Indentation behavior of a ZCAP-3 bulk metallic glass: Effects of the fatigue deformation

2009 ◽  
Vol 24 (7) ◽  
pp. 2346-2352 ◽  
Author(s):  
Fuqian Yang ◽  
Hongmei Dang ◽  
Gongyao Wang ◽  
Yoshihiko Yokoyama ◽  
Peter K. Liaw

The effects of the fatigue deformation on the localized deformation of a ZCAP-3 bulk metallic glass (BMG) were studied using the nanoindentation technique. A localized mechanical hardening was observed in the ZCAP-3 BMG between the shear bands in the fatigue-damaged zone. In contrast to the indentations of the BMG made far away from the fatigue-damaged zone, there was no indentation size effect. Both the reduced contact modulus and the indentation hardness were larger than those corresponding to the indentations of the ZCAP-3 BMG in the undamaged zone. These observations revealed the possible effects of local heating and stress-induced atomic rearrangements (i.e., inelastic deformation) on the reduction of the free volume in the BMG from the propagation of the fatigue crack.

2010 ◽  
Vol 25 (3) ◽  
pp. 592-597 ◽  
Author(s):  
Ding Li ◽  
Mimi Yang ◽  
Fuqian Yang ◽  
Peter K. Liaw

Using the microindentation test, the stress-assisted-electrochemical corrosion of Cu46.25Zr45.25Al7.5Er1 bulk metallic glass (BMG) was studied in a 10 wt% NaCl electrolyte. The microindentation was performed in an indentation load range of 500 to 4000 mN to create shear bands over the deformation zone. Electric current of various densities was passed through the indented BMGs to evaluate the effect of shear bands and localized deformation on the electrochemical corrosion of the BMGs. Surface pits always initiated from the shear-banding zone and the contact edges between the indenter and the BMGs, and the size of the corroded zone grew with the increase in the polarization time, the indentation load, and the current density. Wormlike amorphous whiskers were formed over the corroded zone, and the density of the wormlike whiskers increased with the current density and polarization time.


2011 ◽  
Vol 64 (8) ◽  
pp. 753-756 ◽  
Author(s):  
Jae-il Jang ◽  
Byung-Gil Yoo ◽  
Yong-Jae Kim ◽  
Jun-Hak Oh ◽  
In-Chul Choi ◽  
...  

Author(s):  
Vasily Astanin ◽  
Dmitry Gunderov ◽  
Zhi Qiang Ren ◽  
Ruslan Valiev ◽  
Jing Tao Wang

2003 ◽  
Vol 18 (9) ◽  
pp. 2039-2049 ◽  
Author(s):  
Jun Lu ◽  
Guruswami Ravichandran

An experimental study of the inelastic deformation of bulk metallic glass Zr41.2Ti13.8Cu12.5Ni10Be22.5 under multiaxial compression using a confining sleeve technique is presented. In contrast to the catastrophic shear failure (brittle) in uniaxial compression, the metallic glass exhibited large inelastic deformation of more than 10% under confinement, demonstrating the nature of ductile deformation under constrained conditions in spite of the long-range disordered characteristic of the material. It was found that the metallic glass followed a pressure (p) dependent Tresca criterion τ = τ0 + βp, and the coefficient of the pressure dependence β was 0.17. Multiple parallel shear bands oriented at 45° to the loading direction were observed on the surfaces of the deformed specimens and were responsible for the overall inelastic deformation.


2008 ◽  
Vol 496 (1-2) ◽  
pp. 285-290 ◽  
Author(s):  
L. He ◽  
M.B. Zhong ◽  
Z.H. Han ◽  
Q. Zhao ◽  
F. Jiang ◽  
...  

1995 ◽  
Vol 10 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
M. Atkinson

The variation of apparent hardness observed in previously reported Vickers indentation tests of metals is reexamined. Common deseriptions of the effect are shown to be inaccurate: the variation of apparent hardness is monotonic but not simple. The effect is consistent with varying size of a previously postulated “plastic hinge” at the perimeter of the indent. This complexity confers uncertainty on the estimation of characteristic macrohardness from small scale tests. Association of the indentation size effect with friction and with strain hardening is confirmed.


2021 ◽  
Vol 875 ◽  
pp. 70-75
Author(s):  
Syed Zameer Abbas ◽  
Rashid Ali ◽  
Syed Muttahir Shah ◽  
Owais Jan ◽  
Munim Awan

Bulk metallic glasses (BMGs) are an important class of materials with unique set of properties. A bulk metallic glass with composition of (Fe0.6Co0.4)71Nb4Si5B20 was cast in the form of a 1 mm thick strip in a water cooled copper mold. The BMG produced was characterized for structure, thermal and mechanical properties. The X-ray diffraction performed on the as cast alloy has shown completely amorphous structure. The glass transition and crystallization peak temperatures obtained through differential scanning calorimetry scan were 542 °C and 588.4 °C, respectively. Some cast amorphous alloy sample was annealed below glass transition (450 °C for 30 mi93nutes) and others above glass transition (580 °C for 5 minutes) temperatures. Nano- indentation hardness of 13.3 GPa was obtained for as cast alloy while a hardness values of 12.8 and 15.84 GPa were measured for heat treated alloys at temperature of 450 °C and 580 °C, respectively. Increase in hardness was attributed to formation of crystals in an amorphous matrix whereas decrease in hardness was due to relaxation of quenching residual stresses. The maximum value of elastic modulus obtained through indentation was 255 GPa for 580 °C heat treated sample.


2007 ◽  
Vol 22 (2) ◽  
pp. 501-507 ◽  
Author(s):  
F.F. Wu ◽  
Z.F. Zhang ◽  
S.X. Mao

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.


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