Gregory Gerstein
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View article: Electroplasticity of Metals and Ceramics: Current Status
Electroplasticity of Metals and Ceramics: Current Status Open
This review covers the anelastic deformation observed under electric loading (electroplasticity) of metals and ceramics. The interplay of various complex mechanisms beyond trivial Joule heating leading to enhanced plasticity is discussed i…
View article: Influence of High Current Impulses on Element Distribution in Creep-Deformed Single-Crystal Ni-Based Superalloys
Influence of High Current Impulses on Element Distribution in Creep-Deformed Single-Crystal Ni-Based Superalloys Open
Nickel-based superalloys are typically employed for high-temperature applications. One well-known degradation mechanism is the rafting of the γ ′-phase. In this study, it was investigated, whether a high current impulse treatment is suitab…
View article: Unraveling factors affecting the reversibility of martensitic phase transformation in FeNiCoAlTi shape memory alloys: Insights from HR-EBSD and acoustic emission analysis
Unraveling factors affecting the reversibility of martensitic phase transformation in FeNiCoAlTi shape memory alloys: Insights from HR-EBSD and acoustic emission analysis Open
The reversibility of the martensitic phase transformation is crucial for the functionality of shape memory alloys. The easier the martensite is pinned, the faster occurs the degradation of the shape memory effect during cyclic loading. Thi…
View article: Functional Properties of a Ni-rich Ni–Ti–Hf Shape Memory Alloy Fabricated via Laser Beam Powder Bed Fusion—Impact of Porosity and Precipitation Characteristics on the Thermal Hysteresis
Functional Properties of a Ni-rich Ni–Ti–Hf Shape Memory Alloy Fabricated via Laser Beam Powder Bed Fusion—Impact of Porosity and Precipitation Characteristics on the Thermal Hysteresis Open
Additive manufacturing (AM) is very promising for the fabrication of complex parts made from shape memory alloys (SMAs). In the present study, a Ni–Ti–Hf shape memory alloy has been processed by laser beam powder bed fusion of metals (PBF-…
View article: Influence of Various Processing Routes in Additive Manufacturing on Microstructure and Monotonic Properties of Pure Iron—A Review-like Study
Influence of Various Processing Routes in Additive Manufacturing on Microstructure and Monotonic Properties of Pure Iron—A Review-like Study Open
Additive manufacturing processes have attracted broad attention in the last decades since the related freedom of design allows the manufacturing of parts with unique microstructures and unprecedented complexity in shape. Focusing on the pr…
View article: Grain Boundary Wetting Transition in the Mg-Based ZEK 100 Alloy
Grain Boundary Wetting Transition in the Mg-Based ZEK 100 Alloy Open
Modern magnesium-based alloys are broadly used in various industries as well as for biodegradable medical implants due to their exceptional combination of light weight, strength, and plasticity. The studied ZEK100 alloy had a nominal compo…
View article: Correlating Ultrasonic Velocity in DC04 with Microstructure for Quantification of Ductile Damage
Correlating Ultrasonic Velocity in DC04 with Microstructure for Quantification of Ductile Damage Open
The detection of ductile damage by image-based methods is time-consuming and typically probes only small areas. It is therefore of great interest for various cold forming processes, such as sheet-bulk metal forming, to develop new methods …
View article: Coexistence of Intermetallic Complexions and Bulk Particles in Grain Boundaries in the ZEK100 Alloy
Coexistence of Intermetallic Complexions and Bulk Particles in Grain Boundaries in the ZEK100 Alloy Open
Magnesium-based alloys are highly sought after in the industry due to their lightweight and reliable strength. However, the hexagonal crystal structure of magnesium results in the mechanical properties’ anisotropy. This anisotropy is effec…
View article: Grain Boundary Wetting by the Second Solid Phase: 20 Years of History
Grain Boundary Wetting by the Second Solid Phase: 20 Years of History Open
Grain boundaries (GBs) can be wetted by a second phase. This phase can be not only liquid (or melted), but it can also be solid. GB wetting can be incomplete (partial) or complete. In the case of incomplete (partial) wetting, the liquid fo…
View article: Structure, Phase Composition and Mechanical Properties for the High Entropy Solid Solutions Based upon MnFeCoNiCu System Versus Collective Behaviour of their Constituents
Structure, Phase Composition and Mechanical Properties for the High Entropy Solid Solutions Based upon MnFeCoNiCu System Versus Collective Behaviour of their Constituents Open
Досліджено зміни структури та фазового складу литих багатокомпонентних стопів на основі MnFeCoNiCu в залежності від змін у ентальпії
View article: High Strain Rate and Stress-State-Dependent Martensite Transformation in AISI 304 at Low Temperatures
High Strain Rate and Stress-State-Dependent Martensite Transformation in AISI 304 at Low Temperatures Open
Deformation-induced martensitic transformation as the basis of a hardening process is dependent, among others, on the stress state. In applications such as cryogenic cutting, where a hardened martensitic subsurface can be produced in metas…
View article: Cu-Ni-Based Alloys from Nanopowders as Potent Thermoelectric Materials for High-Power Output Applications
Cu-Ni-Based Alloys from Nanopowders as Potent Thermoelectric Materials for High-Power Output Applications Open
A new approach for the development of thermoelectric materials, which focuses on a high-power factor instead of a large figure of merit zT, has drawn attention in recent years. In this context, the thermoelectric properties of Cu-Ni-based …
View article: Grain Boundary Wetting by a Second Solid Phase in the High Entropy Alloys: A Review
Grain Boundary Wetting by a Second Solid Phase in the High Entropy Alloys: A Review Open
In this review, the phenomenon of grain boundary (GB) wetting by the second solid phase is analyzed for the high entropy alloys (HEAs). Similar to the GB wetting by the liquid phase, the GB wetting by the second solid phase can be incomple…
View article: The Grain Boundary Wetting Phenomena in the Ti-Containing High-Entropy Alloys: A Review
The Grain Boundary Wetting Phenomena in the Ti-Containing High-Entropy Alloys: A Review Open
In this review, the phenomenon of grain boundary (GB) wetting by melt is analyzed for multicomponent alloys without principal components (also called high-entropy alloys or HEAs) containing titanium. GB wetting can be complete or partial. …
View article: A multiscale study of hot-extruded CoNiGa ferromagnetic shape-memory alloys
A multiscale study of hot-extruded CoNiGa ferromagnetic shape-memory alloys Open
Ferromagnetic shape-memory CoNiGa alloys have attracted much scientific interest due to their potential alternative use as high-temperature shape-memory alloys, bearing a high prospect for actuation and damping applications at elevated tem…
View article: Hydrogen-assisted Crack Propagation in Pre-strained Twinning-induced Plasticity Steel: from Initiation at a Small Defect to Failure
Hydrogen-assisted Crack Propagation in Pre-strained Twinning-induced Plasticity Steel: from Initiation at a Small Defect to Failure Open
Hydrogen-assisted crack growth of pre-strained twinning-induced plasticity (TWIP) steel was investigated using artificial defects (micro-drilled holes), which acted as artificial crack initiation sites. Hydrogen was introduced into the spe…
View article: New Multistage Sheet-Bulk Metal Forming Process Using Oscillating Tools
New Multistage Sheet-Bulk Metal Forming Process Using Oscillating Tools Open
A new sheet-bulk metal forming process for the production of bulk components out of a flat sheet has been developed. Superimposed oscillation has been applied to the new process. By this means, process limits regarding better mould filling…
View article: Strain path dependency in incremental sheet-bulk metal forming
Strain path dependency in incremental sheet-bulk metal forming Open
Incremental sheet-bulk metal forming (iSBMF) enables the manufacture of functional lightweight components featuring a load-adapted shape with a high material efficiency. The flexibility of the incremental forming process allows for the mod…
View article: Microstructure Formation in Cast TiZrHfCoNiCu and CoNiCuAlGaIn High Entropy Shape Memory Alloys: A Comparison
Microstructure Formation in Cast TiZrHfCoNiCu and CoNiCuAlGaIn High Entropy Shape Memory Alloys: A Comparison Open
The present study is dedicated to the microstructure characterization of the as-cast high entropy intermetallics that undergo a martensitic transformation, which is associated with the shape memory effect. It is shown that the TiZrHfCoNiCu…
View article: Investigation of the electroplastic effect using nanoindentation
Investigation of the electroplastic effect using nanoindentation Open
A promising approach to deform metallic-intermetallic composite materials is the application of electric current pulses during the deformation process to achieve a lower yield strength and enhanced elongation to fracture. This is known as …
View article: Investigation of the electroplastic effect using nanoindentation
Investigation of the electroplastic effect using nanoindentation Open
A promising approach to deform metallic-intermetallic composite materials is the application of electric current pulses during the deformation process to achieve a lower yield strength and enhanced elongation to fracture. This is known as …
View article: Influence of High Current-Density Impulses on the Stress-Strain Response and Microstructural Evolution of the Single Crystal Superalloy CMSX-4
Influence of High Current-Density Impulses on the Stress-Strain Response and Microstructural Evolution of the Single Crystal Superalloy CMSX-4 Open
Owing to the low formability of single-crystal nickel-based materials, single-crystal components are typically cast. Subsequently, a multi-stage heat treatment is carried out in order to partially compensate the dendrite segregation and to…
View article: Resonant pulsed electromagnetic stirring of melt for effective grain fragmentation
Resonant pulsed electromagnetic stirring of melt for effective grain fragmentation Open
The paper describes the results of an experimental research, demonstrating and explaining the effect of grain fragmentation, caused by pulsed resonant electromagnetic stirring. In the experiments, 6082 aluminium alloy melt was directionall…
View article: Experimental setup to characterize flow-induced anisotropy of sheet metals
Experimental setup to characterize flow-induced anisotropy of sheet metals Open
For many metals, a transient variation of the yield stress can be observed when changing the orientation of a load-path. Such behavior affects the manufacturing process itself, e.g. by increasing forming forces, altered material properties…