Tuning the strain rate sensitivity and ductility of Zr55Al10Cu30Ni5 metallic glass by He+ ion irradiation

2020 ◽  
Vol 840 ◽  
pp. 155562
Author(s):  
Huaican Chen ◽  
Yang Hai ◽  
Gang Wang ◽  
Xiao Liu ◽  
Juping Xu ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Ion Irradiation ◽  
Rate Sensitivity

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.

scholarly journals Effect of Annealing on Strain Rate Sensitivity of Metallic Glass under Nanoindentation

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1063
Author(s):  
Mingcan Li
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Annealing Time ◽  
Isothermal Annealing ◽  
Rate Sensitivity ◽  
Underlying Mechanism ◽  
Shear Transformation ◽  
Shear Transformation Zones

The influence of isothermal annealing on the strain rate sensitivity (SRS) of a Zr-based bulk metallic glass (BMG) was investigated by nanoindentation. A more positive SRS is observed with a decrease in the content of the free volume (FV) of the sample. Furthermore, the SRS becomes nearly constant with increasing annealing time when the FV is annealed out. By taking into consideration the FV-assisted activation and combination of the shear transformation zones (STZs), the underlying mechanism is well understood. The current work may offer useful insights into the correlation between the microstructure and mechanical properties of BMGs.

Structural features and high quasi-static strain rate sensitivity of Au49Cu26.9Ag5.5Pd2.3Si16.3 bulk metallic glass

2012 ◽  
Vol 101 (24) ◽  
pp. 241905 ◽  
Author(s):  
S. V. Ketov ◽  
N. Chen ◽  
A. Caron ◽  
A. Inoue ◽  
D. V. Louzguine-Luzgin
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Structural Features ◽  
Static Strain

scholarly journals High strain rate in situ micropillar compression of a Zr-based metallic glass

2021 ◽  
Author(s):  
Rajaprakash Ramachandramoorthy ◽  
Fan Yang ◽  
Daniele Casari ◽  
Moritz Stolpe ◽  
Manish Jain ◽  
...  
Keyword(s):  
Metallic Glass ◽  
High Strain Rate ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
High Strain ◽  
Deformation Behaviour ◽  
Rate Sensitivity ◽  
Propagation Speed ◽  
Atomic Scale ◽  
Complex Deformation

Abstract High strain rate micromechanical testing can assist researchers in elucidating complex deformation mechanisms in advanced material systems. In this work, the interactions of atomic-scale chemistry and strain rate in affecting the deformation response of a Zr-based metallic glass was studied by varying the concentration of oxygen dissolved into the local structure. Compression of micropillars over six decades of strain rate uncovered a remarkable reversal of the strain rate sensitivity from negative to positive above ~ 5 s−1 due to a delocalisation of shear transformation events within the pre-yield linear regime for both samples, while a higher oxygen content was found to generally decrease the strain rate sensitivity effect. It was also identified that the shear band propagation speed increases with the actuation speed, leading to a transition in the deformation behaviour from serrated to apparent non-serrated plastic flow at ~ 5 s−1. Graphic abstract

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