Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Recent advances in friction-stir welding : Process, weldment structure and properties

A review of dynamic recrystallization phenomena in metallic materials

The application of automated Electron Backscatter Diffraction (EBSD) in the scanning electron microscope, to the quantitative analysis of grain and subgrain structures is discussed and compared with conventional methods of quantitative metallography. It is shown that the technique has reached a state of maturity such that linescans and maps can routinely be obtained and analysed using commercially available equipment and that EBSD in a Field Emission SEM (FEGSEM) allows quantitative analysis of grain/subgrains as small as ∼0.2 μm. EBSD can often give more accurate measurements of grain and subgrain size than conventional imaging methods, often in comparable times. Subgrain/cell measurements may be made more easily than in the TEM although the limited angular resolution of EBSD may be problematic in some cases. Additional information available from EBSD and not from conventional microscopy, gives a new dimension to quantitative metallography. Texture and its correlation with grain or subgrain size, shape and position are readily measured. Boundary misorientations, which are readily obtainable from EBSD, enable the distribution of boundary types to be determined and CSL boundaries can be identified and measured. The spatial distribution of Stored Energy in a sample and the amount of Recrystallization may also be measured by EBSD methods.

Review Grain and subgrain characterisation by electron backscatter diffraction

Materials discovery and design using machine learning

Modelling the kinetics of strain induced precipitation in Nb-microalloyed steels

Strengthening in rapidly solidified age hardened CuCr and CuCrZr alloys

Constitutive equations which describe the flow stress behaviour of materials during hot deformation are used to model forming processes. Since the flow stress depends on both temperature and strain rate, the Zener–Hollomon parameter which combines these factors, is frequently used to describe the shape of such curves. For materials which dynamically recover, (only) the flow stress reaches a steady state value at high strains and methodologies which enable such behaviour to be modelled have previously been presented. Beyond the onset of dynamic recrystallisation, the flow stress of materials, such as steels, reach a peak in flow stress before gradual softening. The relative position of the peak in the flow stress shifts as a function of the Zener–Hollomon parameter further complicating such analyses. The present paper describes the development and application of a methodology for modelling the flow stress of microalloyed steels: materials which exhibit dynamic recrystallisation behaviour.

Development of constitutive equations for modelling of hot rolling

Precipitation of NbC in a model austenitic steel

It is well-accepted that modelling of microstructural evolution of aluminium alloys during thermomechanical processing is highly desirable to predict product properties and/or to design process variables based on requirements for the properties. To do so, having soundly based physical models is of interest for both academic research and industrial practice. In the present paper, models for predicting the evolution of internal state variables such as internal dislocation density, subgrain size and misorientation between subgrains, and subsequent recrystallisation behaviour are developed for both constant and transient deformation conditions. In predicting the evolution of the internal state variables under transient deformation conditions, the internal ‘geometrically necessary’ dislocation density is related to the subgrain boundary dislocation density. In the model to predict static recrystallisation behaviour, nucleation of recrystallisation is initially discussed based on experimental results and quantitative metallographic observations. In the calculation of recrystallisation nucleation density, distribution of subgrain size and misorientation between subgrains are key parameters. The predicted evolution of internal state variables and subsequent recrystallisation kinetics and recrystallised grain size using the developed model are in reasonable agreement with experimental data.

C.M. Sellars

Papers

Modelling the kinetics of strain induced precipitation in Nb-microalloyed steels

Strengthening in rapidly solidified age hardened CuCr and CuCrZr alloys

Development of constitutive equations for modelling of hot rolling

Precipitation of NbC in a model austenitic steel

Microstructural modelling of aluminium alloys during thermomechanical processing