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The local elastic strains during tensile deformation in a CuZrAlAg metallic glass are obtained by fitting an elliptic shape function to the characteristic amorphous ring in electron diffraction patterns. Scanning nanobeam electron diffraction enables strain mapping with a resolution of a few nanometers. Here, a fast direct electron detector is used to acquire the diffraction patterns at a sufficient speed to map the local transient strain during continuous tensile loading in situ in the transmission electron microscope. The elastic strain in tensile direction was found to increase during loading. After catastrophic fracture, a residual elastic strain that relaxes over time was observed.

The local elastic strains during tensile deformation in a CuZrAlAg metallic glass are obtained by fitting an elliptic shape function to the characteristic amorphous ring in electron diffraction patterns. Scanning nanobeam electron diffraction enables strain mapping with a resolution of a few nanometers. Here, a fast direct electron detector is used to acquire the diffraction patterns at a sufficient speed to map the local transient strain during continuous tensile loading in situ in the transmission electron microscope. The elastic strain in tensile direction was found to increase during loading. After catastrophic fracture, a residual elastic strain that relaxes over time was observed. [ABSTRACT FROM AUTHOR]

Crystallization preferentially occurs on the compressive sides of some metallic glasses due to bending, implying that stress state is a critical factor affecting the mechanically induced crystallization. However, the role of stress state in mechanically induced crystallization in metallic glasses is poorly understood. Here, we report on the crystallization kinetics in different deformed regions during Vickers indentation of Zr65Al7.5Ni10Cu12.5Ag5 metallic glass. Our results indicate that the nucleation rate beneath the indenter tip is much higher than that under an indenter edge. It is revealed that the nucleation rate I (m-3s-1) and the effective compressive stress P (MPa) follow an expression I = exp(3.81 + 0.044 P), which agrees well with our experimental results. Our findings reduce the role of stress state in mechanically induced crystallization in metallic glasses, which is helpful in understanding the mechanism of mechanically induced crystallization. [ABSTRACT FROM AUTHOR]

Cu-Zr-based metallic glass (MG) has been applied as a binding agent of Ag paste for front contact formation in Si solar cell by screen printing process. Use of electroconductive MG binder significantly improves the quality of the contact by the formation of highly dense 10-50 nm size Ag crystallites and the noncorrugation of the emitter surface with a very shallow Ag crystallite penetration depth of 10-30 nm. Nanoscale Ag crystallites form on the emitter surface by local Si-Cu-Ag eutectic melting, leading to the formation of pyramidal pits on the Si emitter surface, followed by precipitation of Ag crystallites during cooling. [ABSTRACT FROM AUTHOR]

A Ni–8Zr high strength ultrafine eutectic-dendrite composite with large plasticity has been developed in the Ni–Zr binary eutectic system. The excellent mechanical properties are attributed to the specific heterogeneous microstructure with distinctly different length scales, i.e., micrometer-size ductile dendrites combined with an ultrafine eutectic matrix. The plastic deformation mainly proceeds through a shear banding mechanism. However, there is no significant shear localization due to the constraint effect of ductile solid solution Ni phases including dendrites and/or alternating lamellar layers. Furthermore, excessive shear stress and accumulated shear strain can be effectively released and accommodated by delocalization and multiplication of shear bands. [ABSTRACT FROM AUTHOR]

Microstructural investigations of Fe56Nb4Al40 ultrafine eutectic-dendrite composite reveal that its high room temperature plasticity mainly originates from the evolution of slip in the dendrites and multiple shear banding in the ultrafine eutectic matrix, respectively. Here, we sequentially describe that the shear bands in the ultrafine eutectic matrix are propagated with generation of strain field in the soft alpha-Fe(Al) layers rather than passing through by sharp shear banding in the hard (Fe,Al)2Nb intermetallic layers. Consequently, step morphologies at the interfaces of the alternating lamellae and the dendrite/eutectic matrix strongly support the effective accommodation of shear strain during shear band propagation. [ABSTRACT FROM AUTHOR]