National Physical Laboratory

Three dimensional internal imaging of materials structure

Metallic foamRepresentation of metallic foam that was examined using a SEM with a tilting stage over an angle of 60 degrees
 

Industrial needs for understanding and optimising behaviour of complex materials are increasing rapidly. 3D imaging techniques offer solutions to these challenges by successfully characterising materials from traditional to emerging nano- and bio-technology areas at macro-, micro- and nano-resolution levels; for example: bones, tissue scaffolds, dental restorative materials, foams, nano-composites & other materials with intricate structures.

Beyond its conventional use, true 3D internal imaging information also has the potential to be correlated to materials properties, such as density, hardness and modulus. Inputs to this process are sourced from 3D morphology, distribution, interconnectivity or crystallography of anisotropic/cellular material structures containing two or more phases. The performance of materials at the macro level can thus be predicted from 3D imaging studies of complex internal structures or imperfections in materials at micro- or nano- level.

Over the last 20 years a series of novel and innovative true 3D internal imaging techniques have emerged, which have already found their places in the medical science. Following this success, the same 3D methods are now gradually finding their suitable applications in a much wider advanced materials field.

A review of the current status of true 3D internal imaging techniques has been carried out as part of a feasibility study at NPL. The aim of the project has been to determine overall strengths and weaknesses of key 3D imaging methods that conform to 8 main generic groups. The findings are reported in a NPL report (DEPC-MPE 038) published in March 2007. The investigation focuses on understanding industrial drivers, barriers and scope of 3D imaging tools as well as on identifying new opportunities, novel applications and new developments in emerging new materials with inputs from experts, manufacturers and key players in the UK.  Four brief case studies employing SEM/ FIB, X-ray Micro-focus CT and AFM techniques have been undertaken on a number of well defined artefacts (including bio- and nano-materials), and results of the relative performance and outputs at macro, micro and nano scale examinations are reported. The three most promising 3D imaging techniques, based on their novelty, speed, accuracy, ease of operation and cost-effectiveness are found to be : SEM /FIB, X-ray Micro-focus CT and Ultrasound CT. The study concludes by acknowledging 3D internal imaging to be a powerful tool for characterising next generation of premium value material parts and provides a number of recommendations, which may influence formulation of future UK National Measurement System (NMS) programmes on emerging imaging and characterisation technology. Collaboration in a follow-on project based on “3D Imaging, Characterisation and Modelling” is currently invited from UK companies, academic institutions and other partners.

Collaborators in above case studies
Universities of Exeter, Surrey & Hull; Simpleware Ltd.


For further information contact: sekhar.chakravorty@npl.co.uk

Last Updated: 25 Mar 2010
Created: 25 Jul 2007

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