Article
Nanoscience & Nanotechnology
L. Wu, T. Osada, I Watanabe, T. Yokokawa, T. Kobayashi, K. Kawagishi
Summary: The reported strength predictions of gamma ' hardening for polycrystalline Ni-base superalloys tend to be underestimated, with a need for validated classical strengthening models and proposed modifications to improve predictability.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
K. V. Vamsi, S. Karthikeyan
Summary: An environment dependent nearest neighbor bond (EDNNB) model was developed to estimate the antiphase boundary (APB) energies in ?? precipitates in commercial Ni-base superalloys. The effect of alloying elements on the APB(111) energies was systematically studied, showing that different substitutions have different impacts on the APB energies, with an increase of Ti?Ti and Al?Ti violations beneficial for increasing the strength of the precipitates.
Article
Materials Science, Multidisciplinary
Hengzhe Wang, Haibo Long, Yinong Liu, Yunsong Zhao, Xueqiao Li, Guo Yang, Xiaomeng Yang, Yanhui Chen, Shengcheng Mao, Ze Zhang, Xiaodong Han
Summary: This study investigates the effect of Ru on the solution heat treatment window of a Ni-based single crystal superalloy. The addition of Ru influences the solidification microstructure and widens the window. Ru decreases the partition ratios between the dendrite core and dendrite edge regions, promotes the enrichment of Re at the γ/γ' phase interfaces, inhibits the formation of (Ta, X)C carbide, and helps to widen the solution treatment temperature window of the alloy.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Seth Griffiths, Hossein Ghasemi-Tabasi, Anthony De Luca, Joanna Pado, Shreyas S. Joglekar, Jamasp Jhabvala, Roland E. Loge, Christian Leinenbach
Summary: The removal of Hf has been shown to have a positive effect on improving the performance of the CM247LC alloy, helping to reduce strain age cracking susceptibility, but also leading to a slight decrease in hardness.
MATERIALS CHARACTERIZATION
(2021)
Article
Chemistry, Physical
Emil Eriksson, Fabian Hanning, Joel Andersson, Magnus Hornqvist Colliander
Summary: Understanding the microstructural behaviour of materials during thermomechanical processing is crucial for achieving optimal mechanical properties. We investigated the dynamic recrystallization (DRX) behaviour of Ni-base superalloy Haynes 282 during hot compression and observed the formation of small DRX grains before the peak strain. The DRX process accelerated significantly above a certain strain, and the material was fully recrystallized at a higher strain. Contrary to common assumptions, many DRX grains contained dislocation substructures, even at small strains.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
J. M. Bai, H. P. Zhang, J. T. Liu, Q. S. Sun, C. S. Liu, Y. W. Zhang
Summary: This paper evaluates the mechanical properties of high-performance PM superalloys with Ta addition fabricated by CISRI at room temperature. The study focuses on how the solute element Ta affects the properties of the alloys, utilizing advanced characterization methods to investigate plastic deformation and fracture mechanisms. The results highlight the strengthening effects of APB, ESF, and microtwin structures on the RT yield strength of the PM superalloys.
MATERIALS CHARACTERIZATION
(2022)
Article
Chemistry, Physical
Diego de Araujo Santana, Claudio Shyinti Kiminami, Francisco Gil Coury
Summary: This study focuses on the prediction of yield strength of a newly developed alloy through experimental and modeling approaches. The results demonstrate that different strengthening mechanisms can be modeled independently with satisfactory accuracy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Adelajda Polkowska, Sebastian Lech, Piotr Bala, Wojciech Polkowski
Summary: This study systematically examined the effect of heat-treatment temperature on the structural evolution and mechanical response of Haynes (R) HR-224 (R) alloy, revealing a significant increase in room temperature tensile strength and a reduction of ductility under 600-800 degrees C/2 h heat treatment conditions. Discontinuous precipitation (DP) of (gamma + gamma')/M23C6 was identified as the main structural process affecting the observed mechanical behavior of the material.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
M. Cottura, B. Appolaire, A. Finel, Y. Le Bouar
Summary: Microstructure evolutions in Ni-base superalloys under [110] creep loading were investigated using 3D and 2D phase field simulations. It was found that minor misorientations of the tensile axis lead to rafting, while loading along a perfectly aligned [110] direction results in a microstructure composed of rod-like precipitates. The direction of the mechanical load significantly affects the evolution of microstructure and macroscopic creep behavior.
Article
Nanoscience & Nanotechnology
Simon Schilli, Thomas Seifert, Marion Kreins, Ulrich Krupp
Summary: This paper evaluates the Bauschinger effect and latent hardening of single crystals in finite element calculations using a single crystal plasticity model. The results show that different strength levels observed in micro-bending tests on different crystal orientations can only be described with latent kinematic hardening, while the pronounced Bauschinger effect is well described by both kinematic hardening laws.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Manufacturing
Dominic D. R. Peachey, Christopher P. Carter, Andres Garcia-Jimenez, Anugrahaprada Mukundan, Donovan N. Leonard, Marie-Agathe Charpagne, Zachary C. Cordero
Summary: Metal additive manufacturing processes often result in fine grain structures, which affect high-temperature creep properties. This study demonstrates how directional recrystallization can create large columnar grains, manipulate crystallographic texture to minimize thermal stresses, and selectively enhance fatigue or creep performance of additively manufactured Ni-base superalloys.
ADDITIVE MANUFACTURING
(2022)
Article
Materials Science, Multidisciplinary
Devraj Ranjan, Sankar Narayanan, Kai Kadau, Anirban Patra
Summary: A crystal plasticity finite element (CPFE) framework is proposed for modeling the non-Schmid yield behavior of L1(2) type Ni3Al crystals and Ni-based superalloys, with parameters estimated directly from experimental data. The model accurately predicts yield stress and provides insights into tension-compression asymmetry and dominant slip mechanisms for these materials at different temperatures.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
K. J. Tan, X. G. Wang, J. J. Liang, J. Meng, Y. Z. Zhou, X. F. Sun
Summary: The study focused on the microstructures of a second-generation Ni-based single crystal superalloy after creep and rejuvenation heat treatment. It was found that the rejuvenation heat treatment had a shallow impact on the microstructures, such as the dislocation network, the gamma phase, and the gamma' phase, without significantly affecting the alloy properties. Additionally, the average creep life after rejuvenation heat treatment was comparable to that after standard heat treatment, indicating that RHT could effectively repair damaged parts and prolong the overall life of the sample.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Nanoscience & Nanotechnology
L. Heep, D. Burger, C. Bonnekoh, P. Wollgramm, A. Dlouhy, G. Eggeler
Summary: The low temperature high stress tensile creep behavior of the superalloy single crystal ERBO-1 was investigated, with comparisons made between loading directions of [001] and deviations towards [111] and [011]. The study found that creep rates are influenced by the loading directions, and faster creep rates are observed when dislocations from two octahedral systems experience similar driving forces.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
M. J. Anderson, L. Liao, H. C. Basoalto
Summary: Accurately predicting the time evolution of precipitate size distributions is crucial for optimizing heat treatments and mechanical properties of engineering alloys. While mean-field models typically assume weakly coupled diffusion fields between neighbouring particles, this may not hold true in many applications. Correction factors are necessary to account for deviations from these assumptions.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Physical
Na Ta, Muhammad Umer Bilal, Ines Haeusler, Alaukik Saxena, Yueh-Yu Lin, Felix Schleifer, Michael Fleck, Uwe Glatzel, Birgit Skrotzki, Reza Darvishi Kamachali
Summary: The study investigates the effects of anisotropic interfacial properties and heterogeneous elasticity on the growth and ripening of plate-like theta'-phase in Al-Cu alloy. The results show that anisotropic interfacial mobility and energy significantly affect the aspect ratios of precipitates, while the chemo-mechanical coupling plays a role in the precipitation process. However, the inverse ripening phenomenon observed in another alloy system does not occur for theta'-phase precipitates due to anisotropic stress fields and interactions among different variants.
Article
Chemistry, Physical
Yueh-Yu Lin, Felix Schleifer, Markus Holzinger, Na Ta, Birgit Skrotzki, Reza Darvishi Kamachali, Uwe Glatzel, Michael Fleck
Summary: The effectiveness of precipitation strengthening in metallic alloys depends on the shapes of precipitates, which was studied in two different material systems. The shape formation and evolution of tetragonally misfitting precipitates were investigated through experiments and phase-field simulations, with consistent results obtained. The in-plane shapes of precipitates observed experimentally can be quantitatively reproduced by the phase-field model.
Article
Materials Science, Multidisciplinary
Uwe Glatzel, Felix Schleifer, Christian Gadelmeier, Fabian Krieg, Moritz Mueller, Mike Mosbacher, Rainer Voelkl
Summary: Various alloy compositions were tested for creep behavior in single crystal state, with solid solution strengthening and precipitation hardening identified as major strengthening mechanisms. Configurational entropy has minimal impact on creep strength, while element Re is an effective strengthener.
Article
Materials Science, Multidisciplinary
Selina Koerber, Michael Fleck, Rainer Voelkl, Uwe Glatzel
Summary: The influence of withdrawal rate and wall thickness on the primary and secondary dendrite arm spacings of single-crystal specimens produced by the Bridgman process was investigated. It was found that the primary dendrite arm spacing decreases slightly with decreasing wall thickness, while the secondary dendrite arm spacing is relatively independent of the cast wall thickness. This is due to the presence of a boundary zone next to the ceramic mold/cast metal interface.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Computer Science, Interdisciplinary Applications
Michael Fleck, Felix Schleifer
Summary: The phase-field method is a powerful framework for microstructure evolution modeling, but grid friction, pinning, and anisotropy limit its resolution efficiency and accuracy. The sharp phase-field method and local restoration of translational invariance can eliminate these limitations.
ENGINEERING WITH COMPUTERS
(2023)
Article
Crystallography
Michael Fleck, Felix Schleifer, Patrick Zimbrod
Summary: The sharp phase-field method (SPFM) can eliminate spurious grid friction in moving diffuse interfaces on discrete numerical grids and provides superior interface isotropy compared to other phase-field models.
Article
Materials Science, Multidisciplinary
Felix Schleifer, Yueh-Yu Lin, Uwe Glatzel, Michael Fleck
Summary: This study presents 3D sharp phase-field simulations that capture the ripening behavior of coherent tetragonal precipitates in Ni-base superalloys. The simulations reveal significant deviations from the classical LSW theory of Ostwald ripening, where a ripening exponent of 2 instead of 3 describes the simulated size evolution of the precipitates best. Elastic effects from the misfit strains contribute to these deviations, particularly the size dependence of the precipitate shapes. It is also found that the ripening kinetics accelerate with increasing plate aspect ratios, which are caused by the minimization of elastic energy.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Engineering, Manufacturing
Felix Wich, Stefan Flauder, Natalie Schneider, Michael Fleck, Nico Langhof, Walter Krenkel, Stefan Schaffoener
Summary: This study investigates the influence of hexamethylenetetramine (hexa) content on the rheological features, pyrolysis reactions, mass-loss kinetics, and char yield of phenolic resins. The results show that increasing hexa content leads to lower curing temperatures, higher viscosity, and increased residual carbon. The findings suggest a hexa-induced microgel formation in phenolic resins. The developed viscosity and char yield models offer a valuable tool for customizing resin-hardener mixtures for specific applications and contribute to a better understanding of the pyrolysis process.
ADVANCED MANUFACTURING-POLYMER & COMPOSITES SCIENCE
(2023)
Article
Engineering, Manufacturing
Moritz Mueller, Bernd Bottger, Felix Schleifer, Michael Fleck, Uwe Glatzel
Summary: This paper presents a novel approach to evaluate the matrix channel width distribution in a matrix/gamma' microstructure, which relies on precise determination of the matrix/precipitate interfaces and requires no additional user input. The method is demonstrated on the example of the commercial alloy CSMX-4 and shows good performance in handling both 2D micrographs and 3D phase-field simulation data. The obtained channel width distributions compare well between the 2D and 3D data.
INTEGRATING MATERIALS AND MANUFACTURING INNOVATION
(2023)
Article
Engineering, Manufacturing
Felix Schleifer, Moritz Mueller, Yueh-Yu Lin, Markus Holzinger, Uwe Glatzel, Michael Fleck
Summary: Computational microstructure design aims to fully utilize the potential strengthening effect of precipitates in alloy systems. Accurate models for describing the temporal evolution of precipitate shapes and sizes are important for technological development. This study proposes the use of central moments to bridge the gap between 2D images and 3D simulations. The method demonstrates its accuracy and interoperability through the analysis of representative samples with predefined aspect ratios.
INTEGRATING MATERIALS AND MANUFACTURING INNOVATION
(2022)
