scholarly journals Nanoindentation Investigation on the Size-Dependent Creep Behavior in a Zr-Cu-Ag-Al Bulk Metallic Glass

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 613 ◽  
Author(s):  
Z. Y. Ding ◽  
Y. X. Song ◽  
Y. Ma ◽  
X. W. Huang ◽  
T. H. Zhang
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Creep Behavior ◽  
Creep Mechanism ◽  
Atomic Diffusion ◽  
Transformation Zone ◽  
Size Dependent ◽  
Strain And Strain Rate ◽  
Creep Deformations

Nanoindentation technology has been widely adopted to study creep behavior in small regions. However, nanoindentation creep behavior of metallic glass is still not well understood. In the present work, we investigated nanoindentation size effects on creep deformation in a Zr-based bulk metallic glass at room temperature. The total creep strain and strain rate of steady-state creep were gradually decreased with increasing holding depth under a Berkovich indenter, indicating a length-scale-dependent creep resistance. For a spherical indenter, creep deformations were insignificant in elastic regions and then greatly enhanced by increasing holding strain in plastic regions. Strain rate sensitivities (SRS) decreased with increasing holding depth and holding strain at first, and then stabilized as holding depth was beyond about 500 nm for both indenters. SRS values were 0.4–0.5 in elastic regions, in which atomic diffusion and free volume migration could be the creep mechanism. On the other hand, evolution of the shear transformation zone was suggested as a creep mechanism in plastic regions, and the corresponding SRS values were in the range of 0.05 to 0.3.

scholarly journals Negative Strain Rate Sensitivity Induced by Structure Heterogeneity in Zr64.13Cu15.75Ni10.12Al10 Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 339
Author(s):  
Xiang Wang ◽  
Zhi Qiang Ren ◽  
Wei Xiong ◽  
Si Nan Liu ◽  
Ying Liu ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Strain Rate Sensitivity ◽  
Critical Role ◽  
Rate Sensitivity ◽  
Confined Compression ◽  
Negative Strain Rate Sensitivity ◽  
Cast Specimen ◽  
Structure Heterogeneity

The negative strain rate sensitivity (SRS) of metallic glasses is frequently observed. However, the physical essence involved is still not well understood. In the present work, small-angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (HRTEM) reveal the strong structure heterogeneity at nanometer and tens of nanometer scales, respectively, in bulk metallic glass (BMG) Zr64.13Cu15.75Ni10.12Al10 subjected to fully confined compression processing. A transition of SRS of stress, from 0.012 in the as-cast specimen to −0.005 in compression processed specimen, was observed through nanoindentation. A qualitative formulation clarifies the critical role of internal stress induced by structural heterogeneity in this transition. It reveals the physical origin of this negative SRS frequently reported in structurally heterogeneous BMG alloys and its composites.

Strain-rate dependence of hardening and softening in compression of a bulk-metallic glass

2007 ◽  
Vol 22 (10) ◽  
pp. 2655-2658 ◽  
Author(s):  
W.H. Jiang ◽  
F.X. Liu ◽  
F. Jiang ◽  
K.Q. Qiu ◽  
H. Choo ◽  
...  
Keyword(s):  
Flow Stress ◽  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Plastic Flow ◽  
Shear Banding ◽  
Constant Strain Rate ◽  
Rate Dependence ◽  
Strain Rate Dependence ◽  
Plastic Flow Stress

We investigated the effect of strain rate on the plastic-flow stress of a Zr-based bulk-metallic glass in quasistatic compression. The results indicate that the plastic-flow stress is dependent on the strain rate: an increase in the strain rate leads to a decrease in the plastic-flow stress, and vice versa. However, simply loading, unloading, and reloading at a constant strain rate do not change the plastic-flow stress. This strain-rate dependence of the plastic-flow stress may be related to shear-banding operations.

Impacting behavior of bulk metallic glass powder at an abnormally high strain rate during kinetic spraying

2007 ◽  
Vol 449-451 ◽  
pp. 911-915 ◽  
Author(s):  
Sanghoon Yoon ◽  
Changhee Lee ◽  
Hanshin Choi ◽  
Hwíjun Kim ◽  
Jungchan Bae
Keyword(s):  
Metallic Glass ◽  
High Strain Rate ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Glass Powder ◽  
High Strain ◽  
Kinetic Spraying

scholarly journals Strain rate-dependent compressive deformation behavior of Nd-based bulk metallic glass

2005 ◽  
Vol 13 (8) ◽  
pp. 827-832 ◽  
Author(s):  
L.F. Liu ◽  
L.H. Dai ◽  
Y.L. Bai ◽  
B.C. Wei ◽  
G.S. Yu
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Deformation Behavior ◽  
Compressive Deformation ◽  
Rate Dependent

Effect of strain rate on compressive behavior of a Pd40Ni40P20 bulk metallic glass

2002 ◽  
Vol 10 (11-12) ◽  
pp. 1071-1077 ◽  
Author(s):  
Toshiji Mukai ◽  
T.G Nieh ◽  
Yoshihito Kawamura ◽  
Akihisa Inoue ◽  
Kenji Higashi
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Compressive Behavior
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