Direct observation of nanocrystal-induced enhancement of tensile ductility in a metallic glass composite. (1st November 2021)

• Record Type: Journal Article
• Authors: Gammer, Christoph; Rentenberger, Christian; Beitelschmidt, Denise; Minor, Andrew M.; Eckert, Jürgen
• Is Part Of: Materials & design. Volume 209(2021)
• Publication Date: 2021-11-01
• Subjects: Metallic glass -- Nanocrystals -- Transmission electron microscopy -- In situ deformation; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2021.109970
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: 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. Abstract: 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 Cu36 Zr48 Al8 Ag8 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.