Defect Landscape Engineering Suppresses Helium Damage in Ceramics

TL;DR

This paper introduces defect landscape engineering, a strategy to create vacancy clusters in ceramics before helium exposure, effectively trapping helium in nanobubbles and reducing damage in nuclear and aerospace applications.

Contribution

It demonstrates a novel defect engineering approach that transforms helium defect evolution, enhancing radiation tolerance in ceramics through pre-damage design and atomistic insights.

Findings

Helium is trapped in stable nanobubbles instead of forming cracks.

Pre-created vacancy clusters act as dual-function sinks for defects.

The method is scalable and applicable across various ceramic materials.

Abstract

Helium accumulation in structural ceramics used in nuclear, fusion, and aerospace systems causes swelling, cracking, and early failure, yet controlling this damage has remained elusive. Here, we introduce defect landscape engineering, the deliberate creation of vacancy clusters prior to helium exposure, as a general strategy to suppress helium-induced degradation. Using {\alpha}-SiC as a model, we combine advanced microscopy, strain mapping, helium depth profiling, positron annihilation spectroscopy, and atomistic simulations to demonstrate that tailored pre-damage transforms helium defect evolution. Instead of forming extended platelets and nanocracks, helium is trapped in stable, uniformly dispersed nanobubbles. Simulations reveal that small vacancy clusters act as dual-function sinks for irradiation-induced interstitials and preferential helium traps, fundamentally altering cascade recombination dynamics. This mechanism is composition-independent and scalable, offering a new design principle for radiation-tolerant ceramics across carbides, nitrides, and oxides. By viewing defect control as a tunable parameter instead of a fixed material property, this work outlines a possible design route toward enhanced radiation tolerance in ceramics used in extreme environments.