Incident-angle dependence of deformation characteristics of aluminum surface under low-energy xenon-ion impact

TL;DR

This study uses molecular dynamics simulations to analyze how incident angle and energy affect deformation and defect formation on aluminum surfaces under low-energy xenon-ion impact, relevant for space thruster durability.

Contribution

It introduces a collision model explaining the physical mechanisms behind incident-angle dependence of surface deformation and defect density in aluminum under ion impact.

Findings

Defect density increases linearly with incident energy.

Maximum defect density occurs at around 20-degree incident angle.

A collision model explains the physical mechanisms behind these effects.

Abstract

Ion thruster is a revolution technology with potential applications in space mission but the thrusters operation lifetime is limited by the sputtering from thruster components. In this work, molecular dynamic simulations are performed to explore the dependence of deformation characteristics of an aluminum surface on incident angle and kinetic energy under low-energy xenon-ion impact. The fraction of non-12-coordinated atoms is used to quantitatively characterize the microstructural evolution and defect density levels. It is found that defect density level has a linear relation with incident energy, and there exists a critical incident angle around 20 degrees, at which the aluminum surface has the maximum defect density level. In addition, a collision model is developed to theoretically reveal the physical mechanisms behind the dependence. Our findings may helpful in developing long endurance electric propulsion devices for practical applications.