Alexander M Korsunsky

University of Oxford | OX · Department of Engineering Science

To explore an effective route of customizing the superelasticity (SE) of NiTi shape memory alloys via modifying the grain structure, binary Ni55Ti45 (wt) alloys were fabricated in as-cast, hot swaged, and hot-rolled conditions, presenting contrasting grain sizes and grain boundary types. In situ synchrotron X-ray Laue microdiffraction and in situ s...

The stress-strain curves of most metallic alloys are often described using the relatively simple Ramberg-Osgood relationship. Whilst this description captures the overall stress-strain curve under monotonic tensile loading with reasonable overall accuracy, it often presents significant errors in the immediate post-yield region where the interplay b...

The problems of non-slipping contacts between dissimilar elastic solids are studied under the conditions of plane strain. When two dissimilar solids are incrementally pressed into contact, a relative tangential displacement along the contact interface emerges because of the material property mismatch. The spatial derivative of the relative tangenti...

This work evaluated the fracture toughness of the low-temperature carbonized elastomer-based composites filled with shungite and short carbon fibers. The effects of the carbonization temperature and filler content on the critical stress intensity factor (K1c) were examined. The K1c parameter was obtained using three-point bending tests for specimen...

Point by point strain scanning is often used to map the residual stress (strain) in engineering materials and components. However, the gauge volume and, hence, spatial resolution are limited by the beam defining apertures and can be anisotropic for very low and high diffraction (scattering) angles. Alternatively, wavelength resolved neutron transmi...

Tracking texture evolution during in situ loading is critical to understand and simulate the dynamic behaviour of microstructure in polycrystalline materials, yet conventional texture quantification methods are sometimes restricted due to various factors, such as acquisition time, sample environment and complex setup. To address this, a novel appro...

Siliceous diatom frustules represent an up-and-coming platform for a range of bio-assisted nanofabrication processes able to overcome the complexity and high cost of current engineering technology solutions in terms of negligibly small power consumption and environmentally friendly processing combined with unique highly porous structures and proper...

Mechanical surface modification such as shot peening offer powerful enhancement of fatigue properties of metals and other materials. Cavitation usually causes surface damage in hydraulic machineries. However, careful selection of process parameters allowed developing an approach known as “cavitation peening.” Its advantage is surface roughness incr...

In this paper, and on the basis of the equivalent eigenstrain principle, a fundamental formulation for inhomogeneous inclusion problems is proposed, which is to transform the inhomogeneous in-clusion problems into auxiliary equivalent homogenous inclusion problems. Then, the analysis, which is based on the equivalent homogenous inclusions, would si...

Electrospinning is a well-established method for the fabrication of polymer biomaterials, including those with core-shell nanofibers. The variability of structures presents a great range of opportunities in tissue engineering and drug delivery by incorporating biologically active molecules such as drugs, proteins, and growth factors and subsequent...

All solid state, thin film Li-NMC batteries produced by Physical Vapour Deposition have the potential to revolutionize the internet of things by integrating ultra-fast charging and high energy densities into small portable devices. In these systems, the integrity of the cathode-solid electrolyte interface is of particular importance, as it determin...

Multiscale stresses and strains in polycrystalline metals are always inhomogeneous. In this study, a rate-independent crystal plasticity formulation was implemented for a cubic representative volume element (RVE) of an fcc polycrystal generated by 3D Delaunay tessellation. Multiple realizations were generated with crystallographic orientation permu...

Diatoms are unicellular photosynthetic microalgae with a nanostructured silica cell wall – frustule. Diatoms, considered one of the most abundant and ecologically important phytoplankton groups, can also be easily grown in the laboratory and used for different applications. With long-term cultivation, it is essential to monitor their growth properl...

This thesis focuses on investigating the processing-microstructure-property relationships for the Nitinol material. Processing routes include metal forming process and heat treatment process. Metal forming processes include casting, hot rotary swaging, hot rolling, and cold drawing. The following aspects of the microstructure were taken into consid...

Point by point strain scanning is often used to map the residual stress (strain) in engineering materials and components. However the gauge volume and hence spatial resolution is limited by the beam defining apertures and can be anisotropic for very low and high diffraction (scattering) angles. Alternatively, wavelength resolved neutron transmissio...

Using synchrotron X-ray total scattering and empirical potential structure refinement modelling, we studied systematically in operando condition the disorder-to-order local atomic structure transition in a pure Al and a dilute Al-0.4Sc alloy melt in the temperature range from 690 °C to 657 °C. In the liquid state, icosahedral short-range ordered Sc...

Finite element analysis of magnetic materials allows accurate prediction of losses and is crucial in the design of electromagnetic devices and products. Soft magnetic composites are an alternative to silicon steel laminations, yet the electromagnetic material properties are less well documented and include uncertainties which can lead to inaccurate...

SLM additive manufacturing has demonstrated great potential for aerospace applications when structural elements of individual design and/or complex shape need to be promptly supplied. 3D-printable AlSi10Mg (RS-300) alloy is widely used for the fabrication of different structures in the aerospace industry. The importance of the evaluation of residua...

SLM Additive Manufacturing has demonstrated great potential for aerospace applications when structural elements of individual design and/or complex shape need to be promptly supplied. 3D-printable AlSi10Mg (RS-300) alloy is widely used for the fabrication of different structures in aerospace industry. The importance of the evaluation of residual st...

The present article overviews the current state-of-the-art and future prospects for the use of diatomaceous earth (DE) in the continuously expanding sector of energy science and technology. An eco-friendly direct source of silica and the production of silicon, diatomaceous earth possesses a desirable nano- to micro-structure that offers inherent ad...

In the last decade, perovskite photovoltaics gained popularity as a potential rival for crystalline silicon solar cells, which provide comparable efficiency for lower fabrication costs. However, insufficient stability is still a bottleneck for technology commercialization. One of the key aspects for improving the stability of perovskite solar cells...

Recent years witnessed progressive broadening of the practical use of 3D-printed aluminium alloy parts, in particular for specific aerospace applications where weight saving is of great importance. Selective laser melting (SLM) is an intrinsically multi-parametric fabrication technology that offers multiple means of controlling mechanical propertie...

To reflect human development, it is critical to create a substrate that can support long-term cell survival, differentiation, and maturation. Hydrogels are promising materials for 3D cultures. However, a bulk structure consisting of dense polymer networks often leads to suboptimal microenvironments that impedes nutrient exchange and cell-to-cell in...

Recent years witnessed progressive broadening of the practical use of 3D-printed aluminium alloy parts, in particular for specific aerospace applications where weight saving is of great importance. Selective laser melting (SLM) is an intrinsically multi-parametric fabrication technology that offers multiple means of controlling mechanical propertie...

We report major advances in the analysis of synchrotron 3D datasets acquired from human healthy and carious dental enamel. Synchrotron tomographic data for three human carious samples and a non-carious reference tooth sample were collected with the voxel size of 325 nm for a total volume of 815.4 × 815.4 × 685.4 μm³. The results were compared with...

Enamel caries is a highly prevalent disease that involves demineralisation of the enamel structure. In this study, we report the analysis of artificially demineralised human enamel slices etched using lactic acid (2 % v/v) in comparison with healthy enamel using correlative techniques of optical and electron microscopy, as well as scanning diffract...

The structure of self-reinforced composites (SRCs) based on ultra-high molecular weight polyethylene (UHMWPE) was studied by means of Wide-Angle X-ray Scattering (WAXS), X-ray tomography, Raman spectroscopy, Scanning Electron Microscopy (SEM) and in situ tensile testing in combination with advanced processing tools to determine the correlation betw...

The structure of self-reinforced composites (SRCs) based on ultra-high molecular weight 21 polyethylene (UHMWPE) was studied by means of Wide-Angle X-Ray Scattering (WAXS), X-Ray 22 tomography, Raman spectroscopy, Scanning Electron Microscopy (SEM) and in situ tensile testing 23 in combination with advanced processing tools like Avizo, ImageJ, and...

This study concerns the phase transformation kinetics and pertains to the processes of crystallisation of amorphous polymers, ceramics, and bulk metallic glasses (BMG), as well as solid state transformations by the nucleation and growth mechanism. It is also likely to be relevant to the description of dissolution and precipitation processes, and mo...

Currently, 3D-printed aluminium alloy fabrications made by selective laser melting (SLM) offer a promising route for the production of small series of custom-designed support brackets and heat exchangers with complex geometry and shape and miniature size. Alloy composition and printing parameters need to be optimised to mitigate fabrication defects...

Ptychography is a scanning coherent diffraction imaging technique that provides high-resolution imaging and complete spatial information of the complex probe and object transmission function. The wavefront error caused by aberrated optics has previously been recovered using ptychography when a highly coherent source is used, but has not been demons...

Plastic debris is gradually filling the seas, oceans, and freshwater bodies of the planet. Since the 1950s, a huge amount of plastic has entered into various bodies of water. All these objects decompose at different rates, and aquatic organisms take part in these processes. This book chapter provides an overview of studies carried out in recent dec...

Photosynthetic single-celled diatom algae, due to their unique structure and properties, represent promising candidates for various applications in technology and biomedicine. These nanostructured objects, enveloped within a silica cell wall called a frustule, play a significant role in Earth’s ecology. In this study, we proposed new techniques for...

3D-printed aluminium alloy fabrications made by selective laser melting (SLM) offer a promising route for the production of small series of custom-designed heat exchangers with complex geometry and shape and miniature size. Alloy composition and printing parameters need to be optimized to mitigate fabrication defects (pores and microcracks) and enh...

The thermal stability of Cu/W nano-multilayers deposited on a Si substrate using ion beam deposition was analyzed in situ by GISAXS and transmission EDX—a combination of methods permitting the observation of diffusion processes within buried layers. Further supporting techniques such as XRR, TEM, WAXS, and AFM were employed to develop an extensive...

2020 The 10th International Conference on Key Engineering Materials (ICKEM 2020) Madrid 2020

Carbonized elastomer-based composites (CECs) possess a number of attractive features in terms of thermomechanical and electromechanical performance, durability in aggressive media and facile net-shape formability, but their relatively low ductility and strength limit their suitability for structural engineering applications. Prospective application...

In order to understand the fracture resistance of nanocrystalline thin films, it is necessary to assess nanoscopic multiaxial stress fields accompanying crack growth during irreversible deformation. Here, a clamped cantilever with dimensions of 200 × 23.7 × 40 μm3 was machined by focused ion beam milling from a thin film composed of four alternatin...

The carbonized elastomer-based composites (CECs) possess a number of attractive features in terms of thermomechanical and electromechanical performance, durability in aggressive media and facile net-shape formability, but their relatively low ductility and strength limit their suitability for structural engineering applications. Prospective applica...

Nanostructured metallic multilayers with carefully designed mechanical and functional properties are omnipresent in cutting edge technological applications. To ensure the mechanical integrity of such coatings, the Mode I critical Stress Intensity Factor KIC is used to quantify their fracture toughness in order to avoid material failure by appropria...

In the present study we elucidate the nature of local strain statistics evolution during tensile deformation in poly-crystalline materials. A rate-independent formulation was implemented within a crystal plasticity framework by the means of representative volume element (RVE) analysis. Local elastic strain, as well as stress, were found to obey a n...

Porous ultra-high molecular weight polyethylene (UHMWPE) is a high-performance bioinert polymer used in cranio-facial reconstructive surgery in procedures where relatively low mechanical stresses arise. As an alternative to much stiffer and more costly polyether-ether-ketone (PEEK) polymer, UHMWPE is finding further wide applications in hierarchica...

To explore the possibility of customising the functional behaviour of NiTi shape memory alloy via controlling texture, binary Ni55Ti45 (wt.%) alloys were manufactured in as cast and hot swaged conditions, presenting contrasting initial texture and macroscopic performance. In situ time-of-flight neutron diffraction technique was employed to study th...

Ptychography is a scanning coherent diffraction imaging technique which provides high resolution imaging and complete spatial information of the complex electric field probe and sample transmission function. Its ability to accurately determine the illumination probe has led to its use at modern synchrotrons and free-electron lasers as a wavefront-s...

The pursuit of new nanotechnologies is driven by the demand for miniaturization, ubiquitous computing, increasing connectivity and the Internet of Things (IoT) paradigm, the environmental agenda, and the confluence between microelectronics and biomedical fields. Of particular interest for the present overview are the capabilities of prokaryotic and...

It is interesting to consider just how many of us don't think about the importance of mechanical engineering when we go about our daily lives. Whether we are crossing bridges, getting into our cars, riding on trains, flying in planes or entering buildings, we are relying on mechanical engineers and researchers to have performed an enormous amount o...

Porous ultra-high molecular weight polyethylene (UHMWPE) is a high performance bioinert polymer used in cranio-facial reconstructive surgery in procedures where relatively low mechanical stresses arise. As an alternative to much stiffer and costly polyether-ether-ketone (PEEK) polymer, UHMWPE finds further wide application in hierarchically structu...

This paper presents a summary of recently developed experimental and computational tools to reconstruct residual stress fields and analyze creep in nickel superalloy welds used in aerospace engineering components. This approach combines experimental data with eigenstrain theory to reconstruct stress fields at the macroscopic scale and provided reli...

Cold-worked NiTi wire was subjected to ageing treatment, during which in situ neutron diffraction technique was employed to investigate the microstructure evolution in terms of crystallinity, precipitation, texture, grain size and microstrain. It was found that both heating and rapid cooling bring about significant change in microstructure, whilst...

Photoacoustic imaging is a rapidly maturing imaging modality in biological research and medicine. Its underlying principle is the photoacoustic effect. This method can also be used to study algae containing light-absorbing chromophores, which produce a photoacoustic signal under laser irradiation. Here, we demonstrate successful photoacoustic visua...

Modern advanced manufacturing technologies have made possible the tailored design and fabrication of complex nanoscale architectures with anomalous and enhanced properties, including mechanical and optical metamaterials; structured materials which are able to exhibit unusual mechanical and optical properties that are derived from their geometry rat...