Hardness, yield strength, and plastic flow in thin film metallic-glass

Abstract

Lithiation-induced tensile stress and surface cracking in silicon thin film anode for rechargeable lithium battery J. Appl. Phys. 112, 093507 (2012) Mechanical and thermal behaviors of nitrogen-doped Zr-Cu-Al-Ag-Ta--An alternative class of thin film metallic glass Appl. Phys. Lett. 101, 181902 (2012) Effect of relative humidity on crack propagation in barrier films for flexible electronics J. Appl. Phys. 112, 083520 (2012) Torsion fracture of carbon nanocoils J. Appl. Phys. 112, 084311 (2012) Additional information on J. Appl. Phys. Thin film metallic-glasses (TFMGs) are a promising structural material for fabricating the next generation of micro-and nano-devices; however, a comprehensive study is still lacking today for understanding their mechanical behaviors. In this article, we present a systematic study on the Zr 53 Cu 29 Al 12 Ni 6 TFMGs with varying thicknesses. Other than the intrinsic factor of structural amorphousness, our study pinpoints other extrinsic variables that could affect the hardness and yield strength of the TFMGs. Furthermore, the experimental results from microcompression show that the plastic flow in the TFMG-based micropillars exhibit strong sample size-and-shape dependence, which manifests as a smooth plastic deformation transition from the inhomogeneous to homogeneous mode when the TFMG-based micropillars with a submicron-scale film thickness are deformed into the shape of a low aspect ratio. V C 2012 American Institute of Physics.

Deformation localization in constrained layers of metallic glasses: A parametric modeling analysis

“…Here the yield stress is defined to be the plastic flow stress at 1% offset strain. Note that this curve shows the same trend as in the pillar compression experiment [2,17].…”

Elastic, Plastic, Cracking Aspects of the Hardness of Materials

“…To illustrate further connection with hardness, there are the two reports: first, by Akona, Reis and Ulm [401] on scatching materials ranging in hardness from butter to steel; and secondly, by Keryvin, Crosnier, Laniel, Hoang and Sangleboeuf [402] on scratching a ZrCuAlNi bulk metallic glass. The results of the latter report may be related to hardness and plastic flow measurements obtained on a related material by Ye, Chu, Chen, Wang and Yang [403].…”

Fracture-resistant thin-film metallic glass: Ultra-high plasticity at room temperature

“…26 For a shear band to nucleate and grow, a critical size scale, which is reported to range from ∼100 nm to 500 nm for Zr-based MGs, is required. 17,[27][28][29] Since our TFMG layer thicknesses are smaller than the critical shear-band nucleation size, shear bands do not develop, and TFMG plastic deformation is homogeneous. SAED patterns, including the one shown in the inset of Fig.…”

“…7,[13][14][15][16] For example, 400-nm-thick Zr-based thin-film metallic glasses (TFMGs) in the form of micropillars were found to undergo homogeneous plastic flow with a dramatic plastic strain of 20% during microcompression tests. 17 However, the MG specimens used in all of these experiments were shaped by focused-ion-beam milling, which is known to result in ion damage during sample preparation. In recent years, Greer's group 18,19 reported that electrodeposited (FIB-free) nano-sized Ni-P alloy also exhibit good ductility.…”