Transition to chip serration in simulated cutting of metallic glasses

Karina E Avila,Herbert M Urbassek,Vardan Hoviki Vardanyan

doi:10.1140/epjb/s10051-021-00160-5

Karina E Avila, Herbert M Urbassek + Show 1 more

https://doi.org/10.1140/epjb/s10051-021-00160-5

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Abstract

Cutting of metallic glasses produces as a rule serrated and segmented chips in experiments, while atomistic simulations produce straight unserrated chips. We demonstrate here that with increasing depth of cut – with all other parameters unchanged – chip serration starts to affect the morphology of the chip also in molecular dynamics simulations. The underlying reason is the shear localization in shear bands. As the distance between shear bands increases with increasing depth of cut, the surface morphology of the chip becomes increasingly segmented. The parallel shear bands that formed during cutting do no longer interact with each other when their separation is gtrsim 10 nm. Our results are analogous to the so-called fold instability that has been found when machining nanocrystalline metals.Graphic abstract

Highlights

Cutting of materials is a basic machining process whose fundamentals have been studied for long
Albeit simplified, model [1,2] assumes that the separation of the material and the formation of the chip can be understood by a simple laminar-flow model, in which the material in front of the tool edge flows towards the tool and separates at the tool edge into a downward component, which flows below the tool, and an upwards component, which forms the chip
Previous atomistic simulations [6,7,8,9] proved that this simple geometry is able to describe in high quantitative accuracy the processes occurring in metallic-glass cutting and chip formation [7]

Summary

Introduction

Cutting of materials is a basic machining process whose fundamentals have been studied for long. Albeit simplified, model [1,2] assumes that the separation of the material and the formation of the chip can be understood by a simple laminar-flow model, in which the material in front of the tool edge flows towards the tool and separates at the tool edge into a downward component, which flows below the tool, and an upwards component, which forms the chip. Previous atomistic simulations [6,7,8,9] proved that this simple geometry is able to describe in high quantitative accuracy the processes occurring in metallic-glass cutting and chip formation [7]. As a rule, serrated and segmented chips are found when cutting metallic glasses [10,11,12,13,14,15,16,17]

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