When a metal is plastically deformed, it doesn't just stretch uniformly — the crystal lattice fragments into a hierarchy of structures that govern everything from strength to recrystallization behavior. This Part 2 in Aman's deformation microstructures series zooms in on two of the more subtle but mechanically important features: kink bands and micro-bands.

Kink bands form when slip is geometrically constrained — typically in materials with limited slip systems (think hexagonal close-packed metals like magnesium or titanium, or in heavily oriented composites). Rather than glide freely, the lattice rotates abruptly across narrow boundaries, accommodating strain through reorientation. Micro-bands, by contrast, are a feature of medium-to-high stacking fault energy FCC metals deformed to moderate strains, where dense dislocation walls subdivide grains into elongated cells aligned with active slip planes.

The distinction matters because these features control texture evolution, set up nucleation sites for recrystallization, and influence how a worked metal responds to subsequent annealing. Aman builds on Part 1's coverage of shear bands to show how these smaller-scale features are often the precursors to the more dramatic localized deformation you see at higher strains.

This is genuinely niche graduate-level metallurgy content from a 19-subscriber channel — exactly the kind of patient, mechanism-focused teaching that mainstream materials channels skip over.