Mode

Nucleation + growth

Anneal grain-growth

Nucleation seeds: 120 Temperature (mobility): 600 °C Show grain boundaries Colour mode

Stats

Grains—

Mean grain Ø—

Anneal step / time—

Hall–Petch σ_y—

Polycrystals are built of grains — crystallites that meet at dark grain boundaries. Seeds nucleate with random orientation, then grow. During annealing, boundaries migrate to cut their curvature, so small grains vanish and the mean size D rises as D ∝ tⁿ. Finer grains are stronger: Hall–Petch σ_y = σ₀ + k·D^−1/2.