Stored Mechanical Work in Inhomogeneous Deformation Processes of a Pd-Based Bulk Metallic Glass

Küchemann, Stefan; Wagner, Hannes; Schwabe, Moritz; Bedorf, Dennis; Arnold, W.; Samwer, K.

doi:10.1007/s11661-013-1898-1

Cited by 6 publications

(2 citation statements)

References 17 publications

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“…During heterogeneous deformation, the deformation rate is significantly above the relaxation rate so the strain is localized into thin planar regions * urbassek@rhrk.uni-kl.de; http://www.physik.uni-kl.de/urbassek/ with a thickness of 10-200 nm, called shear bands [10,11]. These shear bands exhibit a severely deformed core featuring a significantly decreased local density [10], enhanced enthalpy [12] and an enhanced diffusion coefficient [13]. Eventually, shear bands lead to the failure of the material, which limits the industrial applications of metallic glasses.…”

Section: Introductionmentioning

confidence: 99%

Nanoscratching of metallic glasses – An atomistic study

Avila

Küchemann

Alhafez

et al. 2019

Tribology International

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Tribological properties of materials play an important role in engineering applications. Up to now, a number of experimental studies have identified correlations between tribological parameters and the mechanical response. Using molecular dynamics simulations, we study abrasive wear behavior via nanoscratching of a Cu 64.5 Zr 35.5 metallic glass. The evolution of the normal and transverse forces and hardness values follows the behavior well known for crystalline substrates. In particular, the generation of the frontal pileup weakens the response of the material to the scratching tip and leads to a decrease of the transverse hardness as compared to the normal hardness. However, metallic glasses soften with increasing temperature, particularly above the glass transition temperature thus showing a higher tendency to structurally relax an applied stress. This plastic response is analyzed focusing on local regions of atoms which underwent strong von-Mises strains, since these are the basis of shear-transformation zones and shear bands. The volume occupied by these atoms increases with temperature, but large increases are only observed above the glass transition temperature. We quantify the generation of plasticity by the concept of plastic efficiency, which relates the generation of plastic volume inside the sample with the formation of external damage, viz. the scratch groove. In comparison to nanoindentation, the generation rate of the plastic volume during nanoscratching is significantly temperature dependent making the glass inside more damage-tolerant at lower temperature but more damage-susceptible at elevated temperatures.

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Section: Introductionmentioning

confidence: 99%

Nanoscratching of metallic glasses – An atomistic study

Avila

Küchemann

Alhafez

et al. 2019

Tribology International

Self Cite

View full text Add to dashboard Cite

show abstract

“…Accordingly, there is also a noticeable difference in the crystallization enthalpy and ∆T between the two crystallization types. Apart from that, the heat flow below the glass transition gives information about relaxation processes which are closely linked to the β-relaxation and which can be enhanced, for instance, by previous deformation [72]. Therefore, we measured the heat flow our samples in a power compensated Differential Scanning Calorimeter 7 (DSC 7) from Perkin Elmer.…”

Section: Characterisation Of Metallic Glassesmentioning

confidence: 99%