Geometry-sensitive plasticity of a monolithic bulk metallic glass

2007 ◽  
Vol 1048 ◽  
Author(s):  
WenFei Wu ◽  
Yi Li
Keyword(s):  
Aspect Ratio ◽  
Plastic Strain ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
New Method ◽  
Catastrophic Failure ◽  
Sample Geometry ◽  
Glassy Alloys ◽  
Geometry Dependence ◽  
Orthogonal Geometry

AbstractWe report a strong geometry-dependence of compressive plasticity in a Zr-based bulk metallic glass (BMG). With a standard orthogonal geometry, the Zr-based BMG typically fractured at a plastic strain less than 2%. However, by modifying the sample geometry while maintaining the sample aspect ratio, a large apparent compressive plastic strain over 10% was achieved consistently. These results present a new method on arresting the catastrophic failure of the glassy alloys and offer ways for BMGs in engineering applications.

Microstructure evolution of bulk metallic glass during thermal oxidation under plastic strain

2019 ◽  
Vol 147 ◽  
pp. 192-200 ◽  
Author(s):  
Mao Zhang ◽  
Jiacheng Zhang ◽  
Lei Deng ◽  
Qiaomin Li ◽  
Junsong Jin ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Metallic Glass ◽  
Thermal Oxidation ◽  
Bulk Metallic Glass ◽  
Microstructure Evolution

Compressive properties of bulk metallic glass with small aspect ratio

2007 ◽  
Vol 22 (2) ◽  
pp. 501-507 ◽  
Author(s):  
F.F. Wu ◽  
Z.F. Zhang ◽  
S.X. Mao
Keyword(s):  
Plastic Deformation ◽  
Aspect Ratio ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Deformation Behavior ◽  
Shear Bands ◽  
Compressive Load ◽  
Small Aspect Ratio ◽  
Compressive Properties ◽  
Deformation Ability

The quasi-static compressive deformation behavior of a Vitreloy 1 bulk metallic glass (BMG) with an aspect ratio of 0.25 was investigated. It is found that the friction and the confinement at the specimen–loading platen interface will cause the dramatic increase in the compressive load, leading to higher compressive strength. In particular, the BMG specimens show great plastic-deformation ability, and plenty of interacted, deflected, wavy, or branched shear bands were observed on the surfaces after plastic deformation. The formation of the strongly interacted, deflected, wavy, or branched shear bands can be attributed to the triaxial stress state in the glassy specimens with a very small aspect ratio.

Nanoscale Molding of a Zirconium Based Bulk Metallic Glass

2007 ◽  
Author(s):  
Kavic Rason ◽  
Brad Kinsey
Keyword(s):  
Aspect Ratio ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
High Aspect Ratio ◽  
Supercooled Liquid ◽  
Mold Material ◽  
Molding Process ◽  
Silicon Mold ◽  
Interfacial Energies ◽  
A Value

Geometrically complex, high aspect ratio microstructures and limited aspect ratio nanostructures have been successfully fabricated in supercooled Bulk Metallic Glass (BMG) substrates by molding against patterned Silicon and Silicon dioxide substrates. However, demand exists for similar metallic substrates with high aspect ratio, nanoscale features. Van Der Waals based interfacial energies between the supercooled liquid BMG and the Silicon cavity represent a substantial obstacle to the direct scaling of the molding process to the nanoscale. In an effort to investigate these effects, experiments were conducted using molds of various compositions: Silicon, SiO2 and SiO2 coated with Gold. The Gold coating failed to impact molding performance due to the thin layer deposited. However, drastically superior results were obtained by using a Silicon mold because of the variation in interfacial interaction between the BMG and the mold material. In addition, a theoretical model to predict achievable aspect ratio is presented and was found to be in qualitative agreement with experimental results. Finally, a value for the surface tension of Viterloy-1b within it’s supercooled liquid state was deduced from experimental data.

The more shearing, the thicker shear band and heat-affected zone in bulk metallic glass

2008 ◽  
Vol 23 (8) ◽  
pp. 2133-2138 ◽  
Author(s):  
H. Guo ◽  
J. Wen ◽  
N.M. Xiao ◽  
Z.F. Zhang ◽  
M.L. Sui
Keyword(s):  
Aspect Ratio ◽  
Shear Band ◽  
Metallic Glass ◽  
Shear Deformation ◽  
Bulk Metallic Glass ◽  
Heat Affected Zone ◽  
Shear Bands ◽  
Source Model ◽  
Ion Milling ◽  
Low Aspect Ratio

In a compression test for a Zr-based bulk metallic glass, a dominant shear band was preserved before fracture by a cylindrical stopper. A heat-affected zone (HAZ) ∼10 μm thick together with shear band was discovered in the center of the deformed sample by preferential ion milling. By using a low aspect ratio sample for compression, diverse micron-scaled HAZs among multiple shear bands were also revealed. Based on above experimental results and the isothermal source model, it was found that the thickness of shear band and its HAZ increased continuously with the progression of shear deformation.

High aspect ratio micro mechanical structures made of bulk metallic glass

2004 ◽  
Vol 375-377 ◽  
pp. 327-331 ◽  
Author(s):  
A.A. Kündig ◽  
A. Dommann ◽  
W.L. Johnson ◽  
P.J. Uggowitzer
Keyword(s):  
Aspect Ratio ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
High Aspect Ratio

Glass-Forming Ability and Mechanical Properties of Fe-Ni-Zr-Si-B Bulk Glassy Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 3405-3408
Author(s):  
K.A. Lee ◽  
J. Namkung ◽  
Moon Chul Kim
Keyword(s):  
Plastic Strain ◽  
Metallic Glass ◽  
Structural Relaxation ◽  
Amorphous Matrix ◽  
Icosahedral Phase ◽  
Glass Forming Ability ◽  
Glass Forming ◽  
Glassy Alloys ◽  
Partial Crystallization ◽  
Crystallization Onset

The effects of structural relaxation and partial crystallization on the mechanical property of the Ti40Zr29Cu9Ni8Be14 bulk metallic glass (BMG) have been investigated. The atomic structure of the as-cast Ti40Zr29Cu9Ni8Be14 metallic glass transforms into a more relaxed state at the temperature region of 452 –585 K, below the crystallization onset temperature of 631 K. Stable icosahedral phase forms in the amorphous matrix by growth of the pre-existing nuclei in the amorphous matrix during first crystallization step. The compressive plastic strain of the as-cast Ti40Zr29Cu9Ni8Be14 BMG is 6.7 %, and decreases when the structural relaxation occurs. However, the plastic strain increases when a few nanometer size icosahedral phase particles form in the amorphous matrix by the partial crystallization treatment.

Free Volume Evolution in Bulk Metallic Glass during High Temperature Creep

2002 ◽  
Vol 754 ◽  
Author(s):  
B. S. Sundar Daniel ◽  
Martin Heilmaier ◽  
Birgit Bartusch ◽  
Jörn Kanzow ◽  
Katja Günther-Schade ◽  
...  
Keyword(s):  
Glass Transition ◽  
Plastic Strain ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Free Volume ◽  
Metallic Glasses ◽  
Constant Strain Rate ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Positron Lifetime Spectroscopy

ABSTRACTMetallic glasses lack long-range translational symmetry and have excess volume trapped within their amorphous structure, which has a direct bearing on their physical properties including deformation characteristics. Moreover, the trapped excess free volume is directly correlated to the defect concentration facilitating the possibility to model the temperature and time dependence of the free volume changes during creep as a trade off between defect generation and annihilation. Using differential scanning calorimetry (DSC) analysis the residual free volume of a metallic glass can be characterised based on the glass transition peak height (Δcp). In the present work constant strain rate tests were carried out at the ‘onset’ (Tgon = 685 K) and ‘point of inflection’ (Tgp = 705 K) of the calorimetric glass transition to study the time dependent flow behaviour in Zr55Cu30Al10Ni5 bulk metallic glass. Modelling based on DSC analysis and positron lifetime spectroscopy on samples creep deformed to different plastic strain values corroborate the stress decrease after the peak stress (‘stress overshoot’) occurring in bulk metallic glasses with increasing plastic strain to be associated with a small increase in free volume.

Phase separation and significant plastic strain in a Zr–Cu–Ni–Al–Fe bulk metallic glass

2016 ◽  
Vol 656 ◽  
pp. 84-89 ◽  
Author(s):  
Shuangshuang Chen ◽  
Jianxin Tu ◽  
Jiajia Wu ◽  
Qiang Hu ◽  
Shenghui Xie ◽  
...  
Keyword(s):  
Phase Separation ◽  
Plastic Strain ◽  
Metallic Glass ◽  
Bulk Metallic Glass

Enhancement of Plasticity in Ti-Based Bulk Metallic Glass

2005 ◽  
Vol 475-479 ◽  
pp. 3409-3414 ◽  
Author(s):  
H.J. Chang ◽  
Won Tae Kim ◽  
Do Hyang Kim
Keyword(s):  
Mechanical Property ◽  
Plastic Strain ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Temperature Region ◽  
Structural Relaxation ◽  
Amorphous Matrix ◽  
Icosahedral Phase ◽  
Partial Crystallization ◽  
Crystallization Onset

The effects of structural relaxation and partial crystallization on the mechanical property of the Ti40Zr29Cu9Ni8Be14 bulk metallic glass (BMG) have been investigated. The atomic structure of the as-cast Ti40Zr29Cu9Ni8Be14 metallic glass transforms into a more relaxed state at the temperature region of 452 –585 K, below the crystallization onset temperature of 631 K. Stable icosahedral phase forms in the amorphous matrix by growth of the pre-existing nuclei in the amorphous matrix during first crystallization step. The compressive plastic strain of the as-cast Ti40Zr29Cu9Ni8Be14 BMG is 6.7 %, and decreases when the structural relaxation occurs. However, the plastic strain increases when a few nanometer size icosahedral phase particles form in the amorphous matrix by the partial crystallization treatment.

Sign in / Sign up

Export Citation Format

Share Document