Microstructural Evolution of Quaternary AlCoCrNi High-Entropy Alloys during Heat Treatment.

This study examines the microstructural evolution and mechanical properties of quaternary AlCoCrNi high-entropy alloys after heat treatment at 873 K for 72 and 192 h. The changes in nanostructure and phase transformation based on the heat treatment duration were as follows: B2 dendrite + BCC interdendrite and sigma phases after 72 h; B2 dendrite and interdendritic sigma phases + BCC after 192 h. After annealing, the morphology of the dendritic region shifted from spherical to needle-like, and the interdendritic region transformed from a spinodal-like to a plate-like morphology.

Recent Developments in Ultrafine Shape Memory Alloys Using Amorphous Precursors.

In this review, we systematically reviewed the recent advances in the development of ultrafine shape memory alloys with unique shape memory effects and superelastic behavior using amorphous metallic materials. Its scientific contribution involves defining and expanding the range of fabrication methods for single-phase ultrafine/nanocrystalline alloys with multicomponent systems. In multicomponent amorphous alloys, the crystallization mechanism depends on the alloy composition and is a selectable factor in the alloy designing method, considering the thermodynamic and physical parameters of constituent elements.

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy.

The effect of the Cr element on the corrosion behavior of as-spun FeCrBSiNb ribbons with = 0, 7.2, 21.6, and 36 in 3.

Development of Precipitation-Strengthened AlNbTiVM (M = Co, Ni) Light-Weight Refractory High-Entropy Alloys.

Single-phase solid-solution refractory high-entropy alloys (RHEAs) have been receiving significant attention due to their excellent mechanical properties and phase stability at elevated temperatures. Recently, many studies have been reported regarding the precipitation-enhanced alloy design strategy to further improve the mechanical properties of RHEAs at elevated temperatures. In this study, we attempted to develop precipitation-hardened light-weight RHEAs via addition of Ni or Co into AlNbTiV HEA.

Role of Nanocrystallites of Al-Based Glasses and HO in Degradation Azo Dyes.

Al-based metallic glasses have a special atomic structure and should have a unique degradation ability in azo dye solutions. The AlNiY (Y3), AlNiY (Y6) and AlNiY (Y9) glassy ribbons are melt spun and used in degrading methyl orange (MO) azo dye solution with adding HO. With increasing , the as-spun ribbons have an increasing GFA (glass formability) and gradually decreased the degradation rate of MO solution.

Thermally-triggered Dual In-situ Self-healing Metallic Materials.

The microstructural evolution and crack filling phenomena of (AlCuSi)(SnBi) (x = 0, 1, and 3 at.%) composites was investigated. The Sn and Bi elements were selected by considering the ability for liquid phase separation when combined with Al, Cu, and Si.

Experimental data of inorganic gel based smart window using silica sol-gel process.

In this article experimental data are presented for inorganic gel based smart window fabricated using silica sol-gel process. Parallel beam transmittances were measured as functions of voltages for samples fabricated with different concentrations of nitric acid. Spectroscopic transmittance data at different driving voltages for samples fabricated with different LC concentrations are shown.

Characterization of Graphene-based FET Fabricated using a Shadow Mask.

To pattern electrical metal contacts, electron beam lithography or photolithography are commonly utilized, and these processes require polymer resists with solvents. During the patterning process the graphene surface is exposed to chemicals, and the residue on the graphene surface was unable to be completely removed by any method, causing the graphene layer to be contaminated. A lithography free method can overcome these residue problems.

Study of Graphene-based 2D-Heterostructure Device Fabricated by All-Dry Transfer Process.

We developed a technique for transferring graphene and hexagonal boron nitride (hBN) in dry conditions for fabrication of van der Waals heterostructures. The graphene layer was encapsulated between two hBN layers so that it was kept intact during fabrication of the device. For comparison, we also fabricated the devices containing graphene on SiO2/Si wafer and graphene on hBN.

Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite.

The outstading mechanical properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the deformation mechanisms by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled deformation modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent mechanical properties.

"Work-Hardenable" ductile bulk metallic glass.

Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (< 1%) at room temperature. We present a new class of bulk metallic glass, which exhibits high strength of up to 2265 MPa together with extensive "work hardening" and large ductility of 18%. Significant increase in the flow stress was observed during deformation.