DEFORMATION BEHAVIORS OF Zr-BASED BULK METALLIC GLASS UNDER IMPACT INDENTATION

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1775-1782 ◽  
Author(s):  
HYUNG-SEOP SHIN ◽  
SOON-NAM CHANG ◽  
DO KYUNG KIM
Keyword(s):  
Metallic Glasses ◽  
Impact Loading ◽  
Shock Loading ◽  
Shear Bands ◽  
Amorphous Metal ◽  
High Yield ◽  
Spherical Indentation ◽  
Loading Conditions ◽  
Structural Applications ◽  
Deformation Behaviors

Metallic glasses are amorphous meta-stable solids and are now being processed in bulk form suitable for structural applications under impact loading. Bulk metallic glasses have many unique mechanical properties such as high yield strength and fracture toughness, good corrosion and wear resistance that distinguish them from crystalline metals and alloys. However, only a few studies could be found mentioning the dynamic response and damage of metallic glasses under impact or shock loading. In this study, we employed a small explosive detonator for the dynamic indentation to a Zr -based bulk amorphous metal in order to evaluate the damage behavior of bulk amorphous metal under impact or shock loading conditions. Results were compared with those of spherical indentation under quasi-static and impact loading and were discussed. The interface bonded specimen method was adopted in order to observe the subsurface damage, especially the formation of shear bands induced during indentation under different loading conditions.

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.

TEM Studies of Shear Bands in a Bulk Metallic Glass Based Composite

2001 ◽  
Vol 7 (S2) ◽  
pp. 1120-1121
Author(s):  
E. Pekarskaya ◽  
C.P. Kim ◽  
W.L. Johnson
Keyword(s):  
Metallic Glasses ◽  
Shear Bands ◽  
High Yield ◽  
In Situ Tem ◽  
Two Phase ◽  
University Of Illinois ◽  
Glass Forming ◽  
The University ◽  
Very High

In 1980’s the discovery of multicomponent systems with exceptional glass forming ability enabled the synthesis of metallic glasses at relatively low cooling rates, 10−1 — 102 K/s and at a larger thicknesses. Bulk metallic glasses normally have very high yield stress, σy = 0.02 · Y (Y is Young’s modulus), high elastic limit of about 2%, but fail with very little global plasticity, typically along a localized shear band at a 45 degree angle with respect to the applied stress.The material studied in the present work is a two-phase Zr56.3Ti13.8Cu6.9Ni5.6Nb5.0Be12.5 alloy,prepared by in-situ processing. The alloy consists of amorphous and crystalline phases. In-situ TEM straining (tensile) experiments were performed at room temperature in JEOL 4000EX operating at 300kV. The experiments were carried out in the Center for Microanalysis of Materials in the University of Illinois at Urbana-Champaign. The goal of the study was to understand the deformation mechanisms of such composite material.

Deformation behaviors and mechanism of Ni–Co–Nb–Ta bulk metallic glasses with high strength and plasticity

2007 ◽  
Vol 22 (4) ◽  
pp. 869-875 ◽  
Author(s):  
Y.H. Liu ◽  
G. Wang ◽  
M.X. Pan ◽  
P. Yu ◽  
D.Q. Zhao ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Flow Behavior ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
High Strength ◽  
Serrated Flow ◽  
Crystalline Materials ◽  
Glass Forming ◽  
Deformation Behaviors ◽  
Strength And Plasticity

A class of Ni–Co–Nb–Ta bulk metallic glasses (BMGs) with a high glass-forming ability is developed. With proper compositional modification, the BMGs exhibit the enhanced plastic strain (up to 4%) and the ultimate strength (up to 3540 MPa). It is found that the interactions of shear bands such as intersecting, arresting, and branching, which normally are related to the plastic metallic glasses, can be observed both in the plastic and brittle Ni–Co–Nb–Ta BMGs. Obvious serrated flow behavior is observed during plastic deformation. The origins of the plasticity and the serrated flow in the Ni-based BMGs are analyzed in analogy to that in crystalline materials.

Performance investigation on advanced high yield strength deformed steel used in structural applications

2020 ◽  
Author(s):  
P. S. Senthil Kumar ◽  
C. Sivakandhan ◽  
K. Vinoth Babu ◽  
D. Pritima ◽  
Satyanarayana ◽  
...  
Keyword(s):  
Yield Strength ◽  
High Yield ◽  
High Yield Strength ◽  
Structural Applications

scholarly journals Morphology of cracks and shear bands in polymer-supported thin film metallic glasses

2021 ◽  
pp. 102547
Author(s):  
Oleksandr Glushko ◽  
Christoph Gammer ◽  
Lisa-Marie Weniger ◽  
Huaping Sheng ◽  
Christian Mitterer ◽  
...  
Keyword(s):  
Thin Film ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Polymer Supported

scholarly journals Boron Concentration Induced Co-Ta-B Composite Formation Observed in the Transition from Metallic to Covalent Glasses

2020 ◽  
Vol 5 (1) ◽  
pp. 18
Author(s):  
Simon Evertz ◽  
Stephan Prünte ◽  
Lena Patterer ◽  
Amalraj Marshal ◽  
Damian M. Holzapfel ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Metallic Glasses ◽  
Boron Concentration ◽  
High Strength ◽  
Point Of View ◽  
Composite Formation ◽  
Structural Applications ◽  
Glassy Materials ◽  
Metallic Bonding ◽  
Composite Region

Due to their unique property combination of high strength and toughness, metallic glasses are promising materials for structural applications. As the behaviour of metallic glasses depends on the electronic structure which in turn is defined by chemical composition, we systematically investigate the influence of B concentration on glass transition, topology, magnetism, and bonding for B concentrations x = 2 to 92 at.% in the (Co6.8±3.9Ta)100−xBx system. From an electronic structure and coordination point of view, the B concentration range is divided into three regions: Below 39 ± 5 at.% B, the material is a metallic glass due to the dominance of metallic bonds. Above 69 ± 6 at.%, the presence of an icosahedra-like B network is observed. As the B concentration is increased above 39 ± 5 at.%, the B network evolves while the metallic coordination of the material decreases until the B concentration of 67 ± 5 at.% is reached. Hence, a composite is formed. It is evident that, based on the B concentration, the ratio of metallic bonding to icosahedral bonding in the composite can be controlled. It is proposed that, by tuning the coordination in the composite region, glassy materials with defined plasticity and processability can be designed.

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