Enhanced plasticity in a Ti-based bulk metallic glass-forming alloy by in situ formation of a composite microstructure

2002 ◽  
Vol 17 (12) ◽  
pp. 3015-3018 ◽  
Author(s):  
G. He ◽  
W. Löser ◽  
J. Eckert ◽  
L. Schultz
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Room Temperature ◽  
Shear Bands ◽  
Temperature Deformation ◽  
Glassy Matrix ◽  
Glass Forming ◽  
Injection Casting ◽  
Composite Microstructure

A bulk metallic glass-forming Ti–Cu–Ni–Sn alloy with in situ formed composite microstructure prepared by both centrifugal and injection casting presents more than 6% plastic strain under compressive stress at room temperature. The in situ formed composite contains dendritic hexagonal-close-packed-Ti solid solution precipitates and a few Ti3Sn, β –(Cu, Sn) grains dispersed in a glassy matrix. The composite microstructure can avoid the development of the highly localized shear bands typical for the room-temperature deformation of monolithic glasses. Instead, highly developed shear bands with evident protuberance are observed, resulting in significant yielding and homogeneous plastic deformation over the entire sample.

Enhanced Work Hardening of Cu-Based Bulk Metallic Glass Composites by In Situ Formed Nano-Scale Heterogeneities

2009 ◽  
Vol 633-634 ◽  
pp. 665-673 ◽  
Author(s):  
M. Calin ◽  
J. Das ◽  
K.B. Kim ◽  
S. Pauly ◽  
N. Mattern ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Work Hardening ◽  
Shear Bands ◽  
Plastic Instability ◽  
Glassy Matrix ◽  
High Fracture ◽  
Glass Composites ◽  
Nano Scale

The work hardening ability under room temperature compression of ductile Cu47.5Zr47.5Al5 and Cu47Ti33Zr11Ni8Si1 bulk metallic glass-forming alloys has been studied and compared. Both alloys exhibit high fracture strength, distinct work hardening and large plastic strain. Systematic investigations on the microstructural evolution reveal the occurrence of nano-scale heterogeneities, of both structural and chemical nature, which enables multiplication, branching, and restriction of the shear bands, thus controlling the plastic instability of metallic glasses. Phase separation in the liquid state leading to chemical inhomogeneities has been revealed for as-cast Cu47.5Zr47.5Al5 samples. In the case of Cu47Ti33Zr11Ni8Si1, a composite-type microstructure with in-situ formed nano-scale precipitates embedded in a glassy matrix is responsible for the distinct work hardening recorded on the stress-strain curves. The present results support the important role of nano-scale heterogeneities for promoting efficient work hardening in Cu-based metallic glass composites.

A Centimeter-Size High Toughness Zr-Cu-Al-Nb Bulk Metallic Glass with Nano-Crystallization and Phase Separation

2018 ◽  
Vol 913 ◽  
pp. 668-673
Author(s):  
Chen Chen ◽  
Xiao Dong Jia ◽  
Hang Zhang ◽  
Ran Wei ◽  
Fu Shan Li
Keyword(s):  
Phase Separation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Shear Bands ◽  
Glassy Matrix ◽  
Glass Forming ◽  
High Toughness ◽  
Copper Mold Casting ◽  
Novel Approach ◽  
Mold Casting

In this paper, a centimeter-size Zr-Cu-Al-Nb bulk metallic glass (BMG) with high notch toughness of 107±13 MPa∙m0.5 was designed and fabricated by copper mold casting. With 1% Nb substitution for Zr in Zr48Cu45Al7 glass forming alloy, the glass forming ability (GFA) and toughness of the BMG were enhanced significantly. The coexistence of nano-crystallization and phase separation in the glassy matrix was observed in Zr47Cu45Al7Nb1, which would possibly lead to the high toughness of this alloy due to the easy and populous nucleation of shear bands and the increasing resistance of shear band propagation. The influences of nano-crystallization and phase separation on the toughness of BMGs are discussed in detail. The strategy utilized in this study provides a novel approach in search for new BMGs with high toughness and good GFA.

scholarly journals In-situ study of crystallization kinetics in ternary bulk metallic glass alloys with different glass forming abilities

2014 ◽  
Vol 105 (20) ◽  
pp. 201906 ◽  
Author(s):  
Si Lan ◽  
Xiaoya Wei ◽  
Jie Zhou ◽  
Zhaoping Lu ◽  
Xuelian Wu ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Crystallization Kinetics ◽  
Glass Forming ◽  
In Situ Study

Compressive Plasticity of Zr-Based Bulk Metallic Glass at Low Temperature

2012 ◽  
Vol 443-444 ◽  
pp. 583-586
Author(s):  
Ya Juan Sun ◽  
Ri Ga Wu ◽  
Hong Jing Wang
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Low Temperatures ◽  
Room Temperature ◽  
Shear Bands ◽  
Strain Curve ◽  
Testing Temperature ◽  
Stress Strain Curve

The mechanical properties of a new Zr-based bulk metallic glass at low temperatures were investigated. The results indicate that the fracture strength increases significantly (4.9%) and the global plasticity increases somewhat when testing temperature is lowered to 123K. The stress-strain curve of the sample deformed exhibits more serrations and smaller stress drop due to formation of more shear bands at low temperature than at room temperature.

Effect of mechanical-annealing on the mechanical properties of a Zr-based bulk metallic glass

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940052
Author(s):  
P. Deng ◽  
X. C. Wang ◽  
F. Zhang ◽  
X. M. Qin ◽  
P. Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Room Temperature ◽  
Constant Pressure ◽  
Aging Treatment ◽  
Model Material ◽  
Glass Forming ◽  
Plastic Stage

The mechanical-annealing referred in this work is also named pre-strain, which is widely investigated in TRIP steel, stainless steel, magnesium alloy and aluminum alloy. In this case, we used preloading to input energy into a bulk metallic glass (BMG) to observe the changes in the structure and mechanical properties. We selected Zr[Formula: see text]Co[Formula: see text]Al[Formula: see text] BMG as a model material owning to its outstanding glass forming ability and excellent mechanical properties. The samples were kept at a constant pressure of 1900, 1700 and 1500 MPa (below the yield strength) for 40, 55 and 70 h. The study found out that the density of those samples increased after being pre-loaded. Then, the samples underwent aging treatment at room-temperature for more than 30 days after unloading. After re-compressing the samples, the results show that the yield strength and fracture strength of the samples decreased, and the amplitude of the serrated plastic flow increased during the plastic stage. Our finding might have some implications for understanding the plastic deformation of BMGs.

scholarly journals An Analytical Method for Studying the Stress-Strain Relations of Bulk Metallic Glass Matrix Composites under Tension

2018 ◽  
Vol 27 (6) ◽  
pp. 096369351802700
Author(s):  
Yunpeng Jiang
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Analytical Method ◽  
Glass Matrix ◽  
Shear Bands ◽  
Matrix Composites ◽  
Stress Strain ◽  
Glass Matrix Composites ◽  
Softening Stage

In this contribution, an analytical model was formulated to predict the tensile stress-strain relations of bulk metallic glass matrix composites (BMGCs) based on Weng's theoretical frame for dual-ductile composites. For in-situ BMGCs, BMG matrix also exhibits the elastic-plastic deform response as well as the dendrite phases during the stretching. The shear bands are regarded as Mode-I cracks, and whereby the strain-softening stage in the stress-strain curves can be well reflected. Furthermore, multi-particle representative volume element based FEM modelling was employed to clearly explain the failure mechanisms in BMGCs as a necessary complement. The predictions are in reasonable agreement with the experimental results. The presented analytical method will shed some light on optimizing the microstructures, and is of convenience in the engineering applications.

Cu-Based Metallic Glass Matrix Composites with High Ductility

2004 ◽  
Vol 449-452 ◽  
pp. 441-444 ◽  
Author(s):  
Yu Chan Kim ◽  
Do Hyang Kim ◽  
Jae Chul Lee
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glass Matrix ◽  
Matrix Composites ◽  
Copper Mold ◽  
Glass Matrix Composite ◽  
Injection Casting ◽  
Metallic Glass Matrix Composite ◽  
Composite Microstructure ◽  
Glass Matrix Composites

A composite microstructure consisted of µm-scale Ta-rich solid solution particles distributed in the bulk metallic glass matrix was successfully obtained by injection casting of the (Cu60Zr30Ti10)95Ta5alloy into a copper mold. The (Cu60Zr30Ti10)95Ta5bulk metallic glass matrix composite shows compressive strength of 2320 MPa and, in particular, a significantly improved plastic strain to failure of about 14.5%. The remarkable ductility improvement in the (Cu60Zr30Ti10)95Ta5composite could be explained by the presence of the highly ductile Tarich particles.

Formation, microstructure, and mechanical properties of in situ Mg–Ni–(Gd,Nd) bulk metallic glass composite

2009 ◽  
Vol 24 (12) ◽  
pp. 3603-3610 ◽  
Author(s):  
Jian Yin ◽  
Guangyin Yuan ◽  
Zhenhua Chu ◽  
Jian Zhang ◽  
W.J. Ding
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Hexagonal Lattice ◽  
Shear Bands ◽  
Glassy Matrix ◽  
Glass Composite ◽  
Specific Strength ◽  
Periodic Arrays ◽  
Bulk Metallic Glass Composite

Based on a ternary Mg75Ni15Gd10 metallic glass former, a new Mg80Ni12Gd4Nd4 bulk metallic glass composite (BMGC) was developed by tailoring the compositions of Mg and rare earth (RE) elements. This BMGC displayed compressive ultimate strength over 900 MPa with a total strain to failure of 4.3% and specific strength of 3.12 × 105 Nm/kg. The improved mechanical properties were attributed to a “dual phases” structure consisting of Mg solid solution flakes and glassy matrix in the Mg80Ni12Gd4Nd4 BMGC. The homogeneously dispersed Mg phases reinforcement in the BMGC were characterized as a long period ordered structure (LPOS) with periodic arrays of six close-packed planes distorted from the ideal hexagonal lattice of 6H-type. The LPOS-Mg in the composite can act as a soft media to trap or interact with the unstable shear bands and contribute to plastic strain. The present study may provide a guideline for designing the Mg–TM–RE-based (TM: transition metals) BMGCs with “dual phases” structures.

In situ spherical B2 CuZr phase reinforced ZrCuNiAlNb bulk metallic glass matrix composite

2010 ◽  
Vol 25 (6) ◽  
pp. 1159-1163 ◽  
Author(s):  
Jinmin Liu ◽  
Haifeng Zhang ◽  
Huameng Fu ◽  
Zhuang-Qi Hu ◽  
Xiaoguang Yuan
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Matrix Composite ◽  
Glass Matrix ◽  
Shear Bands ◽  
Glass Matrix Composite ◽  
Mold Casting ◽  
Metallic Glass Matrix Composite ◽  
Nb Addition

In situ microlevel spherical B2 CuZr phase reinforced Zr49.5Cu36.45Ni4.05Al9Nb1 bulk metallic glass matrix composite was prepared successfully by the copper mold casting method. It was found that mechanical properties of Zr50.5Cu36.45Ni4.05Al9 alloy were improved largely due to the Nb addition. The room-temperature compressive fracture strength and plastic strain for Zr49.5Cu36.45Ni4.05Al9Nb1 rod with a diameter of 5 mm reaches 2037 MPa and 8%, respectively. The improvements are attributed to the precipitation of the spherical B2 CuZr phase distributed uniformly in amorphous matrix, which effectively hampers the propagation of shear bands by deflecting them at the interface and by a multiplication mechanism.

EXPERIMENTAL OBSERVATIONS OF THE FAILURE MECHANISMS IN A BULK METALLIC GLASS COMPOSITE

2007 ◽  
Vol 1048 ◽  
Author(s):  
Hui Wang ◽  
Ashraf Bastawros ◽  
S. Bulent Biner
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Damage Evolution ◽  
Composite System ◽  
Shear Bands ◽  
In Situ Observation ◽  
Glass Composite ◽  
Evolution Behavior ◽  
Bulk Metallic Glass Composite

AbstractThe deformation and damage evolution behavior of a Ni-based bulk metallic glass composite reinforced with elongated brass phase is studied under cylindrical indentation. The estimated fracture toughness values based on the energy dissipation and the in-situ observation during the loading reveal the details of the damage evolution and toughening mechanisms in this composite system. The results indicate that the enhanced toughness of the BMG composite is plausibly an outcome of crack bridging mechanisms by the ductile brass phase, rather than a diffused array of nucleated shear bands in the hard BMG and arrest by the ductile reinforcing phase.

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