A5009782264- High Entropy Alloys Studies
- High-Temperature Coating Behaviors
- Additive Manufacturing Materials and Processes
- Advanced Materials Characterization Techniques
- High Temperature Alloys and Creep
- X-ray Diffraction in Crystallography
- Intermetallics and Advanced Alloy Properties
- Nuclear Materials and Properties
- Thermodynamic and Structural Properties of Metals and Alloys
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced materials and composites
- Nuclear Physics and Applications
- Aerodynamics and Acoustics in Jet Flows
- Power Transformer Diagnostics and Insulation
- Catalytic Processes in Materials Science
- Ferroelectric and Piezoelectric Materials
- Industrial Automation and Control Systems
- Nuclear materials and radiation effects
- Titanium Alloys Microstructure and Properties
- Solidification and crystal growth phenomena
- Fatigue and fracture mechanics
- Microstructure and Mechanical Properties of Steels
- Fusion materials and technologies
- Fluid Dynamics and Turbulent Flows
- Thermal Expansion and Ionic Conductivity
University of Sheffield
2023-2024
University of Cambridge
1998-2022
Rutherford Appleton Laboratory
2016
The formation of single phase solid solutions from combinations multiple principal elements, with differing atomic radii, has led to the suggestion that lattices high-entropy alloys (HEAs) must be severely distorted. To assess this hypothesis, total scattering measurements using neutron radiation have been performed on CrMnFeCoNi alloy and compared similar data five compositionally simpler materials within same system. Bragg diffraction patterns all studied were similar, consistent a...
Severe local lattice distortions (LLDs), originating from the size mismatch among atoms, have been proposed as one of key mechanisms responsible for excellent mechanical properties bcc-structured high-entropy alloys (HEAs). They also connected to phase stability, well physical such electrical conductivity. Experimental measurements LLDs are, however, difficult and often ambiguous. Analysis total scattering data in real space has provide a uniquely suitable probe LLDs, but its widespread...
Local structure and disorder in crystalline materials are increasingly recognized as the key to understanding their functional properties. From negative thermal expansion dielectric response thermoelectric properties ionic conductivity, a clear picture of local atomic arrangements is essential for these phenomena developing new practical systems. The combination total scattering reverse Monte Carlo (RMC) modeling can provide an unprecedented level structural detail. In this article, we...
The as-deposited microstructure of an additively manufactured Ni-based superalloy fabricated using laser powder-bed-fusion has been investigated atomic resolution transmission electron microscopy. It is shown that γ′ precipitates exist in the condition, albeit a non-equilibrium state. are present as nano-structured domains throughout microstructure. These exhibit clear L12 ordering but show highly irregular matrix-precipitate interfaces.
This study aims to utilize a combined machine learning (ML) and CALculation of PHAse Diagrams (CALPHAD) methodology design hardmetal matrix phases for metal‐forming applications that can serve as the basis carbide reinforcement. The vast compositional space high entropy alloys (HEAs) occupy offers promising avenue satisfy application criteria wear resistance ductility. To efficiently explore this space, random forest ML models are constructed trained from publicly available experimental HEA...
The lattice parameters and misfit of the γ γ′ phases in a series model quaternary Ni-based superalloys with without Mo additions have been determined using neutron diffraction between room temperature 700 °C. Despite fact that is typically expected to partition almost exclusively phase thereby increase parameter alone, both were observed addition. Nevertheless, effect on was more pronounced, leading an overall decrease increasing content. Alloys lowest content found be positively misfitting,...
This study investigated the influence of a systematic variation in Ni:Co ratio on lattice misfit γ-γ' Ni-Co-5Al-5Ti-15Cr (at%) alloys over broad temperature range. Seven model superalloys denoted by their nominal Co content, 0Co, 9Co, 19Co, 28Co, 38Co, 47Co and 56Co (at%), were hot-rolled to achieve fine grain size then aged at 800 °C for 1000 h. Neutron diffraction was performed all seven alloy compositions room temperature, 400 °C, 600 700 determine parameters γ γ' phases. Alloys content...
A reverse Monte Carlo analysis of neutron and x-ray total scattering data from two ceria-zirconia samples composition Ce0.75Zr0.25O2 is performed to analyze the distribution cations examine possibility oxide-ion disorder. For first material, heated in air under moderate conditions (800 °C), structure a single-phase solid-solution with statistical cations, but local tetragonal symmetry found, consistent different coordination preferences Ce Zr. second H2 at 1050 °C followed by reoxidation 400...
The effect of partial Fe substitution for Ni on microstructure, lattice misfit, oxidation, creep, and yield strength are investigated six W-free cobalt-based superalloys with compositions Co-(30-x)Ni-xFe-yCr-5Al-3V-2Ti-1.5Nb-1.5Ta-0.08B (at.%), three levels (x=12, 14, or 18) two Cr (y =4 8). Alloys 12 14% exhibit mostly γ/γʹ microstructures after aging up to 1000 h at 850 ºC, while those 18% display additional intermetallic phases. All alloys show positive misfit from 0.56 0.34%,...