Multiscale Modelling and Characterization of Mechanical Properties in Heat-Resistant Alloys

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Metals and Alloys".

Deadline for manuscript submissions: closed (1 August 2021) | Viewed by 16064

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National Institute for Materials Science Sengen, Tsukuba, Ibaraki 305-0047, Japan
Interests: computer aided engineering; micromechanics; multi-scale modeling; instrumented indentation
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Tohoku University, Sendai, Japan

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"Vinca" Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Guest Editor
Shandong University of Science and Technology, Qingdao, China

Special Issue Information

Dear Colleagues,

It is our pleasure to announce a new Special Issue on the topic of “Multiscale Modeling and Characterization of Mechanical Properties in Heat-Resistant Alloys”, which covers both theoretical and experimental approaches to evaluating mechanical properties, such as elastic stiffness, yield strength, and creep at elevated temperatures.

Various heat-resistant alloys have been used in industry; however, the bridge between the bulk mechanical properties and the underlying micro- and nanoscopic local properties remains an issue. Here, we focus on modeling and characterization approaches from multiscale aspects, for example, finite element analysis for representative volume element, mechanism-based constitutive modeling, molecular dynamics for high-temperature modeling approaches, tensile small-specimen test, nano- or micro-indentation test, strain mapping using digital-image collation as characterization approaches. 

We wish to share the recent progress in and up-and-coming approaches to this topic.

Dr. Ikumu Watanabe
Prof. Dr. Nobufumi Ueshima
Dr. Jovana Ruzic
Prof. Dr. Hongzhi Cui
Guest Editors

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Keywords

  • Multiscale modeling
  • Multiscale characterization
  • Mechanical properties
  • Heat-resistant alloys
  • Small-scale material testing
  • Elevated temperature
  • Micromechanics

Published Papers (7 papers)

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Editorial

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2 pages, 149 KiB  
Editorial
Multiscale Modelling and Characterization of Mechanical Properties in Heat-Resistant Alloys
by Ikumu Watanabe, Nobufumi Ueshima, Jovana Ruzic and Hongzhi Cui
Crystals 2022, 12(1), 105; https://doi.org/10.3390/cryst12010105 - 14 Jan 2022
Viewed by 1132
Abstract
Various heat-resistant alloys have been used in industry; however, the bridge between the bulk mechanical properties and the underlying micro- and nanoscopic local properties remains an issue [...] Full article

Research

Jump to: Editorial

10 pages, 2561 KiB  
Article
Characterization of the Strain-Rate-Dependent Plasticity of Alloys Using Instrumented Indentation Tests
by Ta-Te Chen, Ikumu Watanabe and Tatsuya Funazuka
Crystals 2021, 11(11), 1316; https://doi.org/10.3390/cryst11111316 - 28 Oct 2021
Cited by 2 | Viewed by 2014
Abstract
Instrumented indentation tests are an efficient approach for the characterization of stress–strain curves instead of tensile or compression tests and have recently been applied for the evaluation of mechanical properties at elevated temperatures. In high-temperature tests, the rate dependence of the applied load [...] Read more.
Instrumented indentation tests are an efficient approach for the characterization of stress–strain curves instead of tensile or compression tests and have recently been applied for the evaluation of mechanical properties at elevated temperatures. In high-temperature tests, the rate dependence of the applied load appears to be dominant. In this study, the strain-rate-dependent plasticity in instrumented indentation tests at high temperatures was characterized through the assimilation of experiments with a simulation model. Accordingly, a simple constitutive model of strain-rate-dependent plasticity was defined, and the material constants were determined to minimize the difference between the experimental results and the corresponding simulations at a constant high temperature. Finite element simulations using a few estimated mechanical properties were compared with the corresponding experiments in compression tests at the same temperature for the validation of the estimated material responses. The constitutive model and determined material constants can reproduce the strain-rate-dependent material behavior under various loading speeds in instrumented indentation tests; however, the load level of computational simulations is lower than those of the experiments in the compression tests. These results indicate that the local mechanical responses evaluated in the instrumented indentation tests were not consistent with the bulk responses in the compression tests at high temperature. Consequently, the bulk properties were not able to be characterized using instrumented indentation tests at high temperature because of the scale effect. Full article
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16 pages, 5738 KiB  
Article
Constitutive Equation for Flow Stress in Superalloy 718 by Inverse Analysis under Hot Forming in a Region of Precipitation
by Hyung-Won Park, Sosei Kakiuchi, Kyunghyun Kim, Akira Yanagida and Jun Yanagimoto
Crystals 2021, 11(7), 811; https://doi.org/10.3390/cryst11070811 - 12 Jul 2021
Cited by 5 | Viewed by 2345
Abstract
The purpose of this study is to obtain a constitutive equation of high-accuracy flow stress in superalloy 718, which allows fabrication of highly reliable disks for gas turbine engines. Hot compression tests using superalloy 718 at deformation temperatures from 850 to 1100 °C, [...] Read more.
The purpose of this study is to obtain a constitutive equation of high-accuracy flow stress in superalloy 718, which allows fabrication of highly reliable disks for gas turbine engines. Hot compression tests using superalloy 718 at deformation temperatures from 850 to 1100 °C, a 67% height reduction, and strain rates of 1, 10, and 25 s−1 were performed to investigate the flow stress behavior, which excludes environmental effects during hot working by inverse analysis. The effects of dynamic recrystallization and strain-induced dynamic precipitation on the flow stress were also investigated. The dynamically precipitated δ phases deformed at 1050 °C and γ″ phases deformed at 950 °C might affect the increase in the plastic modulus F1 and the decrease in the critical strain εc, deteriorating the accuracy of regression in terms of, for example, the strain rate sensitivity m and the temperature sensitivity A. A constitutive equation for a generalized flow curve for superalloy 718 is proposed by considering these effects. Full article
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12 pages, 3927 KiB  
Article
Correlation between Solution Treatment Temperature, MicroStructure, and Yield Strength of Forged Ti-17 Alloys
by Yoko Yamabe-Mitarai, Syuji Kuroda, Norie Motohashi, Takanobu Hiroto, Akira Ishida, Hideyuki Murakami and Yoshio Itsumi
Crystals 2021, 11(6), 625; https://doi.org/10.3390/cryst11060625 - 31 May 2021
Cited by 4 | Viewed by 1945
Abstract
The Ti compressor disks of aviation jet engines are produced by forging. Their microstructure, which depends on the forging conditions, strongly affects their mechanical properties. In this study, changes in the microstructure of Ti-17 alloy as a result of different solution-treatment (ST) temperatures [...] Read more.
The Ti compressor disks of aviation jet engines are produced by forging. Their microstructure, which depends on the forging conditions, strongly affects their mechanical properties. In this study, changes in the microstructure of Ti-17 alloy as a result of different solution-treatment (ST) temperatures and the related tensile yield strengths were investigated to elucidate the correlation between the ST temperature, microstructure, and yield strength. Ti-17 alloys ingots were isothermally forged at 800 °C and solution-treated at 750, 800, and 850 °C. The microstructure and yield strength were investigated for samples subjected to different ST temperatures. The primary α phase formed during the ST, and the secondary α phase formed during the aging treatment at 620 °C. The yield strength increased with increasing volume fraction of the primary α phase and increased further upon formation of the secondary α phase during the tensile test at room temperature. The correlation of the primary and secondary α phases with yield strength was clarified for tensile properties at room temperature, 450, and 600 °C. An equation to predict the yield strength was constructed using the volume fraction of the primary and secondary α phases. Full article
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11 pages, 3180 KiB  
Article
Anisotropic Multiscale Modelling in SAE-AISI 1524 Gas Tungsten Arc Welded Joints
by Edison A. Bonifaz and Ikumu Watanabe
Crystals 2021, 11(3), 245; https://doi.org/10.3390/cryst11030245 - 28 Feb 2021
Cited by 3 | Viewed by 2353
Abstract
A transient non-linear multiscale finite element heat flow-mechanical model to determine micro residual stresses (type III) and micro plastic strains in SAE-AISI 1524 gas tungsten arc welded joints is developed. To include anisotropy by preferred crystallographic orientation or texture, the global domain was [...] Read more.
A transient non-linear multiscale finite element heat flow-mechanical model to determine micro residual stresses (type III) and micro plastic strains in SAE-AISI 1524 gas tungsten arc welded joints is developed. To include anisotropy by preferred crystallographic orientation or texture, the global domain was decomposed into small subdomains based on the concept of representative volume elements (RVEs). A three-dimensional numerical procedure was developed by using the coupling DREAM.3D-ABAQUS. The macro scale temperature gradient information as prescribed driven (load) boundary conditions was used to calculate the meso thermal cycles, and the meso scale temperature gradient information was used to calculate the micro thermal cycles needed in the subsequent mechanical analysis. Anisotropy was included by randomly entering in each grain of the RVE specimen either the maximum Young’s modulus (Emax) in the stiffest direction <111>, or the minimum Young’s modulus (Emin) in the least stiff direction <100>. Under this assumption, the averaging of the grain orientations over all grains in the textured polycrystal with greater number of grains ocurred, and the strength was diluted by the spread of orientations present. Higher Mises stresses evolved in the sample with coarse grain size (16 µm), which indicates that the strong dependence of residual micro stresses on grain size was reversed. The influence of the grain size on the response of the aggregates is clearly observed. Full article
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17 pages, 16735 KiB  
Article
Tensile Creep Behavior of Single-Crystal High-Entropy Superalloy at Intermediate Temperature
by Takuma Saito, Akira Ishida, Michinari Yuyama, Yuji Takata, Kyoko Kawagishi, An-Chou Yeh and Hideyuki Murakami
Crystals 2021, 11(1), 28; https://doi.org/10.3390/cryst11010028 - 30 Dec 2020
Cited by 6 | Viewed by 2567
Abstract
In this study, we investigated the creep deformation mechanism of a single-crystal high-entropy superalloy (HESA) with the spherical γ′ precipitates at 760 °C. Before the creep tests, long-term aging tests at 760 °C without load were conducted, which showed Ostwald ripening of the [...] Read more.
In this study, we investigated the creep deformation mechanism of a single-crystal high-entropy superalloy (HESA) with the spherical γ′ precipitates at 760 °C. Before the creep tests, long-term aging tests at 760 °C without load were conducted, which showed Ostwald ripening of the secondary γ′ precipitates up to 50 h. The creep tests revealed that in the range of 500 and 600 MPa at 760 °C, the creep deformation mechanism of HESA was independent of applied stress in both the primary and secondary creep regions. The deformation mechanism of HESA was further investigated under the condition of 760 °C and 520 MPa by performing creep interrupted tests and microstructural analysis. Scanning electron microscope observation showed elongated γ′ precipitates along the applied stress axis near the ruptured surface. This could have been caused by the multi-slip around <100> preceded by the lattice rotation into <100> along the tensile axis, which was confirmed by the electron backscatter diffraction analysis. Transmission electron microscope observation of the creep interrupted and ruptured specimens showed bypass and climb motion of dislocations in the 2-h interrupted, shearing of the γ′ precipitates by the paired straight dislocations in the 50-h interrupted, and shearing of the γ′ precipitates by both the straight and the curved paired dislocations in the ruptured specimens, respectively. The secondary γ′ precipitates do not affect creep behavior as long as the deformation mechanism is a bypass and climb motion of dislocations. Full article
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16 pages, 8073 KiB  
Article
Microstructures and Mechanical Properties of Nanocrystalline AZ31 Magnesium Alloy Powders with Submicron TiB2 Additions Prepared by Mechanical Milling
by Haiping Zhou, Chengcai Zhang, Baokun Han, Jianfeng Qiu, Shengxue Qin, Kuidong Gao, Jie Liu, Shuai Sun and Hongbin Zhang
Crystals 2020, 10(6), 550; https://doi.org/10.3390/cryst10060550 - 26 Jun 2020
Cited by 15 | Viewed by 2677
Abstract
In this work, nanocrystalline AZ31 magnesium alloy powders, reinforced by submicron TiB2 particles, were prepared via mechanical milling. It was found that TiB2 particles stimulated the fracture and welding of AZ31/TiB2 powders, leading to the acceleration of the milling process. [...] Read more.
In this work, nanocrystalline AZ31 magnesium alloy powders, reinforced by submicron TiB2 particles, were prepared via mechanical milling. It was found that TiB2 particles stimulated the fracture and welding of AZ31/TiB2 powders, leading to the acceleration of the milling process. Meanwhile, the TiB2 particles were refined to submicron-scale size during the milling process, and their distribution was uniform in the Mg matrix. In addition, the matrix was significantly refined during the milling process, which was also accelerated by the TiB2 particles. The formation of grain boundary segregation layers also led to the weakened TiB2 peaks in the XRD patterns during the mechanical milling. The grain sizes of AZ31–2.5 wt % TiB2, AZ31–5 wt % TiB2 and AZ31–10 wt % TiB2 powders were refined to 53 nm, 37 nm and 23 nm, respectively, after milling for 110 h. Under the combined effect of the nanocrystalline matrix and the well-dispersed submicron TiB2 particles, the AZ31/TiB2 composites exhibited excellent micro-hardness. For the AZ31–10 wt % TiB2 composite, the micro-hardness was enhanced to 153 HV0.5. Full article
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