Nucleation reactions during deformation and crystallization of metallic glass

Perepezko, John, Imhoff, Seth, Chen, Ming-Wei, Gonzalez Sanchez, Sergio and Inoue, Akihisa (2012) Nucleation reactions during deformation and crystallization of metallic glass. Journal of Alloys and Compounds, 536. S55-S59. ISSN 0925 8388

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Abstract

Nucleation reactions play a central role in the synthesis of both bulk metallic glasses and nanostructured materials. For nanostructured materials it is necessary to promote a high nucleation density without significant growth or coarsening. Beyond crystallization reactions nucleation of shear bands is critical for promoting a homogeneous flow and useful ductility for structural applications of bulk metallic glass. The study and analysis of nucleation reactions for these different situations requires a consideration of the stochastic nature of nucleation, the influence of heterogeneous sites, and the controlling transport properties. For shear band nucleation, the stochastic nature can be effectively probed by instrumented nanoindentation tests. The analysis of a statistically significant number of measurements of the first pop-in shear band nucleation events reveals at least two main nucleation sites. In nanostructured composites, the initial nucleation stage is influenced by transient effects as reflected in the delay time prior to steady state nucleation and by heterogeneous nucleation sites that are related to medium range order regions in Al-base amorphous alloys. Moreover, the early growth characteristics are linked to the maximum achievable particle density. The new developments and insight on the fundamental understanding of nanostructure reaction mechanisms offer valuable guidance for control of nanoscale microstructures and for promoting ductile deformation behavior.

Item Type:	Article
Uncontrolled Keywords:	Metallic glasses; Kinetics; Precipitation; Rapid solidification; Mechanical properties
Subjects:	F200 Materials Science H300 Mechanical Engineering
Department:	Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User:	Becky Skoyles
Date Deposited:	09 Nov 2015 12:26
Last Modified:	12 Oct 2019 22:54
URI:	http://nrl.northumbria.ac.uk/id/eprint/24359

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