Evaluation of fracture mechanisms in nanostructured tool materials
Project dates: 1 Sept 2007 – 31 Aug 2011
This project has developed ground-breaking metrology tools, allowing demonstration of the mechanisms underpinning crack initiation and growth in nanostructured tool materials. This enables cost-effective and energy-efficient production over the next few decades.
Advances are currently limited by the statistical nature of fracture and the inability to observe detailed fracture events at the nano- and mesoscale. This obstacle has now been overcome through the development by the Materials Division of a world-leading, high-stiffness in situ stressing system combined with simultaneous high resolution imaging in a field emission SEM and fast high sensitivity analysis.
This new facility has been applied to study crack growth in high-strength tool materials such as hardmetals and ceramics. Fracture in these brittle materials normally occurs catastrophically fast making studies of changes in structure incredibly difficult to observe. The new, NPL-developed facility enables controlled crack growth through the use of a very stiff loading mechanism. In this way the interaction of the crack with details of the microstructure can be studied in-situ and correlated with the stress fields generated by the crack. This will provide essential understanding to developers and users of these materials enabling them to provide new tools giving significant improvements in the efficiency of materials processing.
NPL staff involved with the project
Mark Gee
Bryan Roebuck
Roger Morrell
Ken Mingard
John Nunn
Jerry Lord
Collaborations
- British Hardmetals Association Research Group
- Sandvik Hardmaterials
- Element 6
Publications
- Some aspects of the structure of cobalt and nickel binder phases in hardmetals
M. G. Gee
Acta Materialia, 59, pages 2277–2290 (2011) - The paper from the PM 2011 conference proceedings mentioned below, 'Examination of Fracture and Deformation Mechanisms in WC/Co Hardmetals', has been submitted to Int. J. Refrac. and Hardmaterials.
Conferences and Presentations
- Two presentations on the EBSD work have been made to the British Hardmetals Association Research Group in Spring and Autumn 2010.
- 'Examination of Fracture and Deformation Mechanisms in WC/Co Hardmetals', which described the results of testing, was presented at PM 2011 in Barcelona and published in the conference proceedings.
Further opportunities
A TSB project has been completed which will include work that relies on the EBSD technology being developed in the SR project.