# Adhesive wear mechanisms in the presence of weak interfaces: Insights from an amorphous model system

## TL;DR

This paper develops a theoretical framework and simulation-based insights into adhesive wear mechanisms at sliding interfaces, linking nanoscale processes to macroscopic wear behavior, and introduces a critical length scale for debris formation.

## Contribution

It presents a new mechanism map and an analytical expression for a critical length scale, connecting interface properties and surface roughness to wear regimes.

## Key findings

- Colliding asperities can deform plastically, form wear particles, or slip without damage.
- The framework links weak and strong adhesion regimes and explains non-catastrophic wear.
- A critical length scale predicts when debris formation occurs.

## Abstract

Engineering wear models are generally empirical and lack connections to the physical processes of debris generation at the nanoscale to microscale. Here, we thus analyze wear particle formation for sliding interfaces in dry contact with full and reduced adhesion. Depending on the material and interface properties and the local slopes of the surfaces, we find that colliding surface asperities can either deform plastically, form wear particles, or slip along the contact junction surface without significant damage. We propose a mechanism map as a function of material properties and local geometry, and confirm it using quasi-two-dimensional and three-dimensional molecular dynamics and finite-element simulations on an amorphous, siliconlike model material. The framework developed in the present paper conceptually ties the regimes of weak and strong interfacial adhesion together and can explain that even unlubricated sliding contacts do not necessarily lead to catastrophic wear rates. A salient result of the present paper is an analytical expression of a critical length scale, which incorporates interface properties and roughness parameters. Therefore, our findings provide a theoretical framework and a quantitative map to predict deformation mechanisms at individual contacts. In particular, contact junctions of sizes above the critical length scale contribute to the debris formation.