Direct observation of nanocrystal-induced enhancement of tensile ductility in a metallic glass composite

• Published in: Materials & design 2021-11, Vol.209 (C), p.109970, Article 109970
• Main Authors: Gammer, Christoph, Rentenberger, Christian, Beitelschmidt, Denise, Minor, Andrew M., Eckert, Jürgen
• Format: Article
• Language: English
• Subjects: In situ deformation; Metallic glass; Nanocrystals; Transmission electron microscopy
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2021.109970

[Display omitted] •A combination of elastodynamic deformation and heating was used to make a metallic glass nanocomposite.•Homogenous precipitation of mondisperse round nanocrystals (20 nm) with an average spacing of only 150 nm is achieved.•In situ tensile testing is carried out in a transmission electron microscope.•While the monolithic glass shows catastrophic fracture, the shear band is stopped in the nanocomposite. Bulk metallic glasses (BMGs) have attracted wide interest, but their successful application is hindered by their low ductility at room temperature. Therefore, the use of composites of a BMG matrix with crystalline secondary phases has been proposed to overcome this drawback. In the present work we demonstrate the fabrication of a tailored BMG nanocomposite containing a high density of monodisperse nanocrystals with a size of around 20 nm using a combination of mechanical and thermal treatment of Cu36Zr48Al8Ag8 well below the crystallization temperature. Direct observations of the interaction of the nanocrystals with a shear band during in situ deformation in a transmission electron microscope demonstrate that the achieved nanocomposite has the potential to inhibit catastrophic fracture in tension. This demonstrates that a sufficient number of nanoscale structural heterogeneities can be a route towards BMG composites with superior mechanical properties.