Effect of Cooling Rate, Tungsten Fiber Addition and Annealing on Deformation and Mechanical Properties of Zr-Based Bulk Metallic Glasses Under a Nanoindenter

2015 ◽  
Vol 1120-1121 ◽  
pp. 68-72
Author(s):  
Yi Si
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Cooling Rate ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Tungsten Fiber ◽  
Nanoindentation Instrument ◽  
Scanning Electron ◽  
Fiber Addition

The deformation and mechanical properties of Zr-based bulk metallic glasses (BMGs) under a nanoindenter and the effect of cooling rate, the effect of cooling rate, tungsten fiber addition and annealing on them have been studied by means of a nanoindentation instrument and a scanning electron microscope (SEM). The results indicate that the deformation of Zr-based BMGs under a nanoindenter is characterized by multiple shear bands and viscous flow which confirms the existence of a amount of plastic deformation. For pure quenched Zr-based BMGs, the larger the size of samples or the nearer the location away from the surface of a same sample, the smaller the values of microhardness (Hv) and elastic modulus (E); Annealing and tungsten fiber addition enhance the values of Hv and E; meanwhile, they also significantly change morphology around a nanoindenter and the amount of plastic deformation. The mechanism of plastic deformation is preliminarily analyzed.

Effect of pre-existing shear bands on mechanical properties and serration behaviors in bulk metallic glasses

2017 ◽  
Vol 24 (4) ◽  
pp. 402-410 ◽  
Author(s):  
Xu-dong Yuan ◽  
Sheng-hai Wang ◽  
Kai-kai Song ◽  
Xiao-liang Han ◽  
Yu-sheng Qin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses

scholarly journals Effect of cooling rate on plastic deformation of Zr-based bulk metallic glasses

2012 ◽  
Vol 22 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Chunyan Li ◽  
Shengzhong Kou ◽  
Yanchun Zhao ◽  
Guangqiao Liu ◽  
Yutian Ding
Keyword(s):  
Plastic Deformation ◽  
Cooling Rate ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses

Instrumented indentation study of plastic deformation in bulk metallic glasses

2006 ◽  
Vol 21 (1) ◽  
pp. 75-81 ◽  
Author(s):  
W.H. Li ◽  
T.H. Zhang ◽  
D.M. Xing ◽  
B.C. Wei ◽  
Y.R. Wang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Metallic Glasses ◽  
Deformation Behavior ◽  
Loading Rate ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Plastic Deformation Zone ◽  
Instrumented Indentation ◽  
Depth Sensing ◽  
Plastic Deformation Behavior

Mechanical properties and micro-plastic deformation behavior of five bulk metallic glasses (BMGs) were studied by instrumented indentation. These materials included La60Al10Ni10Cu20, Mg65Cu25Gd10, Zr52.5Al10Ni10Cu15Be12.5, Cu60Zr20Hf10Ti10, and Ni60Nb37Sn3 alloys. Remarkable difference in deformation behavior was found in the load–displacement curves of nanoindentation and pileup morphologies around the indents. Serrated plastic deformation depended on the loading rate was found in Mg-, Zr-, and Cu-based BMGs. The subsurface plastic deformation zone of typical alloys was investigated through bonded interface technique using depth-sensing microindentation. Large and widely spaced shear bands were observed in Mg-based BMG. The effect of loading rate on the indentation deformation behaviors in different BMGs was elucidated by the change of shear band pattern.

scholarly journals Formation and Mechanical Properties of Pd-Si Binary Bulk Metallic Glasses

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Na Chen ◽  
Hongxia Zhang ◽  
Ke-Fu Yao
Keyword(s):  
Mechanical Properties ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
High Strength ◽  
Side Surface ◽  
Alloy System ◽  
Structural Inhomogeneity ◽  
Micrometer Scale ◽  
Scale Shear

Glassy spherical samples in the diameters up to 10 mm were produced in a binary Pd-Si alloy system. These Pd-Si bulk metallic glasses (BMGs) combine high strength of about 1600 MPa and superplasticity of over 70% together. In addition to abundant micrometer-scale shear bands, 10–20 nanometer-sized shear bands were also observed on the side surface of the deformed sample. The excellent ductility shown by the Pd-Si BMGs is suggested to arise from the nanoscale structural inhomogeneity.

Mechanical properties of bulk metallic glasses and composites

2007 ◽  
Vol 22 (2) ◽  
pp. 285-301 ◽  
Author(s):  
J. Eckert ◽  
J. Das ◽  
S. Pauly ◽  
C. Duhamel
Keyword(s):  
Mechanical Properties ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Second Phase ◽  
Matrix Composites ◽  
Future Directions ◽  
Glassy Alloys ◽  
Spatially Inhomogeneous ◽  
Glass Matrix Composites

The development of bulk metallic glasses and composites for improving the mechanical properties has occurred with the discovery of many ductile metallic glasses and glass matrix composites with second phase dispersions with different length scales. This article reviews the processing, microstructure development, and resulting mechanical properties of Zr-, Ti-, Cu-, Mg-, Fe-, and Ni-based glassy alloys and also considers the superiority of composite materials containing different phases for enhancing the strength, ductility, and toughness, even leading to a “work-hardening-like” behavior. The morphology, shape, and length scale of the second phase dispersions are crucial for the delocalization of shear bands. The article concludes with some comments regarding future directions of the investigations of spatially inhomogeneous metallic glasses.

scholarly journals Correlation between fracture surface morphology and toughness in Zr-based bulk metallic glasses

2010 ◽  
Vol 25 (5) ◽  
pp. 982-990 ◽  
Author(s):  
Jin-Yoo Suh ◽  
R. Dale Conner ◽  
C. Paul Kim ◽  
Marios D. Demetriou ◽  
William L. Johnson
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Energy Dissipation ◽  
Fracture Surface ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Fracture Surface Morphology ◽  
Scanning Electron

Fracture surfaces of Zr-based bulk metallic glasses of various compositions tested in the as-cast and annealed conditions were analyzed using scanning electron microscopy. The tougher samples have shown highly jagged patterns at the beginning stage of crack propagation, and the length and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides strong evidence of significant “plastic zone” screening at the crack tip.

Plastic Deformation of Bulk Amorphous Alloys

2000 ◽  
Vol 644 ◽  
Author(s):  
L.Q. Xing ◽  
T.C. Hufnagel ◽  
K.T. Ramesh
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Serrated Flow ◽  
Perfectly Plastic ◽  
Elastic Loading ◽  
The Difference ◽  
Elastic Perfectly Plastic

AbstractWe have studied plastic deformation, including “serrated flow,” of bulk metallic glasses under quasi-static uniaxial compression. The deformation response is essentially elastic-perfectly plastic, but the “plastic” deformation actually consists of sections of elastic loading separated by abrupt load drops. The load drops are due to the formation of shear bands, which represent the primary mechanism of plastic deformationIn Zr-Ti-Cu-Ni-Al bulk metallic glasses, fracture occurs after about 1-2% plastic strain, but in Zr-Ta-Cu-Ni-Al metallic glass the plastic strain to failure can be as large as 6-7%. The difference appears to be due a strong tendency for the shear bands in this alloy to branch. The branching presumably reduces the stress concentration on the shear bands, retarding the onset of fracture. No evidence is seen for the formation of crystalline phases in this alloy.

Defect Analyses of Deformed Zr-Cu-Ni-Al Bulk Metallic Glasses

2009 ◽  
Vol 283-286 ◽  
pp. 453-457
Author(s):  
Jung Hoon Yoo ◽  
Dae Hwang Yoo ◽  
Jung Hwa Seo ◽  
Ji Ling Dong ◽  
Young Sang Na ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Electron Holography ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Localized Plastic Deformation

In Zr-Cu-Ni-Al bulk metallic glasses where there are no dislocations, localized plastic deformation in shear bands occurs largely by the formation and migration of defects such as voids, micropores, shear bands and local variations in composition. Thus, the investigation on defects is critical for the understanding and improvement of plastic deformation in metallic glasses. In this study, microstructures and nano defects in the Zr-Cu-Ni-Al BMGs are characterized by variety of techniques, such as X-ray diffractometry, high resolution transmission electron microscopy, scanning transmission electron microscopy and electron holography.

scholarly journals The Effect of Cooling Rate on Microstructure and Mechanical Properties of Zr-Based Bulk Metallic Glasses

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Weihong Fu ◽  
Yajuan Sun ◽  
Wei Zhang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Alloy Sample ◽  
Cooling Rates ◽  
Glass Forming ◽  
Microstructure And Mechanical Properties

The aim of the present study is to shed some insights on the effect of cooling rate on the microstructure and mechanical properties for glass-forming alloys. A crystalline gradient was observed in the microstructure of 12 mm diameter Zr51Al9.96Ni14.34Cu24.9(Zr51) alloy sample from the edge to center due to uneven cooling rates. Microhardness results indicate that the lower the cooling rate, the higher the hardness for the studied alloy.

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