398158 Combined Modelling and Experimental Investigation of Mechanical Behaviors of Metallic Glasses

Monday, November 17, 2014
Galleria Exhibit Hall (Hilton Atlanta)
Melanie Cantwell, Mechanical Engineering, Worcester Polytechnic Institute, Worcester, MA

Metallic glasses are innovative in the unique combination of steel-like strength and plastic-like formability. Their applications, however, are limited by a catastrophic failure due to the formation and propagation of shear bands. The ‘bulk-scale’ concerns are mitigated by processing metallic glasses as low-dimensional thin films using the near atomic scale control. In this work, we combine computational modelling and experimental testing to gain an understanding of the mechanical behaviors of thin film metallic glasses (TFMGs), particularly the initiation of shear bands. Experimentally, we conducted various nano-indentation tests, and the initiation of the shear bands were reflected by the discrete ripples on the measured load-displacement traces. Further, with increased strain rates of indentation, the shear band initiation was suppressed, leading to increased yield loads. Additionally, the measured yield loads vary with sample location as a result of the structural and chemical inhomogeneity of metallic glasses at nano-scale. The computational simulation results capture the experimental observations, and also provide insight into how the atomistic process leads to the formation of shear bands. This experimental-computational collaboration will give way for a broader grasp of the deformation mechanisms that ultimately yield catastrophic failure.

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