A5051161096- Intermetallics and Advanced Alloy Properties
- Microstructure and mechanical properties
- Microstructure and Mechanical Properties of Steels
- MXene and MAX Phase Materials
- High Temperature Alloys and Creep
- Force Microscopy Techniques and Applications
- Hydrogen embrittlement and corrosion behaviors in metals
- Advanced ceramic materials synthesis
- Aluminum Alloys Composites Properties
- Metallurgy and Material Forming
- Advanced Surface Polishing Techniques
- Optical measurement and interference techniques
- Solidification and crystal growth phenomena
- Metal and Thin Film Mechanics
- Quasicrystal Structures and Properties
- Magnesium Alloys: Properties and Applications
- Semiconductor materials and interfaces
- Electrical and Thermal Properties of Materials
- Laser Material Processing Techniques
- Non-Destructive Testing Techniques
- Advanced Materials Characterization Techniques
- Advanced Chemical Physics Studies
- Advanced materials and composites
- Surface Roughness and Optical Measurements
- Ferroelectric and Piezoelectric Materials
Colorado School of Mines
2019-2021
University of Cambridge
2014-2020
University of Manchester
2011-2016
University of Bologna
2008
The development and validation of crystal plasticity models requires the ability to map deformation at microstructural scale. Here, a new method high-resolution mapping is used measure strain, material rotation lattice in austenitic stainless steel sub-micron resolution. Electron back-scatter diffraction maps are link microstructure. Deformation occurs domains, which most plastic strain originates from activation single slip system with high resolved shear stress. Within localized lamellar...
The stress required to activate twinning of the longitudinal <112¯]{111} system in lamellar γ-TiAl phase alloy Ti-45Al-2Nb-2Mn (at.%)-0.8 vol.% TiB2 was measured at several temperatures up 700 °C by situ micropillar compression soft mode oriented γ-TiAl/α2-Ti3Al stacks. lamellae undergoing deformation were identified electron backscatter diffraction orientation mapping. In some cases, such not constrained domain or colony boundaries and only mechanism observed based on digital image...
The occurrence of longitudinal twinning in the engineering alloy Ti-45Al-2Nb-2Mn (at.%)-0.8 vol.% TiB2 has been studied by measuring changes crystallographic orientation within individual lamellae during microcompression. Twinning this appeared to be a nucleation-limited process with twins growing from lamellar boundaries at resolved shear stresses as low 100 MPa, consistent observations elsewhere. However, instead forming ~ 10–200 nm thickness, polysynthetically twinned crystals, were...
The digital image correlation (DIC) of speckle patterns obtained by vapour-assisted gold remodelling at 200 - 350 °C has already been used to map plastic strains with submicron resolution. However, it not so far proved possible use such for testing high temperatures. Here we demonstrate how a pattern can be made that is stable 700 °C, study deformation in commercial TiAl alloy (Ti-45Al-2Nb-2Mn(at%)-0.8 vol% TiB2). up uniformly sized random array Au islands as small 15 nm diameter, depending...
Abstract Synchrotron X-ray imaging has been used to examine in situ the deformation of dendrites that takes place during solidification a nickel-based superalloy. By combining absorption and diffraction contrast imaging, events could be classified by their localization permanence. In particular, mechanism arising from thermal contraction temperature gradient was elucidated through digital image correlation. It concluded this may explain small misorientations typically observed single crystal...
In this paper the occurrence of twinning parallel to lamellae during compression at 700 °C a polycrystalline nearly lamellar commercial γ-TiAl alloy, Ti-45Al-2Nb-2Mn(at%)-0.8 vol% TiB2, has been studied and shown lead formation cracks colony boundaries. However, longitudinal mode was less common by least factor ten in tests room temperature. Furthermore, debonding boundaries caused shear strain is exacerbated when same variant favourably oriented for occurs repeatedly structure. This effect...
Abstract At the grain boundaries of plastically deforming polycrystals, strain transfer mechanisms can accommodate shear carried by slip bands and mechanical twins to prevent stress build-ups damage. So far, only accommodation obtained through (and twinning) alone has been considered in mechanism known as twin) transfer. Here, a that also requires rotation crystal lattice is demonstrated. A region accumulated develops perpendicular active plane impinged grain. The gradients enable localized...
Microplasticity in a lamellar TiAl alloy upon high cycle tensile fatigue was measured by resolution digital image correlation strain mapping at several stress and increments, 25 °C 670 °C, for two thicknesses. Plastic deformation occurred primarily soft-mode colonies both temperatures, operating slip parallel to the lamellae, near interfaces. strains generally decreased zero colony boundary; transfer across such boundaries rare temperatures. At maximum applied influenced number of bands more...
Abstract When a material that contains precipitates is deformed, the and matrix may strain plastically by different amounts causing stresses to build up at precipitate-matrix interfaces. If premature failure be avoided, it therefore essential reduce difference in plastic between two phases. Here, we conduct nanoscale digital image correlation measure new variable quantifies this show how its value can used estimate associated interfacial stresses, which are found approximately three times...