Hardness Indentation Studies On Metallic Glasses

2002 ◽  
Vol 754 ◽  
Author(s):  
Paul Wesseling ◽  
Peravudh Lowhaphandu ◽  
John. J. Lewandowski
Keyword(s):  
Metallic Glass ◽  
Test Temperature ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Indentation Load ◽  
Amorphous Metals ◽  
Micro Hardness ◽  
Iron Based ◽  
Vickers Micro Hardness

ABSTRACTVickers micro-hardness indentations have been performed on a number of amorphous metals. The effects of changes in indentation load on the hardness and appearance of indents will be discussed for amorphous Al87Ni7Gd6. In addition, the effects of changes in test temperature on the micro-hardness and appearance of indentations in Vitreloy I are presented. A transition in deformation/flow character was detected with increasing test temperature for the Vitreloy I specimens. In addition, preliminary hardness data obtained at room temperature on an iron based metallic glass exhibited values in excess of 12 GPa without cracking.

Ferromagnetic Resonance On Metallic Glass Ribbons

2001 ◽  
Vol 674 ◽  
Author(s):  
M. Chipara ◽  
M. Toacsen ◽  
M. Sorescu
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Metallic Glass ◽  
Ferromagnetic Resonance ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Resonance Condition ◽  
X Band ◽  
Resonance Data

ABSTRACTFerromagnetic resonance data on metallic glasses, at room temperature, in X band, are discussed. The spectra were decomposed into two Lorentzian lines and the angular dependence of their main parameters (line width and position) is fully analyzed. It is proved that the usual approaches are not able to describe accurately the experimental data. This behavior is ascribed to the misalignment of the magnetization with respect to the external magnetic field, and successfully tested by using a “relaxed” resonance condition that allows a small misalignment of the magnetization relative to the external magnetic field.

scholarly journals Improve the Forming Ability of Al-Based Metallic Glass Under Ultrasonic Vibration at Room Temperature

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiong Liang ◽  
Caitao Fan ◽  
Jianan Fu ◽  
Zehang Liu ◽  
Zhenxuan Zhang ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Ultrasonic Vibration ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Deformation Degree ◽  
Maximum Deformation ◽  
Primary Sample

In this work, a rapid and controllable ultrasonic vibration method for forming Al-based metallic glass at room temperature is proposed. This method can dramatically improve the forming ability of Al-based metallic glasses, which are virtually brittle at room temperature and have almost no supercooled liquid region at high temperatures. Under ultrasonic vibration, Al-based metallic glasses exhibited obvious plastic flow, with a maximum deformation degree up to 58% and an average deformation degree up to 43%. It is worth mentioning that no crystalline peaks were found on the X-ray diffraction patterns after deformation under ultrasonic vibration, and the mechanical properties remained the same as the primary sample. The present results provide a new approach for the deformation and forming of Al-based metallic glasses, which can significantly broaden their applications.

Fragmentation of Co-Fe-Ta-B Bulk Metallic Glass

2014 ◽  
Vol 782 ◽  
pp. 553-556
Author(s):  
Jozef Miškuf ◽  
Kornel Csach ◽  
Alena Juríková
Keyword(s):  
Fracture Surface ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Amorphous Structure ◽  
External Loading ◽  
Small Particles ◽  
Failure Characteristics ◽  
Crack Propagation Direction

The main limitation of bulk metallic glasses for their application as structural materials is the large brittleness under the external loading. We analyzed the failure characteristics of Co43Fe20Ta5.5B31.5(at.%) bulk metallic glass deformed in a compression at the room temperature and a low strain rate. Under loading the amorphous structure can store high elastic energy. During the failure this energy is released and the alloy breaks into small particles or powder exhibiting a fragmentation mode. The nanoscale fracture surface morphology respects the micromechanisms of failure of the amorphous structure. The fracture surface consists of a smooth mirror cleavage zone and a river pattern zone with the nanosized dimples arranged in lines respecting the periodic corrugation zones oriented perpendicular to the crack propagation direction.

Room-Temperature Mechanical Properties and Glass Formation of Zr50Cu20Ni15Al(15-X)Tix (x=3, 5, 7) Bulk Metallic Glass Alloys

2011 ◽  
Vol 66-68 ◽  
pp. 741-746
Author(s):  
Jia Hua Zou ◽  
Zhi Chen Zhang ◽  
Shu Quan Sun
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Metallic Glasses ◽  
Glass Formation ◽  
Room Temperature ◽  
Glass Forming Ability ◽  
Glass Forming ◽  
Ti Content ◽  
Ti Addition

In the present study, the Zr-Cu-Ni-Al based bulk metallic glasses with different Ti addition was successfully prepared by suction casting . It was found that the glass forming ability was improved with increasing of Ti content from 3 at.% to 7 at.%. However, with increasing of Ti content, the room-temperature plasticity decreased from 4.33% to 0.66 %.

Hole Punching onto the Zr65Al10Ni10Cu15 BMG Sheet Fabricated by Squeeze Casting

2005 ◽  
Vol 475-479 ◽  
pp. 3423-3426 ◽  
Author(s):  
Ha Guk Jeong ◽  
Woo Jin Kim ◽  
Jung Chan Bae ◽  
Duk Jae Yoon ◽  
Seo Gou Choi ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Metallic Glass ◽  
Metallic Glasses ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Squeeze Casting ◽  
Round Hole ◽  
Pressure Condition ◽  
Casting Method ◽  
Ductile Mode

Bulk metallic glass Zr65Al10Ni10Cu15 was fabricated in a sheet form with thickness 1.5 mm by a squeeze casting method. The structure of the as-cast Zr65Al10Ni10Cu15 sheet was confirmed to be fully amorphous. The sheet was punched into a blank under high hydrostatic pressure at room temperature. A round hole was created with a possible evidence for plastic-like deformation along the edge of rim. No visible cracks were observed around the hole. This result indicates that bulk metallic glasses, which are known to be very brittle at room temperature, can be deformed in a ductile mode under hydrostatic pressure condition. Hydrostatic pressure may suppress the formation and development of micro defects leading to ductile fracture

scholarly journals Low-frequency acoustic measurements on the metallic glass Zr46.8 Ti8.2 Cu7.5 Ni10 Be27.5

2015 ◽  
Author(s):  
Arnold Seiler ◽  
Sebastian Craft ◽  
Georg Weiss
Keyword(s):  
Metallic Glass ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Low Frequency ◽  
Amorphous Solids ◽  
Acoustic Measurements ◽  
Tunneling Model ◽  
Conduction Electrons ◽  
Vibrating Reed

The properties of amorphous solids at low temperatures are well known to be dominated by atomic two-level tunneling systems (TS). While the standard tunneling model successfully describes thermodynamic properties of insulating glasses it fails to predict the elastic properties of metallic glasses. To investigate the role of conduction electrons on the density of states and the dynamics of TS vibrating reed experiments are performed. In superconducting glasses the interaction can be switched on and off by means of a magnetic field which suppresses superconductivity and therefore enables electrons to interact with TS. Here we present measurements of the internal friction and the sound velocity of the splat cooled superconducting metallic glass $\text{Zr}_{46.8}\text{Ti}_{8.2}\text{Cu}_{7.5}\text{Ni}_{10}\text{Be}_{27.5}$ measured at frequencies between 600 Hz and 14 kHz and temperatures from 10 mK to room temperature. Within these experiments we used an improved sample geometry to reduce clamping losses and to excite different modes at various frequencies.

Ti-Based Bulk Metallic Glass with High Cold Workability at Room Temperature

2005 ◽  
Vol 475-479 ◽  
pp. 3431-3434 ◽  
Author(s):  
J.M. Park ◽  
J.S. Park ◽  
J.H. Kim ◽  
Myung Hyun Lee ◽  
Won Tae Kim ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Metallic Glass ◽  
Cold Rolling ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Shear Bands ◽  
Reduction Ratio ◽  
Large Plastic Strain ◽  
Cold Rolled ◽  
Cold Workability

The cold workability of Ti-based bulk metallic glasses (BMGs) have been investigated. Ti45Zr16Be20Cu10Ni9 BMG with a large compressive plastic strain of 4.7 % shows a high cold workability, i.e. total reduction ratio of 50 % by cold rolling at room temperature. The multiple shear bands formed during rolling are effective in enhancing the plasticity. The cold rolled Ti45Zr16Be20Cu10Ni9 BMG (reduction ratio: 30 %) exhibits a large plastic strain of ~14 %.

Nanocrystalline coating enhanced ductility in a Zr-based bulk metallic glass

2007 ◽  
Vol 22 (2) ◽  
pp. 508-513 ◽  
Author(s):  
Hongqi Li ◽  
Li Li ◽  
Cang Fan ◽  
Hahn Choo ◽  
Peter K. Liaw
Keyword(s):  
Shear Band ◽  
Metallic Glass ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Elastic Limit ◽  
Compression Tests ◽  
Fracture Geometry ◽  
Nanocrystalline Coating ◽  
Mean Grain Size ◽  
New Strategy

Compression tests were conducted on the as-cast Zr58Ni13.6Cu18Al10.4 metallic glass at room temperature. The effect of nanocrystalline Ni-15%Fe coating (mean grain size: ∼10 nm) on mechanical properties was investigated. The results demonstrate that the strength, elastic limit, Young’s modulus, and fracture geometry and morphology are not affected by this nanostructured coating. However, the compressive plastic strain increased noticeably when the specimens were coated with a layer of nanocrystal, which is attributed to the increased shear band density. The high shear band density is suggested to be due to the inhibition of shear band operation by nanocrystalline coating. The significance of this study is that a new strategy was developed to improve the ductility of bulk metallic glasses.

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