Additive manufacturing of metallic components – Process, structure and properties

Recording of presentation introducing narrative analysis, outlining what it is, why it can be a useful approach, how to do it and where to find out more. Presentation given at methods@manchester seminar at University of Manchester on 4 March 2010.

What is Narrative Analysis

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Schuh-ActaMater07-Mechanical%20behaviour%20of%20amorphous%20alloys.pdf

Mechanical behavior of amorphous alloys

Materials Challenges in Nuclear Energy

X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information nee...

https://www.tandfonline.com/doi/pdf/10.1179/1743280413Y.0000000023

Quantitative X-ray tomography

ENGIN-X, a new time-of-flight (TOF) neutron diffractometer optimized to measure elastic strains at precise locations in bulky specimens recently commissioned at the ISIS Facility in the Rutherford Laboratory, UK, is described. Fast counting times, together with a flexible and accurate definition of the instrumental gauge volume are the main requirements of neutron strain scanning and have been addressed on ENGIN-X through the design of a novel TOF diffractometer with a tuneable resolution and interchangeable radial collimators. Further, the routine operation of the instrument has been optimized by creating a virtual instrument, i.e. a three-dimensional computer representation of the diffractometer and samples, which assists in the planning and execution of experiments. On comparing ENGIN-X with its predecessor ENGIN, a 25× gain in performance is found, which has allowed the determination of stresses up to 60 mm deep in steel specimens. For comparison with constant-wavelength diffractometers, special attention has been paid to the absolute number of counts recorded during the experiments. A simple expression is presented for the estimation of counting times in TOF neutron strain scanning experiments.

/pdf/engin-x-a-third-generation-neutron-strain-scanner-1n9mtr2xtr.pdf

ENGIN-X: a third-generation neutron strain scanner

Recent advances in residual stress measurement

The positions of Bragg edges in neutron transmission experiments can be defined with high accuracy using the time-of-flight (TOF) technique on pulsed neutron sources. A new dedicated transmission instrument has been developed at ISIS, the UK spallation source, which provides a precision of Δd/d ≃ 10−5 in the determination of interplanar distances. This is achieved by fitting a theoretical three-parameter expression to the normalized Bragg edges appearing in the TOF transmission spectra. The technique is demonstrated by experiments performed on iron, niobium and nickel powders. The applicability of using the instrument for the determination of lattice strains in materials has been investigated using a simple in situ loading experiment. Details of the calibration process are presented and the dependence of the resolution and the experimental times required by the transmission geometry on the instrumental variables are studied. Finally, the requirements for a Rietveld-type refinement of transmission data and the advantages and limitations over traditional neutron diffraction peak analysis are discussed.

Time-of-flight neutron transmission diffraction

https://apo.ansto.gov.au/dspace/bitstream/10238/4393/2/FLORES-JOHNSON_Ballistic_Performance_Of_Multi-Layered_Metallic_Plates_2011_12.pdf

Ballistic performance of multi-layered metallic plates impacted by a 7.62-mm APM2 projectile

As interest in new generations of nuclear reactors is increasing worldwide, renewed research effort into new materials more tolerant to extreme conditions is crucial.

Lyndon Edwards

Papers

ENGIN-X: a third-generation neutron strain scanner

Recent advances in residual stress measurement

Time-of-flight neutron transmission diffraction

Ballistic performance of multi-layered metallic plates impacted by a 7.62-mm APM2 projectile

Greater tolerance for nuclear materials