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MM: Fachverband Metall- und Materialphysik

MM 22: Mechanical properties I - Plastic deformation & fracture

MM 22.6: Talk

Tuesday, April 1, 2014, 11:30–11:45, IFW B

In-situ Fatigue, Fracture and Dynamic Mechanical testing in the SEM — •Douglas Stauffer, Sanjit Bhowmick, Ryan Major, S.A. Syed Asif, and Oden Warren — Hysitron, Inc. 9625 West 76th St. Minneapolis MN

Rapid expansion of in situ nanomechanical testing gives researchers a means of testing and exploring fundamental deformation mechanisms. Here, new instrumentation involving novel control algorithms to control system quality factor is described, which allows the use of dynamic measurements without undesirable system oscillation. These dynamic measurements can then be used to explore frequency dependency, strain rate, fatigue, and crack propagation in a variety of materials. Here, frequency dependent effects are used to explore the effect of electron beam induced viscoplasticity in micron sized silica spheres. When tested without the presence of an electron beam, these spheres fracture at strains of less than 2%. However when irradiated at 20keV and 30pA in an SEM, the spheres can be deformed to strains of more than 50% under certain conditions. Rapid loading and high frequencies, correlated with high strain rates, result in fracture at strains of approximately 10% under e-beam irradiation. This is in contrast to slow loading and low frequency load controlled dynamic loading, where strains as large as 60% without fracture have been achieved.