Effect of Loading Rate on Failure in Bulk Metallic Glasses

2002 ◽  
Vol 754 ◽  
Author(s):  
T. Jiao ◽  
C. Fan ◽  
L.J. Kecskes ◽  
T.C. Hufnagel ◽  
K.T. Ramesh
Keyword(s):  
Metallic Glasses ◽  
High Speed ◽  
Dynamic Compression ◽  
Failure Process ◽  
Compressive Loading ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Experimental Results ◽  
Dynamic Strain ◽  
High Speed Photography

ABSTRACTWe have investigated failure in bulk metallic glass-forming alloys under dynamic compression. We implemented a recovery technique for the compression Kolsky bar to obtain dynamically deformed, intact specimens at various stages of deformation; this allows us to characterize the development of failure. We have also used high-speed photography to examine the failure process during the recovery experiments. The experimental results indicate that the failure under dynamic loading is somewhat different from that under quasi-static loading. Specimens subjected to quasistatic deformation developed multiple shear bands and substantial plastic deformations, while specimens subjected to dynamic (—strain rate ∼103 s-1) compressive loading fail by fracture along one dominant shear band. The mechanisms of dynamic failure in bulk metallic glasses are discussed on the basis of these experimental results.

scholarly journals Plastic Dynamical Model for Bulk Metallic Glasses

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Shaowen Yao ◽  
Zhibo Cheng
Keyword(s):  
Metallic Glasses ◽  
Loading Rate ◽  
Testing Machine ◽  
Compressive Loading ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Experimental Results ◽  
Dynamical Model ◽  
Compression Tests ◽  
Rate Range

Based on previous experimental results of the plastic dynamic analysis of metallic glasses upon compressive loading, a dynamical model is proposed. This model includes the sliding speed of shear bands in the plastically strained metallic glasses, the shear resistance of shear bands, the internal friction resulting from plastic deformation, and the influences from the testing machine. This model analysis quantitatively predicts that the loading rate can influence the transition of the plastic dynamics in metallic glasses from chaotic (low loading rate range) to stable behavior (high loading rate range), which is consistent with the previous experimental results on the compression tests of a Cu50Zr45Ti5 metallic glass. Moreover, we investigate the existence of a nonconstant periodic solution for plastic dynamical model of bulk metallic glasses by using Manásevich–Mawhin continuation theorem.

Deformation and evolution of shear bands under compressive loading in bulk metallic glasses

2006 ◽  
Vol 54 (19) ◽  
pp. 5271-5279 ◽  
Author(s):  
J.Y. Lee ◽  
K.H. Han ◽  
J.M. Park ◽  
K. Chattopadhyay ◽  
W.T. Kim ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Compressive Loading ◽  
Shear Bands ◽  
Bulk Metallic Glasses

scholarly journals Guiding shear bands in bulk metallic glasses using stress fields: A perspective from the activation of flow units

2020 ◽  
Vol 102 (13) ◽  
Author(s):  
K. Kosiba ◽  
S. Scudino ◽  
J. Bednarcik ◽  
J. Bian ◽  
G. Liu ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Stress Fields ◽  
Flow Units

Dynamic Failure Mechanisms in Beryllium-Bearing Bulk Metallic Glasses

1998 ◽  
Vol 554 ◽  
Author(s):  
David M. Owen ◽  
Ares J. Rosakis ◽  
William L. Johnson
Keyword(s):  
Crack Initiation ◽  
Shear Band ◽  
Metallic Glasses ◽  
Impact Loading ◽  
High Speed ◽  
Failure Mechanisms ◽  
Shear Bands ◽  
Dynamic Crack ◽  
Dynamic Failure ◽  
Asymmetric Impact

AbstractThe understanding of dynamic failure mechanisms in bulk metallic glasses is important for the application of this class of materials to a variety of engineering problems. This is true not only for design environments in which components are subject to high loading rates, but also when components are subjected to quasi-static loading conditions where observations have been made of damage propagation occurring in an unstable, highly dynamic manner. This paper presents preliminary results of a study of the phenomena of dynamic crack initiation and growth as well as the phenomenon of dynamic localization (shear band formation) in a beryllium-bearing bulk metallic glass, Zr41.25Ti13.75Ni10Cu12.75Be22.5. Pre-notched and prefatigued plate specimens were subjected to quasi-static and dynamic three-point bend loading to investigate crack initiation and propagation. Asymmetric impact loading with a gas gun was used to induce dynamic shear band growth. The mechanical fields in the vicinity of the dynamically loaded crack or notch tip were characterized using high-speed optical diagnostic techniques. The results demonstrated a dramatic increase in the crack initiation toughness with loading rate and subsequent crack tip speeds approaching 1000 m s−1. Dynamic crack tip branching was also observed under certain conditions. Shear bands formed readily under asymmetric impact loading. The shear bands traveled at speeds of approximately 1300 m s−1 and were accompanied by intense localized heating measured using high-speed full-field infrared imaging. The maximum temperatures recorded across the shear bands were in excess of 1500 K.

scholarly journals Fracture Initiation, Gas Ejection, and Strain Waves Measured on Specimen Surfaces in Model Rock Blasting

2020 ◽  
Author(s):  
Zong-Xian Zhang ◽  
Li Yuan Chi ◽  
Yang Qiao ◽  
De-Feng Hou
Keyword(s):  
High Speed ◽  
Fracture Initiation ◽  
Dynamic Strain ◽  
High Speed Photography ◽  
Surface Cracks ◽  
Rock Blasting ◽  
Measured Velocity ◽  
Strain Waves ◽  
Gas Penetration ◽  
Radial Cracks

AbstractCrack velocity, gas ejection, and stress waves play an important role in determining delay time, designing a blast and understanding the mechanism of rock fragmentation by blasting. In this paper, the emerging times of the earliest cracks and gas ejection on the lateral surfaces of cylindrical granite specimens with a diameter of 240 mm and a length of 300 mm were determined by high-speed photography, and the strain waves measured by an instrument of dynamic strain measurement during model blasting. The results showed that: (1) the measured velocity of gas penetration into the radial cracks was in a range of 196–279 m/s; (2) the measured velocity of a radial crack extending from the blasthole to the specimen surface varied from 489 to 652 m/s; (3) the length of strain waves measured was about 2800 µs, which is approximately 1000 times greater than the detonation time. At about 2850 µs after detonation was initiated, gases were still ejected from the surface cracks, and the specimens still stood at their initial places, although surface cracks had opened widely.

Shear band characteristics in high strain rate naval applications

2019 ◽  
Author(s):  
Michael J. P. Conway ◽  
James D. Hogan
Keyword(s):  
High Speed ◽  
Dynamic Compression ◽  
Shear Banding ◽  
Shear Bands ◽  
Critical Time ◽  
Strain Rates ◽  
Static Case ◽  
Dynamic Experiments ◽  
Naval Steels ◽  
Strain Responses

Abstract This paper explores the dynamic behavior of HSLA 65 naval steels, specifically focusing on the initiation and growth of shear bands in quasi-static and dynamic compression experiments and how these bands affect stress-strain responses. The results indicate that the yield strength for this HSLA 65 increases from 541 ± 8 MPa for quasi-static (10-3 s-1) to 1081 ± 48 MPa for dynamic rates 1853 ± 31 s-1, and the hardening exponent increases from 0.376 ± 0.028 for quasi-static to 0.396 ± 0.006 for dynamic rates. Yield behavior was found to be associated with the onset of shear banding for both strain-rates, confirmed through visualization of the specimen surface using high-speed and ultra-high-speed cameras. For the quasi-static case, shear banding and yielding was observed to occur at 2.5% strain, and were observed to grow at speeds of upwards of 38 mm/s. For the dynamic experiments, the shear banding begins at approximately 1.18 ± 0.06% strain and these can grow upwards of 2122 ± 213 m/s during post-yield softening. Altogether, these measurements are some of the first of their kind in the open literature, and provide guidance on the critical time and length scales in shear banding. This information can be used in the future to design more failure-resistant steels, which has broader applications in construction, defense, and natural resource industries.

scholarly journals Erratum to “On the shear-affected zone of shear bands in bulk metallic glasses” [J. Alloys Compd. 837 (2020) 155494]

2020 ◽  
Vol 842 ◽  
pp. 155852
Author(s):  
Farnaz A. Davani ◽  
Sven Hilke ◽  
Harald Rösner ◽  
David Geissler ◽  
Annett Gebert ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses
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