A5018955239- Microstructure and mechanical properties
- Aluminum Alloys Composites Properties
- Advanced materials and composites
- High Entropy Alloys Studies
- Metal and Thin Film Mechanics
- High-Temperature Coating Behaviors
- Additive Manufacturing Materials and Processes
- Metal Alloys Wear and Properties
- Intermetallics and Advanced Alloy Properties
- Microstructure and Mechanical Properties of Steels
- Metallurgy and Material Forming
- Magnesium Alloys: Properties and Applications
- Perovskite Materials and Applications
- Energy Harvesting in Wireless Networks
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Advanced Surface Polishing Techniques
- Boron and Carbon Nanomaterials Research
- Innovative Energy Harvesting Technologies
- Surface Treatment and Residual Stress
- Material Properties and Failure Mechanisms
- Wireless Power Transfer Systems
- Fatigue and fracture mechanics
- High-Velocity Impact and Material Behavior
- Advanced MEMS and NEMS Technologies
Oregon State University
2004-2024
Hanyang University
2016-2017
Korea Advanced Institute of Science and Technology
1985-1987
New power conversion circuits to interface a piezoelectric micro-power generator have been fabricated and tested. Circuit designs measurement results are presented for half-wave synchronous rectifier with voltage doubler, full-wave passive circuit connected the generator. The measured efficiency of doubler in 0.35-/spl mu/m CMOS process is 88% output exceeds 2.5 /spl mu/W 100-k/spl Omega/, 100-nF load. two rectifiers (passive synchronous) were 0.25-/spl process. peak 66% 220-k/spl Omega/...
Chalcogenide perovskites have emerged as a new class of optoelectronic materials, especially for photovoltaic applications, but fundamental properties and applications chalcogenide remain limited due to the lack high-quality thin films. We report direct epitaxial film growth BaZrS3, prototypical chalcogenide, by pulsed laser deposition. X-ray diffraction studies show that films are strongly textured out-of-plane clear in-plane relationship with substrate. Electron microscopy confirm presence...
This report presents an overview of recent studies demonstrating a bulk-state reaction involving mechanical bonding through the application high-pressure torsion (HPT) processing on two dissimilar engineering metals. approach was developed by revising sample set-up and applying simple procedure alternately stacking different metal disks using several combinations. Thus, this describes development in microstructure after reactions properties HPT-induced Al–Mg, Al–Cu, Al–Fe Al–Ti alloy...
Abstract The magnesium alloy AZ31, which has undergone high-pressure torsion processing, was subjected to in situ annealing microbeam synchrotron high-energy X-ray diffraction and compared the as-received rolled sheet material that investigated through neutron diffraction. While latter only exhibits thermal expansion minor recovery, nanostructured specimen displays a complex evolution, including strong recrystallization, phase transformations, various regimes of grain growth. Nanometer-scale...
An overview of the mechanical bonding dissimilar bulk engineering metals through high‐pressure torsion (HPT) processing at room temperature is described in this Review. A recently developed procedure involves application conventional HPT to alternately stacked two or more disks metals. macroscale microstructural evolution concept making tribomaterials and, for some metal combinations, microscale changes demonstrate synthesis matrix nanocomposites (MMNCs) nucleation nanoscale intermetallic...
Abstract Nanostructuring of bulk metals is now well documented with the development severe plastic deformation (SPD) for improving physical and mechanical properties engineering materials. Processing by high-pressure torsion (HPT), which was developed initially as a grain refinement technique, extended recently to bonding dissimilar during nanostrcturing generally involves significant microstructural heterogeneity. Here we introduce, first time, metastable Al-Mg supersaturated solid solution...
High‐pressure torsion (HPT) is used to investigate the formation of a new metal system by direct bonding separate disks Al and Cu processing at room temperature under compressive pressure 6.0 GPa with increasing numbers HPT turns up 60. A detailed examination microstructure phase analysis reveal presence three intermetallic compounds, 2 Cu, AlCu, 4 9 , in nanostructured matrix grain size ≈30 nm. Processing leads metal–matrix nanocomposite extreme hardness near edge Al–Cu after 60 turns....
The microstructural stability of a nanocrystalline HfNbTiZr multi-principal element alloy was studied by annealing the material in differential scanning calorimeter (DSC). as-received sample obtained severe plastic deformation using high-pressure torsion (HPT) technique. Samples were annealed to characteristic temperatures DSC thermogram, namely up 740, 890 and 1000 K, microstructure heat treated specimens analyzed. It found that heating 740 K yielded decomposition initial body-centered...
Herein, in situ temperature‐dependent neutron experiments investigate the microstructural evolution of additively and conventionally manufactured CoCrFeNi high‐entropy alloys, as‐received, after grain refinement through high‐pressure torsion. The texture during heating is consistent with typical fcc metals. Both conventional modified Williamson–Hall analyses reveal that major contributions microstresses stem from dislocations. For nanostructured material, three temperature regimes are...
Experiments were conducted for the study of evolution microstructure in a nanocrystalline CoCrFeNi multi-principal element alloy during annealing. The state was achieved by high-pressure torsion (HPT) which is well-defined severe plastic deformation technique. heat treatment performed differential scanning calorimeter (DSC). It found that thermogram contains two exothermic peaks with maxima at about 680 and 870 K. For further analysis, different set samples annealed to temperatures below...
This report is aimed at giving an overview of the significance novel and innovative microstructural microscopic characterization techniques for bulk nanostructured metals processed by severe plastic deformation, specifically high-pressure torsion (HPT). In practice, relaxation behavior upon heating 316L stainless steel CoCrFeNi high-entropy alloy was characterized in-situ neutron diffraction measurements; heterogeneous phase distribution HPT-bonded hetero-nanostructured Al–Mg examined using...
The present study demonstrates an innovative approach of utilizing high‐pressure torsion (HPT) processing for the mechanical bonding dissimilar metals during microstructural refinement process. This has been developed recently introducing unique alloy systems with improving physical and properties. Accordingly, focuses specifically on evolution development in micro‐mechanical responses mechanically bonded Al‐Mg Al‐Cu hybrid when synthesized by HPT very high number turns up to 60 under 6.0...