Causal link between CCA microstructure and avalanche statistics

Establish the causal relationship between the measured microstructural state of a complex concentrated alloy—including local chemistry, short-range order, fluctuating fault energies, dendritic segregation, precipitates, and phase boundaries—and the nucleation, arrest, and statistical exponents of avalanche-like plastic events.

Background

The review identifies causality as the principal unresolved issue in understanding intermittent plasticity in complex concentrated alloys. Although multiple microstructural features are plausibly capable of influencing avalanche nucleation and arrest, the available literature rarely connects a quantitatively measured microstructural state directly to a specific avalanche exponent.

This gap is important because changes in an apparent exponent, event-size cutoff, or event rate may arise from several confounding factors, including dislocation mobility, source density, hardening, detection threshold, localization length scale, or a change in the active deformation carrier. Resolving the problem therefore requires coordinated measurements of microstructure, deformation mechanisms, spatial localization, and avalanche statistics rather than statistical fitting alone.