Fracture and fractography

We have experience performing fractography on failed ceramic and metal components and specimens using optical and electron microscopy.  We have also lead many fracture studies as part of materials characterization work. This includes investigating mechanisms for fatigue and fatigue crack growth in ceramics and metals, and slow crack growth (stress corrosion cracking) in ceramics. In a failure investigation, it is critical to understand the relationship of the observed fracture morphology to the operating conditions and history of the failed part or specimen. The fractographs at right from super alpha-2 titanium aluminide are from R.G. Rateick, Jr., PE’s thesis.

Relevant blog postings:

Anodizing aluminum and magnesium causes fatigue strength reduction in many alloys. This posting discusses fatigue debit and the underlying mechanism in aluminum-copper alloys AA2219 and AA2024. It includes additional information on AA6061 and magnesium alloy WE43A-T6.

Electron micrograph of anodic coating on aluminum alloy AA2219-T851 (between arrows) and in a pit caused by dissolution of Al2Cu which explains why anodizing aluminum causes fatigue.
AA2219-T851 plate after anodizing showing pits which cause fatigue strength loss. [1]

Selected publications

Citations for material used with permission

[1] R. G. Rateick, R. J. Griffith, D. A. Hall, and K. A. Thompson, “Relationship of microstructure to fatigue strength loss in anodised aluminium-copper alloys,” Materials Science & Technology, vol. 21, no. 10, pp. 1227–1235, 2005. Copyright © 2005 Institute of Materials, Minerals and Mining, figures reprinted by permission of Taylor & Francis Ltd, http://www.tandfonline.com on behalf of Institute of Materials, Minerals and Mining