# Effect of Crystal Orientation on Dislocation Loop Evolution Under Electron Radiation in Pure Aluminum

## TL;DR

This paper studies how electron radiation affects pure aluminum's crystal structures, showing that crystal orientation influences defect formation and irradiation resistance.

## Contribution

The study reveals how crystallographic orientation affects dislocation loop characteristics and irradiation damage in aluminum under electron radiation.

## Key findings

- The interstitial atom density in <111> dislocation loops is significantly higher than in <110> loops across all irradiation directions.
- Under [110]-direction irradiation, <111> loops have about 55 times higher interstitial atom density than <110> loops.
- The threshold displacement energy of aluminum at room temperature varies with crystal orientation as [110] < [111] < [310] < [100].

## Abstract

Aluminum, the primary structural material used in spacecraft, operates in low Earth orbit (LEO). It is subjected to high-energy electron irradiation with energies ranging from 0.1 to 10 MeV, which produces significant irradiation damage. Understanding the characteristics of irradiation defects with crystallographic orientations is crucial for analyzing the failure of spacecraft components and for developing aerospace materials with improved irradiation resistance. In this study, pure aluminum was irradiated in situ at room temperature using 200 kV transmission electron microscopy. The irradiation defects were comparatively analyzed for four crystallographic orientations, focusing on the size, density, and interstitial content of <111> and <110> dislocation loops. For all four irradiation directions, the interstitial atom density (IAD) within <111> loops is significantly higher than that in <110> loops. Notably, under [110]-direction irradiation, IAD in <111> loops is approximately 55 times that in <110> loops. This phenomenon is attributed to the one-dimensional migration of <110> loops. Among the four irradiation directions, the total IAD in the two types of loops decreases in the order: [110] > [111] > [310] > [100]. The threshold displacement energy (Ed) of aluminum at room temperature is inferred to follow the relationship: [110] < [111] < [310] < [100].