet Metal Workers Internationl Association, Local 292: Troy, MI; Notice of Termination of...

    Science.gov (United States)

    2010-03-30

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-71,630] Sheet Metal Workers Internationl Association, Local 292: Troy, MI; Notice of Termination of Investigation Pursuant to Section 223..., Troy, Michigan. The petitioning workers were filing on behalf of workers employed by several...

  15. Improvements in FE-analysis of real-life sheet metal forming

    NARCIS (Netherlands)

    Huetink, Han; van den Boogaard, Antonius H.; Geijselaers, Hubertus J.M.; Meinders, Vincent T.

    2000-01-01

    An overview will be presented of recent developments concerning the application and development of computer codes for numerical simulation of sheet metal forming processes. In this paper attention is paid to some strategies which are followed to improve the accuracy and to reduce the computation

  16. Plating on some difficult-to-plate metals and alloys

    International Nuclear Information System (INIS)

    Dini, J.W.; Johnson, H.R.

    1980-02-01

    Electrodeposition of coatings on metals such as beryllium, beryllium-copper, Kovar, lead, magnesium, thorium, titanium, tungsten, uranium, zirconium, and their alloys can be problematic. This is due in most cases to a natural oxide surface film that readily reforms after being removed. The procedures we recommend for plating on these metals rely on replacing the oxide film with a displacement coating, or etching to allow mechanical keying between the substrate and plated deposit. The effectiveness of the procedures is demonstrated by interface bond strengths found in ring-shear and conical-head tensile tests

  17. Nuclear criticality safety parameter evaluation for uranium metallic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Andrea; Abe, Alfredo, E-mail: andreasdpz@hotmail.com, E-mail: abye@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Energia Nuclear

    2013-07-01

    Nuclear criticality safety during fuel fabrication process, transport and storage of fissile and fissionable materials requires criticality safety analysis. Normally the analysis involves computer calculations and safety parameters determination. There are many different Criticality Safety Handbooks where such safety parameters for several different fissile mixtures are presented. The handbooks have been published to provide data and safety principles for the design, safety evaluation and licensing of operations, transport and storage of fissile and fissionable materials. The data often comprise not only critical values, but also subcritical limits and safe parameters obtained for specific conditions using criticality safety calculation codes such as SCALE system. Although many data are available for different fissile and fissionable materials, compounds, mixtures, different enrichment level, there are a lack of information regarding a uranium metal alloy, specifically UMo and UNbZr. Nowadays uranium metal alloy as fuel have been investigated under RERTR program as possible candidate to became a new fuel for research reactor due to high density. This work aim to evaluate a set of criticality safety parameters for uranium metal alloy using SCALE system and MCNP Monte Carlo code. (author)

  18. Development of an in-plane biaxial test for forming limit curve (FLC) characterization of metallic sheets

    International Nuclear Information System (INIS)

    Zidane, I; Guines, D; Léotoing, L; Ragneau, E

    2010-01-01

    The main objective of this work is to propose a new experimental device able to give for a single specimen a good prediction of rheological parameters and formability under static and dynamic conditions (for intermediate strain rates). In this paper, we focus on the characterization of sheet metal forming. The proposed device is a servo-hydraulic testing machine provided with four independent dynamic actuators allowing biaxial tensile tests on cruciform specimens. The formability is evaluated thanks to the classical forming limit diagram (FLD), and one of the difficulties of this study was the design of a dedicated specimen for which the necking phenomenon appears in its central zone. If necking is located in the central zone of the specimen, then the speed ratio between the two axes controls the strain path in this zone and a whole forming limit curve can be covered. Such a specimen is proposed through a numerical and experimental validation procedure. A rigorous procedure for the detection of numerical and experimental forming strains is also presented. Finally, an experimental forming limit curve is determined and validated for an aluminium alloy dedicated to the sheet forming processes (AA5086)

  19. Electrical and Magnetic Properties of Binary Amorphous Transition Metal Alloys.

    Science.gov (United States)

    Liou, Sy-Hwang

    The electrical, superconductive and magnetic properties of several binary transition metal amorphous and metastable crystalline alloys, Fe(,x)Ti(,100-x) (30 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Zr(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 93), Fe(,x)Hf(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Nb(,100 -x) (22 (LESSTHEQ) x (LESSTHEQ) 85), Ni(,x)Nb(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 80), Cu(,x)Nb(,100-x) (10 (LESSTHEQ) x (LESSTHEQ) 90) were studied over a wide composition range. Films were made using a magnetron sputtering system, and the structure of the films was investigated by energy dispersive x-ray diffraction. The composition region of each amorphous alloys system was determined and found in good agreement with a model proposed by Egami and Waseda. The magnetic properties and hyperfine interactions in the films were investigated using a conventional Mossbauer spectrometer and a ('57)Co in Rh matrix source. In all Fe-early transition metal binary alloys systems, Fe does not retain its moment in the low iron concentration region and the result is that the critical concentration for magnetic order (x(,c)) is much larger than anticipated from percolation considerations. A direct comparison between crystalline alloys and their amorphous counterparts of the same composition illustrate no clear correlation between crystalline and amorphous states. Pronounced discontinuities in the magnetic properties with variation in Fe content of all Fe-early transition metal alloys at phase boundaries separating amorphous and crystalline states have been observed. This is caused by the differences in the atomic arrangement and the electronic structure between crystalline and amorphous solids. The temperature dependence of resistivity, (rho)(T), of several binary amorphous alloys of Fe-TM (where TM = Ti, Zr, Hf, Nb etc.) has been studied from 2K to 300K. The Fe-poor (x x(,c)) samples have distinctive differences in (rho)(T) at low temperature (below 30K). All the magnetic samples

  20. Titanium Alloys Thin Sheet Welding with the Use of Concentrated Solar Energy

    Science.gov (United States)

    Pantelis, D. I.; Kazasidis, M.; Karakizis, P. N.

    2017-12-01

    The present study deals with the welding of titanium alloys thin sheets 1.3 mm thick, with the use of concentrated solar energy. The experimental part of the work took place at a medium size solar furnace at the installation of the Centre National de la Recherche Scientifique, at Odeillo, in Southern France, where similar and dissimilar defect-free welds of titanium Grades 4 and 6 were achieved, in the butt joint configuration. After the determination of the appropriate welding conditions, the optimum welded structures were examined and characterized microstructurally, by means of light optical microscopy, scanning electron microscopy, and microhardness testing. In addition, test pieces extracted from the weldments were tested under uniaxial tensile loading aiming to the estimation of the strength and the ductility of the joint. The analysis of the experimental results and the recorded data led to the basic concluding remarks which demonstrate increased hardness distribution inside the fusion area and severe loss of ductility, but adequate yield and tensile strength of the welds.

  1. Thickness profile measuring device for rolling metal bands or sheets

    International Nuclear Information System (INIS)

    Campas, J.J.; Terreaux, S.

    1995-01-01

    Previous radiometric thickness gages were affected by insufficient water proofing and limited cooling performances for the detection subsystem (in general specially designed photodiodes). This resulted in poor reliability and life expectancy, in particular when heavy humidity and constant radiative heat are present as for hot rolling in the metal industry. This new gage design brings enhanced performances for these two factors. (D.L.). 4 refs., 3 figs

  2. Techniques for intergranular crack formation and assessment in alloy 600 base and alloy 182 weld metals

    International Nuclear Information System (INIS)

    Lee, Tae Hyun; Hwang, Il Soon; Kim, Hong Deok; Kim, Ji Hyun

    2015-01-01

    A technique developed to produce artificial intergranular stress corrosion cracks in structural components was applied to thick, forged alloy 600 base and alloy 182 weld metals for use in the qualification of nondestructive examination techniques for welded components in nuclear power plants. An externally controlled procedure was demonstrated to produce intergranular stress corrosion cracks that are comparable to service-induced cracks in both the base and weld metals. During the process of crack generation, an online direct current potential drop method using array probes was used to measure and monitor the sizes and shapes of the cracks. A microstructural characterization of the produced cracks revealed realistic conformation of the crack faces unlike those in machined notches produced by an electrodischarge machine or simple fatigue loading using a universal testing machine. A comparison with a destructive metallographic examination showed that the characteristics, orientations, and sizes of the intergranular cracks produced in this study are highly reproducible.

  3. Impact Energy Absorbing Capability of Metal/Polymer Hybrid Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Kyungil; Kwon, O Bum; Park, Hyung Wook [Ulsan Nat’l Institute of Science and Technology, Ulsan (Korea, Republic of)

    2017-02-15

    Recently, the reduction of vehicle weight has been increasingly studied, in order to enhance the fuel efficiency of passenger cars. In particular, the seat frame is being studied actively, owing to considerations of driver safety from external impact damage. Therefore, this study focuses on high strength steel sheet (SPFC980)/polymer heterojunction hybrid materials, and their performance in regards to impact energy absorption. The ratio of impact energy absorption was observed to be relatively higher in the SPFC980/polymer hybrid materials under the impact load. This was found by calculating the equivalent flexural rigidity, which is the bending effect, according to the Castigliano theorem. An efficient wire-web structure was investigated through the simulation of different wire-web designs such as triangular, rectangular, octagonal, and hexagonal structures. The hexagonal wire-web structure was shown to have the least impact damage, according to the simulations. This study can be utilized for seat frame design for passengers’ safety, owing to efficient impact absorption.

  4. Standard specification for cobalt-chromium-nickel-molybdenum-tungsten alloy (UNS R31233) plate, sheet and strip. ASTM standard

    International Nuclear Information System (INIS)

    1998-09-01

    This specification is under the jurisdiction of ASTM Committee B-2 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.07 on Refined Nickel and Cobalt, and Alloys Containing Nickel or Cobalt or Both as Principal Constituents. Current edition approved Apr. 10, 1998 and published September 1998. Originally published as B 818-91. Last previous edition was B 818-93

  5. Metal Compression Forming of aluminum alloys and metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, S.; Ren, W.; Porter, W.D.; Brinkman, C.R.; Sabau, A.S.; Purgert, R.M.

    2000-02-01

    Metal Compression Forming (MCF) is a variant of the squeeze casting process, in which molten metal is allowed to solidify under pressure in order to close porosity and form a sound part. However, the MCF process applies pressure on the entire mold face, thereby directing pressure on all regions of the casting and producing a uniformly sound part. The process is capable of producing parts with properties close to those of forgings, while retaining the near net shape, complexity in geometry, and relatively low cost of the casting process.

  6. Properties of Rolled AZ31 Magnesium Alloy Sheet Fabricated by Continuous Variable Cross-Section Direct Extrusion

    Science.gov (United States)

    Liu, Yang; Li, Feng; Li, Xue Wen; Shi, Wen Yong

    2018-03-01

    Rolling is currently a widely used method for manufacturing and processing high-performance magnesium alloy sheets and has received widespread attention in recent years. Here, we combined continuous variable cross-section direct extrusion (CVCDE) and rolling processes. The microstructure and mechanical properties of the resulting sheets rolled at different temperatures from CVCDE extrudate were investigated by optical microscopy, scanning electron microscope, transmission electron microscopy and electron backscatter diffraction. The results showed that a fine-grained microstructure was present with an average grain size of 3.62 μm in sheets rolled from CVCDE extrudate at 623 K. Dynamic recrystallization and a large strain were induced by the multi-pass rolling, which resulted in grain refinement. In the 573-673 K range, the yield strength, tensile strength and elongation initially increased and then declined as the CVCDE temperature increased. The above results provide an important scientific basis of processing, manufacturing and the active control on microstructure and property for high-performance magnesium alloy sheet.

  7. Some observations on the physical metallurgy of nickel alloy weld metals

    International Nuclear Information System (INIS)

    Skillern, C.G.; Lingenfelter, A.C.

    1982-01-01

    Numerous nickel alloys play critical roles in various energy-related applications. Successful use of these alloys is almost always dependent on the availability of acceptable welding methods and welding products. An understanding of the physical metallurgy of these alloys and their weld metals and the interaction of weld metal and base metal is essential to take full advantage of the useful properties of the alloys. To illustrate this point, this paper presents data for two materials: INCONEL alloy 718 and INCONEL Welding Electrode 132. 8 figures, 9 tables

  8. Prevention of microcracking by REM addition to alloy 690 filler metal in laser clad welds

    International Nuclear Information System (INIS)

    Okauchi, Hironori; Saida, Kazuyoshi; Nishimoto, Kazutoshi

    2011-01-01

    Effect of REM addition to alloy 690 filler metal on microcracking prevention was verified in laser clad welding. Laser clad welding on alloy 132 weld metal or type 316L stainless steel was conducted using the five different filler metals of alloy 690 varying the La content. Ductility-dip crack occurred in laser clad welding when La-free alloy 690 filler metal was applied. Solidification and liquation cracks occurred contrarily in the laser cladding weld metal when the 0.07mass%La containing filler metal was applied. In case of laser clad welding on alloy 132 weld metal and type 316L stainless steel, the ductility-dip cracking susceptibility decreased, and solidification/liquation cracking susceptibilities increased with increasing the La content in the weld metal. The relation among the microcracking susceptibility, the (P+S) and La contents in every weld pass of the laser clad welding was investigated. Ductility-dip cracks occurred in the compositional range (atomic ratio) of La/(P+S) 0.99(on alloy 132 weld metal), >0.90 (on type 316L stainless steel), while any cracks did not occur at La/(P+S) being between 0.21-0.99 (on alloy 132 weld metal) 0.10-0.90 (on type 316L stainless steel). Laser clad welding test on type 316L stainless steel using alloy 690 filler metal containing the optimum La content verified that any microcracks did not occurred in the laser clad welding metal. (author)

  9. Optimal Magnetic Field Shielding Method by Metallic Sheets in Wireless Power Transfer System

    Directory of Open Access Journals (Sweden)

    Feng Wen

    2016-09-01

    Full Text Available To meet the regulations established to limit human exposure to time-varying electromagnetic fields (EMFs such as the International Committee on Non-Ionizing Radiation Protection (ICNIRP guidelines, thin metallic sheets are often used to shield magnetic field leakage in high power applications of wireless power transfer (WPT systems based on magnetic field coupling. However, the metals in the vicinity of the WPT coils cause the decrease of self and mutual inductances and increase of effective series resistance; as such, the electric performance including transmission power and the efficiency of the system is affected. With the research objective of further investigating excellent shielding effectiveness associated with system performance, the utilization of the optimal magnetic field shielding method by metallic sheets in magnetic field coupling WPT is carried out in this paper. The circuit and 3D Finite Element Analysis (FEA models are combined to predict the magnetic field distribution and electrical performance. Simulation and experiment results show that the method is very effective by obtaining the largest possible coupling coefficient of the WPT coils within the allowable range and then reducing the value nearest to and no smaller than the critical coupling coefficient via geometric unbroken metallic sheets. The optimal magnetic field shielding method which considers the system efficiency, transmission power, transmission distance, and system size is also achieved using the analytic hierarchy process (AHP. The results can benefit WPT by helping to achieve efficient energy transfer and safe use in metal shielded equipment.

  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. Comparison of Two Commercial FE-Codes for Sheet Metal Forming

    International Nuclear Information System (INIS)

    Revuelta, A.; Larkiola, J.; Kanervo, K.; Korhonen, A. S.; Myllykoski, P.

    2007-01-01

    There is urgent need to develop new advanced fast and cost-effective mass-production methods for small sheet metal components. Traditionally progressive dies have been designed by using various CAD techniques. Recent results in mass production of small sheet metal parts using progressive dies and a transfer press showed that the tool design time may be cut in up to a half by using 3D finite element simulation of forming. In numerical simulation of sheet metal forming better constitutive models are required to obtain more accurate results, reduce the time for tool design and cut the production costs further. Accurate models are needed to describe the initial yielding, subsequent work hardening and to predict the formability. In this work two commercially available finite element simulation codes, PAM-STAMP and LS-DYNA, were compared in forming of small austenitic stainless steel sheet part for electronic industry. Several constitutive models were used in both codes and the results were compared. Comparisons were made between the same models in each of the codes and also between different models in the same code. Material models ranged from very simple to advanced ones, which took into account anisotropy and both isotropic and kinematic hardening behavior. In order to make a valid comparison we employed similar finite element meshes. The effects of the material models parameters were studied and the results were compared with experiments. The effects of the computational time were also studied

  12. Feasibility Study on Flexibly Reconfigurable Roll Forming Process for Sheet Metal and Its Implementation

    Directory of Open Access Journals (Sweden)

    Jun-Seok Yoon

    2014-06-01

    Full Text Available A multicurved sheet metal surface for a skin structure has usually been manufactured using a conventional die forming process involving the use of both a die and a press machine in accordance with the product shape. However, such processes are economically inefficient because additional production costs are incurred for the development and management of forming tools. To overcome this drawback, many alternative processes have been developed; however, these still suffer from problems due to defects such as dimples and wrinkles occurring in the sheet. In this study, a new sheet metal forming process called the flexibly reconfigurable roll forming (FRRF process is proposed as an alternative to existing processes. Unlike existing processes, FRRF can reduce additional production costs resulting from material loss and significantly reduce forming errors. Furthermore, it involves the use of a smaller apparatus. The methodology and applicable procedure of the FRRF process are described. Numerical forming simulations of representative multicurved sheet surfaces are conducted using FEM. In addition, a simple apparatus is developed for verifying the feasibility of this process, and a doubly curved metal is formed to verify the applicability of the reconfigurable roller, a critical component in this forming process.

  13. Properties- and applications of quasicrystals and complex metallic alloys.

    Science.gov (United States)

    Dubois, Jean-Marie

    2012-10-21

    This article aims at an account of what is known about the potential for applications of quasicrystals and related compounds, the so-called family of Complex Metallic Alloys (CMAs‡). Attention is focused at aluminium-based CMAs, which comprise a large number of crystalline compounds and quasicrystals made of aluminium alloyed with transition metals (like Fe or Cu) or normal metals like Mg. Depending on composition, the structural complexity varies from a few atoms per unit cell up to thousands of atoms. Quasicrystals appear then as CMAs of ultimate complexity and exhibit a lattice that shows no periodicity anymore in the usual 3-dimensional space. Properties change dramatically with lattice complexity and turn the metal-type behaviour of simple Al-based crystals into a far more complex behaviour, with a fingerprint of semi-conductors that may be exploited in various applications, potential or realised. An account of the ones known to the author is given in the light of the relevant properties, namely light absorption, reduced adhesion and friction, heat insulation, reinforcement of composites for mechanical devices, and few more exotic ones. The role played by the search for applications of quasicrystals in the development of the field is briefly addressed in the concluding section.

  14. A Model Based Approach to Increase the Part Accuracy in Robot Based Incremental Sheet Metal Forming

    International Nuclear Information System (INIS)

    Meier, Horst; Laurischkat, Roman; Zhu Junhong

    2011-01-01

    One main influence on the dimensional accuracy in robot based incremental sheet metal forming results from the compliance of the involved robot structures. Compared to conventional machine tools the low stiffness of the robot's kinematic results in a significant deviation of the planned tool path and therefore in a shape of insufficient quality. To predict and compensate these deviations offline, a model based approach, consisting of a finite element approach, to simulate the sheet forming, and a multi body system, modeling the compliant robot structure, has been developed. This paper describes the implementation and experimental verification of the multi body system model and its included compensation method.

  15. Corrosion fatigue of biomedical metallic alloys: mechanisms and mitigation.

    Science.gov (United States)

    Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

    2012-03-01

    Cyclic stresses are often related to the premature mechanical failure of metallic biomaterials. The complex interaction between fatigue and corrosion in the physiological environment has been subject of many investigations. In this context, microstructure, heat treatments, plastic deformation, surface finishing and coatings have decisive influence on the mechanisms of fatigue crack nucleation and growth. Furthermore, wear is frequently present and contributes to the process. However, despite all the effort at elucidating the mechanisms that govern corrosion fatigue of biomedical alloys, failures continue to occur. This work reviews the literature on corrosion-fatigue-related phenomena of Ti alloys, surgical stainless steels, Co-Cr-Mo and Mg alloys. The aim was to discuss the correlation between structural and surface aspects of these materials and the onset of fatigue in the highly saline environment of the human body. By understanding such correlation, mitigation of corrosion fatigue failure may be achieved in a reliable scientific-based manner. Different mitigation methods are also reviewed and discussed throughout the text. It is intended that the information condensed in this article should be a valuable tool in the development of increasingly successful designs against the corrosion fatigue of metallic implants. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. The corrosion behaviour of nanograined metals and alloys

    Directory of Open Access Journals (Sweden)

    Herrasti, P.

    2012-10-01

    Full Text Available There has been considerable interest in the properties of nanocrystalline materials over the last decade. Such materials include metals and alloys with a crystal size within the order of 1 to 100 nm. The interest arises due to the substantial differences in electrical, optical and magnetic properties and also due to their high adsorption capability and chemical reactivity compared to their larger grained counterparts. In this paper, the corrosion of nanocrystalline metals and alloys is investigated and compared to the corrosion of microcrystalline materials having a similar composition. The focus is on the corrosion of nickel, copper, cobalt and iron alloys. Key aspects of different corrosion behaviour such grain boundaries and size are identified.

    En la última década ha habido un gran interes en las propiedades de materiales nanocristalinos. Estos materiales incluyen metales y aleaciones con un tamaño de cristal del orden de 1 a 100 nm. El interes por estos materiales es debido a las grandes diferencias en cuanto a sus propiedades electricas, opticas y magneticas, asi como a su alta capacidad de adsorción y reactividad química en relación a los mismos materiales con tamaños de grano mayores. En este trabajo se ha investigado y comparado la corrosión de materiales nano y microcristalinos de similar composición química. Principalmente se ha centrado en la corrosión de metales tales como niquel, cobre, cobalto y aleaciones de hierro. Se ha comprobado que los diferentes comportamientos frente al proceso de corrosión están intimamente ligados con los bordes de grano y el tamaño de dichos granos.

  17. A vanadium alloy for the application in a liquid metal blanket of a fusion reactor

    Science.gov (United States)

    Borgstedt, H. U.; Grundmann, M.; Konys, J.; Perić, Z.

    1988-07-01

    The vanadium alloy V3Ti1Si has been corrosion tested in liquid lithium and the eutectic alloy Pb-17Li at 550°C. This alloy has a comparable corrosion resistance to the alloy V15Cr5Ti in lithium. In this molten metal it is superior to stainless steel AISI 316. In the Pb-17Li melt it is even superior to martensitic steels. The alloy has only a weak tendency to be dissolved. It is sensitive to an exchange of non-metallic elements, which causes the formation of a hardened surface layer. These chemical effects are influenced by the mass and surface ratios of the vanadium alloy to the molten metals and other structural materials. These ratios are unfavorable in the two test loops. The effects might be less pronounced in a vanadium alloy/liquid metal fusion reactor blanket.

  18. Direct Solid-State Conversion of Recyclable Metals and Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Z; Manchiraju, K [Southwire Co.

    2012-02-22

    This project is to develop and demonstrate the concept feasibility of a highly energy-efficient solid-state material synthesis process, friction stir extrusion (FSE) technology. Specifically, the project seeks to explore and demonstrate the feasibility to recycle metals, produce nano-particle dispersion strengthened bulk materials and/or nano-composite materials from powders, chips or other recyclable feedstock metals or scraps through mechanical alloying and thermo-mechanical processing in a single-step. In this study, we focused on metal recycling, producing nano-engineered wires and evaluating their potential use in future generation long-distance electric power delivery infrastructure. More comprehensive R&D on the technology fundamentals and system scale-up toward early-stage applications in two targeted “showcase” fields of use: nano engineered bulk materials and Al recycling will be considered and planned as part of Project Continuation Plan.

  19. Fatigue Characterization of Functionally Graded Metallic Alloys

    International Nuclear Information System (INIS)

    Silva, F. S.

    2008-01-01

    Functionally graded components exhibit spatial variations of mechanical properties in contrast with, and as an alternative to, purely homogeneous components. A large class of graded materials, however, are in fact mostly homogeneous materials with property variations (chemical or mechanical) restricted to a specific area or layer produced by applying for example a coating or by introducing sub-surface residual stresses. However, it is also possible to obtain graded materials with a smooth transition of mechanical properties along the entire component, for example in a 40 mm component. This is possible, for example, by using centrifugal casting technique or incremental melting and solidification technique. In this paper we will study fully metallic functionally graded components with a smooth gradient, focusing on fatigue crack propagation. Fatigue propagation will be assessed in the direction parallel to the gradation (in different homogeneous layers of the functionally graded component) to assess what would be fatigue crack propagation on the direction perpendicular to the gradation. Fatigue crack growth rate (standard mode I fatigue crack growth) will be correlated to the mode I stress intensity factor range. Other mechanical properties of different layers of the component (Young's modulus) will also be considered in this analysis. The effect of residual stresses along the component gradation on crack propagation will also be taken into account. A qualitative analysis of the effects of some important features, present in functionally graded materials, will be made based on the obtained results

  20. Defect features, texture and mechanical properties of friction stir welded lap joints of 2A97 Al-Li alloy thin sheets

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haiyan [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072 (China); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072 (China); Liang, Pei; Liu, Fenjun [Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072 (China)

    2017-03-15

    1.4 mm 2A97 Al-Li alloy thin sheets were welded by friction stir lap welding using the stirring tools with different pin length at different rotational speeds. The influence of pin length and rotational speed on the defect features and mechanical properties of lap joints were investigated in detail. Microstructure observation shows that the hook defect geometry and size mainly varies with the pin length instead of the rotational speed. The size of hook defects on both the advancing side (AS) and the retreating side (RS) increased with increasing the pin length, leading to the effective sheet thickness decreased accordingly. Electron backscatter diffraction analysis reveals that the weld zones, especially the nugget zone (NZ), have the much lower texture intensity than the base metal. Some new texture components are formed in the thermo-mechanical affected zone (TMAZ) and the NZ of joint. Lap shear test results show that the failure load of joints generally decreases with increasing the pin length and the rotational speed. The joints failed during the lap shear tests at three locations: the lap interface, the RS of the top sheet and the AS of the bottom sheet. The fracture locations are mainly determined by the hook defects. - Highlights: • Hook defect size mainly varies with the pin length of stirring tool. • The proportion of LAGBs and substructured grains increases from NZ to TMAZ. • Weld zones, especially the NZ, have the much lower texture intensity than the BM. • Lap shear failure load and fracture location of joints is relative to the hook defects.

  1. Defect features, texture and mechanical properties of friction stir welded lap joints of 2A97 Al-Li alloy thin sheets

    International Nuclear Information System (INIS)

    Chen, Haiyan; Fu, Li; Liang, Pei; Liu, Fenjun

    2017-01-01

    1.4 mm 2A97 Al-Li alloy thin sheets were welded by friction stir lap welding using the stirring tools with different pin length at different rotational speeds. The influence of pin length and rotational speed on the defect features and mechanical properties of lap joints were investigated in detail. Microstructure observation shows that the hook defect geometry and size mainly varies with the pin length instead of the rotational speed. The size of hook defects on both the advancing side (AS) and the retreating side (RS) increased with increasing the pin length, leading to the effective sheet thickness decreased accordingly. Electron backscatter diffraction analysis reveals that the weld zones, especially the nugget zone (NZ), have the much lower texture intensity than the base metal. Some new texture components are formed in the thermo-mechanical affected zone (TMAZ) and the NZ of joint. Lap shear test results show that the failure load of joints generally decreases with increasing the pin length and the rotational speed. The joints failed during the lap shear tests at three locations: the lap interface, the RS of the top sheet and the AS of the bottom sheet. The fracture locations are mainly determined by the hook defects. - Highlights: • Hook defect size mainly varies with the pin length of stirring tool. • The proportion of LAGBs and substructured grains increases from NZ to TMAZ. • Weld zones, especially the NZ, have the much lower texture intensity than the BM. • Lap shear failure load and fracture location of joints is relative to the hook defects.

  2. Transport mechanisms in the laser alloying of metals

    Science.gov (United States)

    Pawlak, Ryszard; Tomczyk, Mariusz; Walczak, Maria

    2003-10-01

    This article presents some investigations of a laser alloyed surface layer of nickel doped with gold and of copper doped with aluminum. The velocity of the convectino flow in the laser pool predicted by computation implies that there may exist good miscibility for the range of components different from those obtained by the conventional method. This indicates a predominant role of the Marangoni convection for mixing elements. Some metallurgical cross-sections of Ni-Au; Mo-Au; Cu-Al; Cu-Au layers, alloyed by an Nd-YAG laser, for different contents of doping elements are presented. They may be interesting information about miscibility of these metals during laser pulse τ1=4ms.

  3. Behaviour of metals and alloys in molten fluoride media

    International Nuclear Information System (INIS)

    Fabre, St.

    2009-01-01

    Fluoride salts are contemplated for Generation IV nuclear systems which structural materials need to resist corrosion at high temperatures. Corrosion of metals in molten fluorides has been investigated in support of the Molten Salt Reactor's development and led to an optimized alloy, Hastelloy-N, but it lacked fundamentals data for the comprehension of materials' degradation mechanisms. The main objective of this work is then to help with the understanding of the corrosion behaviour of nickel and its alloys in fluoride salts. An experimental method was built up using electrochemical techniques and enabled to investigate the thermochemical conditions of the media and the influence of different parameters (media, temperature and quantity of impurities) on the behaviour of the materials. Most tests were performed in LiF-NaF mixtures between 800 and 1000 C. Pure metals can be classified as follows: Cr ≤ Fe ≤ Ni ≤ Mo ≤ W in increasing stability order and two specific behaviours were evidenced: Cr and Fe corrode in the melt, whereas Ni, Mo and W are stable, underlining the significance level of the redox couple controlling the reactions in the mixture. Moreover, corrosion current densities increase with temperature, fluoro-acidity and the quantity of dissolved oxide in the melt. Binary Ni-Cr alloys were also tested; selective attack of Cr is first observed before both elements are oxidized. Combining thermochemical calculations and experimental results enables to propose an approach to establish an optimized composition for a stable alloy. Immersion tests were finally achieved in addition to the electrochemical tests: interpretations of both methods were compared and completed. (author)

  4. Effect of heat treatment on interfacial and mechanical properties of A6022/A7075/A6022 roll-bonded multi-layer Al alloy sheets

    Science.gov (United States)

    Cha, Joon-Hyeon; Kim, Su-Hyeon; Lee, Yun-Soo; Kim, Hyoung-Wook; Choi, Yoon Suk

    2016-09-01

    Multi-layered Al alloy sheets can exhibit unique properties by the combination of properties of component materials. A poor corrosion resistance of high strength Al alloys can be complemented by having a protective surface with corrosion resistant Al alloys. Here, a special care should be taken regarding the heat treatment of multi-layered Al alloy sheets because dissimilar Al alloys may exhibit unexpected interfacial reactions upon heat treatment. In the present study, A6022/A7075/A6022 sheets were fabricated by a cold roll-bonding process, and the effect of the heat treatment on the microstructure and mechanical properties was examined. The solution treatment gave rise to the diffusion of Zn, Mg, Cu and Si elements across the core/clad interface. In particular, the pronounced diffusion of Zn, which is a major alloying element (for solid-solution strengthening) of the A7075 core, resulted in a gradual hardness change across the core/clad interface. Mg2Si precipitates and the precipitate free zone were also formed near the interface after the heat treatment. The heat-treated sheet showed high strengths and reasonable elongation without apparent deformation misfit or interfacial delamination during the tensile deformation. The high strength of the sheet was mainly due to the T4 and T6 heat treatment of the A7075 core.

  5. Calcium-Antimony Alloys as Electrodes for Liquid Metal Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ouchi, T; Kim, H; Ning, XH; Sadoway, DR

    2014-08-08

    The performance of a calcium-antimony (Ca-Sb) alloy serving as the positive electrode in a Ca vertical bar vertical bar Sb liquid metal battery was investigated in an electrochemical cell, Ca(in Bi) vertical bar LiCl-NaCl-CaCl2 vertical bar Ca(in Sb). The equilibrium potential of the Ca-Sb electrode was found to lie on the interval, 1.2-0.95 V versus Ca, in good agreement with electromotive force (emf) measurements in the literature. During both alloying and dealloying of Ca at the Sb electrode, the charge transfer and mass transport at the interface are facile enough that the electrode potential varies linearly from 0.95 to 0.75 V vs Ca(s) as current density varies from 50 to 500 mA cm(-2). The discharge capacity of the Ca vertical bar vertical bar Sb cells increases as the operating temperature increases due to the higher solubility and diffusivity of Ca in Sb. The cell was successfully cycled with high coulombic efficiency (similar to 100%) and small fade rate (<0.01% cycle(-1)). These data combined with the favorable costs of these metals and salts make the Ca vertical bar vertical bar Sb liquid metal battery attractive for grid-scale energy storage. (C) The Author(s) 2014. Published by ECS. All rights reserved.

  6. 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.

  7. Direct Solid-State Conversion of Recyclable Metals and Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Manchiraju

    2012-03-27

    Friction Stir Extrusion (FSE) is a novel energy-efficient solid-state material synthesis and recycling technology capable of producing large quantity of bulk nano-engineered materials with tailored, mechanical, and physical properties. The novelty of FSE is that it utilizes the frictional heating and extensive plastic deformation inherent to the process to stir, consolidate, mechanically alloy, and convert the powders, chips, and other recyclable feedstock materials directly into useable product forms of highly engineered materials in a single step (see Figure 1). Fundamentally, FSE shares the same deformation and metallurgical bonding principles as in the revolutionary friction stir welding process. Being a solid-state process, FSE eliminates the energy intensive melting and solidification steps, which are necessary in the conventional metal synthesis processes. Therefore, FSE is highly energy-efficient, practically zero emissions, and economically competitive. It represents a potentially transformational and pervasive sustainable manufacturing technology for metal recycling and synthesis. The goal of this project was to develop the technological basis and demonstrate the commercial viability of FSE technology to produce the next generation highly functional electric cables for electricity delivery infrastructure (a multi-billion dollar market). Specific focus of this project was to (1) establish the process and material parameters to synthesize novel alloys such as nano-engineered materials with enhanced mechanical, physical, and/or functional properties through the unique mechanical alloying capability of FSE, (2) verifying the expected major energy, environmental, and economic benefits of FSE technology for both the early stage 'showcase' electric cable market and the anticipated pervasive future multi-market applications across several industry sectors and material systems for metal recycling and sustainable manufacturing.

  8. 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.

  9. 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

  10. Scalable shape- and size-controlled synthesis of metal nano-alloys

    KAUST Repository

    Bakr, Osman M.

    2016-01-21

    Embodiments of the present disclosure provide for a continuous-flow reactor, methods of making metal nano-alloys, and metal nano-alloys. An embodiment of the continuous-flow reactor includes a first tubular component having a tubular inlet and a tubular outlet, and a heated tube-in-tube gas reactor fluidly connected to the first tubular component, wherein the heated tube-in-tube gas reactor comprises an inner tube having a gas permeable surface and an outer tube. An embodiment of the method of producing metal nano-alloys, includes contacting a reducible metal precursor and a reducing fluid in a continuous-flow reactor to form a mixed solution; and flowing the mixed solution through the continuous-flow reactor for a residence time to form the metal nano-alloys. An embodiment of the composition includes a plurality of metal nano-alloys having a monodisperse size distribution and a uniform shape distribution.

  11. Enhancement of surface integrity of titanium alloy with copper by means of laser metal deposition process

    CSIR Research Space (South Africa)

    Erinosho, MF

    2016-04-01

    Full Text Available The laser metal deposition process possesses the combination of metallic powder and laser beam respectively. However, these combinations create an adhesive bonding that permanently solidifies the laser-enhanced-deposited powders. Titanium alloys (Ti...

  12. EXPERIMENTAL TESTING OF DRAW—BEAD RESTRAINING FORCE IN SHEET METAL FORMING

    Institute of Scientific and Technical Information of China (English)

    J.H.Yang; J.Chen; 等

    2003-01-01

    Due to complexities of draw-bead restraining force calculated according to theory and depending on sheet metal forming properties experiment testing system,a simplified method to calculate draw-bead restraining force is put forward by experimental method in cup-shaped drawing process.The experimental results were compared with numer-ical results and proved agreement.It shows the method is effective.

  13. Agile Production of Sheet Metal Aviation Components Using Disposable Electromagnetic Actuators

    OpenAIRE

    Carson, B.; Daehn, G.; Psyk, V.; Tekkaya, A. E.; Weddeling, C.; Woodward, S.

    2010-01-01

    Electromagnetic forming is a process used to produce high strain rates that improve the formability of sheet metal. The objective of this paper is to discuss the feasibility of the use of disposable actuators during electromagnetic forming of two aluminum components: an industry part whose main feature is a convex flange with two joggles, and a simple part with a one-dimensional curve throughout. The main forming complications after the parts were formed using conventional methods were the pr...

  14. Industrial sheet metals for nanocrystalline dye-sensitized solar cell structures

    Energy Technology Data Exchange (ETDEWEB)

    Toivola, Minna; Ahlskog, Fredrik; Lund, Peter [Laboratory of Advanced Energy Systems, Department of Engineering Physics and Mathematics, Helsinki University of Technology, P.O. Box 4100, FIN-02015 TKK (Finland)

    2006-11-06

    Direct integration of dye-sensitized solar cells (DSSC) onto industrial sheet metals has been studied. The stability of the metals, including zinc-coated and plain carbon steel, stainless steel and copper in a standard iodine electrolyte was investigated with soaking and encapsulation tests. Stainless and carbon steel showed sufficient stability and were used as the cell counter-electrodes, yielding cells with energy conversion efficiencies of 3.6% and 3.1%, respectively. A DSSC built on flexible steel substrates is a promising approach especially from the viewpoint of large-scale, cost-effective industrial manufacturing of the cells. (author)

  15. Metal Injection Molding (MIM of Magnesium and Its Alloys

    Directory of Open Access Journals (Sweden)

    Martin Wolff

    2016-05-01

    Full Text Available Current research has highlighted that magnesium and its alloys as biodegradable material are highly suitable for biomedical applications. The new material fully degrades into nontoxic elements and offers material properties matching those of human bone tissue. As biomedical implants are rather small and complex in shape, the metal injection molding (MIM technique seems to be well suited for the near net shape mass production of such parts. Furthermore, MIM of Mg-alloys is of high interest in further technical fields. This study focusses on the performance of MIM-processing of magnesium alloy powders. It includes Mg-specific development of powder blending, feedstock preparation, injection molding, solvent and thermal debinding and final sintering. Even though Mg is a highly oxygen-affine material forming a stable oxide layer on each particle surface, the material can be sintered to nearly dense parts, providing mechanical properties matching those of as cast material. An ultimate tensile strength of 142 MPa, yield strength of 67 MPa, elastic modulus of 40 GPa and 8% elongation at fracture could be achieved using novel organic polymer binders for the feedstock preparation. Thus, first implant demonstrator parts could be successfully produced by the MIM technique.

  16. Protection of zirconium and its alloys by metallic coatings

    International Nuclear Information System (INIS)

    Loriers, H.; Lafon, A.; Darras, R.; Baque, P.

    1968-01-01

    At 600 deg. C in an atmosphere of carbon dioxide, zirconium and its alloys undergo corrosion which presents two aspects simultaneously: - formation of a surface layer of zirconia, - dissolution of oxygen in the alloy sub-layer leading to brittleness. The two phenomena greatly restrict the possibilities of using zirconium alloys as a canning material for fuel elements in CO 2 cooled nuclear reactors. An attempt has thus been made to limit, and perhaps to suppress, the corrosion effects in zirconium under these conditions by protecting it with metallic coatings. A first attempt to obtain a protection using copper-based coatings did not produce the result hoped for. Aluminium coatings produced by vacuum evaporation, followed by a consolidating thermal treatment make it possible to prevent the formation of the zirconia layer, but they do not eliminate the hardening effect produced by oxygen diffusion. On the other hand, electrolytically produced chromium deposits whose adherence is improved by a thermal vacuum treatment, counteract both these phenomena simultaneously. A similar result has been obtained with coatings of molybdenum produced by the technique of high-frequency inductive plasma sputtering. The particular effectiveness of the last two types of coatings is due to their structures characterized by the existence of an adherent film of chromium or molybdenum in the free state. (authors) [fr

  17. Final Air Toxics Standards for Clay Ceramics Manufacturing, Glass Manufacturing, and Secondary Nonferrous Metals Processing Area Sources Fact Sheet

    Science.gov (United States)

    This page contains a December 2007 fact sheet with information regarding the National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Clay Ceramics Manufacturing, Glass Manufacturing, and Secondary Nonferrous Metals Processing Area Sources

  18. Development of a Prediction Model Based on RBF Neural Network for Sheet Metal Fixture Locating Layout Design and Optimization.

    Science.gov (United States)

    Wang, Zhongqi; Yang, Bo; Kang, Yonggang; Yang, Yuan

    2016-01-01

    Fixture plays an important part in constraining excessive sheet metal part deformation at machining, assembly, and measuring stages during the whole manufacturing process. However, it is still a difficult and nontrivial task to design and optimize sheet metal fixture locating layout at present because there is always no direct and explicit expression describing sheet metal fixture locating layout and responding deformation. To that end, an RBF neural network prediction model is proposed in this paper to assist design and optimization of sheet metal fixture locating layout. The RBF neural network model is constructed by training data set selected by uniform sampling and finite element simulation analysis. Finally, a case study is conducted to verify the proposed method.

  19. Development of a Prediction Model Based on RBF Neural Network for Sheet Metal Fixture Locating Layout Design and Optimization

    Directory of Open Access Journals (Sweden)

    Zhongqi Wang

    2016-01-01

    Full Text Available Fixture plays an important part in constraining excessive sheet metal part deformation at machining, assembly, and measuring stages during the whole manufacturing process. However, it is still a difficult and nontrivial task to design and optimize sheet metal fixture locating layout at present because there is always no direct and explicit expression describing sheet metal fixture locating layout and responding deformation. To that end, an RBF neural network prediction model is proposed in this paper to assist design and optimization of sheet metal fixture locating layout. The RBF neural network model is constructed by training data set selected by uniform sampling and finite element simulation analysis. Finally, a case study is conducted to verify the proposed method.

  20. On the resistivity of metal-tellurium alloys for low concentrations of tellurium

    International Nuclear Information System (INIS)

    Gorecki, J.

    1982-04-01

    The resistivity and thermoelectric power of metal-tellurium liquid alloys have been discussed for the case of small tellurium concentration. Nearly free electron model of conduction band has been used. The rapid increase of resistivity in transition metal-tellurium alloys has been predicted. (author)

  1. Lithium alloys and metal oxides as high-capacity anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Liang, Chu; Gao, Mingxia; Pan, Hongge; Liu, Yongfeng; Yan, Mi

    2013-01-01

    Highlights: •Progress in lithium alloys and metal oxides as anode materials for lithium-ion batteries is reviewed. •Electrochemical characteristics and lithium storage mechanisms of lithium alloys and metal oxides are summarized. •Strategies for improving electrochemical lithium storage properties of lithium alloys and metal oxides are discussed. •Challenges in developing lithium alloys and metal oxides as commercial anodes for lithium-ion batteries are pointed out. -- Abstract: Lithium alloys and metal oxides have been widely recognized as the next-generation anode materials for lithium-ion batteries with high energy density and high power density. A variety of lithium alloys and metal oxides have been explored as alternatives to the commercial carbonaceous anodes. The electrochemical characteristics of silicon, tin, tin oxide, iron oxides, cobalt oxides, copper oxides, and so on are systematically summarized. In this review, it is not the scope to retrace the overall studies, but rather to highlight the electrochemical performances, the lithium storage mechanism and the strategies in improving the electrochemical properties of lithium alloys and metal oxides. The challenges and new directions in developing lithium alloys and metal oxides as commercial anodes for the next-generation lithium-ion batteries are also discussed

  2. Investigation of irradiation strengthening of bcc metals and their alloys. Progress report, January 1977--October 1977

    International Nuclear Information System (INIS)

    1977-01-01

    Progress is reported in the areas of (a) the effect of neutron damage on the dislocation kinetics in bcc metals and their alloys, and (b) the effect of 3 He on the deformation characteristics of body centered cubic metals and their alloys. Results obtained from these projects are discussed

  3. Directed light fabrication of refractory metals and alloys

    International Nuclear Information System (INIS)

    Fonseca, J.C.; Lewis, G.K.; Dickerson, P.G.; Nemec, R.B.

    1999-01-01

    This report covers deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. (1) Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. (2) The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. (3) The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06microm), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. (4) The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required

  4. Directed light fabrication of refractory metals and alloys

    International Nuclear Information System (INIS)

    Fonseca, J.C.; Lewis, G.K.; Dickerson, P.G.; Nemec, R.B.

    1999-01-01

    This report covers work performed under Order No. FA0000020 AN Contract DE-AC12-76SN00052 for deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents the progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. 1. Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. 2. The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. 3. The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06microm), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. 4. The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required

  5. Effects of aging and sheet thickness on the room temperature deformation behavior and in-plane anisotropy of cold rolled and solution treated Nimonic C-263 alloy sheet

    Energy Technology Data Exchange (ETDEWEB)

    Ankamma, Kandula; Chandra Mohan Reddy, Gangireddy [Mahatma Ghandi Institute of Technology, Hyderabad (India). Mechanical Engineering Dept.; Singh, Ashok Kumar; Prasad, Konduri Satya [Defence Research and Development Organisation (DRDO), Hyderabad (India). Defence Metallurgical Research Lab.; Komaraiah, Methuku [Malla Reddy College of Engineering and Technology, Secunderabad (India); Eswara Prasad, Namburi [Regional Centre for Military Airworthiness (Materials), Hyderabad (India)

    2011-10-15

    The deformation behavior under uni-axial tensile loading is investigated and reported in the case of cold rolled Nimonic C-263 alloy sheet products of different thicknesses (0.5 mm and 1 mm) in the solution treated and aged conditions. The studies conducted include (i) Microstructure, (ii) X-ray diffraction, (iii) Texture and (iv) Tensile properties and inplane anisotropy in the yield behavior (both tensile yield strength and ultimate tensile strength as well as ductility). The results of the present study showed that despite the presence of weak crystallographic texture in this crystal symmetric material, the degrees of in-plane anisotropy in strength as well as plastic deformation properties are found to be significant in both solution treated and aged conditions, thus having significant technological relevance for both further processing and design purposes. Further, the influence of aging and sheet thickness on the tensile deformation behaviour is also found to be considerable. A brief discussion on the technological implications of these results is also included. (orig.)

  6. Evaluation of different finish line designs in base metal alloys

    Directory of Open Access Journals (Sweden)

    Aghandeh R

    1999-06-01

    Full Text Available This investigation was performed according to the widespread application of base metal alloys"nand few articles published about the marginal integrity of restorations fabricated by these metals."nThree standard dies of a maxillary first premolar were prepared with a flat shoulder finish line in buccal"naspect and chamfer in palatal. One of them left with no change. On the buccal aspect of the second and"nthird dies 135?and 1607 bevel were added respectively"nUsing dual wax technique, nine wax patterns were formed on each die and casting procedure of selected"nnon precious alloy was performed by centrifugal method. Marginal gaps of each copping seated on dies"nwere measured by scanning electron microscope (SEM with X500 magnification. Measurements were"ndone on three areas of marked dies on buccal aspect. Measurement son palatal aspect was done on"nmarked midpalatal point as control."nResults and statistical analysis showed no significant difference among marginal gaps in lingual aspect."nBut on the buccal aspect there were statistically significant differences among the groups (P<0.001. Flat"nshoulder had the best marginal integrity (mean 4 micron. Shoulder with 160' bevel had the most marginal"ngap (mean 26.5 micron and shoulder with 1357 bevel was between two other groups (mean 15.7 micron.

  7. Ultrashort pulse laser machining of metals and alloys

    Science.gov (United States)

    Perry, Michael D.; Stuart, Brent C.

    2003-09-16

    The invention consists of a method for high precision machining (cutting, drilling, sculpting) of metals and alloys. By using pulses of a duration in the range of 10 femtoseconds to 100 picoseconds, extremely precise machining can be achieved with essentially no heat or shock affected zone. Because the pulses are so short, there is negligible thermal conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond approximately 0.1-1 micron (dependent upon the particular material) from the laser machined surface. Due to the short duration, the high intensity (>10.sup.12 W/cm.sup.2) associated with the interaction converts the material directly from the solid-state into an ionized plasma. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high quality machined surfaces with negligible redeposition either within the kerf or on the surface. Since there is negligible heating beyond the depth of material removed, the composition of the remaining material is unaffected by the laser machining process. This enables high precision machining of alloys and even pure metals with no change in grain structure.

  8. Ductility dip cracking susceptibility of Inconel Filler Metal 52 and Inconel Alloy 690

    International Nuclear Information System (INIS)

    Kikel, J.M.; Parker, D.M.

    1998-01-01

    Alloy 690 and Filler Metal 52 have become the materials of choice for commercial nuclear steam generator applications in recent years. Filler Metal 52 exhibits improved resistance to weld solidification and weld-metal liquation cracking as compared to other nickel-based filler metals. However, recently published work indicates that Filler Metal 52 is susceptible to ductility dip cracking (DDC) in highly restrained applications. Susceptibility to fusion zone DDC was evaluated using the transverse varestraint test method, while heat affected zone (HAZ) DDC susceptibility was evaluated using a newly developed spot-on-spot varestraint test method. Alloy 690 and Filler Metal 52 cracking susceptibility was compared to the DDC susceptibility of Alloy 600, Filler Metal 52, and Filler Metal 625. In addition, the effect of grain size and orientation on cracking susceptibility was also included in this study. Alloy 690, Filler Metal 82, Filler Metal 52, and Filler Metal 625 were found more susceptible to fusion zone DDC than Alloy 600. Filler Metal 52 and Alloy 690 were found more susceptible to HAZ DDC when compared to wrought Alloy 600, Filler Metal 82 and Filler Metal 625. Filler Metal 52 exhibited the greatest susceptibility to HAZ DDC of all the weld metals evaluated. The base materials were found much more resistant to HAZ DDC in the wrought condition than when autogenously welded. A smaller grain size was found to offer greater resistance to DDC. For weld metal where grain size is difficult to control, a change in grain orientation was found to improve resistance to DDC

  9. The evaluation of the use of metal alloy fuels in pressurized water reactors

    International Nuclear Information System (INIS)

    Lancaster, D.

    1992-01-01

    The use of metal alloy fuels in a PWR was investigated. It was found that it would be feasible and competitive to design PWRs with metal alloy fuels but that there seemed to be no significant benefits. The new technology would carry with it added economic uncertainty and since no large benefits were found it was determined that metal alloy fuels are not recommended. Initially, a benefit was found for metal alloy fuels but when the oxide core was equally optimized the benefit faded. On review of the optimization of the current generation of ''advanced reactors,'' it became clear that reactor design optimization has been under emphasized. Current ''advanced reactors'' are severely constrained. The AP-600 required the use of a fuel design from the 1970's. In order to find the best metal alloy fuel design, core optimization became a central effort. This work is ongoing

  10. The evaluation of the use of metal alloy fuels in pressurized water reactors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lancaster, D.

    1992-10-26

    The use of metal alloy fuels in a PWR was investigated. It was found that it would be feasible and competitive to design PWRs with metal alloy fuels but that there seemed to be no significant benefits. The new technology would carry with it added economic uncertainty and since no large benefits were found it was determined that metal alloy fuels are not recommended. Initially, a benefit was found for metal alloy fuels but when the oxide core was equally optimized the benefit faded. On review of the optimization of the current generation of ``advanced reactors,`` it became clear that reactor design optimization has been under emphasized. Current ``advanced reactors`` are severely constrained. The AP-600 required the use of a fuel design from the 1970`s. In order to find the best metal alloy fuel design, core optimization became a central effort. This work is ongoing.

  11. Influence of S. mutans on base-metal dental casting alloy toxicity.

    Science.gov (United States)

    McGinley, E L; Dowling, A H; Moran, G P; Fleming, G J P

    2013-01-01

    We have highlighted that exposure of base-metal dental casting alloys to the acidogenic bacterium Streptococcus mutans significantly increases cellular toxicity following exposure to immortalized human TR146 oral keratinocytes. With Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), S. mutans-treated nickel-based (Ni-based) and cobalt-chromium-based (Co-Cr-based) dental casting alloys were shown to leach elevated levels of metal ions compared with untreated dental casting alloys. We targeted several biological parameters: cell morphology, viable cell counts, cell metabolic activity, cell toxicity, and inflammatory cytokine expression. S. mutans-treated dental casting alloys disrupted cell morphology, elicited significantly decreased viable cell counts (p casting alloys induced elevated levels of cellular toxicity compared with S. mutans-treated Co-Cr-based dental casting alloys. While our findings indicated that the exacerbated release of metal ions from S. mutans-treated base-metal dental casting alloys was the likely result of the pH reduction during S. mutans growth, the exact nature of mechanisms leading to accelerated dissolution of alloy-discs is not yet fully understood. Given the predominance of S. mutans oral carriage and the exacerbated cytotoxicity observed in TR146 cells following exposure to S. mutans-treated base-metal dental casting alloys, the implications for the long-term stability of base-metal dental restorations in the oral cavity are a cause for concern.

  12. Radial-rotation profile forming: A new processing technology of incremental sheet metal forming

    Science.gov (United States)

    Laue, Robert; Härtel, Sebastian; Awiszus, Birgit

    2018-05-01

    Incremental forming processes (i.e., spinning) of sheet metal blanks into cylindrical cups are suitable for lower lot sizes. The produced cups were frequently used as preforms to produce workpieces in further forming steps with additional functions like profiled hollow parts [1]. The incremental forming process radial-rotation profile forming has been developed to enable the production of profiled hollow parts with low sheet thinning and good geometrical accuracy. The two principal forming steps are the production of the preform by rotational swing-folding [2] and the subsequent radial profiling of the hollow part in one clamping position. The rotational swing-folding process is based on a combination of conventional spinning and swing-folding. Therefore, a round blank rotates on a profiled mandrel and due to the swinging of a cylindrical forming tool, the blank is formed to a cup with low sheet thinning. In addition, thickening results at the edge of the blank and wrinkling occurs. However, the wrinkles are formed into the indentation of the profiled mandrel and can be reshaped as an advantage in the second process step, the radial profiling. Due to the rotation and continuous radial feed of a profiled forming tool to the profiled mandrel, the axial profile is formed in the second process step. Because of the minor relative movement in axial direction between tool and blank, low sheet thinning occurs. This is an advantage of the principle of the process.

  13. 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

  14. M551 metals melting experiment. [space manufacturing of aluminum alloys, tantalum alloys, stainless steels

    Science.gov (United States)

    Li, C. H.; Busch, G.; Creter, C.

    1976-01-01

    The Metals Melting Skylab Experiment consisted of selectively melting, in sequence, three rotating discs made of aluminum alloy, stainless steel, and tantalum alloy. For comparison, three other discs of the same three materials were similarly melted or welded on the ground. The power source of the melting was an electron beam unit. Results are presented which support the concept that the major difference between ground base and Skylab samples (i.e., large elongated grains in ground base samples versus nearly equiaxed and equal sized grains in Skylab samples) can be explained on the basis of constitutional supercooling, and not on the basis of surface phenomena. Microstructural observations on the weld samples and present explanations for some of these observations are examined. In particular, ripples and their implications to weld solidification were studied. Evidence of pronounced copper segregation in the Skylab A1 weld samples, and the tantalum samples studied, indicates a weld microhardness (and hence strength) that is uniformly higher than the ground base results, which is in agreement with previous predictions. Photographs are shown of the microstructure of the various alloys.

  15. Validation of formability of laminated sheet metal for deep drawing process using GTN damage model

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Yongbin; Cha, Wan-gi; Kim, Naksoo [Department of Mechanical Engineering, Sogang University, 1 Sinsu-dong, Mapo-gu, Seoul, 121-742 (Korea, Republic of); Ko, Sangjin [Mold/die and forming technology team, Product prestige research lab, LG electronics, 222, LG-ro, Jinwi-myeon, Pyeongtaek-si, Gyeonggi-do, 451-713 (Korea, Republic of)

    2013-12-16

    In this study, we studied formability of PET/PVC laminated sheet metal which named VCM (Vinyl Coated Metal). VCM offers various patterns and good-looking metal steel used for appliances such as refrigerator and washing machine. But, this sheet has problems which are crack and peeling of film when the material is formed by deep drawing process. To predict the problems, we used finite element method and GTN (Gurson-Tvergaard-Needleman) damage model to represent damage of material. We divided the VCM into 3 layers (PET film, adhesive and steel added PVC) in finite element analysis model to express the crack and peeling phenomenon. The material properties of each layer are determined by reverse engineering based on tensile test result. Furthermore, we performed the simple rectangular deep drawing and simulated it. The simulation result shows good agreement with drawing experiment result in position, punch stroke of crack occurrence. Also, we studied the fracture mechanism of PET film on VCM by comparing the width direction strain of metal and PET film.

  16. Radiation hardening and embrittlement of some refractory metals and alloys

    International Nuclear Information System (INIS)

    Fabritsiev, S.; Pokrovskyb

    2007-01-01

    Tungsten is proposed for application in the ITER divertor and limiter as plasma facing material. The tungsten operation temperature in the ITER divertor is relatively high. Hence, the ductile properties of tungsten will be controlled by the low temperature radiation embrittlement. The mechanism of radiation hardening and embrittlement under neutron irradiation at low temperature is well studied for FCC metals, in particular for copper. At the same time, low-temperature radiation hardening of BCC materials, in particular for refractory metals, is less studied. This study presents the results of investigation into radiation hardening and embrittlement of pure metals: W, Mo and Nb, and W-Re and Ta-4W alloys. The materials were in the annealed conditions. The specimens were irradiated in the SM-2 reactor to doses of 10 -4 -10 -1 dpa at 80 C and then tested for tension at 80 C. The study of the stress-strain curves of unirradiated specimens revealed a yield drop for W, Mo, Nb, Ta-4W, W-Re. After the yield drop some metals (Mo,Nb) retain their capability for strain hardening and demonstrate a high elongation (20-50%). Radiation hardening is maximum in Mo (∝400MPa) and minimum in Nb (∝100 MPa). In this case the dependence slope for Nb is similar to that for pure copper irradiated in SM-2 under the same conditions. Ii and Ta-4W have a higher slope. Measurement of electrical resistivity of irradiated specimens showed that for all materials it is increased monotonously with an increase in the irradiation dose. A minimum gain in electrical resistivity with a dose was observed for Nb (∝3% at 0.1 dpa). As for Mo it was essentially higher, i.e. ∝ 30%. The gain was maximum for W-Re alloy. Comparison of radiation hardening dose dependencies obtained in this study with the data for FCC metals (Cu) showed that in spite of the quantitative difference the qualitative behavior of these two classes of metals is similar. (orig.)

  17. Improvement of formability for fabricating thin continuously corrugated structures in sheet metal forming process

    International Nuclear Information System (INIS)

    Choi, Sung Woo; Park, Sang Hu; Park, Seong Hun; Ha, Man Yeong; Jeong, Ho Seung; Cho, Jong Rae

    2012-01-01

    A stamping process is widely used for fabricating various sheet metal parts for vehicles, airplanes, and electronic devices by the merit of low processing cost and high productivity. Recently, the use of thin sheets with a corrugated structure for sheet metal parts has rapidly increased for use in energy management devices, such as heat exchangers, separators in fuel cells, and many others. However, it is not easy to make thin corrugated structures directly using a single step stamping process due to their geometrical complexity and very thin thickness. To solve this problem, a multi step stamping (MSS) process that includes a heat treatment process to improve formability is proposed in this work: the sequential process is the initial stamping, heat treatment, and final shaping. By the proposed method, we achieved successful results in fabricating thin corrugated structures with an average thickness of 75μm and increased formability of about 31% compared to the single step stamping process. Such structures can be used in a plate-type heat exchanger requiring low weight and a compact shape

  18. Pore-level determination of spectral reflection behaviors of high-porosity metal foam sheets

    Science.gov (United States)

    Li, Yang; Xia, Xin-Lin; Ai, Qing; Sun, Chuang; Tan, He-Ping

    2018-03-01

    Open cell metal foams are currently attracting attention and their radiative behaviors are of primary importance in high temperature applications. The spectral reflection behaviors of high-porosity metal foam sheets, bidirectional reflectance distribution function (BRDF) and directional-hemispherical reflectivity were numerically investigated. A set of realistic nickel foams with porosity from 0.87 to 0.97 and pore density from 10 to 40 pores per inch were tomographied to obtain their 3-D digital cell network. A Monte Carlo ray-tracing method was employed in order to compute the pore-level radiative transfer inside the network within the limit of geometrical optics. The apparent reflection behaviors and their dependency on the textural parameters and strut optical properties were comprehensively computed and analysed. The results show a backward scattering of the reflected energy at the foam sheet surface. Except in the cases of large incident angles, an energy peak is located almost along the incident direction and increases with increasing incident angles. Through an analytical relation established, the directional-hemispherical reflectivity can be related directly to the porosity of the foam sheet and to the complex refractive index of the solid phase as well as the specularity parameter which characterizes the local reflection model. The computations show that a linear decrease in normal-hemispherical reflectivity occurs with increasing porosity. The rate of this decrease is directly proportional to the strut normal reflectivity. In addition, the hemispherical reflectivity increases as a power function of the incident angle cosine.

  19. Effects of thermal aging on microstructures of low alloy steel–Ni base alloy dissimilar metal weld interfaces

    International Nuclear Information System (INIS)

    Choi, Kyoung Joon; Kim, Jong Jin; Lee, Bong Ho; Bahn, Chi Bum; Kim, Ji Hyun

    2013-01-01

    In this study, the advanced instrumental analysis has been performed to investigate the effect of long-term thermal aging on the microstructural evolution in the fusion boundary region between weld metal and low alloy steel in dissimilar metal welds. A representative dissimilar weld mock-up made of Alloy 690-Alloy 152-A533 Gr. B was fabricated and aged at 450 °C for 2750 h. The micro- and nano-scale characterization were conducted mainly near in a weld root region by using optical microscopy, scanning electron microscopy, transmission electron microscopy, and three dimensional atom probe tomography. It was observed that the weld root was generally divided into several regions including dilution zone in the Ni-base alloy weld metal, fusion boundary, and heat-affected zone in the low alloy steel. A steep gradient was shown in the chemical composition profile across the interface between A533 Gr. B and Alloy 152. The precipitation of carbides was also observed along and near the fusion boundary of as-welded and aged dissimilar metal joints. It was also found that the precipitation of Cr carbides was enhanced by the thermal aging near the fusion boundary

  20. Effects of thermal aging on microstructures of low alloy steel–Ni base alloy dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Kim, Jong Jin [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Lee, Bong Ho [National Center for Nanomaterials Technology (NCNT), Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Bahn, Chi Bum [Argonne National Laboratory, 9700 S. Cass Ave, Lemont, IL 60439 (United States); Kim, Ji Hyun, E-mail: kimjh@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2013-10-15

    In this study, the advanced instrumental analysis has been performed to investigate the effect of long-term thermal aging on the microstructural evolution in the fusion boundary region between weld metal and low alloy steel in dissimilar metal welds. A representative dissimilar weld mock-up made of Alloy 690-Alloy 152-A533 Gr. B was fabricated and aged at 450 °C for 2750 h. The micro- and nano-scale characterization were conducted mainly near in a weld root region by using optical microscopy, scanning electron microscopy, transmission electron microscopy, and three dimensional atom probe tomography. It was observed that the weld root was generally divided into several regions including dilution zone in the Ni-base alloy weld metal, fusion boundary, and heat-affected zone in the low alloy steel. A steep gradient was shown in the chemical composition profile across the interface between A533 Gr. B and Alloy 152. The precipitation of carbides was also observed along and near the fusion boundary of as-welded and aged dissimilar metal joints. It was also found that the precipitation of Cr carbides was enhanced by the thermal aging near the fusion boundary.

  1. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

  2. The quantitative representation of fiber-and sheet-texture in metals of cubic system

    International Nuclear Information System (INIS)

    Kim, H.J.; Kim, S.C.; Chun, B.C.; Lee, C.Y.

    1983-01-01

    This is the first article of a series dealing with studies on the quantitative representation of fiber-and sheet-type textures in metals of cubic crystal system. Texture measurements by neutron diffraction method are analyzed using Bunge's series expansion method and the effect of series truncation is studied for samples of various texture sharpness. The present article describes two computer programs, TXFIB and TXSHT, develped for the analysis of the respective fiber-and sheet-type texture. Using these computer programs, the orientation distribution function can be expanded in the series of generalized spherical harmonics up to 58th term from 6 experimental pole figures as input. Estimations of various errors involved in the texture analysis and texture sharpness index are also included in the programs. (Author)

  3. Wetting and spreading behavior of molten brazing filler metallic alloys on metallic substrate

    Science.gov (United States)

    Kogi, Satoshi; Kajiura, Tetsurou; Hanada, Yukiakira; Miyazawa, Yasuyuki

    2014-08-01

    Wetting and spreading of molten brazing filler material are important factors that influence the brazing ability of a joint to be brazed. Several investigations into the wetting ability of a brazing filler alloy and its surface tension in molten state, in addition to effects of brazing time and temperature on the contact angle, have been carried out. In general, dissimilar-metals brazing technology and high-performance brazed joint are necessities for the manufacturing field in the near future. Therefore, to address this requirement, more such studies on wetting and spreading of filler material are required for a deeper understanding. Generally, surface roughness and surface conditions affect spreading of molten brazing filler material during brazing. Wetting by and interfacial reactions of the molten brazing filler material with the metallic substrate, especially, affect strongly the spreading of the filler material. In this study, the effects of surface roughness and surface conditions on the spreading of molten brazing filler metallic alloys were investigated. Ag-(40-x)Cu-xIn and Ag- (40-x)Cu-xSn (x=5, 10, 15, 20, 25) alloys were used as brazing filler materials. A mild-steel square plate (S45C (JIS); side: 30 mm; thickness: 3mm) was employed as the substrate. A few surfaces with varying roughness were prepared using emery paper. Brazing filler material and metallic base plate were first washed with acetone, and then a flux was applied to them. The filler, 50 mg, was placed on the center of the metallic base with the flux. A spreading test was performed under Ar gas using an electrically heated furnace, after which, the original spreading area, defined as the sessile drop area, and the apparent spreading area, produced by the capillary grooves, were both evaluated. It was observed that the spreading area decreased with increasing In and Sn content.

  4. Microstructure, mechanical properties and stress corrosion cracking of Al–Zn–Mg–Zr alloy sheet with trace amount of Sc

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Pan, Qinglin, E-mail: pql1964@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiming; Huang, Zhiqi [Guangdong Fenglu Aluminum Co., Ltd, Foshan 528133 (China); Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2015-11-25

    Microstructural and property evolution of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy sheet during its preparation were investigated in detail by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Vickers micro-hardness test and room temperature tensile test. Stress corrosion cracking (SCC) behavior of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy under different heat treatments was studied using slow strain rate test. The results showed that serious dendritic segregation existed in as-cast condition. The suitable homogenization treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was 470 °C/24 h. After homogenization treatment, dissoluble Zn and Mg enriched non-equilibrium phases dissolved into α-Al matrix completely. The suitable solid solution-aging treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was solution treated at 470 °C for 60 min, followed by water quenching and then aged at 120 °C for 24 h. Under this aging temper, the grain structures were composed of sub-grains, η′ phases and nanometer-sized, spherical Al{sub 3}(Sc, Zr) particles. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The improved corrosion resistance from increasing aging temperature or prolonging aging time was due to the discontinuous η precipitates along the grain boundary and the high area fraction of GBPs. The main strengthening mechanisms of Al–Zn–Mg–0.10%Sc–0.10%Zr alloy are precipitation strengthening derived from η′ precipitates, dispersion strengthening, sub-grain strengthening and grain refinement caused by coherent Al{sub 3}(Sc, Zr) particles. - Highlights: • The suitable homogenization treatment of the alloy has been identified. • Evolution of microstructure and mechanical properties is investigated. • Strengthening mechanisms of the alloy has been established. • The basic mechanism has

  5. Metallic Reinforcement of Direct Squeeze Die Casting Aluminum Alloys for Improved Strength and Fracture Resistance

    Energy Technology Data Exchange (ETDEWEB)

    D. Schwam: J.F. Wallace: Y. Zhu: J.W. Ki

    2004-10-01

    The utilization of aluminum die casting as enclosures where internal equipment is rotating inside of the casting and could fracture requires a strong housing to restrain the fractured parts. A typical example would be a supercharger. In case of a failure, unless adequately contained, fractured parts could injure people operating the equipment. A number of potential reinforcement materials were investigated. The initial work was conducted in sand molds to create experimental conditions that promote prolonged contact of the reinforcing material with molten aluminum. Bonding of Aluminum bronze, Cast iron, and Ni-resist inserts with various electroplated coatings and surface treatments were analyzed. Also toughening of A354 aluminum cast alloy by steel and stainless steel wire mesh with various conditions was analyzed. A practical approach to reinforcement of die cast aluminum components is to use a reinforcing steel preform. Such performs can be fabricated from steel wire mesh or perforated metal sheet by stamping or deep drawing. A hemispherical, dome shaped casting was selected in this investigation. A deep drawing die was used to fabricate the reinforcing performs. The tendency of aluminum cast enclosures to fracture could be significantly reduced by installing a wire mesh of austenitic stainless steel or a punched austenitic stainless steel sheet within the casting. The use of reinforcements made of austenitic stainless steel wire mesh or punched austenitic stainless steel sheet provided marked improvement in reducing the fragmentation of the casting. The best strengthening was obtained with austenitic stainless steel wire and with a punched stainless steel sheet without annealing this material. Somewhat lower results were obtained with the annealed punched stainless steel sheet. When the annealed 1020 steel wire mesh was used, the results were only slightly improved because of the lower mechanical properties of this unalloyed steel. The lowest results were

  6. Microstructure and mechanical properties of Mg-Al-Mn-Ca alloy sheet produced by twin roll casting and sequential warm rolling

    International Nuclear Information System (INIS)

    Wang Yinong; Kang, Suk Bong; Cho, Jaehyung

    2011-01-01

    Research highlights: → This work, taking AM30 + 0.2Ca alloy as experimental material, will provide some new information as follows: one is microstructural difference between twin roll cast and ingot cast AM31-0.2Ca alloy. The other is the comparison of tensile properties after warm rolling and annealing. Suggesting the possibility of the development of wrought magnesium alloy sheets by strip casting. - Abstract: Microstructural evolution and mechanical properties of twin roll cast (TRC) Mg-3.3 wt.%Al-0.8 wt.%Mn-0.2 wt.%Ca (AM31 + 0.2Ca) alloy strip during warm rolling and subsequent annealing were investigated in this paper. The as-TRC alloy strip shows columnar dendrites in surface and equiaxed dendrites in center regions, as well as finely dispersed primary Al 8 Mn 5 particles on interdendritic boundaries which result in the beneficial effect on microstructural refinement of strip casting. The warm rolled sheets show intensively deformed band or shear band structures, as well as finely and homogeneously dispersed Al-Mn particles. No evident dynamic recrystallization (DRX) takes place during warm rolling process, which is more likely attributed to the finely dispersed particle and high solid solution of Al and Mn atoms in α-Mg matrix. After annealing at 350 deg. C for 1 h, the warm rolled TRC sheets show fine equiaxed grains around 7.8 μm in average size. It has been shown that the present TRC alloy sheet has superior tensile strength and comparative elongation compared to commercial ingot cast (IC) one, suggesting the possibility of the development of wrought magnesium alloy sheets by twin roll strip casting processing. The microstructural evolution during warm rolling and subsequent annealing as well as the resulting tensile properties were analyzed and discussed.

  7. Applications for Gradient Metal Alloys Fabricated Using Additive Manufacturing

    Science.gov (United States)

    Hofmann, Douglas C.; Borgonia, John Paul C.; Dillon, Robert P.; Suh, Eric J.; Mulder, jerry L.; Gardner, Paul B.

    2013-01-01

    assortment of "post-processing" methods to locally alter properties (such as coating, heat treating, work hardening, shot peening, etching, anodizing, among others). Building the final part in an additive process allows for the development of an entirely new class of metals, so-called "functionally graded metals" or "gradient alloys." By carefully blending feedstock materials with different properties in an AM process, hardware can be developed with properties that cannot be obtained using other techniques but with the added benefit of the net-shaped fabrication that AM allows.

  8. Preparation of rare earth and other metal alloys containing aluminum and silicon

    International Nuclear Information System (INIS)

    Mitchell, A.; Goldsmith, J.R.; Gray, M.

    1981-01-01

    A method is provided for making alloys of aluminum and silicon with a third metal which may be a rare earth or a member of groups 4b, 5b, or 6b of the periodic table. The flux system CaF 2 -CaO-Al 2 O 3 is used as a solvent to provide a reactive medium for the alloy-forming reactions. Aluminum is supplied as a reducing agent, and silicon is added as a sink for the alloying metal. The resulting alloy may be used in steels. (L.L.)

  9. Tribological evaluation of surface modified H13 tool steel in warm forming of Ti–6Al–4V titanium alloy sheet

    OpenAIRE

    Wang, Dan; Li, Heng; Yang, He; Ma, Jun; Li, Guangjun

    2014-01-01

    The H13 hot-working tool steel is widely used as die material in the warm forming of Ti–6Al–4V titanium alloy sheet. However, under the heating condition, severe friction and lubricating conditions between the H13 tools and Ti–6Al–4V titanium alloy sheet would cause difficulty in guaranteeing forming quality. Surface modification may be used to control the level of friction force, reduce the friction wear and extend the service life of dies. In this paper, four surface modification methods (c...

  10. Improved alloys for a liquid metal fast breeder reactor

    International Nuclear Information System (INIS)

    1981-01-01

    An alloy is specified suitable for use at elevated temperatures and especially in a liquid metal fast breeder reactor consisting essentially of a nickel-chromium steel having a specified range of composition of C, Mn, Si, Zr, V, Ni, Cr, Ti, Al, Mo, B, and the balance iron with incidental impurities, the alloy exhibiting a swelling at peak swelling temperature of less than 10% wherein the matrix composition has after heat treatment at a temperature within the range of 1000 0 C to 1100 0 C for about one half hour followed by aging at a temperature within the range of from 700 0 C to 815 0 C for a time period of between 10 to 24 hours, the longer hours being associated with the lower temperatures and vice-versa, and after the removal of the non-equilibrium gamma prime and other precipitated phases a composition within a specified range of composition of Ni, Cr, Ti, Al, Mo, the balance being essentially iron. (U.K.)

  11. Finite element simulation and Experimental verification of Incremental Sheet metal Forming

    Science.gov (United States)

    Kaushik Yanamundra, Krishna; Karthikeyan, R., Dr.; Naranje, Vishal, Dr

    2018-04-01

    Incremental sheet metal forming is now a proven manufacturing technique that can be employed to obtain application specific, customized, symmetric or asymmetric shapes that are required by automobile or biomedical industries for specific purposes like car body parts, dental implants or knee implants. Finite element simulation of metal forming process is being performed successfully using explicit dynamics analysis of commercial FE software. The simulation is mainly useful in optimization of the process as well design of the final product. This paper focuses on simulating the incremental sheet metal forming process in ABAQUS, and validating the results using experimental methods. The shapes generated for testing are of trapezoid, dome and elliptical shapes whose G codes are written and fed into the CNC milling machine with an attached forming tool with a hemispherical bottom. The same pre-generated coordinates are used to simulate a similar machining conditions in ABAQUS and the tool forces, stresses and strains in the workpiece while machining are obtained as the output data. The forces experimentally were recorded using a dynamometer. The experimental and simulated results were then compared and thus conclusions were drawn.

  12. Refractory metal alloys and composites for space power systems

    International Nuclear Information System (INIS)

    Stephens, J.R.; Petrasek, D.W.; Titran, R.H.

    1994-01-01

    Space power requirements for future NASA and other United States missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the space shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary power source to meet these high levels of electrical demand. One method to achieve maximum efficiency is to operate the power supply, energy conversion system, and related components at relatively high temperatures. NASA Lewis Research Center has undertaken a research program on advanced technology of refractory metal alloys and composites that will provide base line information for space power systems in the 1900's and the 21st century. Basic research on the tensile and creep properties of fibers, matrices, and composites will be discussed

  13. Crystallization of some amorphous metallic alloys studied by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Sitek, J.; Miglierini, M.; Lipka, J.; Valko, P.; Toth, I.

    1990-01-01

    The present work provides an analysis of crystallization processes in amorphous metallic alloys Fe 80 Si 4 Cr 1.8 B 14 and Fe 67 Co 18 B 14 Si 1 . Crystallization of the first sample started at the temperature of 648 K. The fully crystalline state was observed after annealing at 748 K. We identified four sextets. One corresponds to crystalline Fe 2 B and the three others to FeSi solid solution with 10 at.% of Si. Crystallization of Fe 67 Co 18 B 14 Si 1 started at the temperature of 623 K. We identified two crystalline phases. The first may have its origin as (Fe 1-x Co x ) 3 B, the second one may correspond to a Fe-Co solid solution with a different Co content. (orig.)

  14. Leakage current characteristics of the multiple metal alloy nanodot memory

    International Nuclear Information System (INIS)

    Lee, Gae Hun; Lee, Jung Min; Yang, Hyung Jun; Song, Yun Heub; Bea, Ji Chel; Tanaka, Tetsu

    2010-01-01

    The leakage current characteristics of a multiple metal alloy nanodot device for a nonvolatile random access memory using FePt materials are investigated. Several annealing conditions are evaluated and optimized to suppress the leakage current and to better the memory characterisctics. This work confirmed that the annealing condition of 700 .deg. C in a high vacuum ambience (under 1 x 10 -5 Pa) simultaneously provided good cell characteristics from a high dot density of over 1 x 10 13 /cm 2 and a low leakage current. In addition, a smaller nanodot diameter was found to give a lower leakage current for the multiple nanodot memory. Finally, for the proposed annealing condition, the quadruple FePt multiple nanodot memory with a 2-nm dot diameter provided good leakage current characteristics, showing a threshold voltage shift of under 5% at an initial retention stage of 1000 sec.

  15. Full Electroresistance Modulation in a Mixed-Phase Metallic Alloy

    Science.gov (United States)

    Liu, Z. Q.; Li, L.; Gai, Z.; Clarkson, J. D.; Hsu, S. L.; Wong, A. T.; Fan, L. S.; Lin, M.-W.; Rouleau, C. M.; Ward, T. Z.; Lee, H. N.; Sefat, A. S.; Christen, H. M.; Ramesh, R.

    2016-03-01

    We report a giant, ˜22 %, electroresistance modulation for a metallic alloy above room temperature. It is achieved by a small electric field of 2 kV /cm via piezoelectric strain-mediated magnetoelectric coupling and the resulting magnetic phase transition in epitaxial FeRh /BaTiO3 heterostructures. This work presents detailed experimental evidence for an isothermal magnetic phase transition driven by tetragonality modulation in FeRh thin films, which is in contrast to the large volume expansion in the conventional temperature-driven magnetic phase transition in FeRh. Moreover, all the experimental results in this work illustrate FeRh as a mixed-phase model system well similar to phase-separated colossal magnetoresistance systems with phase instability therein.

  16. Development of dynamic explicit crystallographic homogenization finite element analysis code to assess sheet metal formability

    International Nuclear Information System (INIS)

    Nakamura, Yasunori; Tam, Nguyen Ngoc; Ohata, Tomiso; Morita, Kiminori; Nakamachi, Eiji

    2004-01-01

    The crystallographic texture evolution induced by plastic deformation in the sheet metal forming process has a great influence on its formability. In the present study, a dynamic explicit finite element (FE) analysis code is newly developed by introducing a crystallographic homogenization method to estimate the polycrystalline sheet metal formability, such as the extreme thinning and 'earing'. This code can predict the plastic deformation induced texture evolution at the micro scale and the plastic anisotropy at the macro scale, simultaneously. This multi-scale analysis can couple the microscopic crystal plasticity inhomogeneous deformation with the macroscopic continuum deformation. In this homogenization process, the stress at the macro scale is defined by the volume average of those of the corresponding microscopic crystal aggregations in satisfying the equation of motion and compatibility condition in the micro scale 'unit cell', where the periodicity of deformation is satisfied. This homogenization algorithm is implemented in the conventional dynamic explicit finite element code by employing the updated Lagrangian formulation and the rate type elastic/viscoplastic constitutive equation.At first, it has been confirmed through a texture evolution analyses in cases of typical deformation modes that Taylor's 'constant strain homogenization algorithm' yields extreme concentration toward the preferred crystal orientations compared with our homogenization one. Second, we study the plastic anisotropy effects on 'earing' in the hemispherical cup deep drawing process of pure ferrite phase sheet metal. By the comparison of analytical results with those of Taylor's assumption, conclusions are drawn that the present newly developed dynamic explicit crystallographic homogenization FEM shows more reasonable prediction of plastic deformation induced texture evolution and plastic anisotropy at the macro scale

  17. Influence of Filler Alloy Composition and Process Parameters on the Intermetallic Layer Thickness in Single-Sided Cold Metal Transfer Welding of Aluminum-Steel Blanks

    Science.gov (United States)

    Silvayeh, Zahra; Vallant, Rudolf; Sommitsch, Christof; Götzinger, Bruno; Karner, Werner; Hartmann, Matthias

    2017-11-01

    Hybrid components made of aluminum alloys and high-strength steels are typically used in automotive lightweight applications. Dissimilar joining of these materials is quite challenging; however, it is mandatory in order to produce multimaterial car body structures. Since especially welding of tailored blanks is of utmost interest, single-sided Cold Metal Transfer butt welding of thin sheets of aluminum alloy EN AW 6014 T4 and galvanized dual-phase steel HCT 450 X + ZE 75/75 was experimentally investigated in this study. The influence of different filler alloy compositions and welding process parameters on the thickness of the intermetallic layer, which forms between the weld seam and the steel sheet, was studied. The microstructures of the weld seam and of the intermetallic layer were characterized using conventional optical light microscopy and scanning electron microscopy. The results reveal that increasing the heat input and decreasing the cooling intensity tend to increase the layer thickness. The silicon content of the filler alloy has the strongest influence on the thickness of the intermetallic layer, whereas the magnesium and scandium contents of the filler alloy influence the cracking tendency. The layer thickness is not uniform and shows spatial variations along the bonding interface. The thinnest intermetallic layer (mean thickness < 4 µm) is obtained using the silicon-rich filler Al-3Si-1Mn, but the layer is more than twice as thick when different low-silicon fillers are used.

  18. Dissolution of metallic uranium and its alloys. Part 1. Review of analytical and process-scale metallic uranium dissolution

    International Nuclear Information System (INIS)

    Laue, C.A.; Gates-Anderson, D.; Fitch, T.E.

    2004-01-01

    This review focuses on dissolution/reaction systems capable of treating uranium metal waste to remove its pyrophoric properties. The primary emphasis is the review of literature describing analytical and production-scale dissolution methods applied to either uranium metal or uranium alloys. A brief summary of uranium's corrosion behavior is included since the corrosion resistance of metals and alloys affects their dissolution behavior. Based on this review, dissolution systems were recommended for subsequent screening studies designed to identify the best system to treat depleted uranium metal wastes at Lawrence Livermore National Laboratory (LLNL). (author)

  19. Joining of Dissimilar alloy Sheets (Al 6063&AISI 304 during Resistance Spot Welding Process: A Feasibility Study for Automotive industry

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2014-12-01

    Full Text Available Present design trends in automotive manufacture have shifted emphasis to alternative lightweight materials in order to achieve higher fuel efficiency and to bring down vehicle emission. Although some other joining techniques are more and more being used, spot welding still remains the primary joining method in automobile manufacturing so far. Spot welds for automotive applications should have a sufficiently large diameter, so that nugget pullout mode is the dominant failure mode. Interfacial mode is unacceptable due to its low load carrying and energy absorption capability. Strength tests with different static loading were performed in, to reveal the failure mechanisms for the lap-shear geometry and the cross-tension geometry. Based on the literature survey performed, venture into this work was amply motivated by the fact that a little research work has been conducted to joining of dissimilar materials like non ferrous to ferrous. Most of the research works concentrated on joining of different materials like steel to steel or aluminium alloy to aluminium alloy by resistance spot welding. In this work, an experimental study on the resistance spot weldability of aluminium alloy (Al 6063 and austenitic stainless steel (AISI304 sheets, which are lap joined by using a pedestal type resistance spot welding machine. Welding was conducted using a 45-deg truncated cone copper electrode with 10-mm face diameter. The weld nugget diameter, force estimation under lap shear test and T – peel test were investigated using digital type tensometer attached with capacitive displacement transducer (Mikrotech, Bangalore, Model: METM2000ER1. The results shows that joining of Al 6063 and AISI 304 thin sheets by RSW method are feasible for automotive structural joints where the loads are below 1000N act on them, it is observed that by increasing the spots per unit length, then the joint with standing strength to oppose failure is also increased linearly incase of

  20. Assessment of the vibration on the foam legged and sheet metal-legged passenger seat

    Directory of Open Access Journals (Sweden)

    L. Dahil

    2015-10-01

    Full Text Available In this study, it was aim ed to decrease the vibration reaching to passenger from the legs of vehicle seats. In order to determine the levels of vibrations reaching at passengers, a test pad placed under the passenger seat was used, and HVM100 device was used for digitizing the information obtained. By transferring the vibration data to system by using HVM100 device, the acceleration graphics were prepared with Blaze software. As a result, it was determined that the acceleration values of seat legs made of foam material were lower than that of seat legs made of 2 mm thick sheet metal, so they damped the vibration better.

  1. Off-Line Testing of Tribo-Systems for Sheet Metal Forming Production

    DEFF Research Database (Denmark)

    Bay, Niels; Ceron, Ermanno

    2014-01-01

    Off-line testing of new tribo-systems for sheet metal forming production is an important issue, when new, environmentally benign lubricants are to be introduced. To obtain useful results it is, however, vital to ensure similar conditions as in the production process regarding the main tribo...... leading to very high tool/workpiece interface pressure and temperature in the second re-draw. Under such conditions only the best lubricant systems work satisfactory, and the paper shows how the performance of different tribo-systems in production may be predicted by off-line testing combined...

  2. Control the springback of metal sheets by using an artificial neural network

    International Nuclear Information System (INIS)

    Crina, Axinte

    2007-01-01

    One of the greatest challenges of manufacturing sheet metal parts is to obtain consistent parts dimensions. Springback is the major cause of variations and inconsistencies in the final part geometry. Obtaining a consistent and desirable amount of springback is extremely difficult due to the non-linear effects and interactions of process and material parameters. In this work, the ability of an artificial neural network model to predict optimum process parameters and tools geometry which allow to obtain minimum amount of springback is tested, in the case of a cylindrical deep-drawing process

  3. kW-class direct diode laser for sheet metal cutting based on commercial pump modules

    Science.gov (United States)

    Witte, U.; Schneider, F.; Holly, C.; Di Meo, A.; Rubel, D.; Boergmann, F.; Traub, M.; Hoffmann, D.; Drovs, S.; Brand, T.; Unger, A.

    2017-02-01

    We present a direct diode laser with an optical output power of more than 800 W ex 100 μm with an NA of 0.17. The system is based on 6 commercial pump modules that are wavelength stabilized by use of VBGs. Dielectric filters are used for coarse and dense wavelength multiplexing. Metal sheet cutting tests were performed in order to prove system performance and reliability. Based on a detailed analysis of loss mechanisms, we show that the design can be easily scaled to output powers in the range of 2 kW and to an optical efficiency of 80%.

  4. Effect of strain path change on limits to ductility of anisotropic metal sheets

    DEFF Research Database (Denmark)

    Kuroda, M.; Tvergaard, Viggo

    2000-01-01

    of the anisotropic plasticity models, and it is shown that elastic straining plays a large role, as the stresses quickly move from one point of the yield surface to another. When the load is removed between steps, the stress point moves in a different manner, which results in quite different flow localization......Localized necking in thin metal sheets is analyzed by using the M-K-model approach, and the effect of a number of different non-proportional strain paths prior to the occurrence flow localization are considered. The analyses account for plastic anisotropy, using four different anisotropic...

  5. Forming limit diagrams for anisotropic metal sheets with different yield criteria

    DEFF Research Database (Denmark)

    Kuroda, M.; Tvergaard, Viggo

    2000-01-01

    For thin metal sheets subject to stretching under various in-plane tensile stress histories, localized necking is analyzed by using the M-K-model approach, and forming limit diagrams are drawn based on the critical strains for localization. The analyses account for plastic anisotropy......, and predictions are shown based on four different anisotropic plasticity models, which have all been fitted to agree with the same set of experimental data. Situations where the tensile axis is along one of the orthotropic axes of the anisotropy are studied, as well as situations where the tensile axis...

  6. Incremental electrohydraulic forming - A new approach for the manufacture of structured multifunctional sheet metal blanks

    Science.gov (United States)

    Djakow, Eugen; Springer, Robert; Homberg, Werner; Piper, Mark; Tran, Julian; Zibart, Alexander; Kenig, Eugeny

    2017-10-01

    Electrohydraulic Forming (EHF) processes permit the production of complex, sharp-edged geometries even when high-strength materials are used. Unfortunately, the forming zone is often limited as compared to other sheet metal forming processes. The use of a special industrial-robot-based tool setup and an incremental process strategy could provide a promising solution for this problem. This paper describes such an innovative approach using an electrohydraulic incremental forming machine, which can be employed to manufacture the large multifunctional and complex part geometries in steel, aluminium, magnesium and reinforced plastic that are employed in lightweight constructions or heating elements.

  7. Control of Springback in Sheet Metal U-bending Through Design Experiment

    International Nuclear Information System (INIS)

    Chirita, Bogdan; Brabie, Gheorghe

    2007-01-01

    For the U-bending of sheet metals, springback represents the most important failure mode that is affecting the parts. The purpose of this study was to develop a method for the reduction or the elimination of springback from the designing stage of the forming process. This paper describes a numerical procedure that combines simulation of springback by finite element method with a fractional factorial design and proposes the optimization of the forming parameters and tools geometry for the reduction of springback intensity. At the end of the study we were able to obtain an important improvement of part precision using the parameters predicted by the factorial design

  8. Thermal Aging Effects on Heat Affected Zone of Alloy 600 in Dissimilar Metal Weld

    Energy Technology Data Exchange (ETDEWEB)

    Ham, Jun Hyuk; Choi, Kyoung Joon; Yoo, Seung Chang; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2016-05-15

    Dissimilar metal weld (DMW), consists of Alloy 600, Alloy 182, and A508 Gr.3, is now being widely used as the reactor pressure vessel penetration nozzle and the steam generator tubing material for pressurized water reactors (PWR) because of its mechanical property, thermal expansion coefficient, and corrosion resistance. The heat affected zone (HAZ) on Alloy 600 which is formed by welding process is critical to crack. According to G.A. Young et al. crack growth rates (CGR) in the Alloy 600 HAZ were about 30 times faster than those in the Alloy 600 base metal tested under the same conditions [3]. And according to Z.P. Lu et al. CGR in the Alloy 600 HAZ can be more than 20 times higher than that in its base metal. To predict the life time of components, there is a model which can calculate the effective degradation years (EDYs) of the material as a function of operating temperature. This study was conducted to investigate how thermal aging affects the hardness of dissimilar metal weld from the fusion boundary to Alloy 600 base metal and the residual strain at Alloy 600 heat affected zone. Following conclusions can be drawn from this study. The hardness, measured by Vickers hardness tester, peaked near the fusion boundary between Alloy 182 and Alloy 600, and it decreases as the picked point goes to Alloy 600 base metal. Even though the formation of precipitate such as Cr carbide, thermal aging doesn't affect the value and the tendency of hardness because of reduced residual stress. According to kernel average misorientation mapping, residual strain decreases when the material thermally aged. And finally, in 30 years simulated specimen, the high residual strain almost disappears. Therefore, the influence of residual strain on primary water stress corrosion cracking can be diminished when the material undergoes thermal aging.

  9. Liquid phase diffusion bonding of A1070 by using metal formate coated Zn sheet

    Science.gov (United States)

    Ozawa, K.; Koyama, S.; shohji, I.

    2017-05-01

    Aluminium alloy have high strength and easily recycle due to its low melting point. Therefore, aluminium is widely used in the manufacturing of cars and electronic devices. In recent years, the most common way for bonding aluminium alloy is brazing and friction stir welding. However, brazing requires positional accuracy and results in the formation of voids by the flax residue. Moreover, aluminium is an excellent heat radiating and electricity conducting material; therefore, it is difficult to bond together using other bonding methods. Because of these limitations, liquid phase diffusion bonding is considered to the suitable method for bonding aluminium at low temperature and low bonding pressure. In this study, the effect of metal formate coating processing of zinc surface on the bond strength of the liquid phase diffusion bonded interface of A1070 has been investigated by SEM observation of the interfacial microstructures and fractured surfaces after tensile test. Liquid phase diffusion bonding was carried out under a nitrogen gas atmosphere at a bonding temperature of 673 K and 713 K and a bonding load of 6 MPa (bonding time: 15 min). As a result of the metal formate coating processing, a joint having the ultimate tensile strength of the base aluminium was provided. It is hypothesized that this is because metallic zinc is generated as a result of thermal decomposition of formate in the bonded interface at lower bonding temperatures.

  10. Development of powder metallurgy 2XXX series Al alloy plate and sheet materials for high temperature aircraft structural applications, FY 1983/1984

    Science.gov (United States)

    Chellman, D. J.

    1985-01-01

    The objective of this investigation is to fabricate and evaluate PM 2124 Al alloy plate and sheet materials according to NASA program goals for damage tolerance and fatigue resistance. Previous research has indicated the outstanding strength-toughness relationship available with PM 2124 Al-Zr modified alloy compositions in extruded product forms. The range of processing conditions was explored in the fabrication of plate and sheet gage materials, as well as the resultant mechanical and metallurgical properties. The PM composition based on Al-3.70 Cu-1.85 Mg-0.20 Mn with 0.60 wt. pct. Zr was selected. Flat rolled material consisting of 0.250 in. thick plate was fabricated using selected thermal mechanical treatments (TMT). The schedule of TMT operations was designed to yield the extreme conditions of grain structure normally encountered in the fabrication of flat rolled products, specifically recrystallized and unrecrystallized. The PM Al alloy plate and sheet materials exhibited improved strength properties at thin gages compared to IM Al alloys, as a consequence of their enhanced ability to inhibit recrystallization and grain growth. In addition, the PM 2124 Al alloys offer much better combinations of strength and toughnessover equivalent IM Al. The alloy microstructures were examined by optical metallographic texture techniques in order to establish the metallurgical basis for these significant property improvements.

  11. Synthesis of alumina-metal nanocomposites by mechanical alloying

    International Nuclear Information System (INIS)

    Osso, D.; Caer, G. le; Begin-Colin, S.; Mocellin, A.; Matteazzi, P.

    1993-01-01

    The synthesis of nanometer-sized α-Al 2 O 3 -metal composites can be performed by room temperature ball-milling of mixtures of metal-oxides and aluminium as shown by Matteazzi and Le Caer. The average crystallite size of the alumina-metal composite so obtained is in general about 10nm. Such composites may also be prepared by direct grinding of a mixture of α-Al 2 O 3 and of a metal or an alloy. The present work is devoted to the study of the reaction mechanisms by X-Ray diffraction and 57 Fe Moessbauer spectroscopy for the α-Al 2 O 3 -Cr, α-Al 2 O 3 -Fe, α-Al 2 O 3 -(Fe-Cr) and α-Al 2 O 3 -Ti systems. Moessbauer spectroscopy shows that non-completely reduced Fe, partly in the form of Fe 2+ , still exists at the end of the synthesis and belongs to a ternary Al-Fe-O oxide in α-Al 2 O 3 -Fe composites although it cannot be indexed by X-Ray diffraction. The Fe 2+ component is mainly associated with iron environments in or similar to those of hercynite. Species like Fe 3+ in Al 2 O 3 or in grain boundaries are observed, Fe 4+ and Fe 0 cannot be excluded. Differences are obtained by reactive milling and by direct milling the reaction products. Reactive milling of Al-TiO 2 (anatase) yields α-Al 2 O 3 -Ti nanocomposites. The transient formation of a high-pressure orthorhombic form of TiO 2 of the α-PbO 2 type is observed. (orig.)

  12. Microstructural and hardness investigations on a dissimilar metal weld between low alloy steel and Alloy 82 weld metal

    International Nuclear Information System (INIS)

    Chen, Z.R.; Lu, Y.H.; Ding, X.F.; Shoji, T.

    2016-01-01

    The investigation on microstructure and hardness at the fusion boundary (FB) region of a dissimilar metal weld (DMW) between low alloy steel (LAS) A508-III and Alloy 82 weld metal (WM) was carried out. The results indicated that there were two kinds of FBs, martensite FB and sharp FB, with obvious different microstructures, alternately distributed in the same FB. The martensite FB region had a gradual change of elemental concentration across FB, columnar WM grains with high length/width ratios, a thick martensite layer and a wide heat affected zone (HAZ) with large prior austenite grains. By comparison, the sharp FB region had a relatively sharp change of elemental concentration across the FB, WM grains with low length/width ratios and a narrow HAZ with smaller prior austenite grains. The martensite possessed a K-S orientation relationship with WM grains, while no orientation relationship was found between the HAZ grains and WM grains at the sharp FB. Compared with sharp FB there were much more Σ3 boundaries in the HAZ beside martensite FB. The hardness maximum of the martensite FB was much higher than that of the sharp FB, which was attributed to the martensite layer at the martensite FB. - Highlights: •Martensite and sharp FBs with different microstructures were found in the same FB. •There were high length/width-ratio WM grains and a wide HAZ beside martensite FB. •There were low length/width-ratio WM grains and a narrow HAZ beside sharp FB. •Compared with sharp FB, there were much more Σ3 boundaries in HAZ of martensite FB. •Hardness maximium of martensite FB was much higher than that of sharp FB.

  13. Microstructure of bonding interface for resistance welding of Zr-based metallic glass sheets

    International Nuclear Information System (INIS)

    Kuroda, Toshio; Ikeuchi, Kenji; Shimada, Masahiro; Kobayashi, Akira; Kimura, Hisamichi; Inoue, Akihisa

    2009-01-01

    Resistance welding of Zr 55 Cu 30 Al 10 Ni 5 metallic glass sheets was investigated at 723 K in a supercooled liquid region. The welding time was changed from 5 s to 20 s at 723 K. The joint interface of the metallic glass was no defect and no crack. X-ray diffraction technique of the bonding interface of specimens was performed. The specimens showed halo patterns showing existence of only glassy phase, when the welding time was 5 s and 10 s. X-ray diffraction patterns of specimen bonded for 20 s showed crystalline peaks with halo patterns for the welding for 20 s. The crystalline phase at the bonding interface was small. Transmission electron micrograph at the bonding interface showed nanostructures of NiZr 2 and Al 5 Ni 3 Zr 2 . (author)

  14. Friction and solid-solid adhesion on complex metallic alloys

    Science.gov (United States)

    Dubois, Jean-Marie; Belin-Ferré, Esther

    2014-01-01

    The discovery in 1987 of stable quasicrystals in the Al–Cu–Fe system was soon exploited to patent specific coatings that showed reduced friction in ambient air against hard antagonists. Henceforth, it was possible to develop a number of applications, potential or commercially exploited to date, that will be alluded to in this topical review. A deeper understanding of the characteristics of complex metallic alloys (CMAs) may explain why material made of metals like Al, Cu and Fe offers reduced friction; low solid–solid adhesion came later. It is linked to the surface energy being significantly lower on those materials, in which translational symmetry has become a weak property, that is determined by the depth of the pseudo-gap at the Fermi energy. As a result, friction is anisotropic in CMAs that builds up according to the translation symmetry along one direction, but is aperiodic along the other two directions. A review is given in this article of the most salient data found along these lines during the past two decades or so. PMID:27877675

  15. 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

  16. 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.

  17. Physical chemistry of the chlorination reactions of metals and alloys

    International Nuclear Information System (INIS)

    De Micco, Georgina

    2007-01-01

    This thesis has contributed towards the knowledge of complex systems.The chlorination reactions are non-catalytic solid-gas heterogeneous reactions which, in addition to the difficulties associated with the reactions occurring in an interface, have the particular features of chlorides compounds and their interactions.The questions arising from this type of study can not be solved by the application of an individual analysis technique.From the experimental point of view it is complicated, and many instrumental techniques need to be applied in order to obtain significant results as well as meaningful interpretations.The system under study is the chlorination of ternary and binary alloys containing Al, Cu and Zn and the pure metals, as these elements belong to the spent nuclear fuel cladding.The aim of the research has been to develop a process that eliminates most of the aluminium, which is the more abundant specie. In this way, the amount of material to be conditioned (vitrified) is reduced.The objectives proposed for each system have been achieved, and the results obtained can also be applied to similar systems for metal recycling [es

  18. Tunable color parallel tandem organic light emitting devices with carbon nanotube and metallic sheet interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, Jorge; Desirena, Haggeo; De la Rosa, Elder [Centro de Investigaciones en Optica, A.P. 1-948, León, Guanajuato 37160 (Mexico); Papadimitratos, Alexios [Solarno Inc., Coppell, Texas 75019 (United States); University of Texas at Dallas, Richardson, Texas 75080 (United States); Zakhidov, Anvar A., E-mail: Zakhidov@utdallas.edu [Solarno Inc., Coppell, Texas 75019 (United States); University of Texas at Dallas, Richardson, Texas 75080 (United States); Energy Efficiency Center, National University of Science and Technology, MISiS, Moscow 119049 (Russian Federation)

    2015-11-21

    Parallel tandem organic light emitting devices (OLEDs) were fabricated with transparent multiwall carbon nanotube sheets (MWCNT) and thin metal films (Al, Ag) as interlayers. In parallel monolithic tandem architecture, the MWCNT (or metallic films) interlayers are an active electrode which injects similar charges into subunits. In the case of parallel tandems with common anode (C.A.) of this study, holes are injected into top and bottom subunits from the common interlayer electrode; whereas in the configuration of common cathode (C.C.), electrons are injected into the top and bottom subunits. Both subunits of the tandem can thus be monolithically connected functionally in an active structure in which each subunit can be electrically addressed separately. Our tandem OLEDs have a polymer as emitter in the bottom subunit and a small molecule emitter in the top subunit. We also compared the performance of the parallel tandem with that of in series and the additional advantages of the parallel architecture over the in-series were: tunable chromaticity, lower voltage operation, and higher brightness. Finally, we demonstrate that processing of the MWCNT sheets as a common anode in parallel tandems is an easy and low cost process, since their integration as electrodes in OLEDs is achieved by simple dry lamination process.

  19. Adaptive scallop height tool path generation for robot-based incremental sheet metal forming

    Science.gov (United States)

    Seim, Patrick; Möllensiep, Dennis; Störkle, Denis Daniel; Thyssen, Lars; Kuhlenkötter, Bernd

    2016-10-01

    Incremental sheet metal forming is an emerging process for the production of individualized products or prototypes in low batch sizes and with short times to market. In these processes, the desired shape is produced by the incremental inward motion of the workpiece-independent forming tool in depth direction and its movement along the contour in lateral direction. Based on this shape production, the tool path generation is a key factor on e.g. the resulting geometric accuracy, the resulting surface quality, and the working time. This paper presents an innovative tool path generation based on a commercial milling CAM package considering the surface quality and working time. This approach offers the ability to define a specific scallop height as an indicator of the surface quality for specific faces of a component. Moreover, it decreases the required working time for the production of the entire component compared to the use of a commercial software package without this adaptive approach. Different forming experiments have been performed to verify the newly developed tool path generation. Mainly, this approach serves to solve the existing conflict of combining the working time and the surface quality within the process of incremental sheet metal forming.

  20. Some recent developments in sheet metal forming for production of lightweight automotive parts

    Science.gov (United States)

    Tisza, M.; Lukács, Zs; Kovács, P.; Budai, D.

    2017-09-01

    Low cost manufacturing in the automotive industry is one of the main targets due to the ever increasing global competition among car manufacturers all over the World. Sheet metal forming is one of the most important key technologies in the automotive industry; therefore the elaboration of new, innovative low cost manufacturing processes is one of the main objectives in sheet metal forming as well. In 2015 with the initiative of the Imperial College London a research consortium was established under the umbrella Low Cost Materials Processing Technologies for Mass Production of Lightweight Vehicles. The primary aim of this project is to provide affordable low cost weight reduction in mass production of vehicles considering the entire life-cycle. In this project, 19 European Institutions (Universities and Research Institutions) from 9 European countries are participating with the above targets. The University of Miskolc is one of the members of this research Consortium. In this paper, some preliminary results with the contributions of the University of Miskolc will be introduced.

  1. Investigation of fatigue strength of tool steels in sheet-bulk metal forming

    Science.gov (United States)

    Pilz, F.; Gröbel, D.; Merklein, M.

    2018-05-01

    To encounter trends regarding an efficient production of complex functional components in forming technology, the process class of sheet-bulk metal forming (SBMF) can be applied. SBMF is characterized by the application of bulk forming operations on sheet metal, often in combination with sheet forming operations [1]. The combination of these conventional process classes leads to locally varying load conditions. The resulting load conditions cause high tool loads, which lead to a reduced tool life, and an uncontrolled material flow. Several studies have shown that locally modified tool surfaces, so-called tailored surfaces, have the potential to control the material flow and thus to increase the die filling of functional elements [2]. A combination of these modified tool surfaces and high tool loads in SBMF is furthermore critical for the tool life and leads to fatigue. Tool fatigue is hardly predictable and due to a lack of data [3], a challenge in tool design. Thus, it is necessary to provide such data for tool steels used in SBMF. The aim of this study is the investigation of the influence of tailored surfaces on the fatigue strength of the powder metallurgical tool steel ASP2023 (1.3344, AISI M3:2), which is typically used in cold forging applications, with a hardness 60 HRC ± 1 HRC. To conduct this investigation, the rotating bending test is chosen. As tailored surfaces, a DLC-coating and a surface manufactured by a high-feed-milling process are chosen. As reference a polished surface which is typical for cold forging tools is used. Before the rotating bending test, the surface integrity is characterized by measuring topography and residual stresses. After testing, the determined values of the surface integrity are correlated with the reached fracture load cycle to derive functional relations. Based on the gained results the investigated tailored surfaces are evaluated regarding their feasibility to modify tool surfaces within SBMF.

  2. The evolution of texture in aluminum alloy sheet during asymmetric rolling

    International Nuclear Information System (INIS)

    Kim, K-H.; Lee, D.N.

    2000-01-01

    Asymmetric rolling, in which the upper and lower roll radii are different, imposes shear deformation on sheets through the thickness, which in turn gives rise to shear deformation textures in the sheets through the thickness. A component of ND// in the shear deformation textures can improve the plastic strain ratios of aluminum sheets. In order to understand the evolution of ND// , the strain histories and distributions in the sheets during the asymmetric rolling are calculated by the finite element method. The strain history and distribution are used to calculate crystallographic orientations and stable orientations based on the Taylor-Bishop-Hill theory and the Renouward-Wintenberger theory. The shear deformation texture can vary with the ratio of shear to normal strain increments. As the ratio increases from zero to infinity, the texture moves from the plane strain compression texture (β fiber) to the ideal shear deformation texture consisting of {001} , {111} , and {111} . The ratio increases with rolling reduction per pass in asymmetric rolling. However, it is practically difficult to the rolling reduction per pass high enough to obtain the ideal shear deformation texture. Imposing the positive and negative shear deformations on the sheet by reversing the shearing direction can give rise to the ideal shear deformation texture. This has been discussed. (author)

  3. Effects of different production technologies on mechanical and metallurgical properties of precious metal denture alloys

    Science.gov (United States)

    Ferro, Paolo; Battaglia, Eleonora; Capuzzi, Stefano; Berto, Filippo

    2017-12-01

    Precious metal alloys can be supplied in traditional plate form or innovative drop form with high degree of purity. The aim of the present work is to evaluate the influence of precious metal alloy form on metallurgical and mechanical properties of the final dental products with particular reference to metal-ceramic bond strength and casting defects. A widely used alloy for denture was selected; its nominal composition was close to 55 wt% Pd - 34 wt% Ag - 6 wt% In - 3 wt% Sn. Specimens were produced starting from the alloy in both plate and drop forms. A specific test method was developed to obtain results that could be representative of the real conditions of use. In order to achieve further information about the adhesion behaviour and resistance, the fracture surfaces of the samples were observed using `Scanning Electron Microscopy (SEM)'. Moreover, material defects caused by the moulding process were studied. The form of the alloy before casting does not significantly influence the shear bond strength between the metal and the ceramic material (p-value=0,976); however, according to SEM images, products from drop form alloy show less solidification defects compared to products obtained with plate form alloy. This was attributed to the absence of polluting additives used in the production of drop form alloy. This study shows that the use of precious metal denture alloys supplied in drop form does not affect the metal-ceramic bond strength compared to alloys supplied in the traditional plate form. However, compared to the plate form, the drop form is found free of solidification defects, less expensive to produce and characterized by minor environmental impacts.

  4. Double fillet lap of laser welding of thin sheet AZ31B Mg alloy

    Science.gov (United States)

    Ishak, Mahadzir; Salleh, M. N. M.

    2018-05-01

    In this paper, we describe the experimental laser welding of thin sheet AZ31B using double fillet lap joint method. Laser welding is capable of producing high quality weld seams especially for small weld bead on thin sheet product. In this experiment, both edges for upper and lower sheets were subjected to the laser beam from the pulse wave (PW) mode of fiber laser. Welded sample were tested their joint strength by tensile-shear strength method and the fracture loads were studied. Strength for all welded samples were investigated and the effect of laser parameters on the joint strength and appearances were studied. Pulsed energy (EP) from laser process give higher effect on joint strength compared to the welding speed (WS) and angle of irradiation (AOI). Highest joint strength was possessed by sample with high EP with the same value of WS and AOI. The strength was low due to the crack defect at the centre of weld region.

  5. Analysis of sulphur, phosphorus and silica in metals, alloys, inorganic compounds and solvents

    International Nuclear Information System (INIS)

    Upadhya, J.C.; Naik, S.S.; Khedikar, W.K.; Sudersanan, M.; Mathur, P.K

    1999-10-01

    Procedures for the analysis of sulphur, phosphorus and silica in various metals and alloys like mild steel, carbon steel and stainless steel as well as nickel base alloys are described. Procedures were also developed for the analysis of sulphur in thoria pellets and in other materials like crack check fluids, coal etc. Typical results obtained are summarised. (author)

  6. Dissimilar Joining of Stainless Steel and 5083 Aluminum Alloy Sheets by Gas Tungsten Arc Welding-Brazing Process

    Science.gov (United States)

    Cheepu, Muralimohan; Srinivas, B.; Abhishek, Nalluri; Ramachandraiah, T.; Karna, Sivaji; Venkateswarlu, D.; Alapati, Suresh; Che, Woo Seong

    2018-03-01

    The dissimilar joining using gas tungsten arc welding - brazing of 304 stainless steel to 5083 Al alloy had been conducted with the addition of Al-Cu eutectic filler metal. The interface microstructure formation between filler metal and substrates, and spreading of the filler metal were studied. The interface microstructure between filler metal and aluminum alloy characterized that the formation of pores and elongated grains with the initiation of micro cracks. The spreading of the liquid braze filler on stainless steel side packed the edges and appeared as convex shape, whereas a concave shape has been formed on aluminum side. The major compounds formed at the fusion zone interface were determined by using X-ray diffraction techniques and energy-dispersive X-ray spectroscopy analysis. The micro hardness at the weld interfaces found to be higher than the substrates owing to the presence of Fe2Al5 and CuAl2 intermetallic compounds. The maximum tensile strength of the weld joints was about 95 MPa, and the tensile fracture occurred at heat affected zone on weak material of the aluminum side and/or at stainless steel/weld seam interface along intermetallic layer. The interface formation and its effect on mechanical properties of the welds during gas tungsten arc welding-brazing has been discussed.

  7. Experimental Characterization and Material Modelling of an AZ31 Magnesium Sheet Alloy at Elevated Temperatures under Consideration of the Tension-Compression Asymmetry

    Science.gov (United States)

    Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Dykiert, M.

    2017-09-01

    Magnesium sheet alloys have a great potential as a construction material in the aerospace and automotive industry. However, the current state of research regarding temperature dependent material parameters for the description of the plastic behaviour of magnesium sheet alloys is scarce in literature and accurate statements concerning yield criteria and appropriate characterization tests to describe the plastic behaviour of a magnesium sheet alloy at elevated temperatures in deep drawing processes are to define. Hence, in this paper the plastic behaviour of the well-established magnesium sheet alloy AZ31 has been characterized by means of convenient mechanical tests (e. g. tension, compression and biaxial tests) at temperatures between 180 and 230 °C. In this manner, anisotropic and hardening behaviour as well as differences between the tension-compression asymmetry of the yield locus have been estimated. Furthermore, using the evaluated data from the above mentioned tests, two different yield criteria have been parametrized; the commonly used Hill’48 and an orthotropic yield criterion, CPB2006, which was developed especially for materials with hexagonal close packed lattice structure and is able to describe an asymmetrical yielding behaviour regarding tensile and compressive stress states. Numerical simulations have been finally carried out with both yield functions in order to assess the accuracy of the material models.

  8. Effect of Annealing on Mechanical Properties and Formability of Cold Rolled Thin Sheets of Fe-P P/M Alloys

    Science.gov (United States)

    Trivedi, Shefali; Ravi Kumar, D.; Aravindan, S.

    2016-10-01

    Phosphorus in steel is known to increase strength and hardness and decrease ductility. Higher phosphorus content (more than 0.05%), however, promotes brittle behavior due to segregation of Fe3P along the grain boundaries which makes further mechanical working of these alloys difficult. In this work, thin sheets of Fe-P alloys (with phosphorus in range of 0.1-0.35%) have been developed through processing by powder metallurgy followed by hot rolling and cold rolling. The effect of phosphorus content and annealing parameters (temperature and time) on microstructure, mechanical properties, formability in biaxial stretching and fracture behavior of the cold rolled and annealed sheets has been studied. A comparison has also been made between the properties of the sheets made through P/M route and the conventional cast route with similar phosphorus content. It has been shown that thin sheets of Fe-P alloys with phosphorous up to 0.35% possessing a good combination of strength and formability can be produced through rolling of billets of these alloys made through powder metallurgy technique without the problem of segregation.

  9. Study of microstructural evolution in friction-stir welded thin-sheet Al-Cu-Li alloy using transmission-electron microscopy

    International Nuclear Information System (INIS)

    Shukla, A.K.; Baeslack, W.A.

    2007-01-01

    Microstructure evolution in friction-stir welded thin-sheet Al-Cu-Li alloy was studied using transmission-electron microscopy (TEM) and the dissolution and coarsening of T 1 and θ' precipitates were related to the microhardness profile of the weld

  10. Polarographic methods for the analysis of beryllium metal and its alloys

    International Nuclear Information System (INIS)

    Wells, J.M.

    1975-10-01

    This report describes polarographic methods for the analysis of beryllium metal and its alloys. The elements covered by these methods are aluminium, bismuth, cadmium, cobalt, copper, iron, lead, molybdenum, nickel, thallium, tungsten, uranium, vanadium and zinc. (author)

  11. The efficacy of noble metal alloy urinary catheters in reducing catheter-associated urinary tract infection

    Directory of Open Access Journals (Sweden)

    Alanood Ahmed Aljohi

    2016-01-01

    Results: A 90% relative risk reduction in the rate of CAUTI was observed with the noble metal alloy catheter compared to the standard catheter (10 vs. 1 cases, P = 0.006. When considering both catheter-associated asymptomatic bacteriuria and CAUTI, the relative risk reduction was 83% (12 vs. 2 cases, P = 0.005. In addition to CAUTI, the risk of acquiring secondary bacteremia was lower (100% for the patients using noble metal alloy catheters (3 cases in the standard group vs. 0 case in the noble metal alloy catheter group, P = 0.24. No adverse events related to any of the used catheters were recorded. Conclusion: Results from this study revealed that noble metal alloy catheters are safe to use and significantly reduce CAUTI rate in ICU patients after 3 days of use.

  12. Liquid alkali metals and alkali-based alloys as electron-ion plasmas

    International Nuclear Information System (INIS)

    Tosi, M.P.

    1981-06-01

    The article reviews the theory of thermodynamic and structural properties of liquid alkali metals and alkali-based alloys, within the framework of linear screening theory for the electron-ion interactions. (author)

  13. Half-metallic ferromagnetism in (Z B, Al, Ga, and In) Heusler alloys ...

    Indian Academy of Sciences (India)

    K H SADEGHI

    2018-01-03

    11], and zincblende (ZB) transition-metal pnictides and chalcogenides [12–17]. Among HM ferromagnets, Heusler alloys are attractive because of their technical applications (in spin-injection devices [18], spin-filters [19], ...

  14. Dispersion strengthened ferritic alloy for use in liquid-metal fast breeder reactors (LMFBRS)

    International Nuclear Information System (INIS)

    Fischer, J.J.

    1978-01-01

    A dispersion-strengthened ferritic alloy is provided which has high-temperature strength and is readily fabricable at ambient temperatures, and which is useful as structural elements of liquid-metal fast breeder reactors. 4 tables

  15. Identification of non-linear kinematic hardening with bending and unbending tests in anisotropic sheet-metals

    International Nuclear Information System (INIS)

    Brunet, M.; Morestin, F.; Godereaux, S.

    2000-01-01

    An inverse identification technique is proposed based on bending-unbending experiments on anisotropic sheet-metal strips. The initial anisotropy theory of plasticity is extended to include the concept of combined isotropic and non-linear kinematic hardening. This theory is adopted to characterise the anisotropic hardening due to loading-unloading which occurs in sheet-metal forming processes. To this end, a specific bending-unbending apparatus has been built to provide experimental moment-curvature curves. The constant bending moment applied over the length of the specimen to determine numerically the strain-stress behaviour but without Finite Element Analysis. Four constitutive parameters have to be identified by an inverse approach. Our identification results show that bending-unbending tests are suitable to model quite accurately the constitutive behaviour of sheet metals under complex loading paths. (author)

  16. Implementation of virtual models from sheet metal forming simulation into physical 3D colour models using 3D printing

    Science.gov (United States)

    Junk, S.

    2016-08-01

    Today the methods of numerical simulation of sheet metal forming offer a great diversity of possibilities for optimization in product development and in process design. However, the results from simulation are only available as virtual models. Because there are any forming tools available during the early stages of product development, physical models that could serve to represent the virtual results are therefore lacking. Physical 3D-models can be created using 3D-printing and serve as an illustration and present a better understanding of the simulation results. In this way, the results from the simulation can be made more “comprehensible” within a development team. This paper presents the possibilities of 3D-colour printing with particular consideration of the requirements regarding the implementation of sheet metal forming simulation. Using concrete examples of sheet metal forming, the manufacturing of 3D colour models will be expounded upon on the basis of simulation results.

  17. Combined transmission electron microscope and ion channeling study of metastable metal alloys formed by ion implantation

    International Nuclear Information System (INIS)

    Cullis, A.G.; Borders, J.A.; Hirvonen, J.K.; Poate, J.M.

    1977-01-01

    Recently, ion implantation has been used to produce metastable alloy layers with a range of structures from crystalline substitutional solid solutions to amorphous. The technique offers the possibility of producing metastable metal layers with unique physical properties. Its application in the formation of alloys exhibiting different although complementary types of metastability is described. The metal combinations chosen (Ag-Cu and Ta-Cu) show little mutual solubility under equilibrium conditions

  18. Experimental determination of spring back and thinning effect of aluminum sheet metal during L-bending operation

    International Nuclear Information System (INIS)

    Dilip Kumar, K.; Appukuttan, K.K.; Neelakantha, V.L.; Naik, Padmayya S.

    2014-01-01

    Highlights: • The spring back and thinning effect during L-bending was determined on aluminum sheet. • Beyond a particular clearance, the above said effects are linearly increasing. • Below the critical clearance scratches will occur on the surface due to wear. • As the clearance reduces, the wear rate increases on the punching surface. - Abstract: In automotive industry, significant efforts are being put forth to replace steel sheets with aluminum sheets for various applications. Besides its higher cost, there are several technical hurdles for wide usage of aluminum sheets in forming. Major problems in aluminum sheet metal forming operations are deformation errors and spring back effect. These problems are dependent on the number of parameters such as die and tool geometry, friction condition, loading condition and anisotropic properties of the metal. To predict the exact shape, the geometry based punch contact program must be used. The shape changes once the punch is withdrawn, because of the materials elasticity. Prediction of such a spring back effect is a major challenging problem in industry involving sheet metal forming operations. It also needs applying appropriate back tension during the forming complex shapes. Slight deformation of the metal leads to non-axisymmetric loading. One can predict the residual stress by determining plastic and elastic deformation. Thus appropriate spring back effect can be investigated. The present investigation was carried out to determine the spring back and thinning effect of aluminum sheet metal during L-bending operation. Number of specimens with thickness varying from 0.5 mm to 3.5 mm were prepared. The experiments were conducted for different clearances between punch and die. It is observed that, beyond a particular clearance for each thickness of the sheet metal, the spring back and thinning effects were linearly increasing. However, below the critical clearance, scratches on the surface of the sheet metal were

  19. Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure

    Directory of Open Access Journals (Sweden)

    T.S. Yang

    2018-01-01

    Full Text Available Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

  20. Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure.

    Science.gov (United States)

    Yang, T S; Yao, S H; Chang, Y Y; Deng, J H

    2018-01-08

    Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

  1. Review of alkali metal and refractory alloy compatibility for Rankine cycle applications

    International Nuclear Information System (INIS)

    DiStefano, J.R.

    1989-01-01

    The principal corrosion mechanisms in refractory metal-alkali systems are dissolution, mass transfer, and impurity reactions. In general, niobium, tantalum, molybdenum, and tungsten have low solubilities in the alkali metals, even to very high temperatures, and static corrosion studies have verified that the systems are basically compatible. Loop studies with niobium and tantalum based alloys do not indicate any serious problems due to temperature gradient mass transfer. Above 1000 K, dissimilar metal mass transfer is noted between the refractory metals and iron or nickel based alloys. The most serious corrosion problems encountered are related to impurity reactions associated with oxygen

  2. Numerical simulation of the alloying process during impulse induction heating of the metal substrate

    Science.gov (United States)

    Popov, V. N.

    2017-10-01

    2D numerical modeling of the processes during the alloying of the substrate surface metal layer is carried out. Heating, phase transition, heat and mass transfer in the molten metal, solidification of the melt are considered with the aid the proposed mathematical model. Under study is the applicability of the high-frequency electromagnetic field impulse for metal heating and melting. The distribution of the electromagnetic energy in the metal is described by empirical formulas. According to the results of numerical experiments, the flow structure in the melt and distribution of the alloying substances is evaluated.

  3. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. I. Model and validation

    Energy Technology Data Exchange (ETDEWEB)

    Hegde, Ganesh, E-mail: ghegde@purdue.edu; Povolotskyi, Michael; Kubis, Tillmann; Klimeck, Gerhard, E-mail: gekco@purdue.edu [Network for Computational Nanotechnology (NCN), Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Boykin, Timothy [Department of Electrical and Computer Engineering, University of Alabama, Huntsville, Alabama (United States)

    2014-03-28

    Semi-empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper, an environment-aware and transferable TB model suitable for electronic structure and transport simulations in technologically relevant metals, metallic alloys, metal nanostructures, and metallic interface systems are described. Part I of this paper describes the development and validation of the new TB model. The new model incorporates intra-atomic diagonal and off-diagonal elements for implicit self-consistency and greater transferability across bonding environments. The dependence of the on-site energies on strain has been obtained by appealing to the Moments Theorem that links closed electron paths in the system to energy moments of angular momentum resolved local density of states obtained ab initio. The model matches self-consistent density functional theory electronic structure results for bulk face centered cubic metals with and without strain, metallic alloys, metallic interfaces, and metallic nanostructures with high accuracy and can be used in predictive electronic structure and transport problems in metallic systems at realistically extended length scales.

  4. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. I. Model and validation

    International Nuclear Information System (INIS)

    Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Klimeck, Gerhard; Boykin, Timothy

    2014-01-01

    Semi-empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper, an environment-aware and transferable TB model suitable for electronic structure and transport simulations in technologically relevant metals, metallic alloys, metal nanostructures, and metallic interface systems are described. Part I of this paper describes the development and validation of the new TB model. The new model incorporates intra-atomic diagonal and off-diagonal elements for implicit self-consistency and greater transferability across bonding environments. The dependence of the on-site energies on strain has been obtained by appealing to the Moments Theorem that links closed electron paths in the system to energy moments of angular momentum resolved local density of states obtained ab initio. The model matches self-consistent density functional theory electronic structure results for bulk face centered cubic metals with and without strain, metallic alloys, metallic interfaces, and metallic nanostructures with high accuracy and can be used in predictive electronic structure and transport problems in metallic systems at realistically extended length scales

  5. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. I. Model and validation

    Science.gov (United States)

    Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Boykin, Timothy; Klimeck, Gerhard

    2014-03-01

    Semi-empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper, an environment-aware and transferable TB model suitable for electronic structure and transport simulations in technologically relevant metals, metallic alloys, metal nanostructures, and metallic interface systems are described. Part I of this paper describes the development and validation of the new TB model. The new model incorporates intra-atomic diagonal and off-diagonal elements for implicit self-consistency and greater transferability across bonding environments. The dependence of the on-site energies on strain has been obtained by appealing to the Moments Theorem that links closed electron paths in the system to energy moments of angular momentum resolved local density of states obtained ab initio. The model matches self-consistent density functional theory electronic structure results for bulk face centered cubic metals with and without strain, metallic alloys, metallic interfaces, and metallic nanostructures with high accuracy and can be used in predictive electronic structure and transport problems in metallic systems at realistically extended length scales.

  6. Local lattice relaxations in random metallic alloys: Effective tetrahedron model and supercell approach

    DEFF Research Database (Denmark)

    Ruban, Andrei; Simak, S.I.; Shallcross, S.

    2003-01-01

    We present a simple effective tetrahedron model for local lattice relaxation effects in random metallic alloys on simple primitive lattices. A comparison with direct ab initio calculations for supercells representing random Ni0.50Pt0.50 and Cu0.25Au0.75 alloys as well as the dilute limit of Au-ri......-rich CuAu alloys shows that the model yields a quantitatively accurate description of the relaxtion energies in these systems. Finally, we discuss the bond length distribution in random alloys....

  7. The Fifth International Ural seminar. Radiation damage physics of metals and alloys. Abstracts

    International Nuclear Information System (INIS)

    2003-01-01

    Presented are the abstracts of The Fifth International Ural seminar Damage physics of metals and alloys. General problems of radiation damage physics, radiation effect on change of microstucture and the properties of metals and alloys, as well as materials for nuclear and thermonuclear energetics are considered. The themes of reports are the following: correlation effects in cascades of atom-atomic collisions; radiation-induced strengthening critical current density in YBa 2 Cu 3 O 7-x superconductors; conditions of forming and hydrides growth in irradiated zirconium alloys [ru

  8. Production of titanium alloys with uniform distribution of heat resisting metals

    International Nuclear Information System (INIS)

    Reznichenko, V.A.; Goncharenko, T.V.; Khalimov, F.B.; Vojtechova, E.A.

    1976-01-01

    Consideration is given to the process of the formation of a titanium sponge alloyed with niobium or tantalum, in the joint metallic reduction of titanium, niobium and tantanum chlorides. A percentage composition of the phases observed and the structure of the alloyed sponge have been studied. It is shown that after one remelting operation of the alloyed sponge the alloys of titanium with niobium and tantalum have a uniform component distribution. At the stage of chloride reduction there appear solid solutions based on titanium and an alloying component. The stage of vacuum separation of the reaction mass is associated with a mutual dissolution of the primary phases and the formation of the solid solutions of the alloyed titanium sponge, which, by their composition, are close to the desired alloy composition. The principal features of the formation of a titanium sponge alloyed with niobium and tantalum are in a perfect agreemet with those typical of Ti-Mo and Ti-W sponges, therefore it can be assumed that these features will be also common to the other cases of the metallic reduction of titanium and refractory metals chlorides

  9. Production of titanium alloys with uniform distribution of heat resisting metals

    Energy Technology Data Exchange (ETDEWEB)

    Reznichenko, V A; Goncharenko, T V; Khalimov, F B; Voitechova, E A

    1976-01-01

    Consideration is given to the process of the formation of a titanium sponge alloyed with niobium or tantalum, in the joint metallic reduction of titanium, niobium and tantanum chlorides. A percentage composition of the phases observed and the structure of the alloyed sponge have been studied. It is shown that after one remelting operation of the alloyed sponge the alloys of titanium with niobium and tantalum have a uniform component distribution. At the stage of chloride reduction there appear solid solutions based on titanium and an alloying component. The stage of vacuum separation of the reaction mass is associated with a mutual dissolution of the primary phases and the formation of the solid solutions of the alloyed titanium sponge, which, by their composition, are close to the desired alloy composition. The principal features of the formation of a titanium sponge alloyed with niobium and tantalum are in a perfect agreemet with those typical of Ti-Mo and Ti-W sponges, therefore it can be assumed that these features will be also common to the other cases of the metallic reduction of titanium and refractory metals chlorides.

  10. Ultrasonic characterization of microstructure in powder metal alloy

    Science.gov (United States)

    Tittmann, B. R.; Ahlberg, L. A.; Fertig, K.

    1986-01-01

    The ultrasonic wave propagation characteristics were measured for IN-100, a powder metallurgy alloy used for aircraft engine components. This material was as a model system for testing the feasibility of characterizing the microstructure of a variety of inhomogeneous media including powder metals, ceramics, castings and components. The data were obtained for a frequency range from about 2 to 20 MHz and were statistically averaged over numerous volume elements of the samples. Micrographical examination provided size and number distributions for grain and pore structure. The results showed that the predominant source for the ultrasonic attenuation and backscatter was a dense (approx. 100/cubic mm) distribution of small micropores (approx. 10 micron radius). Two samples with different micropore densities were studied in detail to test the feasibility of calculating from observed microstructural parameters the frequency dependence of the microstructural backscatter in the regime for which the wavelength is much larger than the size of the individual scattering centers. Excellent agreement was found between predicted and observed values so as to demonstrate the feasibility of solving the forward problem. The results suggest a way towards the nondestructive detection and characterization of anomalous distributions of micropores when conventional ultrasonic imaging is difficult. The findings are potentially significant toward the application of the early detection of porosity during the materials fabrication process and after manufacturing of potential sites for stress induced void coalescence leading to crack initiation and subsequent failure.

  11. Multi-scale modeling of ductile failure in metallic alloys

    International Nuclear Information System (INIS)

    Pardoen, Th.; Scheyvaerts, F.; Simar, A.; Tekoglu, C.; Onck, P.R.

    2010-01-01

    Micro-mechanical models for ductile failure have been developed in the seventies and eighties essentially to address cracking in structural applications and complement the fracture mechanics approach. Later, this approach has become attractive for physical metallurgists interested by the prediction of failure during forming operations and as a guide for the design of more ductile and/or high-toughness microstructures. Nowadays, a realistic treatment of damage evolution in complex metallic microstructures is becoming feasible when sufficiently sophisticated constitutive laws are used within the context of a multilevel modelling strategy. The current understanding and the state of the art models for the nucleation, growth and coalescence of voids are reviewed with a focus on the underlying physics. Considerations are made about the introduction of the different length scales associated with the microstructure and damage process. Two applications of the methodology are then described to illustrate the potential of the current models. The first application concerns the competition between intergranular and transgranular ductile fracture in aluminum alloys involving soft precipitate free zones along the grain boundaries. The second application concerns the modeling of ductile failure in friction stir welded joints, a problem which also involves soft and hard zones, albeit at a larger scale. (authors)

  12. Corrosion resistance of metals and alloys in molten alkalies

    International Nuclear Information System (INIS)

    Zarubitskij, O.G.; Dmitruk, B.F.; Minets, L.A.

    1979-01-01

    Literature data on the corrosion of non-ferrous and noble metals, iron and steels in the molten alkalis and mixtures of their base are presented. It is shown that zirconium, niobium and tantalum are characterized by high corrosion stability in the molten NaOH. Additions of NaOH and KOH to the alkali chloride melts result in a 1000 time decrease of zirconium corrosion rate at 850 deg. The data testify to the characteristic passivating properties of OH - ions; Mo and W do not possess an ability to selfpassivation in hydroxide melts. Corrosion resistance of carbon and chromium-nickel steels in hydroxide melts depends considerably on the temperature, electrolyte composition and atmosphere over them. At the temperatures up to 600 deg C chromium-nickel steel is corrosion resistant in the molten alkali only in the inert atmosphere. Corrosion rate of chromium-nickel alloy is the lower the less chromium and the more nickel it contains. For the small installations the 4Kh18N25S2 and Kh23N28M3D3T steels can be recommended

  13. Multiscale modeling of ductile failure in metallic alloys

    Science.gov (United States)

    Pardoen, Thomas; Scheyvaerts, Florence; Simar, Aude; Tekoğlu, Cihan; Onck, Patrick R.

    2010-04-01

    Micromechanical models for ductile failure have been developed in the 1970s and 1980s essentially to address cracking in structural applications and complement the fracture mechanics approach. Later, this approach has become attractive for physical metallurgists interested by the prediction of failure during forming operations and as a guide for the design of more ductile and/or high-toughness microstructures. Nowadays, a realistic treatment of damage evolution in complex metallic microstructures is becoming feasible when sufficiently sophisticated constitutive laws are used within the context of a multilevel modelling strategy. The current understanding and the state of the art models for the nucleation, growth and coalescence of voids are reviewed with a focus on the underlying physics. Considerations are made about the introduction of the different length scales associated with the microstructure and damage process. Two applications of the methodology are then described to illustrate the potential of the current models. The first application concerns the competition between intergranular and transgranular ductile fracture in aluminum alloys involving soft precipitate free zones along the grain boundaries. The second application concerns the modeling of ductile failure in friction stir welded joints, a problem which also involves soft and hard zones, albeit at a larger scale.

  14. Impact of the De-Alloying Kinetics and Alloy Microstructure on the Final Morphology of De-Alloyed Meso-Porous Metal Films

    Directory of Open Access Journals (Sweden)

    Bao Lin

    2014-10-01

    Full Text Available Nano-textured porous metal materials present unique surface properties due to their enhanced surface energy with potential applications in sensing, molecular separation and catalysis. In this paper, commercial alloy foils, including brass (Cu85Zn15 and Cu70Zn30 and white gold (Au50Ag50 foils have been chemically de-alloyed to form nano-porous thin films. The impact of the initial alloy micro-structure and number of phases, as well as chemical de-alloying (DA parameters, including etchant concentration, time and solution temperature on the final nano-porous thin film morphology and properties were investigated by electron microscopy (EM. Furthermore, the penetration depth of the pores across the alloys were evaluated through the preparation of cross sections by focus ion beam (FIB milling. It is demonstrated that ordered pores ranging between 100 nm and 600 nm in diameter and 2–5 μm in depth can be successfully formed for the range of materials tested. The microstructure of the foils were obtained by electron back-scattered diffraction (EBSD and linked to development of pits across the material thickness and surface during DA. The role of selective etching of both noble and sacrificial metal phases of the alloy were discussed in light of the competitive surface etching across the range of microstructures and materials tested.

  15. Development of JSTAMP-Works/NV and HYSTAMP for Multipurpose Multistage Sheet Metal Forming Simulation

    International Nuclear Information System (INIS)

    Umezu, Yasuyoshi; Watanabe, Yuko; Ma, Ninshu

    2005-01-01

    Since 1996, Japan Research Institute Limited (JRI) has been providing a sheet metal forming simulation system called JSTAMP-Works packaged the FEM solvers of LS-DYNA and JOH/NIKE, which might be the first multistage system at that time and has been enjoying good reputation among users in Japan. To match the recent needs, 'faster, more accurate and easier', of process designers and CAE engineers, a new metal forming simulation system JSTAMP-Works/NV is developed. The JSTAMP-Works/NV packaged the automatic healing function of CAD and had much more new capabilities such as prediction of 3D trimming lines for flanging or hemming, remote control of solver execution for multi-stage forming processes and shape evaluation between FEM and CAD.On the other way, a multi-stage multi-purpose inverse FEM solver HYSTAMP is developed and will be soon put into market, which is approved to be very fast, quite accurate and robust.Lastly, authors will give some application examples of user defined ductile damage subroutine in LS-DYNA for the estimation of material failure and springback in metal forming simulation

  16. Development of JSTAMP-Works/NV and HYSTAMP for Multipurpose Multistage Sheet Metal Forming Simulation

    Science.gov (United States)

    Umezu, Yasuyoshi; Watanabe, Yuko; Ma, Ninshu

    2005-08-01

    Since 1996, Japan Research Institute Limited (JRI) has been providing a sheet metal forming simulation system called JSTAMP-Works packaged the FEM solvers of LS-DYNA and JOH/NIKE, which might be the first multistage system at that time and has been enjoying good reputation among users in Japan. To match the recent needs, "faster, more accurate and easier", of process designers and CAE engineers, a new metal forming simulation system JSTAMP-Works/NV is developed. The JSTAMP-Works/NV packaged the automatic healing function of CAD and had much more new capabilities such as prediction of 3D trimming lines for flanging or hemming, remote control of solver execution for multi-stage forming processes and shape evaluation between FEM and CAD. On the other way, a multi-stage multi-purpose inverse FEM solver HYSTAMP is developed and will be soon put into market, which is approved to be very fast, quite accurate and robust. Lastly, authors will give some application examples of user defined ductile damage subroutine in LS-DYNA for the estimation of material failure and springback in metal forming simulation.

  17. Identification of a process window for tailored carburization of sheet metals in hot stamping

    Science.gov (United States)

    Horn, Alexander; Merklein, Marion

    2018-05-01

    Due to governmental regulations concerning the reduction of CO2 emissions and increasing safety standards, hot stamping of high strength boron manganese steel sheets has evolved into a state of the art process for manufacturing structural car body parts. The combined forming and in-die quenching process enables the formation of a fully martensitic microstructure. Therefore, press hardened steels offer high strength, but low ductility. In order to further improve passenger safety, a tailored configuration of mechanical properties is desired. Besides state of the art methods, like the application of locally different heat treatment temperatures or varying quenching rates, the adjustment of mechanical properties of sheet metals by a tailored carburization is a novel approach. For the carburization process, the specimens are first coated with graphite and subsequently heat treated. Within this contribution, different coating strategies as well as heat treatment temperatures and dwell times are investigated. For the determination of a process window, mechanical properties such as tensile strength and microhardness will be analyzed and correlated with the resulting microstructure.

  18. Precision machining, sheet-metal work and welding at the heart of CERN

    CERN Multimedia

    2001-01-01

    From the writing of specifications and the production of high-tech components, to technology transfer and call-out work on-site, the MF group in EST Division offers CERN users a wide variety of services. Its full range of activities is presented in a new brochure. In addition to its many physicists and engineers, CERN also has teams of mechanics, welders and sheet-metalworkers whose expertise is a precious asset for the Organization. Within the MF Group (Manufacturing Facilities, EST Division) these teams perform precision machining, sheet-metal work and welding. As an example, the Group has been responsible for producing radiofrequency accelerating cells to a precision of the order of 1/100th mm and with a surface roughness of only 0.1 micron. The Group's workshops also manufactured the stainless steel vacuum chamber for the brand new n-TOF experiment (Bulletin n°47/2000), a 200-m long cylindrical chamber with a diameter of just 800 millimetres! The MF Group is assisted in its task of providing me...

  19. Development of Mo base alloys for conductive metal-alumina cermet applications

    International Nuclear Information System (INIS)

    Stephens, J.J.; Damkroger, B.K.; Monroe, S.L.

    1996-01-01

    A study of thermal expansion for binary Mo-V and ternary Mo-V-Fe/Mo-V-Co alloys has been conducted, with the aim of finding a composition which matches the CTE of 94% alumina ceramic. The overall goal was to identify an alloy which can be used in conductive 27 vol.% metal/73 vol.% alumina cermets. Besides thermal expansion properties, two additional requirements exist for this alloy: (1) compatibility with a hydrogen sinter fire atmosphere and (2) a single phase BCC microstructure. They have identified a ternary alloy with a nominal composition of Mo-22wt.% V-3Fe for use in cermet fabrication efforts. This paper summarizes thermal expansion properties of the various alloys studied, and compares the results with previous CTE data for Mo-V binary alloys

  20. Computing elastic anisotropy to discover gum-metal-like structural alloys

    Science.gov (United States)

    Winter, I. S.; de Jong, M.; Asta, M.; Chrzan, D. C.

    2017-08-01

    The computer aided discovery of structural alloys is a burgeoning but still challenging area of research. A primary challenge in the field is to identify computable screening parameters that embody key structural alloy properties. Here, an elastic anisotropy parameter that captures a material's susceptibility to solute solution strengthening is identified. The parameter has many applications in the discovery and optimization of structural materials. As a first example, the parameter is used to identify alloys that might display the super elasticity, super strength, and high ductility of the class of TiNb alloys known as gum metals. In addition, it is noted that the parameter can be used to screen candidate alloys for shape memory response, and potentially aid in the optimization of the mechanical properties of high-entropy alloys.

  1. Development of high-capacity nickel-metal hydride batteries using superlattice hydrogen-absorbing alloys

    International Nuclear Information System (INIS)

    Yasuoka, Shigekazu; Magari, Yoshifumi; Murata, Tetsuyuki; Tanaka, Tadayoshi; Ishida, Jun; Nakamura, Hiroshi; Nohma, Toshiyuki; Kihara, Masaru; Baba, Yoshitaka; Teraoka, Hirohito

    2006-01-01

    New R-Mg-Ni (R: rare earths) superlattice alloys with higher-capacity and higher-durability than the conventional Mm-Ni alloys with CaCu 5 structure have been developed. The oxidation resistibility of the superlattice alloys has been improved by optimizing the alloy composition by such as substituting aluminum for nickel and optimizing the magnesium content in order to prolong the battery life. High-capacity nickel-metal hydride batteries for the retail market, the Ni-MH2500/900 series (AA size type 2500mAh, AAA size type 900mAh), have been developed and commercialized by using an improved superlattice alloy for negative electrode material. alized by using an improved superlattice alloy for negative electrode material. (author)

  2. Heat of solution and site energies of hydrogen in disordered transition-metal alloys

    International Nuclear Information System (INIS)

    Brouwer, R.C.; Griessen, R.

    1989-01-01

    Site energies, long-range effective hydrogen-hydrogen interactions, and the enthalpy of solution in transition-metal alloys are calculated by means of an embedded-cluster model. The energy of a hydrogen atom is assumed to be predominantly determined by the first shell of neighboring metal atoms. The semiempirical local band-structure model is used to calculate the energy of the hydrogen atoms in the cluster, taking into account local deviations from the average lattice constant. The increase in the solubility limit and the weak dependence of the enthalpy of solution on hydrogen concentration in disordered alloys are discussed. Calculated site energies and enthalpies of solution in the alloys are compared with experimental data, and good agreement is found. Due to the strong interactions with the nearest-neighbor metal atoms, hydrogen atoms can be used to determine local lattice separations and the extent of short-range order in ''disordered'' alloys

  3. Characterization and modelling techniques for gas metal arc welding of DP 600 sheet steels

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, K.; Prahl, U.; Bleck, W. [RWTH Aachen University, Department of Ferrous Metallurgy (IEHK) (Germany); Reisgen, U.; Schleser, M.; Abdurakhmanov, A. [RWTH Aachen University, Welding and Joining Institute (ISF) (Germany)

    2010-11-15

    The objectives of the present work are to characterize the Gas Metal Arc Welding process of DP 600 sheet steel and to summarize the modelling techniques. The time-temperature evolution during the welding cycle was measured experimentally and modelled with the softwaretool SimWeld. To model the phase transformations during the welding cycle dilatometer tests were done to quantify the parameters for phase field modelling by MICRESS {sup registered}. The important input parameters are interface mobility, nucleation density, etc. A contribution was made to include austenite to bainite transformation in MICRESS {sup registered}. This is useful to predict the microstructure in the fast cooling segments. The phase transformation model is capable to predict the microstructure along the heating and cooling cycles of welding. Tensile tests have shown the evidence of failure at the heat affected zone, which has the ferrite-tempered martensite microstructure. (orig.)

  4. Analysis of acoustic emission during abrasive waterjet machining of sheet metals

    Science.gov (United States)

    Mokhtar, Nazrin; Gebremariam, MA; Zohari, H.; Azhari, Azmir

    2018-04-01

    The present paper reports on the analysis of acoustic emission (AE) produced during abrasive waterjet (AWJ) machining process. This paper focuses on the relationship of AE and surface quality of sheet metals. The changes in acoustic emission signals recorded by the mean of power spectral density (PSD) via covariance method in relation to the surface quality of the cut are discussed. The test was made using two materials for comparison namely aluminium 6061 and stainless steel 304 with five different feed rates. The acoustic emission data were captured by Labview and later processed using MATLAB software. The results show that the AE spectrums correlated with different feed rates and surface qualities. It can be concluded that the AE is capable of monitoring the changes of feed rate and surface quality.

  5. Testing and Prediction of Limits of Lubrication in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Bay, Niels

    2012-01-01

    Increasing focus on environmental issues in industrial production has urged a number of sheet metal forming companies to look for new tribo-systems, here meaning the combination of tool_material/workpiece_material/lubricant, in order to substitute hazardous lubricants such as chlorinated paraffin...... laboratory and production tests as well as numerical analyses in order to evaluate and compare performance of the new tribo-systems. A part is selected from industrial production and analyzed by this methodology in order to substitute the existing tribo-system with a new one....... oils. Testing of new tribo-systems under production conditions is, however, very costly. For preliminary testing it is more feasible to introduce laboratory tests. In this paper a new methodology for testing new tribo-systems is presented. The methodology describes a series of investigations combining...

  6. Practical Aspects of CALS in Design and Manufacturing of Sheet Metal Products

    DEFF Research Database (Denmark)

    Shpitalni, Moshe; Alting, Leo; Bilberg, Arne

    1998-01-01

    The transition from design to process planning and to the various stages of manufacturing is traditionally sequential. In many cases, practical problems associated with manufacturing cannot be resolved if only individual processes are examined. These problems can be overcome, however, by adopting...... with the design and manufacture of sheet metal parts. It is demonstrated that through implementation of the CALS approach, the overall process can be optimised and products can be manufactured significantly more accurately, faster and less expensively.......The transition from design to process planning and to the various stages of manufacturing is traditionally sequential. In many cases, practical problems associated with manufacturing cannot be resolved if only individual processes are examined. These problems can be overcome, however, by adopting...

  7. Outstanding resistance and passivation behaviour of new Fe-Co metal-metal glassy alloys in alkaline media.

    Directory of Open Access Journals (Sweden)

    Khadijah M Emran

    Full Text Available The electrochemical behavior of the oxide layers on two metal-metal glassy alloys, Fe78Co9Cr10Mo2Al1 (VX9and Fe49Co49V2 (VX50 (at.%, were studied using electrochemical techniques including electrochemical frequency modulation (EFM, electrochemical impedance spectroscopy (EIS and cyclic polarization (CP measurements. The morphology and composition of the alloy surfaces were investigated using X-ray photoelectron spectroscopy (XPS, scanning electron microscopy (SEM and atomic force microscopy (AFM. The corrosion rate and surface roughness of both alloys increased as the concentration of NaOH in aqueous solution was raised. The presence of some protective elements in the composition of the alloys led to the formation of a spontaneous passive layer on the alloy surface. The higher resistance values of both alloys were associated with the magnitude of the dielectric properties of the passive films formed on their surfaces. Both alloys are classified as having outstanding resistance to corrosion, which results from the formation of a passive film that acts as an efficient barrier to corrosion in alkaline solution.

  8. Research on Liquid Forming Process of Nickel Superalloys Thin Sheet Metals

    Directory of Open Access Journals (Sweden)

    Hyrcza-Michalska M.

    2017-12-01

    Full Text Available The paper presents the study of drawability of thin sheet metals made of a nickel superalloy Inconel type. The manufacturing process of axisymmetric cup – cone and a closed section profile in the form of a circular tube were designed and analyzed. In both cases, working fluid-oil was used in place of the rigid tools. The process of forming liquid is currently the only alternative method for obtaining complex shapes, coatings, and especially if we do it with high-strength materials. In the case of nickel superalloys the search for efficient methods to manufacture of the shaped shell is one of the most considerable problems in aircraft industry [1-5]. However, the automotive industries have the same problem with so-called advanced high-strength steels (AHSS. Due to this, both industrial problems have been examined and the emphasis have been put on the process of liquid forming (hydroforming. The study includes physical tests and the corresponding numerical simulations performed, using the software Eta/Dynaform 5.9. Numerical analysis of the qualitative and quantitative forecasting enables the formability of materials with complex and unusual characteristics of the mechanical properties and forming technology. It has been found that only the computer aided design based on physical and numerical modeling, makes efficient plastic processing possible using a method of hydroforming. Drawability evaluation based on the determination of the mechanical properties of complex characteristics is an indispensable element of this design in the best practice of industrial manufacturing products made of thin sheet metals.

  9. Weld metal grain refinement of aluminium alloy 5083 through controlled additions of Ti and B

    Energy Technology Data Exchange (ETDEWEB)

    Schempp, Philipp; Rethmeier, Michael [Federal Institute for Materials Research and Testing BAM, Berlin (Germany). Div. ' ' Safety of Joined Components' ' ; Fraunhofer Institute for Production Systems and Design Technology IPK, Berlin (Germany). Dept. ' ' Joining and Coating Technology' ' ; Schwenk, Christopher; Cross, Carl Edward [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2011-07-01

    The refinement of the weld metal grain structure may lead to a significant change in its mechanical properties and in the weldability of the base metal. One possibility to achieve weld metal grain refinement is the inoculation of the weld pool. In this study, it is shown how additions of titanium and boron influence the weld metal grain structure of GTA welds of the aluminium alloy 5083 (Al Mg4.5Mn0.7). For this purpose, inserts consisting of base metal and additions of the master alloy Al Ti5B1 have been cast, deposited in the base metal and fused in a GTA welding process. The increase of the Ti and B content led to a significant decrease of the weld metal mean grain size and to a change in grain shape. The results provide a basis for a more precise definition of the chemical composition of commercial filler wires and rods for aluminium arc welding. (orig.)

  10. Gas atomization of Cu-modified AB5 metal hydride alloys

    International Nuclear Information System (INIS)

    Young, K.; Ouchi, T.; Banik, A.; Koch, J.; Fetcenko, M.A.; Bendersky, L.A.; Wang, K.; Vaudin, M.

    2011-01-01

    Research highlights: → The gas atomization process together with a hydrogen annealing process was demonstrated on AB5 alloys. → The method was found to be effective in restoring the original cycle life sacrificed by the incorporation of copper in the alloy formula as a means of improving the low temperature performance of AB 5 alloys. → The new process also improves high rate, low temperature, and charge retention performances for both Cu-free and Cu-containing AB 5 alloys. - Abstract: Gas atomization together with a hydrogen annealing process has been proposed as a method to achieve improved low-temperature performance of AB 5 alloy electrodes in Ni/MH batteries and restore the original cycle life which was sacrificed by the incorporation of copper in the alloy formula. While the gas atomization process reduces the lattice constant aspect ratio c/a of the Cu-containing alloys, the addition of a hydrogen annealing step recovers this property, although it is still inferior to the conventionally prepared annealed Cu-free alloy. This observation correlates very well with the cycle life performance. In addition to extending the cycle life of the Cu-containing metal hydride electrode, processing by gas atomization with additional hydrogen annealing improves high-rate, low-temperature, and charge retention performances for both Cu-free and Cu-containing AB 5 alloys. The degradation mechanisms of alloys made by different processes through cycling are also discussed.

  11. Electron-beam welding of thorium-doped iridium alloy sheets

    International Nuclear Information System (INIS)

    David, S.A.; Liu, C.T.; Hudson, J.D.

    1979-04-01

    Modified iridium alloys containing 100 ppM Th were found to be very susceptible to hot-cracking during gas tungsten-arc and electron-beam welding. However, the electron-beam welding process showed greater promise of success in welding these alloys, in particular Ir--0.3% W doped with 200 ppM Th and 50 ppM Al. The weldability of this particular alloy was extremely sensitive to the welding parameters, such as beam focus condition and welding speed, and the resulting fusion zone structure. At low speed successful electron-beam welds were made over a narrow range of beam focus conditions. However, at high speeds successful welds can be made over an extended range of focus conditions. The fusion zone grain structure is a strong function of welding speed and focus condition, as well. In the welds that showed hot-cracking, a region of positive segregation of thorium was identified at the fusion boundary. This highly thorium-segregated region seems to act as a potential source for the nucleation of a liquation crack, which later grows as a centerline crack

  12. Investigations on the Hot Stamping of AW-7921-T4 Alloy Sheet

    Directory of Open Access Journals (Sweden)

    M. Kumar

    2017-01-01

    Full Text Available AW-7xxx alloys have been nowadays considered for greater light weighting potential in automotive industry due to its higher strength compared to AW-5xxx and AW-6xxx alloys. However, due to their lower formability the forming processes are still in development. This paper investigates one such forming process called hot stamping. The investigation started by carrying out hot tensile testing of an AW-7xxx alloy, that is, AW-7921 at temperatures between 350°C and 475°C, to measure the strength and formability. Formability was found to improve with increasing temperature and was sensitive to the strain rate. Dynamic recovery is considered as usual reason for the formability improvement. However, examining the precipitation states of the as-received condition and after hot stamping using differential scanning calorimetry (DSC, the dissolution of precipitates was also believed to contribute to this increase in formability. Following solution heat treatment there was no precipitation during cooling across the cooling rates investigated (5–10°C/s. Samples taken from parts hot stamped at 10 and 20 mm s−1 had similar yield strengths. A 3-step paint baking heat treatment yielded a higher postpaint baking strength than a single step treatment.

  13. Modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile

    Science.gov (United States)

    Sharma, Amit; Yadava, Vinod

    2012-02-01

    Thin sheets of aluminium alloys are widely used in aerospace and automotive industries for specific applications. Nd:YAG laser beam cutting is one of the most promising sheetmetal cutting process for cutting sheets for any profile. Al-alloy sheets are difficult to cut by laser beam because of its highly reflective nature. This paper presents modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile. In the present study, four input process parameters such as oxygen pressure, pulse width, pulse frequency, and cutting speed and two output parameters such as average kerf taper ( Ta) and average surface roughness ( Ra) are considered. The hybrid approach comprising of Taguchi methodology (TM) and response surface methodology (RSM) is used for modelling whereas multi-objective optimization is performed using hybrid approach of TM and grey relational analysis (GRA) coupled with entropy measurement methodology. The entropy measurement methodology is employed for the calculation of weight corresponding to each quality characteristic. The results indicate that the hybrid approaches applied for modelling and optimization of the LBC process are reasonable.

  14. The effect of sheet processing on the microstructure, tensile, and creep behavior of INCONEL alloy 718

    Science.gov (United States)

    Boehlert, C. J.; Dickmann, D. S.; Eisinger, Ny. N. C.

    2006-01-01

    The grain size, grain boundary character distribution (GBCD), creep, and tensile behavior of INCONEL alloy 718 (IN 718) were characterized to identify processing-microstructure-property relationships. The alloy was sequentially cold rolled (CR) to 0, 10, 20, 30, 40, 60, and 80 pct followed by annealing at temperatures between 954 °C and 1050 °C and the traditional aging schedule used for this alloy. In addition, this alloy can be superplastically formed (IN 718SPF) to a significantly finer grain size and the corresponding microstructure and mechanical behavior were evaluated. The creep behavior was evaluated in the applied stress (σ a ) range of 300 to 758 MPa and the temperature range of 638 °C to 670 °C. Constant-load tensile creep experiments were used to measure the values of the steady-state creep rate and the consecutive load reduction method was used to determine the values of backstress (σ0). The values for the effective stress exponent and activation energy suggested that the transition between the rate-controlling creep mechanisms was dependent on effective stresses (σ e =σ a σ0) and the transition occurred at σ e ≅ 135 MPa. The 10 to 40 pct CR samples exhibited the greatest 650 °C strength, while IN 718SPF exhibited the greatest room-temperature (RT) tensile strength (>1550 MPa) and ductility (ɛ f >16 pct). After the 954 °C annealing treatment, the 20 pct CR and 30 pct CR microstructures exhibited the most attractive combination of elevated-temperature tensile and creep strength, while the most severely cold-rolled materials exhibited the poorest elevated-temperature properties. After the 1050 °C annealing treatment, the IN 718SPF material exhibited the greatest backstress and best creep resistance. Electron backscattered diffraction was performed to identify the GBCD as a function of CR and annealing. The data indicated that annealing above 1010 °C increased the grain size and resulted in a greater fraction of twin boundaries, which in

  15. Hydro mechanical deep-drawing and high pressure sheet metal forming as forming technologies for the production of complex parts made of magnesium sheet metal AZ31B-0; Hydromechanisches Tiefziehen und Hochdruckblechumformung als Verfahren zur Herstellung komplexer Bauteile aus Magnesiumfeinblechen des Typs AZ31B-0

    Energy Technology Data Exchange (ETDEWEB)

    Viehweger, B.; Richter, G.; Duering, M.; Karabet, A. [Lehrstuhlleiter, BTU Cottbus, Lehrstuhl Konstruktion und Fertigung, Konrad-Wachsmann Allee 1, 03046 Cottbus (Germany); Sviridov, A.; Hartmann, H.; Richter, U. [Forschungs- und Qualitaetszentrum Oderbruecke gGmbH Eisenhuettenstadt (Germany)

    2004-07-01

    Semi - finished sheet - metal products made of magnesium alloys such as AZ31B are known as better deformable at temperatures in the range of 175 C - 240 C. By means of hydroforming technologies, as there are hydro mechanical deep-drawing and high pressure sheet metal forming, the influence of different forming parameters on the forming results has been investigated. A more complex experimental geometry was deformed applying forming temperatures of 175 C, 200 C, 225 C and 240 C and accordingly adjusted forces of the blank holder. Concerning the applied forming - methods and experimental parameters the forming results have been evaluated and compared regarding the decrease of sheet thickness and the development of small radii. For some experimental parts, which have been deformed by means of high pressure sheet metal forming at temperatures of 175 C and 225 C, supplementary investigations have been carried out in order to determine the evolution of characteristic surface values in dependence on the forming operation. On the basis of these results practical recommendations for the limits of application of aforementioned forming technologies for AZ31B-0 magnesium sheet metal are given. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Eine gute Umformbarkeit von Blechhalbzeugen aus Magnesiumknetlegierungen stellt sich bekanntlich bei Anwendung von Umformtemperaturen im Bereich von 175 C - 240 C ein. Anhand der wirkmedienbasierten Umformverfahren hydromechanisches Tiefziehen und Hochdruckblechumformung ist an handelsueblichen AZ31B-0 Feinblechen die Einstellung unterschiedlicher Umformparameter erprobt worden. Unter Verwendung von Umformtemperaturen von 175 C, 200 C, 225 C und 240 C und entsprechend angepassten Niederhalterdruecken ist eine praxisnahe Versuchsgeometrie ''Minihood'' ausgeformt worden. Im Hinblick auf angewendete Umformverfahren und Versuchsparameter wurde an den Versuchsbauteilen die Blechdickenabnahme und die

  16. Near net shape processing of zirconium or hafnium metals and alloys

    International Nuclear Information System (INIS)

    Evans, S.C.

    1992-01-01

    This patent describes a process for producing a metal shape. It comprises: plasma arc melting a metal selected from zirconium, hafnium and alloys thereof comprising at least about 90 w/o of these metals to form a liquid pool; pouring the metal form the pool into a mold to form a near net shape; and reducing the metal from its near net shape to a final size while maintaining the metal temperature below the alpha-beta transition temperature throughout the size reducing step

  17. Crystal-Structure Contribution to the Solid Solubility in Transition Metal Alloys

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt; Nørskov, Jens Kehlet

    1998-01-01

    The solution energies of 4d metals in other 4d metals as well as the bcc-hcp structural energy differences in random 4d alloys are calculated by density functional theory. It is shown that the crystal structure of the host plays a crucial role in the solid solubility. A local virtual bond...

  18. The thermodynamics of latent fingerprint corrosion of metal elements and alloys.

    Science.gov (United States)

    Bond, John W

    2008-11-01

    Redox reactions taking place between the surface of a metal and fingerprint residue have been expressed thermodynamically in terms of both the Nernst equation for reduction potential and the complexation constant for the formation of complex metal halide ions in aqueous solution. These expressions are used to explain experimental results for the corrosion of 10 different metal elements by fingerprint residue in air at room temperature. Corrosion of noble metals, such as silver and gold, supports the proposition that the degree of metal corrosion is enhanced by the presence of chloride ions in eccrine sweat. Extending the experiments to include 10 metal alloys enabled the construction of a fingerprint corrosion series for 20 different metals. Fingerprint corrosion on metals alloyed with > approximately 40% copper was found to display third level fingerprint detail. A comparison of both conventional ink on paper and digital (Livescan) fingerprinting techniques with fingerprints deposited on 9 Karat gold alloy has shown that gold alloy depositions are least susceptible to third level detail obliteration by poor fingerprint capturing techniques.

  19. Nano-structureal and nano-chemical analysis of Ni-based alloy/low alloy steel dissimilar metal weld interfaces

    International Nuclear Information System (INIS)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun

    2012-01-01

    The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

  20. Nano-structureal and nano-chemical analysis of Ni-based alloy/low alloy steel dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of)

    2012-06-15

    The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

  1. Wear resistance of layers hard faced by the high-alloyed filler metal

    OpenAIRE

    Dušan Arsić; Vukić Lazić; Ruzica R. Nikolic; Milan Mutavdžić; Srbislav Aleksandrović; Milan Djordjević

    2016-01-01

    The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by ...

  2. Formation and Applications of Bulk Glassy Alloys in Late Transition Metal Base System

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Shen Baolong

    2006-01-01

    This paper reviews our recent results of the formation, fundamental properties, workability and applications of late transition metal (LTM) base bulk glassy alloys (BGAs) developed since 1995. The BGAs were obtained in Fe-(Al,Ga)-(P,C,B,Si), Fe-(Cr,Mo)-(C,B), Fe-(Zr,Hf,Nb,Ta)-B, Fe-Ln-B(Ln=lanthanide metal), Fe-B-Si-Nb and Fe-Nd-Al for Fe-based alloys, Co-(Ta,Mo)-B and Co-B-Si-Nb for Co-based alloys, Ni-Nb-(Ti,Zr)-(Co,Ni) for Ni-based alloys, and Cu-Ti-(Zr,Hf), Cu-Al-(Zr,Hf), Cu-Ti-(Zr,Hf)-(Ni,Co) and Cu-Al-(Zr,Hf)-(Ag,Pd) for Cu-based alloys. These BGAs exhibit useful properties of high mechanical strength, large elastic elongation and high corrosion resistance. In addition, Fe- and Co-based glassy alloys have good soft magnetic properties which cannot be obtained for amorphous and crystalline type magnetic alloys. The Fe- and Ni-based BGAs have already been used in some application fields. These LTM base BGAs are promising as new metallic engineering materials

  3. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2016-07-01

    Full Text Available Effects of substitutions of rare earth (RE elements (Y, La, Ce, and Nd to the Zr-based AB2 multi-phase metal hydride (MH alloys on the structure, gaseous phase hydrogen storage (H-storage, and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15 are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation and is recommended for all the AB2 MH alloys for electrochemical applications.

  4. An Investigation on Metallic Ion Release from Four Dental Casting Alloys

    Directory of Open Access Journals (Sweden)

    F. Nejatidanesh

    2005-12-01

    Full Text Available Statement of Problem: Element release from dental casting alloys into the oral environment is of clinical concern and is considered to be a potential health problem to all patients.Purpose: The aim of this study was to investigate the metallic ion release of four base metal alloys.Materials and Methods: Two Ni-Cr (Minalux and Supercast and two Co-Cr alloys (Minalia and Wironit were examined. Nine specimens of each type were prepared in 13×11×1.4 mm dimensions and each of the four alloys (3 specimens per group were conditioned in artificial saliva at 37 c for one, three and seven days.The conditioning media were analyzed for element-release using Inductive CoupledPlasma Atomic Emission Spectrophotometer (ICPAES. Collected data were statistically analyzed using ANOVA and Duncan multiple range test (P< 0.05.Results: The greatest amount of element release was seen after seven days (134.9 ppb Supercast, 159.2 ppb Minalux, 197.2 ppb Minalia, and 230.2 ppb Wironit. There was a significant difference between the released elements from the alloys after the three conditioning times (p<0.001.Conclusion: Element release from the studied alloys is proportional to the conditioning time. The Ni-Cr alloys tested in this investigation were more resistant to corrosion as compared to the Co-Cr alloys in artificial saliva. Supercast had the highest corrosion resistance.

  5. Influence of alkali metal hydroxides on corrosion of Zr-base alloys

    International Nuclear Information System (INIS)

    Jeong, Yong Hwan

    1996-01-01

    The influence of group-1 alkali hydroxides on different Zr-based alloys have been carried out in static autoclaves at 350 deg C in pressurized water, conditioned in low(0.32 mmol), medium(4.3 mmol) and high(31.5 mmol) equimolar concentration of Li-, Na-, K-, Rb- and Cs-hydroxide. Two types of alloys have been investigated: Zr-Sn-(TRM, Transition metal) and Zr-Sn-Nb-(TRM, Transition metal). From the experiments the cation could be identified as the responsible species for corrosion of Zr alloy in alkalized water. The radius of the cation governs the accelerated corrosion in the pre-transition region of Zr alloy. Incorporation of alkali cation into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significant lower effect for the other bases. Nb containing alloys showed lower corrosion resistance than Zr-Sn-TRM alloys in all alkali solutions. Both types of alloys were corroded significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behavior in the different alkali environments and taking into account the tendency to accelerate the corrosion of Zr alloys, CsOH and KOH are possible alternate alkali for PWR (Pressurized Water Reactor) application. (author)

  6. Characterization of a Fe-based alloy system for an AFCI metallic waste form - 16134

    International Nuclear Information System (INIS)

    Williamson, Mark J.; Sindelar, Robert L.

    2009-01-01

    The AFCI waste management program aims to provide a minimum volume stable waste form for high level radioactive waste from the various process streams. The AFCI Integrated Waste Management Strategy document has identified a Fe-Zr metallic waste form (MWF) as the baseline alloy for disposal of Tc metal, undissolved solids, and TRUEX fission product wastes. Several candidate alloys have been fabricated using vacuum induction melting to investigate the limits of waste loading as a function of Fe and Zr content. Additional melts have been produced to investigate source material composition. These alloys have been characterized using SEM/EDS and XRD. Phase assemblage and specie partitioning of Re metal (surrogate for Tc) and noble metal FP elements into the phases is reported. (authors)

  7. Proofs of cluster formation and transitions in liquid metals and alloys

    International Nuclear Information System (INIS)

    Filippov, E.S.

    1985-01-01

    Calculational and experimental proofs are presented indicating to existence of clusters in liquid metals and alloys. Systems of liquid alloys both on the base of ferrous metals and non-ferrous metals (Fe-C, Ni-C, Co-C, Fe-Ni, Ni-Mo, Co-Cr, Co-V as well as In-Sn, Bi-Sn, Si-Ge and others) are studied experimentally. It is shown that the general feature of the systems studied is sensitivity of a volume to change in structure, to replacement fcc structure on bcc or to initiation-dissociation of intermetallic compounds AxBy. It is shown that both in pure liquid metals and in their.alloys there are clusters as ordered aggregate of atoms

  8. Development of shear bands in amorphous-crystalline metallic alloys

    International Nuclear Information System (INIS)

    Pozdnyakov, V.A.

    2004-01-01

    A theoretical study is made into conditions of shear band evolution in amorphous-crystalline alloys with various morphological types of structural constituents. The condition of shear band evolution in thin amorphous alloys in the interior of the crystalline matrix is obtained. It is shown that a scale effect exists which manifests itself in suppression of the process of localized plastic flow with amorphous alloy thickness decreasing down to the limit. The analysis of the condition for shear band evolution in an amorphous alloy with nanocrystalline inclusions is accomplished. The relationship of a critical stress of shear band evolution to a volume fraction of disperse crystal inclusions is obtained. A consideration is also given to the evolution of shear bands in the material containing amorphous and crystalline areas of micro meter size. For the alloy with the structure of this type conditions for propagation of localized flows by a relay race type mechanism are determined [ru

  9. 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.

  10. Nondestructive Evaluation of Friction Stir-Welded Aluminum Alloy to Coated Steel Sheet Lap Joint

    Science.gov (United States)

    Das, H.; Kumar, A.; Rajkumar, K. V.; Saravanan, T.; Jayakumar, T.; Pal, Tapan Kumar

    2015-11-01

    Dissimilar lap joints of aluminum sheet (AA 6061) of 2 mm thickness and zinc-coated steel sheet of 1 mm thickness were produced by friction stir welding with different combinations of rotational speed and travel speed. Ultrasonic C- and B-scanning, and radiography have been used in a complementary manner for detection of volumetric (cavity and flash) and planar (de bond) defects as the defects are in micron level. Advanced ultrasonic C-scanning did not provide any idea about the defects, whereas B-scanning cross-sectional image showed an exclusive overview of the micron-level defects. A digital x-ray radiography methodology is proposed for quality assessment of the dissimilar welds which provide three-fold increase in signal-to-noise ratio with improved defect detection sensitivity. The present study clearly shows that the weld tool rotational speed and travel speed have a decisive role on the quality of the joints obtained by the friction stir welding process. The suitability of the proposed NDE techniques to evaluate the joint integrity of dissimilar FSW joints is thus established.

  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. Thermochemical Properties of Group IVB and VB Transition Metal Alloys with Platinum Group Metals: Acid - Stabilization.

    Science.gov (United States)

    Cima, Michael John

    Solid-state galvanic cell measurements and oxide equilibration experiments are used to derive thermochemical quantities for a variety of acid-base stabilized alloys such as Nb-Pd, Nb-Rh, Ti-Pd, and Ti-Rh. The experiments have effectively resulted in the titration of palladium by niobium metal. The excess partial molar Gibbs energy of niobium at infinite dilution was determined to be -62 kcal/mole at 1000^circ C and the Gibbs energy of formation of {rm NbPd}_{3.55} is -42 kcal/mole. These results and those for the other systems are used to assess the importance of crystal field effects in the context of the generalized Lewis acid-base theory.

  13. Study of the embedded atom method of atomistic calculations for metals and alloys

    International Nuclear Information System (INIS)

    Johnson, R.A.

    1990-10-01

    Two projects were completed in the past year. The stability of a series of binary alloys was calculated using the embedded-atom method (EAM) with an analytic form for two-body potentials derived previously. Both disordered alloys and intermetallic compounds with the L1 0 and L1 2 structures were studied. The calculated heats of solution of alloys of Cu, Ag, Au, Ni, and Pt were satisfactory, while results for alloys containing Pd were too high. Atomistic calculations using the EAM were also carried out for point defects in hcp metals. By comparison with results in the literature, it was found that many body effects from the EAM significantly alter predicted physical properties of hcp metals. For example, the EAM calculations yield anisotropic vacancy diffusion with greater vacancy mobility in the basal plane, and imply that diffusion will start at a lower fraction of the melting temperature

  14. Controlling magnetism of MoS2 sheets by embedding transition-metal atoms and applying strain.

    Science.gov (United States)

    Zhou, Yungang; Su, Qiulei; Wang, Zhiguo; Deng, Huiqiu; Zu, Xiaotao

    2013-11-14

    Prompted by recent experimental achievement of transition metal (TM) atoms substituted in MoS2 nanostructures during growth or saturating existing vacancies (Sun et al., ACS Nano, 2013, 7, 3506; Deepak et al., J. Am. Chem. Soc., 2007, 129, 12549), we explored, via density functional theory, the magnetic properties of a series of 3d TM atoms substituted in a MoS2 sheet, and found that Mn, Fe, Co, Ni, Cu and Zn substitutions can induce magnetism in the MoS2 sheet. The localizing unpaired 3d electrons of TM atoms respond to the introduction of a magnetic moment. Depending on the species of TM atoms, the substituted MoS2 sheet can be a metal, semiconductor or half-metal. Remarkably, the applied elastic strain can be used to control the strength of the spin-splitting of TM-3d orbitals, leading to an effective manipulation of the magnetism of the TM-substituted MoS2 sheet. We found that the magnetic moment of the Mn- and Fe-substituted MoS2 sheets can monotonously increase with the increase of tensile strain, while the magnetic moment of Co-, Ni-, Cu- and Zn-substituted MoS2 sheets initially increases and then decreases with the increase of tensile strain. An instructive mechanism was proposed to qualitatively explain the variation of magnetism with elastic strain. The finding of the magnetoelastic effect here is technologically important for the fabrication of strain-driven spin devices on MoS2 nanostructures, which allows us to go beyond the current scope limited to the spin devices within graphene and BN-based nanostructures.

  15. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming Analysis, Simulation and Engineering Applications

    CERN Document Server

    Hu, Ping; Liu, Li-zhong; Zhu, Yi-guo

    2013-01-01

    Over the last 15 years, the application of innovative steel concepts in the automotive industry has increased steadily. Numerical simulation technology of hot forming of high-strength steel allows engineers to modify the formability of hot forming steel metals and to optimize die design schemes. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming focuses on hot and cold forming theories, numerical methods, relative simulation and experiment techniques for high-strength steel forming and die design in the automobile industry. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming introduces the general theories of cold forming, then expands upon advanced hot forming theories and simulation methods, including: • the forming process, • constitutive equations, • hot boundary constraint treatment, and • hot forming equipment and experiments. Various calculation methods of cold and hot forming, based on the authors’ experience in commercial CAE software f...

  16. Relationship between Microstructure and Ductility Dip Cracking resistance of Alloy 600/690 weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Jae Yong; Lee, Chang Hee [Hanyang University, Seoul (Korea, Republic of); Kim, Min Chul; Lee, Ho Jin; Kim, Keoung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Kwang Soo; Shim, Deog Nam [Doosan HEAVY Industries and Construction, Seoul (Korea, Republic of)

    2009-10-15

    Ni-Cr-Fe alloys are used extensively in nuclear power systems for their resistance to general corrosion, localized corrosion, and environmentally assisted cracking. However, concerns with stress corrosion cracking of moderate chromium (14.22 wt-%) alloys such as Alloy 600 and its filler metals(FMs) (E-182 and EN82) have driven the application of higher chromium (28.30 wt-%) alloys like Alloy 690. While Alloy 690 and its FMs show outstanding resistance to environmentally assisted cracking in most water-reactor environments, these alloys are prone to welding defects, most notably to ductility dip cracking(DDC). The DDC occurs at temperatures between 0.5 and 0.8 of their melting temperature. This ductility drop may result in intergranular elevated temperature cracking often referred to as DDC. The DDC may occur during the high temperature processing of these alloys or during welding if the imposed strain exhausts the available ductility within this temperature range. Several alloy systems including Ni-base alloys, Ni.Cu alloys, Cu alloys, stainless steels and steels, have been reported to be susceptible to DDC. A complete understanding of the DDC mechanism does not exist, which makes DDC control in actual production conditions a very difficult task. In this study, the DDC resistance was evaluated with different FMs which have different chemical composition. The microstructural features of FMs such as precipitation behavior and grain boundaries morphology were observed, and it were correlated with the DDC susceptibility. The hot ductility test and strainto- fracture test was used to evaluate the DDC susceptibility at high temperature.

  17. Relationship between Microstructure and Ductility Dip Cracking resistance of Alloy 600/690 weld metals

    International Nuclear Information System (INIS)

    Ryu, Jae Yong; Lee, Chang Hee; Kim, Min Chul; Lee, Ho Jin; Kim, Keoung Ho; Park, Kwang Soo; Shim, Deog Nam

    2009-01-01

    Ni-Cr-Fe alloys are used extensively in nuclear power systems for their resistance to general corrosion, localized corrosion, and environmentally assisted cracking. However, concerns with stress corrosion cracking of moderate chromium (14.22 wt-%) alloys such as Alloy 600 and its filler metals(FMs) (E-182 and EN82) have driven the application of higher chromium (28.30 wt-%) alloys like Alloy 690. While Alloy 690 and its FMs show outstanding resistance to environmentally assisted cracking in most water-reactor environments, these alloys are prone to welding defects, most notably to ductility dip cracking(DDC). The DDC occurs at temperatures between 0.5 and 0.8 of their melting temperature. This ductility drop may result in intergranular elevated temperature cracking often referred to as DDC. The DDC may occur during the high temperature processing of these alloys or during welding if the imposed strain exhausts the available ductility within this temperature range. Several alloy systems including Ni-base alloys, Ni.Cu alloys, Cu alloys, stainless steels and steels, have been reported to be susceptible to DDC. A complete understanding of the DDC mechanism does not exist, which makes DDC control in actual production conditions a very difficult task. In this study, the DDC resistance was evaluated with different FMs which have different chemical composition. The microstructural features of FMs such as precipitation behavior and grain boundaries morphology were observed, and it were correlated with the DDC susceptibility. The hot ductility test and strainto- fracture test was used to evaluate the DDC susceptibility at high temperature

  18. Comparison of laboratory and field experience of PWSCC in Alloy 182 weld metal

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P.; Meunier, M.-C.; Steltzlen, F. [AREVA NP, Tour AREVA, Paris La Defense (France); Calonne, O.; Foucault, M. [AREVA NP, Centre Technique, Le Creusot Cedex (France); Combrade, P. [ACXCOR, Saint Etienne (France); Amzallag, C. [EDF, SEPTEN, Villeurbanne (France)

    2007-07-01

    Laboratory studies of stress corrosion cracking of the nickel base weld metal, Alloy 182, in simulated PWR primary water suggest similar resistance to crack initiation and somewhat enhanced propagation rates relative to wrought Alloy 600. By contrast, field experience of cracking in the primary circuits of PWRs shows in general much better performance for Alloy 182 relative to Alloy 600 than would be anticipated from laboratory studies. This paper endeavours to resolve this apparent conundrum. It draws on the conclusions of recent research that has focussed on the role of surface finish, particularly cold work and residual stresses resulting from different fabrication processes, on the risk of initiating IGSCC in nickel base alloys in PWR primary water. It also draws on field experience of stress corrosion cracking that highlights the important role of surface finish for crack initiation. (author)

  19. Development of high-capacity nickel-metal hydride batteries using superlattice hydrogen-absorbing alloys

    Science.gov (United States)

    Yasuoka, Shigekazu; Magari, Yoshifumi; Murata, Tetsuyuki; Tanaka, Tadayoshi; Ishida, Jun; Nakamura, Hiroshi; Nohma, Toshiyuki; Kihara, Masaru; Baba, Yoshitaka; Teraoka, Hirohito

    New R-Mg-Ni (R: rare earths) superlattice alloys with higher-capacity and higher-durability than the conventional Mm-Ni alloys with CaCu 5 structure have been developed. The oxidation resistibility of the superlattice alloys has been improved by optimizing the alloy composition by such as substituting aluminum for nickel and optimizing the magnesium content in order to prolong the battery life. High-capacity nickel-metal hydride batteries for the retail market, the Ni-MH2500/900 series (AA size type 2500 mAh, AAA size type 900 mAh), have been developed and commercialized by using an improved superlattice alloy for negative electrode material.

  20. Ultrafast magnetization dynamics of lanthanide metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sultan, Muhammad

    2012-05-14

    In this study, the laser-induced magnetization dynamics of the lanthanide ferromagnets Gadolinium (Gd), Terbium (Tb) and their alloys is investigated using femtosecond (fs) time-resolved x-ray magnetic circular dichroism (XMCD), the magneto-optical Kerr effect (MOKE) and magnetic second harmonic generation (MSHG). The magnetization dynamics is analyzed from the time scale of a few fs up to several hundred picoseconds (ps). The contributions of electrons, phonons, spin fluctuations, as well as the temporal regimes corresponding to the spin-orbit and exchange interactions are disentangled. In addition to possible applications in magnetic storage devices, understanding magnetization dynamics in lanthanides is also important because of their different magnetic structure compared to well-studied itinerant ferromagnets. Lanthanides are model Heisenberg-ferromagnets with localized 4f magnetic moments and long range magnetic ordering through indirect exchange interaction. By optical excitation of the conduction electrons, which mediate the exchange interaction, and studying the induced dynamics of the localized 4f and delocalized 5d6s magnetic moments, one can obtain insight into the angular momentum transfer at ultrafast time scales. Moreover, lanthanides offer the possibility to tune spin-lattice coupling via the 4f shell occupation and the concomitant changes in the 4f spin and orbital moments due to Hund's rules. Utilizing this fact, the importance of spin-lattice coupling in laser-induced demagnetization is also analyzed by comparing the magnetization dynamics in Gd and Tb. By investigating the magnetization dynamics of localized 4f moments of Gd and Tb using time-resolved XMCD, it is found that the demagnetization proceeds in both metals in two time scales, following fs laser excitation, which are classified as: (i) non-equilibrium (t > 1 ps), with respect to equilibration of electron and phonon temperatures. The

  1. Catalogue of X-Ray Texture Data for Al-Cu-Li Alloy 1460, 2090, 2096 and 2195 Near-Net-Shape Extrusions, Sheet and Plate

    Science.gov (United States)

    Hales, Stephen J.; Hafley, Robert A.; Alexa, Joel A.

    1998-01-01

    The effect of crystallographic texture on the mechanical properties of near-net-shape extrusions is of major interest ff these products are to find application in launch vehicle or aircraft structures. The objective of this research was to produce a catalogue containing quantitative texture information for extruded product, sheet and plate. The material characterized was extracted from wide, integrally stiffened panels fabricated from the Al-Cu-Li alloys 1460, 2090, 2096 and 2195. The textural characteristics of sheet and plate products of the same alloys were determined for comparison purposes. The approach involved using X-ray diffraction to generate pole figures in combination with orientation distribution function analysis. The data were compiled as a function of location in the extruded cross-sections and the variation in the major deformation- and recrystallization-related texture components was identified.

  2. An advanced constitutive model in the sheet metal forming simulation: the Teodosiu microstructural model and the Cazacu Barlat yield criterion

    International Nuclear Information System (INIS)

    Alves, J.L.; Oliveira, M.C.; Menezes, L.F.

    2004-01-01

    Two constitutive models used to describe the plastic behavior of sheet metals in the numerical simulation of sheet metal forming process are studied: a recently proposed advanced constitutive model based on the Teodosiu microstructural model and the Cazacu Barlat yield criterion is compared with a more classical one, based on the Swift law and the Hill 1948 yield criterion. These constitutive models are implemented into DD3IMP, a finite element home code specifically developed to simulate sheet metal forming processes, which generically is a 3-D elastoplastic finite element code with an updated Lagrangian formulation, following a fully implicit time integration scheme, large elastoplastic strains and rotations. Solid finite elements and parametric surfaces are used to model the blank sheet and tool surfaces, respectively. Some details of the numerical implementation of the constitutive models are given. Finally, the theory is illustrated with the numerical simulation of the deep drawing of a cylindrical cup. The results show that the proposed advanced constitutive model predicts with more exactness the final shape (medium height and ears profile) of the formed part, as one can conclude from the comparison with the experimental results

  3. A sheet metal forming simulation of automotive outer panels considering the behavior of air in die cavity

    Science.gov (United States)

    Choi, Kwang Yong; Kim, Yun Chang; Choi, Hee Kwan; Kang, Chul Ho; Kim, Heon Young

    2013-12-01

    During a sheet metal forming process of automotive outer panels, the air trapped between a blank sheet and a die tool can become highly compressed, ultimately influencing the blank deformation and the press force. To prevent this problem, vent holes are drilled into die tools and needs several tens to hundreds according to the model size. The design and the drilling of vent holes are based on expert's experience and try-out result and thus the process can be one of reasons increasing development cycle. Therefore the study on the size, the number, and the position of vent holes is demanded for reducing development cycle, but there is no simulation technology for analyzing forming defects, making numerical sheet metal forming process simulations that incorporate the fluid dynamics of air. This study presents a sheet metal forming simulation of automotive outer panels (a roof and a body side outer) that simultaneously simulates the behavior of air in a die cavity. Through CAE results, the effect of air behavior and vent holes to blank deformation was analyzed. For this study, the commercial software PAM-STAMP{trade mark, serif} and PAM-SAFE{trade mark, serif} was used.

  4. Testing new tribo-systems for sheet metal forming of advanced high strength steels and stainless steels

    DEFF Research Database (Denmark)

    Bay, Niels; Ceron, Ermanno

    2014-01-01

    of a methodology for off-line testing of new tribo-systems for advanced high strength steels and stainless steels. The methodology is presented and applied to an industrial case, where different tribo-systems are tested. A universal sheet tribotester has been developed, which can run automatically repetitive......Testing of new tribo-systems in sheet metal forming has become an important issue due to new legislation, which forces industry to replace current, hazardous lubricants. The present paper summarizes the work done in a recent PhD project at the Technical University of Denmark on the development...

  5. Anomalous effect of small doses of ionizing radiation on metals and alloys

    International Nuclear Information System (INIS)

    Chernov, I.P.; Mamontov, A.P.; Botaki, A.A.; Cherdantsev, P.A.; Chakhlov, B.V.; Sharov, S.R.; Timoshnikov, Yu.A.; Filipenko, L.A.

    1986-01-01

    The effect of small doses of 60 Co gamma rays on copper, tungsten, and WCo alloys has been investigated. A decrease in the concentration of material defects under the influence of small doses of ionizing radiation was found. Also the structural rearrangement of the crystal was found to be still in progress after irradiation ceased. The mechanism of the anomalous effect of small doses of ionizing radiation on metals and alloys is discussed in terms of the electron energy scheme. (U.K.)

  6. X-ray and neutron diffraction studies of some liquid alkali metals and alloys

    International Nuclear Information System (INIS)

    Huijben, M.J.

    1978-01-01

    Experimental techniques and correction procedures have been searched for, which allow a reliable and accurate determination of the structure factors of simple liquid metals, particularly in the small-angle region. A study of binary alloys was carried out and showed that clustering of like atoms (a tendency to phase separation) occurs, indicating special structural aspects. The densities of Na-K, Na-Cs, K-Rb alloys were also measured. (C.F.)

  7. Studies on the finite element simulation in sheet metal stamping processes

    Science.gov (United States)

    Huang, Ying

    The sheet metal stamping process plays an important role in modern industry. With the ever-increasing demand for shape complexity, product quality and new materials, the traditional trial and error method for setting up a sheet metal stamping process is no longer efficient. As a result, the Finite Element Modeling (FEM) method has now been widely used. From a physical point of view, the formability and the quality of a product are influenced by several factors. The design of the product in the initial stage and the motion of the press during the production stage are two of these crucial factors. This thesis focuses on the numerical simulation for these two factors using FEM. Currently, there are a number of commercial FEM software systems available in the market. These software systems are based on an incremental FEM process that models the sheet metal stamping process in small incremental steps. Even though the incremental FEM is accurate, it is not suitable for the initial conceptual design for its needing of detailed design parameters and enormous calculation times. As a result, another type of FEM, called the inverse FEM method or one-step FEM method, has been proposed. While it is less accurate than that of the incremental method, this method requires much less computation and hence, has a great potential. However, it also faces a number of unsolved problems, which limits its application. This motivates the presented research. After the review of the basic theory of the inverse method, a new modified arc-length search method is proposed to find better initial solution. The methods to deal with the vertical walls are also discussed and presented. Then, a generalized multi-step inverse FEM method is proposed. It solves two key obstacles: the first one is to determine the initial solution of the intermediate three-dimensional configurations and the other is to control the movement of nodes so they could only slide on constraint surfaces during the search by

  8. 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.

  9. Microstructure and anisotropic mechanical behavior of friction stir welded AA2024 alloy sheets

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhihan [State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Li, Wenya, E-mail: liwy@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Li, Jinglong [State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Chao, Y.J. [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Vairis, A. [Mechanical Engineering Department, TEI of Crete, Heraklion, Crete 71004 (Greece)

    2015-09-15

    The anisotropic mechanical properties of friction stir welded (FSW) AA2024-T3 alloy joints were investigated based on the uniaxial tensile tests. The joint microstructure was examined by using electron back-scattered diffraction and transmission electron microscope. Results show that the evident anisotropic failure and yielding are present in the FSW joints. With the increase of loading angle from 0° to 90° the ultimate tensile strength and elongation of the specimens consistently decrease, or at first decrease and then increase, depending on the FSW process parameters. The specimen cut from the weld direction, i.e. a loading angle of 0°, exhibits the highest strength and elongation. - Highlights: • Microstructure and anisotropy of friction stir welded joints were studied. • The evident anisotropic failure and yielding are present in joints. • The lowest yield stress and UTS are at 45° and 60° loadings, respectively. • Rotation speed heavily impact on the anisotropy of joints.

  10. Microstructure and anisotropic mechanical behavior of friction stir welded AA2024 alloy sheets

    International Nuclear Information System (INIS)

    Zhang, Zhihan; Li, Wenya; Li, Jinglong; Chao, Y.J.; Vairis, A.

    2015-01-01

    The anisotropic mechanical properties of friction stir welded (FSW) AA2024-T3 alloy joints were investigated based on the uniaxial tensile tests. The joint microstructure was examined by using electron back-scattered diffraction and transmission electron microscope. Results show that the evident anisotropic failure and yielding are present in the FSW joints. With the increase of loading angle from 0° to 90° the ultimate tensile strength and elongation of the specimens consistently decrease, or at first decrease and then increase, depending on the FSW process parameters. The specimen cut from the weld direction, i.e. a loading angle of 0°, exhibits the highest strength and elongation. - Highlights: • Microstructure and anisotropy of friction stir welded joints were studied. • The evident anisotropic failure and yielding are present in joints. • The lowest yield stress and UTS are at 45° and 60° loadings, respectively. • Rotation speed heavily impact on the anisotropy of joints

  11. Microstructure of friction stir welded joints of 2017A aluminium alloy sheets.

    Science.gov (United States)

    Mroczka, K; Dutkiewicz, J; Pietras, A

    2010-03-01

    The present study examines a friction stir welded 2017A aluminium alloy. Transmission electron microscope investigations of the weld nugget revealed the average grain size of 5 microm, moderate density of dislocations as well as the presence of nanometric precipitates located mostly in grains interiors. Scanning electron microscope observations of fractures showed the presence of ductile fracture in the region of the weld nugget with brittle precipitates in the lower part. The microhardness analysis performed on the cross-section of the joints showed fairly small changes; however, after the artificial ageing process an increase in hardness was observed. The change of the joint hardness subject to the ageing process indicates partial supersaturation in the material during friction stir welding and higher precipitation hardening of the joint.

  12. Designing the Color of Hot-Dip Galvanized Steel Sheet Through Destructive Light Interference Using a Zn-Ti Liquid Metallic Bath

    Science.gov (United States)

    Levai, Gabor; Godzsák, Melinda; Török, Tamas I.; Hakl, Jozsef; Takáts, Viktor; Csik, Attila; Vad, Kalman; Kaptay, George

    2016-07-01

    The color of hot-dip galvanized steel sheet was adjusted in a reproducible way using a liquid Zn-Ti metallic bath, air atmosphere, and controlling the bath temperature as the only experimental parameter. Coloring was found only for samples cooled in air and dipped into Ti-containing liquid Zn. For samples dipped into a 0.15 wt pct Ti-containing Zn bath, the color remained metallic (gray) below a 792 K (519 °C) bath temperature; it was yellow at 814 K ± 22 K (541 °C ± 22 °C), violet at 847 K ± 10 K (574 °C ± 10 °C), and blue at 873 K ± 15 K (600 °C ± 15 °C). With the increasing bath temperature, the thickness of the adhered Zn-Ti layer gradually decreased from 52 to 32 micrometers, while the thickness of the outer TiO2 layer gradually increased from 24 to 69 nm. Due to small Al contamination of the Zn bath, a thin (around 2 nm) alumina-rich layer is found between the outer TiO2 layer and the inner macroscopic Zn layer. It is proven that the color change was governed by the formation of thin outer TiO2 layer; different colors appear depending on the thickness of this layer, mostly due to the destructive interference of visible light on this transparent nano-layer. A complex model was built to explain the results using known relationships of chemical thermodynamics, adhesion, heat flow, kinetics of chemical reactions, diffusion, and optics. The complex model was able to reproduce the observations and allowed making predictions on the color of the hot-dip galvanized steel sample, as a function of the following experimental parameters: temperature and Ti content of the Zn bath, oxygen content, pressure, temperature and flow rate of the cooling gas, dimensions of the steel sheet, velocity of dipping the steel sheet into the Zn-Ti bath, residence time of the steel sheet within the bath, and the velocity of its removal from the bath. These relationships will be valuable for planning further experiments and technologies on color hot-dip galvanization of steel

  13. The use of alloy 117 as a liquid metal current collector

    Science.gov (United States)

    Maribo, David; Sondergaard, Neal

    1987-09-01

    Low melting point, bismuth based alloys are potential replacements for NaK78 as liquid metal slip ring material because of their lower reactivity and potentially greater hydrodynamic stability. This paper describes experiments with one such alloy in a model of a 300 kW superconducting homopolar motor using close clearance braid type collectors. Slip ring tip velocities varied from 5 to 20 m/s and currents ranging from 500 to 2000 A. Viscous power losses tend to follow a simple turbulent mode. In all, the data supports the use of low melting point alloys as an alternative to Na78.

  14. Screened Coulomb interactions in metallic alloys. I. Universal screening in the atomic-sphere approximation

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt

    2002-01-01

    We have used the locally self-consistent Green's-function (LSGF) method in supercell calculations to establish the distribution of the net charges assigned to the atomic spheres of the alloy components in metallic alloys with different compositions and degrees of order. This allows us to determine......-site local interaction zone. We demonstrate that the basic mechanism that governs the charge distribution is the screening of the net charges of the alloy components that makes the direct Coulomb interactions short ranged. In the atomic-sphere approximation, this screening appears to be almost independent...

  15. Thermomechanical processing of plasma sprayed intermetallic sheets

    Science.gov (United States)

    Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  16. Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

    Science.gov (United States)

    Li, M. M.; Yang, C. C.; Wang, C. C.; Wen, Z.; Zhu, Y. F.; Zhao, M.; Li, J. C.; Zheng, W. T.; Lian, J. S.; Jiang, Q.

    2016-06-01

    Nickel metal hydride (Ni-MH) batteries have demonstrated key technology advantages for applications in new-energy vehicles, which play an important role in reducing greenhouse gas emissions and the world’s dependence on fossil fuels. However, the poor high-rate dischargeability of the negative electrode materials—hydrogen storage alloys (HSAs) limits applications of Ni-MH batteries in high-power fields due to large polarization. Here we design a hybrid electrode by integrating HSAs with a current collector of three-dimensional bicontinuous nanoporous Ni. The electrode shows enhanced high-rate dischargeability with the capacity retention rate reaching 44.6% at a discharge current density of 3000 mA g-1, which is 2.4 times that of bare HSAs (18.8%). Such a unique hybrid architecture not only enhances charge transfer between nanoporous Ni and HSAs, but also facilitates rapid diffusion of hydrogen atoms in HSAs. The developed HSAs/nanoporous metals hybrid structures exhibit great potential to be candidates as electrodes in high-performance Ni-MH batteries towards applications in new-energy vehicles.

  17. Formation and stability of aluminum-based metallic glasses in Al-Fe-Gd alloys

    International Nuclear Information System (INIS)

    He, Y.; Poon, S.J.; Shiflet, G.J.

    1988-01-01

    Metallic glasses, a class of amorphous alloys made by rapid solidification, have been studied quite extensively for almost thirty years. It has been recognized for a long time that metallic glasses are usually very strong and ductile, and exhibit high corrosion resistance relative to crystalline alloys with the same compositions. Recently, metallic glasses containing as much as 90 atomic percent aluminum have been discovered independently by two groups. This discovery has both scientific and technological implications. The formability of these new glasses have been found to be unusual. Studies of mechanical properties in these new metallic glasses show that many of them have tensile strengths over 800MPa, greatly exceeding the strongest commercial aluminum alloys. The high strengths of aluminum-rich metallic glasses can be of significant importance in obtaining high strength low density materials. Therefore, from both scientific and technological standpoints, it is important to understand the formation and thermal stability of these metallic glasses. Al-Fe-Gd alloys were chosen for a more detailed study since they exhibit high tensile strengths

  18. Life cycle assessment of metal alloys for structural applications

    Science.gov (United States)

    Malovrh Rebec, K.; Markoli, B.; Leskovar, B.

    2018-03-01

    The study compared environmental footprints of two types of Al-alloys: well-known 5083 aluminium alloy with magnesium and traces of manganese and chromium in its composition. This material is highly resistant to seawater corrosion and the influence of industrial chemicals. Furthermore, it retains exceptional strength after welding. The comparisons were made to an innovative alloy where the aluminium based matrix is reinforced by metastable quasicrystals (QC), thus avoiding magnesium in its composition. Furthermore, we checked other aluminium ingots’ footprints and compared European average and Germany country specific production data. Environmental footprints were assessed via cradle to gate life cycle assessment. Our findings normalized to 1 m2 plate suggest, that newly proposed alloy could save around 50 % in value of parameters abiotic resources depletion of fossil fuels, acidification, eutrophication, global warming potential and photochemical ozone creation potential if we compare Qc5 to 6 mm 5083 alloy plate. Only abiotic resources depletion of elements and ozone depletion parameters increase for Qc5 compared to 6 mm 5083 alloy plate.

  19. Shop Math for the Metal Trades. Combination Welder Apprentice, Machinist Helper, Precision Metal Finisher, Sheet Metal Worker Apprentice. A Report on Metal Trades Industry Certified, Single-Concept, Mathematical Learning Projects to Eliminate Student Math Fears.

    Science.gov (United States)

    Newton, Lawrence R.

    This project (1) identifies basic and functional mathematics skills (shop mathematics skills), (2) provides pretests on these functional mathematics skills, and (3) provides student learning projects (project sheets) that prepare metal trades students to read, understand, and apply mathematics and measuring skills that meet entry-level job…

  20. Depth concentrations of deuterium ions implanted into some pure metals and alloys

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Wisniewski, R.; Kitowski, K.; Wilczynska, T.; Hofman, A.; Kulikauskas, V.; Shiryaev, A.A.; Zubavichyus, Ya.V.

    2011-01-01

    Pure metals (Cu, Ti, Zr, V, Pd) and diluted Pd alloys (Pd-Ag, Pd-Pt, Pd-Ru, Pd-Rh) were implanted by 25-keV deuterium ions at fluences in the range (1.2-2.3) x 10 22 D + /m 2 . The post-treatment depth distributions of deuterium ions were measured 10 days and three months after the implantation by using Elastic Recoil Detection Analysis (ERDA) and Rutherford Backscattering (RBS). Comparison of the obtained results allowed us to make conclusions about relative stability of deuterium and hydrogen gases in pure metals and diluted Pd alloys. Very high diffusion rates of implanted deuterium ions from V and Pd pure metals and Pd alloys were observed. Small-angle X-ray scattering revealed formation of nanosized defects in implanted corundum and titanium