Anomalous elastic response of amorphous alloys suggesting collective motions of many atoms

Mizubayashi, H.; Usui, T.; Tanimoto, H.

doi:10.1016/j.msea.2003.08.100

Cited by 3 publications

(6 citation statements)

References 26 publications

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“…The out line of the (f/f 0 ) 2 vs. ε t data observed for a-Zr 55 Cu 30 Al 10 Ni 5 , a-Zr 50 Cu 50 and a-Cu 50 Ti 50 were very similar to that already reported [15] except that the amounts of the increases in (f/f 0 ) 2 observed in the present a-Zr 50 Cu 50 and a-Cu 50 Ti 50 specimens were about 60 % of those in the a-Zr 50 Cu 50 and a-Cu 50 Ti 50 specimens used in [15]. A change in E(ε t0 ,f 0 ) under PEC with i d ~ 10 7 A/m 2 was measured in a He gas atmosphere of about 0.1 atm in order to minimize an increase in the specimen temperature due to joule heating [14]. Fig.…”

Section: Resultsmentioning

confidence: 99%

“…where Z*, S, e and ρ R denote the effective charge number, a dimensional cross-section of an atom, the elementary charge and the specific resistivity of the a-alloy, respectively (see [14,17] Fig. 7 shows the schematic drawing for the strain and frequency dependence of the Young's modulus of metallic glasses reported in [7,14], where E s ,. E(ε t0 , f) and E(ε t , f 0 ) are depicted by the line AB, the curve ACD and the curve CE, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…(c) Similar to (b) but here shown are the E(ε t0 , f) data (•) and E s observed for the specimen after annealing at 570 K for 0.5 h, the E(ε t0 , f) data (△) and E s observed for the two specimens after annealing at 700 K for 0.5 h and the E(ε t0 , f) data (■) and E s observed for the specimen after annealing at 850 K for 0. The schematic drawing for the strain and frequency dependence of the Young's modulus of metallic glasses [7,14].…”

Section: Resultsmentioning

confidence: 99%

“…E(ε t0 ,f) was measured as a function of the specimen length at ε t0 of 10 -6 and E(ε t ,f 0 ) was measured as a function of the vibrating amplitude at f 0 of ~100 Hz, respectively. A change in E(ε t0 ,f 0 ) under PEC was measured as a function of the current density i d at ε t0 of 10 -6 and f 0 between ~10 and 1000 Hz, where the measurement setup was similar to that reported in [14].…”

Section: Methodsmentioning

confidence: 99%

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Elasticity study on collective motion in metallic glasses

Takahashi

Tanimoto

Mizubayashi

2006

Materials Science and Engineering: A

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The frequency (f) dependence, E(ε t0 , f), and the strain amplitude (ε t) dependence, E(ε t , f 0), of the dynamic Young's modulus in a-Cu 50 Ti 50 (MMG), a-Zr 50 Cu 50 (MMG) and a-Zr 55 Cu 30 Al 10 Ni 5 (BMG) were investigated at room temperature by means of the vibrating reed method in the frequency range between 10 1 Hz and 10 4 Hz, where ε t0~1 0-6 , f 0~1 0 2 Hz and MMG and BMG are abbreviations of marginal and bulk metallic glasses, respectively. The effect of passing direct-current (PEC) on E(ε t0 , f 0) was also investigate. The strong decrease in E(ε t0 , f) between 10 1 Hz and 10 4 Hz, the strong increase in E(ε t , f 0) with increasing ε t below 0.2% and the net increase in E(ε t0 , f 0) under PEC with the current density of 10 7 A/m 2 were commonly found, indicating that the resonant collective motions of many atoms were excited in metallic glasses. For a-Zr 50 Cu 50 and a-Zr 55 Cu 30 Al 10 Ni 5 , the effective charge, Z*, for the effects of PEC was found to be 10 5 and showed decrease with increasing f. The magnitudes of all the changes were similar among the metallic glasses, indicating that the correlation between the collective motions and the free volume contained in metallic glasses is not too strong. The underlying mechanism was discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Elasticity study on collective motion in metallic glasses

Takahashi

Tanimoto

Mizubayashi

2006

Materials Science and Engineering: A

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“…The effective charge number, Z Ã , to explain the concentration of electromigration force was the order of 10 5 for various amorphous alloys. 6,7,18,19) It is noted that for the electromigration effect, the value of Z Ã is larger by four to five digits than the effective charge number, z Ã , of a single atom in a concentrated alloy. 20) A model to explain the effect of passing electric current on the dynamic Young's modulus is as follows: The concentration of the electromigration force associated with a collective motion of many atoms causes a decrease in the motional amplitude of its resonant motion excited by elastic vibrations because of saturation of the localized shear deformation of surrounding atoms.…”

Section: Introductionmentioning

confidence: 99%

Transformation to Nanocrystallites in Amorphous Alloys Induced by Resonant Electropulsing

2005

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The electropulsing-induced low temperature crystallization (e-LTC) of marginal amorphous (a-) alloys, a-Cu 50 Ti 50 and a-Pd 80 Si 20 , and a bulk amorphous alloy, a-Zr 60 Cu 30 Al 10 , was investigated by electropulsing at room temperature (RT) and in liquid nitrogen (LN 2 ). Electropulsing was made by means of discharge of a condenser which is characterized by the initial current density, i d0 , and the decay time, , where the frequency of the principal constituent Fourier component of the electropulsing is 1=2. The range of i d0 was between 10 8 and 10 10A/m 2 and that of was between 0.1 and 20 ms. For all the amorphous alloys, the e-LTC took place during single electropulsing with i d0 beyond the threshold current density, i d0,c , where i d0,c was a function of . The maximum specimen temperature during the e-LTC was, e.g., 200 K for electropulsing in LN 2 , indicating that the e-LTC is associated with an athermal process, the resonant collective motion of the relatively high density region here. The dependence of i d0,c on found for electropulsing in LN 2 showed good agreement with that observed at RT, indicating that the density fluctuation responsible for the e-LTC was that frozen at the glass transition temperature. The transmission electron microscopy observation revealed that crystallites formed by the e-LTC showed crystallographic alignment with each other, suggesting that the transformation of the relatively high density regions to a crystalline phase took place. The underlying mechanism of the e-LTC was discussed.

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Inhibition of Electropulsing Nanocrystallization in Amorphous ZrCu under Helium Atmosphere

et al. 2020

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Nanocrystallization of amorphous ZrCu was induced by applying a pulse current (electropulsing), which exponentially decayed from a certain initial current density (i d0) with the time constant of 3 ms. For electropulsing, the ribbon specimen was sandwiched between high-thermalconductive AlN (thermal conductivity ¬ = 170 W/m/K at 273 K) plates to remove the Joule heat. Nanocrystallization was found when electropulsing was conducted in a vacuum below 10 ¹2 Pa at the pulse current of i d0 ² 0.6 GA/m 2. In contrast, electropulsing conducted under 10 5 Pa He (¬ = 0.144 W/m/K at 273 K) required i d0 above 1.1 GA/m 2. Thermal conductivity and heat capacity of 10 5 Pa He were negligibly smaller than those of the AlN plates. The increase in i d0 for nanocrystallization with increasing He pressure indicates that He penetrated the amorphous structure to inhibit the activation of cooperative motions of many atoms and larger i d0 is required for nanocrystallization at higher He pressure.

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Anomalous elastic response of amorphous alloys suggesting collective motions of many atoms

Cited by 3 publications

References 26 publications

Elasticity study on collective motion in metallic glasses

Elasticity study on collective motion in metallic glasses

Transformation to Nanocrystallites in Amorphous Alloys Induced by Resonant Electropulsing

Inhibition of Electropulsing Nanocrystallization in Amorphous ZrCu under Helium Atmosphere

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