Nanoscale strength distribution in amorphous versus crystalline metals
Author(s)
Packard, Corinne E.; Franke, Oliver; Homer, Eric R.; Schuh, Christopher A.
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Low-load nanoindentation can be used to assess not only the plastic yield point, but the distribution of yield points in a material. This paper reviews measurements of the so-called nanoscale strength distribution (NSD) on two classes of materials: crystals and metallic glasses. In each case, the yield point has a significant spread (10–50% of the mean normalized stress), but the origins of the distribution are shown to be very different in the two materials classes. In crystalline materials the NSD can arise from thermal fluctuations and is attended by significant rate and temperature dependence. In metallic glasses well below their glass-transition temperature, the NSD is reflective of fluctuations in the sampled structure and is not very sensitive to rate or temperature. Computer simulations using shear transformation zone dynamics are used to separate the effects of thermal and structural fluctuations in metallic glasses, and support the latter as dominating the NSD of those materials at low temperatures. Finally, the role of the NSD as a window on structural changes due to annealing or prior deformation is discussed as a direction for future research on metallic glasses in particular.
Date issued
2011-01Department
Massachusetts Institute of Technology. Department of Materials Science and EngineeringJournal
Journal of Materials Research
Publisher
Cambridge University Press (Materials Research Society)
Citation
Packard, C.E., O. Franke, E.R. Homer, and C.A. Schuh. “Nanoscale strength distribution in amorphous versus crystalline metals.” Journal of Materials Research 25, no. 12 (December 31, 2010): 2251-2263. © 2010 Materials Research Society
Version: Final published version
ISSN
0884-2914
2044-5326