Indentation creep of an Fe-based bulk metallic glass

Huang, Yongjiang; Shen, Jun; Chiu, Yu-Lung; Chen, John J. J.; Sun, Jianfei

doi:10.1016/j.intermet.2008.09.014

Cited by 82 publications

(18 citation statements)

References 36 publications

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“…In addition, the holding stage could be time-saving due to the high accuracy for obtaining the time-dependent plastic deformation. However, the stress distribution beneath the indenter is much more complicated and plastic deformation always occurred before the holding stage [15][16][17][18]. Thus, metallic glasses having high glass transition temperature (T g ) can even creep at room temperature in nanoindentation.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, metallic glasses having high glass transition temperature (T g ) can even creep at room temperature in nanoindentation. To authors' best knowledge, the creep behaviors of metallic glasses concerned with loading rate [16], holding load [16,17] and initial strain [18] were qualitatively explained through free volume. In our previous work, the loading rate effect on creep was found to be composition-dependent and apparently related to the STZ size [19].…”

Section: Introductionmentioning

confidence: 99%

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Nanoindentation investigation on the creep mechanism in metallic glassy films

Peng

Feng

et al. 2016

Materials Science and Engineering: A

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a b s t r a c tUsing the magnetron sputtering technique, two metallic glassy films namely Cu 44.3 Zr 45.1 Al 10.6 and Cu 44.2 Zr 43 Al 11.3 Ti 1.5 were prepared by alloy targets. The minor Ti addition effectively induces excess free volume. Upon spherical nanoindentation, the creep behaviors of both films were studied at various peak loads. As the increase of peak load, the creep deformations became more severely in both samples. Interestingly, Cu-Zr-Al-Ti film crept stronger than Cu-Zr-Al at small-load holdings (nominal elastic regimes), whereas it is opposite at high-load holdings (plastic regimes). The creep characteristic could be intrinsically related to the scale variation of the shear transformation zone (STZ) with Ti addition. Statistical analysis was employed to estimate the STZ volume, which increased by 60% with Ti addition in the Cu-Zr-Al film. The finite element modeling indicated that STZs would be activated even at the minimum load we adopted. Higher activation energy of larger STZs in Cu-Zr-Al-Ti enables less flow units, which offsets the creep enhancement by the excess free volume with Ti addition. The deeper the pressed depth of the indenter, the more contribution of the STZ operation on creep deformation. In addition, experimental observation on the creep flow rates implies that STZ could be the dominating mechanism at the steady-state creep. This study reveals that STZ volume could also be important to the time-dependent plastic deformation in metallic glass, besides as a key parameter for instantaneous plasticity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanoindentation investigation on the creep mechanism in metallic glassy films

Peng

Feng

et al. 2016

Materials Science and Engineering: A

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“…Moreover, creep flow was more pronounced with decreasing thickness in a Cu-Zr-Al thin film [18]. However, it is unable to reach a conclusion on creep characteristic of metallic glasses from the reported results due to different imposed testing conditions and sample status [14][15][16][17][18]. With this in mind, metallic glassy thin films with eight compositions were carefully prepared by PVD method, ensuring film thickness, surface roughness and structure state are almost equal in different samples.…”

Section: Introductionmentioning

confidence: 95%

“…The stress distribution beneath the indenter is much more complicated than that in uniaxial testing and plastic deformation always occurs before holding stage. Therefore metallic glasses with high glass transition temperature (T g ) can even creep at room temperature by nanoindentation [14,15]. The nanoindentation induced creep behaviors of metallic glasses have been qualitatively studied, concerned with the effects of loading rate and imposed initial displacement and/or strain [16,17].…”

Section: Introductionmentioning

confidence: 99%

On the spherical nanoindentation creep of metallic glassy thin films at room temperature

Zhang

Feng

et al. 2017

Materials Science and Engineering: A

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Metallic glassy thin films with eight kind of compositions were successfully prepared on Si substrate by magnetron sputtering. The room-temperature creep tests were performed at plastic regions for each sample relying on spherical nanoindetation. The creep deformations were studied by recording the total creep displacement and strain after 2000 s holding. More pronounced creep deformation was observed in the sample with lower glass transition temperature (T g). Strain rate sensitivity (SRS) was then calculated from the steadystate creep and exhibited a negative correlation with increasing T g. It is suggested that creep mechanism of the nano-sized metallic glass was T g-dependent, according to the demarcation of SRS values. Based on the obtained SRS, shear transformation zone (STZ) size in each sample could be estimated. The results indicated that an STZ involves about 25-60 atoms for the employed eight samples and is strongly tied to T g. The characteristic of STZ size in metallic glassy thin films was discussed in terms of applied method and deformation modes.

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“…Recently, the creep behaviors of BMGs have been reported using compression tests and nanoindentation technology [6][7][8][9][10][11][12][13][14][15]. Huang et al studied the room temperature creep behaviors of a Fe 41 Co 7 Cr 15 Mo 14 C 15 B 6 Y 2 BMG using the nanoindentation technique and found that the creep exponent varied with the peak load or loading rate, which has been interpreted based on the shear transformation zone theory [6]. Yu et al suggested that the nanoindentation creep behaviors of Co 56 Ta 9 B 35 metallic glass could be described by a Kelvin model [7].…”

Section: Introductionmentioning

confidence: 99%

Tensile Creep Characterization and Prediction of Zr-Based Metallic Glass at High Temperatures

Wang

Pan

Shi

et al. 2018

Metals

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Abstract:The high temperature creep behaviors of a Zr-based bulk metallic glass (BMG) are studied by uniaxial tensile creep experiments under applied stresses of 50-180 MPa at temperatures of 660-700 K. The microstructural observations of the BMG samples after creep tests show that crystalline phases can be detected under high temperature or high applied stress. Constitutive models for predicting the high temperature creep behaviors of the studied Zr-based BMG are established based on the θ projection method. The creep activation energy and stress exponent are also calculated to establish the creep model. The parameters of the established models are found to be closely associated with the applied stress and temperature. The results show an excellent agreement between the measured and predicted results, confirming the validity of the established model to accurately estimate the high temperature creep curves for the Zr-based BMG. Moreover, based on the classical diffusion creep theory, a schematic model is proposed to describe the creep behaviors of BMGs from the framework of free volume theory.

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Indentation creep of an Fe-based bulk metallic glass

Cited by 82 publications

References 36 publications

Nanoindentation investigation on the creep mechanism in metallic glassy films

Nanoindentation investigation on the creep mechanism in metallic glassy films

On the spherical nanoindentation creep of metallic glassy thin films at room temperature

Tensile Creep Characterization and Prediction of Zr-Based Metallic Glass at High Temperatures

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