A5027828219- Titanium Alloys Microstructure and Properties
- Microstructure and mechanical properties
- Intermetallics and Advanced Alloy Properties
- Metal and Thin Film Mechanics
- Advanced Materials Characterization Techniques
- Hydrogen embrittlement and corrosion behaviors in metals
- Nuclear Materials and Properties
- Metallurgy and Material Forming
- High-Velocity Impact and Material Behavior
- High Temperature Alloys and Creep
- Botany and Plant Ecology Studies
- Ecology and biodiversity studies
- Aluminum Alloy Microstructure Properties
- Fire effects on ecosystems
- Forest ecology and management
- Rangeland and Wildlife Management
- Surface Treatment and Residual Stress
- Archaeology and Natural History
- Magnesium Alloys: Properties and Applications
- Fatigue and fracture mechanics
- Avian ecology and behavior
- Peatlands and Wetlands Ecology
- Animal Behavior and Reproduction
- Microplastics and Plastic Pollution
- Remote Sensing and LiDAR Applications
US Forest Service
2010-2023
Northern Research Station
2010-2023
Rolls-Royce (United Kingdom)
2013-2022
Imperial College London
2021
United States Department of Agriculture
1996-2015
Forest Products Laboratory
2015
Twin Cities Orthopedics
1985
University of Minnesota
1985
British Institute of International and Comparative Law
1985
Michigan State University
1979
Screw dislocations: A hard case to crack The motion of dislocations or defects in a metal influences its strength and toughness. If these can be “pinned” by adding alloying elements, it should possible create stronger alloy. It was thought that there shouldn't much an interaction between screw any elements. However, Yu et al. show for α-Ti, the profound hardening effect oxygen is due strong interactions with core dislocations. First-principles calculations reveal distortion interstitial...
A detailed analysis has been conducted of Ti–6Al–4V processed by metallic shot peening and laser shock peening. Analysis incremental hole drilling, electron backscattered diffraction microscopy, transmission microscopy Kikuchi is evaluated discussed. The results this highlight the very different dislocation structures in surfaces these two techniques. Transmission also used to evaluate sub-grains generated notable feature material almost complete absence deformation twinning, contrasting...
ABSTRACT A crystal plasticity model for near‐alpha hcp titanium alloys embodying a quasi‐cleavage failure mechanism is presented and employed to investigate the conditions necessary in order facet nucleation occur cold‐dwell fatigue. polycrystal used effects of combinations crystallographic orientations (and particular, rogue grain combination), essential role (cold) creep during hold periods loading cycle more damaging effect load rather than strain nucleation. Direct comparisons...
Elastically anisotropic, physically based, length-scale- and rate-dependent crystal plasticity finite element investigations of a model hcp polycrystal are presented systematic study was carried out on the effects combinations crystallographic orientations local, grain-level stresses accumulated slip in cycles containing cold dwell. It is shown that most damaging combination one comprising primary hard grain with c -axis near-parallel to loading direction an adjacent soft having near-normal...
Fatigue is a difficult multi-scale modelling problem nucleating from localised plasticity at the scale of dislocations and microstructure with significant engineering safety implications. Cold dwell fatigue phenomenon in titanium where stress holds moderate temperatures lead to substantial reductions cyclic life, has been implicated service failures. Using discrete dislocation complemented by transmission electron microscopy, we successfully predict lifetimes for 'worst case' microstructures...
This paper introduces the concept of effective structural size in titanium alloys and its importance with respect to material production routes component lifing/design. Traditionally, process route optimization has relied on optical microscopy, which may be misleading when predicting mechanical properties. Similarly, continuum mechanics current lifing methods are based empirical data analysis. The advent advanced characterization techniques, e.g. EBSD combined crystal plasticity modelling,...
The gas turbine has truly remarkable scope with respect to the range of stress, temperature and environmental conditions it can generate. As such, material limitations are seldom derived from a single or simple property this resulting complexity makes business case decisions on new development non-trivial. This is particularly true for ‘step change’ materials where robust manufacturing supply chain/process route may not exist ability utilise experience bound validation certification needs be...
The relationship between material failure and surface roughness has been investigated using two titanium alloys: Ti64 the more ductile Ti407. Three types were created (polished, sandblasted scratched) with instances spanning a wide range of average roughness. surfaces tested in three-point bending imparted on tensile under-surface rectangular beam specimen. Results showed to be highly sensitive both magnitude orientation High maximum stress direction (and scratch like features perpendicular...
ABSTRACT Long‐term monitoring and research projects are essential to understand ecological change the effectiveness of management activities. An inherent characteristic long‐term is need for consistent data collection over time, requiring rigorous attention quality assurance. Recent papers have provided broad recommendations management; however, practitioners more detailed guidance examples. We present general yet development comprehensive, concise, effective projects. The presented as a...