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Article
Open AccessIntrinsic factors responsible for brittle versus ductile nature of refractory high-entropy alloys
Refractory high-entropy alloys (RHEAs) are of interest for ultrahigh-temperature applications. To overcome their drawbacks — low-temperature brittleness and poor creep strength at high temperatures — improved ...
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Article
Open AccessUniaxial mechanical properties of face-centered cubic single- and multiphase high-entropy alloys
Since the high entropy concept was proposed at the beginning of the millennium, the research focus of this alloy family has been wide ranging. The initial search for single-phase alloys has expanded with the a...
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Chapter
Plaston—Elemental Deformation Process Involving Cooperative Atom Motion
The concept of ‘plaston’ that involves cooperative atom motion under shear stress is discussed as a deformation carrier that nucleates and moves in the deformation front under shear stress in many different ma...
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Chapter
Proposing the Concept of Plaston and Strategy to Manage Both High Strength and Large Ductility in Advanced Structural Materials, on the Basis of Unique Mechanical Properties of Bulk Nanostructured Metals
Advanced structural materials are required to show both high strength and large ductility/toughness, but we have not yet acquired the guiding principle for that. The bulk nanostructured metals are polycrystall...
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Article
Open AccessRoom-temperature deformation of single crystals of ZrB2 and TiB2 with the hexagonal AlB2 structure investigated by micropillar compression
The plastic deformation behavior of single crystals of two transition-metal diborides, ZrB2 and TiB2 with the AlB2 structure has been investigated at room temperature as a function of crystal orientation and spec...
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Article
Open AccessCorrelative atom probe tomography and scanning transmission electron microscopy reveal growth sequence of LPSO phase in Mg alloy containing Al and Gd
Atom probe tomography (APT) and transmission electron microscopy (TEM)/scanning transmission electron microscopy (STEM) have been used correlatively to explore atomic-scale local structure and chemistry of the...
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Article
Open AccessRoom temperature deformation of single crystals of Ti5Si3 with the hexagonal D88 structure investigated by micropillar compression tests
Micropillar compression tests of Ti5Si3 single crystals were conducted at room temperature as a function of loading axis orientation and specimen size in order to investigate their room temperature plastic deform...
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Article
Open AccessA formation criterion for Order-Disorder (OD) phases of the Long-Period Stacking Order (LPSO)-type in Mg-Al-RE (Rare Earth) Ternary Systems
The formation of OD (order-disorder) phases of the LPSO (long-period stacking ordered)-type in Mg-Al-RE (RE (rare earth) = Y, La, Ce, Nd, Sm, Dy, Ho, Er and Yb) ternary systems has been investigated for both a...
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Article
Open AccessSize effect, critical resolved shear stress, stacking fault energy, and solid solution strengthening in the CrMnFeCoNi high-entropy alloy
High-entropy alloys (HEAs) comprise a novel class of scientifically and technologically interesting materials. Among these, equatomic CrMnFeCoNi with the face-centered cubic (FCC) structure is noteworthy becau...
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Chapter and Conference Paper
Microstructural change of monocrystalline Co-Al-W-based γ/γ′ two phase alloys by high temperature creep
Microstructural change of recently discovered Co-Al-W-based γ/γ′ two phase alloys by creep with a tensile stress of 137 MPa at 1000 °C were examined. Before and after creep testing, the microstructures were in...
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Article
Microstructures and Mechanical Properties of MoSi2 / Mo5Si3 / Mo5Si3C Ternary Eutectic Composite
Microstructures and mechanical properties of directionally solidified (DS) MoSi2 / Mo5Si3 / Mo5Si3C ternary eutectic composites were investigated. Ternary eutectic microstructure of a script-lamellar type that is...
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Article
Micropillar Compression of MoSi2 Single Crystals
Deformation behavior of MoSi2 has been studied by micropillar compressions of single crystalline specimens prepared by focused ion beam (FIB) technique as a function of crystal orientation at room temperature. Ac...
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Article
Effects of Alloying Elements on the Temperature Dependence of Yield Stress in L12-Co3(Al,W)
The effects of alloying elements (Ni/Ta) on the temperature dependence of yield stress in Co3(Al,W) with the L12 structure have been investigated through compression tests of nearly single-phase polycrystalline a...
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Article
What Controls Temperature Dependence of Yield Stress in L12-Ordered Intermetallic Compounds?
The temperature dependence of yield stress and the associated dislocation dissociation in L12 intermetallic compounds are investigated in order to check the feasibility of the classification of L12 intermetallic ...
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Article
Arrangements of Fe-Centered Zn12 Icosahedra in Fe-Zn Intermetallic Compounds Determined by Ultra-High Resolution Scanning Transmission Electron Microscopy
The crystal structure of the δ1p phase in the Fe-Zn system has been refined by singlecrystal synchrotron X-ray diffraction combined with ultra-high resolution scanning transmission electron microscopy. The crysta...
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Article
Compression Deformation of Single-Crystal Pt3Al with the L12 Structure.
The plastic deformation behaviour of single crystals of Pt3Al with a chemical composition of Pt-27 at.%Al was investigated in compression from 77K to 1,273K. The L12 structure is not stable below around 220 K, tr...
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Article
Compression of Single-Crystal Micropillars of the ζ Intermetallic Phase in the Fe-Zn System
The deformation behaviour of the ζ (zeta) phase in the Fe-Zn system has been investigated via room-temperature compression tests of single-crystal micropillar specimens prepared by the focused ion beam method....
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Article
Micro-pillar Compression of Ni-base Superalloy Single Crystals
Micro-compression behavior of single crystalline Ni-base superalloy CMSX-4 has been studied especially focusing on a specimen size range comparable to the size of Ni3Al (γ’) precipitates of about 500 nm using squ...
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Article
Effects of Ternary Additions on the Microstructure of Directionally-Solidified MoSi2/Mo5Si3 Eutectic Composites
Microstructural variations of directionally-solidified (DS) MoSi2/Mo5Si3 eutectic composites caused by ternary additions of V, Cr, Nb, Ta and W were investigated. Ternary addition of relatively large amount of V ...
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Article
Crystal Structure Evolution of La2Ni7 during Hydrogenation
Atomic scale characterization of the La2Ni7 hydrides by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) revealed that not only the anisotropic expansion of the La2Ni4 unit lay...
