Metallic glasses (MGs) are attracting intense research interest. Owing to their atomic arrangement lacking long-range order, they show unique mechanical and physical properties, such as large elastic strain limit, high strength, hardness, corrosion and wear resistance [1]. However, MGs lack tensile plasticity and thus fail catastrophically at room temperature. Several approaches were explored in recent years trying to improve plasticity by artificially introducing crystalline phases or bringing the material to a higher energy state by so-called rejuvenation. In a previous study, Cu-Zr-based metallic glass composites have been characterized by multiscale electron microscopic and hardness testing techniques, suggesting promising structures. 

This work examines their mechanical properties using in-situ testing in a transmission electron microscope (TEM). It will be demonstrated, how the interplay between local structural heterogeneities in amorphous and crystalline structures affects the overall mechanical properties. For a deeper understanding of the observed deformation mechanisms nanobeam electron diffraction (NBED) will be used in combination with a high speed direct electron detector. Previous studies have shown, that this novel technique is able to map local elastic strains with nanoscale spatial resolution [2]. 

The authors gratefully acknowledge the financial support from the Austrian Science Fund (FWF) (Y1236-N37).

References

[1] A.L. Greer, Metallic glasses on the threshold, Mater. Today 12 (1-2) (2009);

[2] C. Gammer, J. Kacher, C. Czarnik, O. L. Warren, J. Ciston, and A. M. Minor, Local nanoscale strain mapping of a metallic glass during in situ testing, Appl. Phys. Lett. 112, 171905 (2018).