A5040008010- Intermetallics and Advanced Alloy Properties
- High Entropy Alloys Studies
- High-Temperature Coating Behaviors
- High Temperature Alloys and Creep
- Additive Manufacturing Materials and Processes
- Metal and Thin Film Mechanics
- Microstructure and mechanical properties
- Advanced materials and composites
- Advanced Materials Characterization Techniques
- Nuclear Materials and Properties
- Metallic Glasses and Amorphous Alloys
- Aluminum Alloys Composites Properties
- Semiconductor materials and interfaces
- Metallurgical and Alloy Processes
- Microstructure and Mechanical Properties of Steels
- Shape Memory Alloy Transformations
- MXene and MAX Phase Materials
- Advanced ceramic materials synthesis
- Aluminum Alloy Microstructure Properties
- Titanium Alloys Microstructure and Properties
- High-Velocity Impact and Material Behavior
- Hydrogen embrittlement and corrosion behaviors in metals
- Metal Alloys Wear and Properties
- nanoparticles nucleation surface interactions
- Quasicrystal Structures and Properties
Ruhr University Bochum
2014-2024
University of Tennessee at Knoxville
2014-2024
Oak Ridge National Laboratory
2015-2024
Naval Research Laboratory Materials Science and Technology Division
2019-2021
Government of the United States of America
2019-2020
Material Sciences (United States)
2018
The Ohio State University
2015
Knoxville College
2002-2012
National Institute of Materials Physics
2012
Karlsruhe Institute of Technology
2011
A metal alloy that is stronger when cold Metal alloys normally consist of one dominant element, with others in small amounts to improve specific properties. For example, stainless steel primarily iron nickel and chromium but may contain trace other elements. Gludovatz et al. explored the properties a high-entropy made from equal chromium, manganese, iron, cobalt, nickel. Not only does this show excellent strength, ductility, toughness, these at cryogenic temperatures where most change...
Abstract High-entropy alloys are an intriguing new class of metallic materials that derive their properties from being multi-element systems can crystallize as a single phase, despite containing high concentrations five or more elements with different crystal structures. Here we examine equiatomic medium-entropy alloy only three elements, CrCoNi, single-phase face-centred cubic solid solution, which displays strength-toughness exceed those all high-entropy and most multi-phase alloys. At...
An equiatomic CoCrFeMnNi high-entropy alloy (HEA), produced by arc melting and drop casting, was subjected to severe plastic deformation (SPD) using high-pressure torsion. This process induced substantial grain refinement in the coarse-grained casting leading a size of approximately 50 nm. As result, strength increased significantly 1950 MPa, hardness ∼520 HV. Analyses transmission electron microscopy (TEM) 3-dimensional atom probe tomography (3D-APT) showed that, after SPD, remained true...
The tensile properties of CrCoNi, a medium-entropy alloy, have been shown to be significantly better than those CrMnFeCoNi, high-entropy alloy. To understand the deformation mechanisms responsible for its superiority, tests were performed on CrCoNi at liquid nitrogen temperature (77 K) and room (293 interrupted different strains. Microstructural analyses by transmission electron microscopy showed that, during early stage plasticity, occurs glide 1/2<110> dislocations dissociated into...
At low homologous temperatures (down to cryogenic temperatures), the CrMnFeCoNi high-entropy alloy possesses good combination of strength, work hardening rate (WHR), ductility, and fracture toughness. To improve understanding deformation mechanisms responsible for its mechanical properties, tensile tests were performed at liquid nitrogen room temperature (77 K 293 K) interrupted different strains quantify evolution microstructure by transmission electron microscopy. Dislocation densities,...
Abstract Damage tolerance can be an elusive characteristic of structural materials requiring both high strength and ductility, properties that are often mutually exclusive. High-entropy alloys interest in this regard. Specifically, the single-phase CrMnFeCoNi alloy displays tensile levels ∼1 GPa, excellent ductility (∼60–70%) exceptional fracture toughness ( K JIc >200 MPa√m). Here through use situ straining aberration-corrected transmission electron microscope, we report on salient...
Abstract Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply situ , aberration-corrected scanning, transmission electron microscopy examine deformation mechanisms medium-entropy alloy CrCoNi that exhibits one highest combinations strength, toughness on record. Ab initio modelling suggests it has negative stacking-fault energy...
By controlling the specimen aspect ratio and strain rate, compressive strains as high 80% were obtained in an otherwise brittle metallic glass. Physical mechanical properties measured after deformation, a systematic strain-induced softening was observed which contrasts sharply with hardening typically crystalline metals. If deformed glass is treated composite of hard amorphous grains surrounded by soft shear-band boundaries, analogous to nanocrystalline materials that exhibit inverse...
Abstract 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 because its ductility strength increase decreasing temperature while maintaining outstanding fracture toughness at cryogenic temperatures. Here we report for first time by single-crystal micropillar compression that bulk room critical resolved shear stress (CRSS) ~33–43 MPa, ~10...
Elastic moduli of a set equiatomic alloys (CrFeCoNi, CrCoNi, CrFeNi, FeCoNi, MnCoNi, MnFeNi, and CoNi), which are medium-entropy subsystems the CrMnFeCoNi high-entropy alloy were determined as function temperature over range 293 K–1000 K. Thermal expansion coefficients for these 100 K–673 All single-phase had face-centered cubic (FCC) crystal structure, except CrFeNi is two-phase containing small amount body-centered (BCC) precipitates in FCC matrix. The dependences thermal elastic obtained...
Although the phase stability of high-entropy alloys in Cr-Mn-Fe-Co-Ni system has received considerable attention recently, knowledge their thermodynamic equilibrium states and precipitation kinetics during high-temperature exposure is limited. In present study, an off-equiatomic Cr26Mn20Fe20Co20Ni14 alloy was solutionized isothermally aged at temperatures between 600 °C 1000 for times to h. original single-phase fcc matrix, intermetallic σ found form all investigated temperatures. Its...