Advanced Engineering Materials

Cover image for Vol. 12 Issue 3

Special Issue: „Integrated Materials Modelling: Practice-Oriented Modelling Tools”

March 2010

Volume 12, Issue 3

Pages 87–241

Issue edited by: Volker Mohles

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Communications
    1. (Adv. Eng. Mater. 3/2010)

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201090004

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  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Communications
    1. (Adv. Eng. Mater. 3/2010) (pages 87–92)

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201090005

  3. Editorial

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Communications
    1. Editorial (page 93)

      Priv. Doz. Dr. rer. nat. Volker Mohles

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000060

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Communications
    1. Modeling of Hot Ductility During Solidification of Steel Grades in Continuous Casting – Part I (pages 94–100)

      Dieter Senk, Sonja Stratemeier, Bernd Böttger, Klaus Göhler and Ingo Steinbach

      Article first published online: 25 MAR 2010 | DOI: 10.1002/adem.201000021

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      It is shown that simulations combined with experiments can predict the relations between temperature distribution, solidification velocity, chemical composition and mechanical properties of the steel shell. Simulation results and experimental microstructure parameters are used as input data for hot tearing criteria. A critical choice of hot tearing criteria is developed. The new “damage model” is going to be implemented in industry to determine hot cracking susceptibility in continuous slab casting.

    2. Modelling of Hot Ductility during Solidification of Steel Grades in Continuous Casting – Part II (pages 101–109)

      Bernd Böttger, Sonja Stratemeier, Emir Subasic, Klans Göhler, Ingo Steinbach and Dieter Senk

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000022

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      In continuous casting, the probability of hot-cracks strongly depends on the microstructure. This paper focuses on solidification modelling, which delivers most of the parameters for the physically based hot-cracking criteria within the integrated approach. Solidification is simulated using a multiphase-field model coupled to thermodynamic and diffusion databases using an integrated mesoscale temperature solver. The results are compared to experimental EDX mappings of different steel grades.

    3. Modeling of Coating Process, Phase Changes, and Damage of Plasma Sprayed Thermal Barrier Coatings on Ni-Base Superalloys (pages 110–126)

      Tilmann Beck, Marcin Białas, Piotr Bednarz, Lorenz Singheiser, Kirsten Bobzin, Nazlim Bagcivan, Daniel Parkot, Tatyana Kashko, Ivica Petković, Bengt Hallstedt, Sergey Nemna and Jochen M. Schneider

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000023

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      Modeling activities on plasma sprayed thermal barrier coating are presented. Through-process modeling of the APS deposition of a ZrO2 based TBC is described. A homogenization method is introduced to describe the mechanical properties of the resulting TBC. Moreover, simulations of interdiffusion and phase transformations of MCrAlY and intermetallic oxidation protection coatings on Ni-base alloy substrates are presented. Finally, damage simulations of oxidation protection coatings by fatigue cracks and by TBC delamination during thermocyclic loading are discussed.

    4. Derivation of Recovery Kinetics From Stress Relaxation Tests (pages 127–130)

      Sheila Bhaumik, Volker Mohles, Günter Gottstein, Christoph Heering and Gerhard Hirt

      Article first published online: 29 MAR 2010 | DOI: 10.1002/adem.201000025

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      In literature, standard annealing experiments, like double tension (DT) tests, have been widely used for evaluation of recovery kinetics. These standard methods are generally time consuming and cost intensive since they imply numerous test series. Here, stress relaxation tests are performed and discussed as a direct replacement for the much more laborious DT tests.

    5. Recrystallization Modeling of AA8XXX Alloys with Cellular Automata Considering Recovering Kinetics (pages 131–140)

      Carmen Schäfer, Gerda Pomana, Volker Mohles, Günter Gottstein, Olaf Engler and Jürgen Hirsch

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000026

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      A through-process modeling scheme for the prediction of recrystallization textures and microstructures after final annealing, subsequent to cold rolling is proposed and applied to a commercial Al–Fe–Si alloy. The heart of the setup is a cellular automaton for modeling of recrystallization which considers changes in dislocation density by recovery and changes in Zener and solute drag due to microchemistry evolution. However, recrystallization is the crucial point in the whole setup, since it leads to significant changes in microstructure and texture. The simulated results are compared to experiments.

    6. Physical and Numerical Simulation of Cold Rolling of an AlFeSi Alloy in Consideration of Static Recovery (pages 141–146)

      Christoph Heering, Xiaoli Li, Markus Bambach and Gerhard Hirt

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000024

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      In this paper, basic experiments regarding the influence of static recovery on the flow stress of AlFeSi alloys are presented. From these tests, stress–time curves were generated that describe the static recovery kinetics. The stress–time curves were used to calibrate an empirical recovery model which is embedded in a physically based flow stress model. Cold rolling experiments were performed and simulated using the physical flow stress model.

    7. Methodology for Thermomechanical Simulation and Validation of Mechanical Weld-Seam Properties (pages 147–152)

      Wolfgans Bleck, Uwe Reisgen, Oleg Mokrov, Eduardo Rossiter and Thomas Rieger

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000027

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      A methodology for the simulation and validation of the mechanical properties in submerged-arc-weld seams is presented. The thermal cycle in the heat-affected zone (HAZ) is simulated with the SimWeld software (ISF) and subsequently imposed on an adapted tensile specimen. The methodology can predict the mechanical properties in the HAZ and generate input data for FE simulations.

    8. Simulation of Welding and Distortion in Ship Building (pages 153–157)

      Thomas Rieger, Stefan Gazdag, Ulrich Prahl, Oleg Mokrov, Eduardo Rossiter and Uwe Reisgen

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000029

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      The distortion simulation during welding of stiffeners on heavy plates is discussed. To describe the energy input an equivalent heat source was computed by the software SimWeld and combined with an FEM simulation of the global structure using SYSWELD software. The simulation results showed good agreement with the experiment. Using this approach the prediction quality was significantly improved against the typical method of heat source parameter identification using experimental results.

    9. Modeling the Porosity Formation in Austenitic SGI Castings by Using a Physics-Based Material Model (pages 158–169)

      B. Pustal, B. Hallstedt, W. Schäfer, C. Bartels, E. Subasic, H. Siebert, J. M. Schneider and A. Bührig-Polaczek

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.201000028

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      On solidification microsegregations build up in solid phases. Diffusion, which is a kinetic process, usually reduces the occurrence of microsegregations. This work is aimed at modeling such kinetic effects on solidification using a holistic approach. By performing macroscopically coupled simulations, the different cooling characteristics within the casting lead to pronounced differences in phase fractions which influence the shrinkage behavior of austenitic cast iron. Based on phase fraction predictions, the porosity formation is simulated and compared to experiments.

    10. A New Way to Improve Glass-Forming Ability by Controlling the Preparation Conditions of Bulk Metallic Glass (pages 170–175)

      Jie Mao, Hai-Feng Zhang, Hua-Meng Fu, Ai-Min Wang, Hong Li and Zhuang-Qi Hu

      Article first published online: 4 JAN 2010 | DOI: 10.1002/adem.200900264

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      The effects of mold preheating temperature on the glass-forming ability of Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8 alloys are investigated using traditional copper mold casting (see image). A new way to improve the glass-forming ability by preheating the mold is presented. The mechanism is also discussed from the perspectives of heat transfer efficiency and the wettability between the liquid alloy and the copper mold.

    11. The Precipitation Behavior of Superalloy ATI Allvac 718Plus (pages 176–183)

      Gerald A. Zickler, Rene Radis, Ronald Schnitzer, Ernst Kozeschnik, Martin Stockinger and Harald Leitner

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.200900282

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      The precipitation kinetics of intermetallic δ (Ni3Nb) and γ′ (Ni3(Al,Ti)) phases in the nickel-based superalloy ATI Allvac 718Plus are of high interest due to their significant influence on the mechanical properties. Therefore, the microstructure is investigated by APT and simulated by computer modeling. It is shown that chemical compositions of the phases change during isothermal aging, and the precipitation kinetics interact with each other.

    12. Metastable Austenite in 17–4 Precipitation-Hardening Stainless Steel Produced by Selective Laser Melting (pages 184–188)

      Luca Facchini, Nério Vicente Jr., Ivan Lonardelli, Emanuele Magalini, Pierfrancesco Robotti and Alberto Molinari

      Article first published online: 22 FEB 2010 | DOI: 10.1002/adem.200900259

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      A 17-4 precipitation hardening stainless steel produced by selective laser melting contains 72% metastable, heavily faulted austenite and 28% highly dislocated and twinned martensite (see image). Its mechanical behavior is characterized by exceptional work hardening and a two-step plastic field. These are due to the strain-induced transformation of austenite and to the structural characteristics of the deformed austenite and martensite, in which at first stacking faults, and then twins are accumulated.

    13. Cost-Efficient Metal–Ceramic Composites—Novel Foam-Preforms, Casting Processes and Characterisation (pages 189–196)

      Gisela Standke, Thorsten Müller, Achim Neubrand, Jörg Weise and Mirko Göpfert

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.200900285

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      SiC foams with a rough surface and a ceramic content of 20–30% are seen as a new preform class for metal–matrix-composites in order to achieve good mechanical interlocking of the composite components. Metal infiltration was carried out with high pressure die casting for aluminium alloys and sand casting for cast iron. Best results were achieved for Al-MMCs at which the specific stiffness of the composite was doubled in comparison to conventional alloys.

    14. Novel TRIP-Steel/Mg-PSZ Composite–Open Cell Foam Structures for Energy Absorption (pages 197–204)

      Christos G. Aneziris, Harry Berek, Manuel Hasterok, Horst Biermann, Stefan Wolf and Lutz Krüger

      Article first published online: 4 JAN 2010 | DOI: 10.1002/adem.200900273

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      In terms of the present work the powder coating of polyurethane foam technology at room temperature has been applied in order to produce open cell composite foams based on MgO partially stabilized zirconia (Mg-PSZ) reinforced austenitic stainless (TRIP) steel matrix composites. One of the main topics of this work was the study of the stress-induced martensitic transformation of partially stabilized zirconia as a function of the compressive strain.

    15. Microwave Assisted Synthesis of Yb:Y2O3 Based Materials for Laser Source Application (pages 205–209)

      Anna Luisa Costa, Marina Serantoni, Magda Blosi, Elisa Mercadelli, Laura Esposito, Andreana Piancastelli and Alessandra Sanson

      Article first published online: 1 APR 2010 | DOI: 10.1002/adem.200900272

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      Yb:Y2O3 submicrometric particles were synthesized through co-precipitation of Yb and Y nitrate in water. Microwave heating and controlled release of ammonia through urea decomposition at reaction temperature leaded to the formation of disaggregated, monosized spherical particles of carbo-hydroxy-nitrate precursors. Pure crystalline Yb:Y2O3 powder that preserved the described morphology was obtained after calcination in air. This powder mixed with commercial alumina powder was used to produce transparent Yb:YAG ceramics.

    16. Slip Casting of ZrB2–SiC Composite Aqueous Suspensions (pages 210–215)

      Valentina Medri, Claudio Capiani and Davide Gardini

      Article first published online: 22 FEB 2010 | DOI: 10.1002/adem.200900275

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      Ultra-high temperature ceramics (UHTCs) exhibit a number of properties (thermal and chemical stability, high strength, and hardness, ablation/oxidation) for sustained use in the extreme environments experienced by re-entry space vehicles. ZrB2–SiC ceramic composites are candidate materials for ultra-high temperature application and the production of near-net-shaped devices reduces the costs due to the expensive machining.

    17. Microwave Hybrid Post-Heat Treatment of Reaction Sintered Alumina/Lanthanum Hexaaluminate Composite Ceramics (pages 216–221)

      Zahra Negahdari and Monika Willert-Porada

      Article first published online: 8 MAR 2010 | DOI: 10.1002/adem.200900319

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      Lanthanum hexaaluminate (LHA) is a defective compound. With increase in the LHA content the defect concentration increases in alumina/LHA composite ceramics. The net result is that in microwave electric fields the migration of charged defects can produce a near-surface depletion or accumulation. This constitutes a nonlinear driving force for diffusional flows of defects and ions within the material which enhance LHA in situ formation and sintering of composite ceramics.

    18. Oriented Grain Growth Analyses With In Situ Annealing Experiments Using High Energy Synchrotron Radiation (pages 222–227)

      Caterina Elisabetta Tommaseo and Helmut Klein

      Article first published online: 22 FEB 2010 | DOI: 10.1002/adem.200900267

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      The texture and grain growth evolution in Al–Mn alloys is investigated using high energy synchrotron radiation and 2D diffraction imaging (see image), showing new insights on oriented grain growth depending on the manganese concentration. The grain orientations as a function of the orientation angle γ and temperature at fixed orientation angle ω in the 111 crystallographic direction are detected simultaneously during in situ heating experiments. Texture components can be calculated from these data.

    19. Applying SEM-Based X-ray Microtomography to Observe Self-Healing in Solvent Encapsulated Thermoplastic Materials (pages 228–234)

      Steven D. Mookhoek, Sheridan C. Mayo, Anthony E. Hughes, Scott A. Furman, Hartmut R. Fischer and Sybrand van der Zwaag

      Article first published online: 12 FEB 2010 | DOI: 10.1002/adem.200900289

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      In this work SEM-based X-ray microtomography is used to characterize liquid-based self-healing materials. 3D X-ray microtomography coupled with image segmentation and analysis allows a quantitative analysis of the fracture and release processes in a microcapsule-based self-healing thermoplastic material. The method is able to produce data of sufficient resolution (<10 μm) to observe ∼60 μm microcapsules containing solvent within a polymeric material and in particular their behavior around a crack zone after fracture and healing. It is demonstrated that microtomography offers large potential for non-destructive quantitative characterization of liquid-based self-healing materials in the future.

    20. Process Cost Comparison for Conventional and Near-Net-Shape Cermet Fabrication (pages 235–241)

      Yuhong Xiong and Julie M. Schoenung

      Article first published online: 4 MAR 2010 | DOI: 10.1002/adem.200900311

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      Technical cost modeling is applied to compare the fabrication costs for tungsten carbide-cobalt parts between the conventional powder metallurgy (P/M) process and the Laser Engineering Net Shaping (LENS) process. Relative cost per part (the cost difference between them) as a function of part size (cm3 values in the legend) and complexity for a given order size is estimated. Results show that the LENS process is economically preferable if part size is small or part shape is complex. The P/M process is more suitable to produce large parts in simple shapes.