Dr Tan Sui


Lecturer in Materials Engineering
BEng DPhil (Oxon) CSci FIMMM
+44 (0)1483 689670
15 AA 02

Biography

Areas of specialism

Multi-beam microscopy techniques (FIB-DIC, SEM, EDX, EBSD, STEM, Raman and TOF-SIMS); Multi-modal synchrotron X-ray techniques (SAXS/WAXS, Imaging and Spectroscopy)

University roles and responsibilities

  • FEPS representative for human tissue research
  • MES representative for social media

    Affiliations and memberships

    Fellow
    Institute of Materials, Minerals & Mining (IOM3)
    Level 5 Award in Management and Leadership
    Chartered Management Institute (CMI)
    Member
    EPSRC-WES membership - A Centenary Celebration: Women's Engineering Society Membership
    Member
    EPSRC Peer Review Associate College
    Member
    International Association for Dental Research (IADR) Member
    Committee Member
    Advances in Functional Materials (AFM), Los Angeles, USA
    Committee Member
    International Conference on Mechanical and Aerospace Engineering (ICMAE)
    Review Editor
    Frontiers in Dental Medicine

    Business, industry and community links

    Diamond Light Source
    Joint PhD studentship
    Culham Centre for Fusion Energy
    Doctoral College Studentship Award
    Pilkington Technology Management
    Joint EPSRC CDT in MiNMaT EngD Project

    Research

    Research interests

    Research projects

    Research collaborations

    Supervision

    Postgraduate research supervision

    My teaching

    My publications

    Publications

    Tan Sui, Jiří Dluhoš, Tao Li, Kaiyang Zeng, Adrian Cernescu, Gabriel Landini, Alexander Korsunsky (2018)Structure-Function Correlative Microscopy of Peritubular and Intertubular Dentine, In: Materials11(9) MDPI

    Peritubular dentine (PTD) and intertubular dentine (ITD) were investigated by 3D correlative Focused Ion Beam (FIB)-Scanning Electron Microscopy (SEM)-Energy Dispersive Spectroscopy (EDS) tomography, tapping mode Atomic Force Microscopy (AFM) and scattering-type Scanning Near-Field Optical Microscopy (s-SNOM) mapping. The brighter appearance of PTD in 3D SEM-Backscattered-Electron (BSE) imaging mode and the corresponding higher grey value indicate a greater mineral concentration in PTD (~160) compared to ITD (~152). However, the 3D FIB-SEM-EDS reconstruction and high resolution, quantitative 2D map of the Ca/P ratio (~1.8) fail to distinguish between PTD and ITD. This has been further confirmed using nanoscale 2D AFM map, which clearly visualised biopolymers and hydroxyapatite (HAp) crystallites with larger mean crystallite size in ITD (32 ± 8 nm) than that in PTD (22 ± 3 nm). Correlative microscopy reveals that the principal difference between PTD and ITD arises primarily from the nanoscale packing density of the crystallites bonded together by thin biopolymer, with moderate contribution from the chemical composition difference. The structural difference results in the mechanical properties variation that is described by the parabolic stiffness-volume fraction correlation function introduced here. The obtained results benefit a microstructure-based mechano-chemical model to simulate the chemical etching process that can occur in human dental caries and some of its treatments.

    Tan Sui, Enrico Salvati, Robert A Harper, Hongjia Zhang, Richard M Shelton, Gabriel Landini, Alexander M Korsunsky (2018)In situ monitoring and analysis of enamel demineralisation using synchrotron X-ray scattering, In: Acta Biomaterialia77pp. 333-341 Elsevier

    Dental caries is one of the most common chronic diseases that affect human teeth. It often initiates in enamel, undermining its mechanical function and structural integrity. Little is known about the enamel demineralisation process caused by dental caries in terms of the microstructural changes and crystallography of the inorganic mineral phase. To improve the understanding of the carious lesion formation process and to help identify efficient treatments, the evolution of the microstructure at the nano-scale in an artificially induced enamel erosion region was probed using advanced synchrotron small-angle and wide-angle X-ray scattering (SAXS and WAXS). This is the first in vitro and time-resolved investigation of enamel demineralisation using synchrotron X-ray techniques which allows in situ quantification of the microstructure evolution over time in a simulated carious lesion. The analysis revealed that alongside the reduction of mineral volume, a heterogeneous evolution of hydroxyapatite (HAp) crystallites (in terms of size, preferred orientation and degree of alignment) could be observed. It was also found that the rate and direction of dissolution depends on the crystallographic orientation. Based on these findings, a novel conceptual view of the process is put forward that describes the key structural parameters in establishing high fidelity ultrastructure-based numerical models for the simulation of the enamel demineralisation process.

    Jinan Hu, Tan Sui (2020)Insights into the reinforcement role of peritubular dentine subjected to acid dissolution, In: Journal of the Mechanical Behavior of Biomedical Materials103103614 Elsevier

    Human dentine is a mineralised dental tissue that consists of dentinal tubules surrounded by two distinct dentinal phases: peritubular dentine (PTD) and intertubular dentine (ITD). Dental caries, which manifests itself as a consequence of demineralisation, is one of the most common chronic diseases that affect the function of human teeth. Due to the difference in the packing density of crystallites, PTD and ITD exhibit different reaction rates to acid dissolution. The present study evaluates how the effective Young’s modulus degrades and how the effective stress redistributes in demineralised human dentine as a result of incremental acid dissolution process. An analytical two-layer composite model is proposed and used for the effective Young’s modulus calculation. 3D numerical representative volume elements (RVEs) with different variations in PTD fraction and dentinal tubule density are established to evaluate effective stress redistribution and examine the critical factors that can affect the mechanical performance. The models are then applied on an actual dentine bulk sample. The results reveal how PTD serves as a protection to ITD thus highlight the important role that PTD plays for the structural integrity of dentine. The obtained insights are crucial for advancing the understanding of a variety of natural and therapeutic effects from the mechanical perspective, e.g. the mechanical performance assessment of human dentine subject to complex dynamic processes of de- and re-mineralisation that can occur in human dental caries and dental treatments. It will ultimately inspire the biomimetic design towards strengthening the dentine and dentine-like materials.

    Hongbo Wan, Nathanael Leung, Sana Algharaibeh, Tan Sui, Qiang Liu, Hua-Xin Peng, Bo Su (2020)Cost-effective fabrication of bio-inspired nacre-like composite materials with high strength and toughness, In: Composites Part B: Engineering202108414 Elsevier

    A cost-effective one-step densification process based on bi-directional freeze casting was investigated to produce nacre-like alumina/poly (methyl methacrylate) (PMMA) composites with a unique micro-layered (μL) architecture. This method has the advantage of shorter processing time, as it requires only sintering once instead of twice as in the fabrication of conventional brick-and-mortar (BM) composites via freeze casting. By tuning the processing parameters, composites with different ceramic content and layer thickness were obtained. The resultant mechanical properties of μL composites showed that ceramic content and wall thickness affected mechanical properties significantly. The μL composite with fine ceramic walls (8 μm) and relatively high ceramic fraction (72 vol%) exhibited an exceptional combination of high flexural strength (178 MPa) and fracture toughness (12.5 MPa m1/2). The μL composites were also compared with the conventional BM composites. Although the fracture behaviour of both composites exhibited similar extrinsic toughening mechanisms, the μL composites with longer ceramic walls displayed superior mechanical properties in terms of strength and fracture toughness in comparison with the BM composites comprising short ceramic walls (i.e. bricks), due to the effectiveness of stress transfer of load-bearing ceramic phase within the composites.

    Yiqiang Wang, Omar Mohamed, Keren Dunn, Tan Sui, Mutaz Bashir, Peter Cooper, Adomas Lukenskas, Guiyi Wu, Michael Gorley (2021)Effects of stress triaxiality and strain rate on the fracture of a CuCrZr alloy, In: Journal of nuclear materials543152546 Elsevier B.V

    Precipitation hardened Copper-Chromium-Zirconium (CuCrZr) alloy is a prime candidate for divertor components in future European DEMOnstration (DEMO) fusion reactors. To develop the DEMO Design Criteria for In-vessel Components (DDC-IC), the failure criterion of CuCrZr needs to be investigated. Hence, the effects of stress triaxiality and loading strain rate on the fracture of solution heat treated and annealed CuCrZr alloys were studied using digital-imaging-correlation and electron microscopy techniques. It was found that an increase in the stress triaxiality caused a significant decrease of over 50% in the equivalent strain to fracture. On the other hand, increasing applied strain rate from 1.3 × 10−5 s−1to 8.6 × 10−3 s−1 had no considerable effects on the yield stress and elongation. However, higher flow stresses and a larger number density of voids were observed under the highest applied strain rate of 8.6 × 10−3 s−1. Fracture surface analysis showed that the failure model was dominated by void growth and coalescence for all the tests. This work has been performed within the Engineering Data and Design Integration (EDDI) sub-project of the EUROfusion Materials work package and aimed to contribute to the development of the DEMO Design Criteria for In-vessel Components.

    K. Kageyama, F. Adziman, E. Alabort, Tan Sui, A. M. Korsunsky, R. C. Reed (2018)In Situ Diagnostics of Damage Accumulation in Ni-Based Superalloys Using High-Temperature Computed Tomography, In: Metallurgical and Materials Transactions A49(9)pp. 4274-4289 Springer Verlag

    The design, operation, and performance of a laboratory-scale X-ray computed tomography arrangement that is capable of elevated-temperature deformation studies of superalloys to 800 °C and possibly beyond are reported. The system is optimized for acquisition of three-dimensional (3D) backprojection images recorded sequentially during tensile deformation at strain rates between 10−4 and 10−2 s−1, captured in situ. It is used to characterize the evolution of damage—for example, void formation and microcracking—in Nimonic 80A and Inconel 718 superalloys, which are studied as exemplar polycrystalline alloys with lesser and greater ductility, respectively. the results indicate that such damage can be resolved to within 30 to 50 μm. Collection of temporally and spatially resolved data for the damage evolution during deformation is proven. Hence, the processes leading to creep fracture initiation and final rupture can be quantified in a novel way.

    Guanhua Sun, Shan Lin, Hong Zheng, Yunzhi Tan, Tan Sui (2020)The virtual element method strength reduction technique for the stability analysis of stony soil slopes, In: Computers and Geotechnics119103349 Elsevier

    Based on the incremental method of elastic-plastic mechanics and bilinear projection operators, by combining the strength reduction method with the φ-v inequality, this paper proposes a virtual element method strength reduction technique for slope stability analysis. The deformations of a homogeneous slope and heterogeneous slope are solved under different strength reduction factors, and the mesh dependency problem of the method is discussed. Numerical examples verify the correctness and effectiveness of the proposed method. The results demonstrate that due to the differences in the physical and mechanical properties of soil and rocks, stress becomes concentrated in the contact zone between soil and rocks, and thus, the plastic zone surrounds the rocks. Therefore, it is difficult to form regular connections in a plastic zone, such as a soil slope. This method can be used to analyse the stability of a stony soil slope and to study the effects of particle size, rock content, rock density, and rock spatial distribution on the mechanical behaviour of stony soil slopes.

    Haibin Wang, Yinghao Sun, Yunzhi Tan, Tan Sui, Guanhua Sun (2019)Deformation characteristics and stability evolution behavior of Woshaxi landslide during the initial impoundment period of the Three Gorges reservoir, In: Environmental Earth Sciences78(20)592 Springer-Verlag

    The study area, Woshaxi landslide, is 400 m long and 700 m wide, with an average thickness of approximately 15 m and a volume of 4.2 × 106 m3. The Woshaxi landslide, which is located on the Qinggan River, a tributary of the Yangtze River in the Three Gorges reservoir area, is just 1.5 km from the Qianjiangping landslide. The Qianjiangping landslide following the Three Gorges reservoir impoundment was caused by the combined effects of rainfall and reservoir water-level fluctuation. In this study, the Woshaxi landslide’s deformation characteristics and mechanism are investigated based on deformation monitoring data and a geological survey during the initial impoundment period of the Three Gorges reservoir. Furthermore, based on the characteristics of the combined effects of reservoir water level fluctuation and rainfall in the Three Gorges reservoir area, the stability evolution behavior of the Woshaxi landslide during the initial impoundment period of the Three Gorges reservoir is investigated.

    Tan Sui, Enrico Salvati, Hongjia Zhang, Kirill Nyaza, Fedor S. Senatov, Alexei I. Salimon, Alexander M. Korsunsky (2018)Probing the complex thermo-mechanical properties of a 3D-printed polylactide-hydroxyapatite composite using in situ synchrotron X-ray scattering, In: Journal of Advanced Research Elsevier

    Polylactide (PLA)-hydroxyapatite (HAp) composite components have attracted extensive attentions for a variety of biomedical applications. This study seeks to explore how the biocompatible PLA matrix and the bioactive HAp fillers respond to thermo-mechanical environment of a PLA-HAp composite manufactured by 3D printing using Fused Filament Fabrication (FFF). The insight is obtained by in situ synchrotron small- and wide- angle X-ray scattering (SAXS/WAXS) techniques. The thermo-mechanical cyclic loading tests (0-20MPa, 22-56°C) revealed strain softening (Mullins effect) of PLA-HAp composite at both room and elevated temperatures (50°C) due to the increased chain mobility. Above this temperature the deformation behaviour of the soft PLA lamella changes drastically. The thermal test (0-110°C) identified multiple crystallisation mechanisms of the PLA amorphous matrix, including reversible stress-induced large crystal formation at room temperature, reversible coupled stress-temperature-induced PLA crystal formation appearing at around 60°C, as well as irreversible heating-induced crystallisation above 92°C. The shape memory test (0-3.75MPa, 0-70°C) of the PLA-HAp composite demonstrates a fixing ratio (strain upon unloading/strain before unloading) of 65% and rather a ∼100% recovery ratio, showing an improved shape memory property. These findings provide a new framework for systematic characterisation of the thermo-mechanical response of composites, and open up ways towards improved material design and enhanced functionality for biomedical applications.

    S Ying, L Ma, Tan Sui, C Papadaki, E Salvati, L Brandt, H Zhang, A Korsunsky (2018)Nanoscale Origins of the Size Effect in the Compression Response of Single Crystal Ni-Base Superalloy Micro-Pillars, In: Materials11(4)561 MDPI

    Nickel superalloys play a pivotal role in enabling power-generation devices on land, sea, and in the air. They derive their strength from coherent cuboidal precipitates of the ordered γ’ phase that is different from the γ matrix in composition, structure and properties. In order to reveal the correlation between elemental distribution, dislocation glide and the plastic deformation of microand nano-sized volumes of a nickel superalloy, a combined in situ nanoindentation compression study was carried out with a scanning electron microscope (SEM) on micro- and nano-pillars fabricated by focused ion beam (FIB) milling of Ni-base superalloy CMSX4. The observed mechanical response (hardening followed by softening) was correlated with the progression of crystal slip that was revealed using FIB nano-tomography and energy-dispersive spectroscopy (EDS) elemental mapping. A hypothesis was put forward that the dependence of material strength on the size of the sample (micropillar diameter) is correlated with the characteristic dimension of the structural units (γ’ precipitates). By proposing two new dislocation-based models, the results were found to be described well by a new parameter-free Hall–Petch equation.

    Hongjia Zhang, Tan Sui, Enrico Salvati, Dominik Daisenberger, Alexander Lunt, Kai Fong, Xu Song, Alexander Korsunsky (2018)Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation, In: Materials11(3) MDPI

    High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning) or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short). As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated using multiple direction strain data, leading to full in-plane strain evaluation. It is therefore concluded that XRD-DIC provides a reliable and robust method for strain evaluation from 2D powder diffraction data. The XRD-DIC approach simplifies the analysis process by skipping 2D to 1D conversion, and opens new possibilities for robust 2D powder diffraction data analysis for full in-plane strain evaluation.

    T. Sui, E. Salvati, H. Zhang, I.P. Dolbnya, A.M. Korsunsky (2019)Multiscale synchrotron scattering studies of the temperature-dependent changes in the structure and deformation response of a thermoplastic polyurethane elastomer, In: Materials Today Advances4100024 Elsevier

    The distinct molecular architecture and thermomechanical properties of polyurethane block copolymers make them suitable for applications ranging from textile fibers to temperature sensors. In the present study, differential scanning calorimetry (DSC) analysis and macroscopic stress relaxation measurements are used to identify the key internal processes occurring in the temperature ranges between −10 °C and 0 °C and between 60 °C and 70 °C. The underlying physical phenomena are elucidated by the small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) study of synchrotron beams, allowing the exploration of the structure-property relationships as a function of temperature. In situ multiscale deformation analysis under uniaxial cyclic thermomechanical loading reveals a significant anomaly in the strain evolution at the nanoscale (assessed via SAXS) in the range between −10 °C and 0 °C owing to the ‘melting’ of the soft matrix. Furthermore, WAXS measurement of crystal strain within the hard regions reveals significant compressive residual strains arising from unloading at ∼60 °C, which are associated with the dynamic shape memory effect in polyurethane at these temperatures.

    A.M. Korsunsky, E. Salvati, A.G.J. Lunt, Tan Sui, M.Z. Mughal, R. Daniel, J. Keckes, E. Bemporad, M. Sebastiani (2018)Nanoscale residual stress depth profiling by Focused Ion Beam milling and eigenstrain analysis, In: Materials & Design145pp. 55-64 Elsevier

    Residual stresses play a crucial role in determining material properties and behaviour, in terms of structural integrity under monotonic and cyclic loading, and for functional performance, in terms of capacitance, conductivity, band gap, and other characteristics. The methods for experimental residual stress analysis at the macro- and micro-scales are well established, but residual stress evaluation at the nanoscale faces major challenges, e.g. the need for sample sectioning to prepare thin lamellae, by its very nature introducing major modifications to the quantity being evaluated. Residual stress analysis by micro-ring core Focused Ion Beam milling directly at sample surface offers lateral resolution better than 1 μm, and encodes information about residual stress depth variation. We report a new method for residual stress depth profiling at the resolution better than 50 nm by the application of a mathematically straightforward and robust approach based on the concept of eigenstrain. The results are validated by direct comparison with measurements by nano-focus synchrotron X-ray diffraction.

    Additional publications