Macroscopic thermoplastic model applied to the high pressure torsion of metallic glasses

Abstract

Shear deformation generated temperature rise in metallic glasses is estimated in a macroscopic three-dimensional axial symmetric thermoplastic model. Numerical solution of heat-conduction equation provides the time evolution and spatial distribution of temperature for high pressure torsion in the present paper. We have shown that small sample thickness and/or high deformation rate enables the temperature to exceed the glass transition in the entire sample, yielding a transition of the deformation mode from inhomogeneous to homogeneous viscous flow. However, in other cases only a small temperature increase is predicted in line with literature data.

Estimation of heat production during high pressure torsion of Cu-based metallic glass

“…4b becomes steeper, yielding the temperature to exceed T g in larger volumes of the sample. This is going to be examined in detail in an upcoming paper [20].…”

Effects of severe plastic deformation on the structure and thermo-mechanical properties of Zr55Cu30Al10Ni5 bulk metallic glass

“…The thermo-mechanical behavior of the HPT disks can be explained in terms of a three-dimensional thermoplastic model based on heat conduction [33]. In brief, the disk-shape sample with a radius of R and thickness L is placed between two cylindrical stainless steel anvils.…”

Effect of accumulated shear on the microstructure and morphology of severely deformed Cu60Zr30Ti10 metallic glass

“…The above conflict obtained between the SEM images and the synchrotron data, however, can be resolved by a recently developed three-dimensional thermoplastic model based on heat conduction [26]. In brief, the temperature evolution in the disk-shape sample during the HPT-process can be derived from the heat conduction equation with a source term, S(r,t):…”

“…Noteworthy that the material parameters of widely investigated metallic glasses have only a slight influence on the temperature evolution [26]. The more detailed description of the model is given elsewhere [26].…”

“…Later the effect of the instrumental parameters on the temperature rise was discussed in terms of a quasi three-dimensional model [26], and the role of the most important parameter, i.e. the shear rate on the microstructure and thermal stability was investigated in detail [27].…”