Eutectic grain

The grain diffused from the molten bath at eutectic composition and eutectic temperature.

For example, from the solidifying austenite-graphite eutectic of cast iron, the eutectic grain is diffused from a crystal nucleus through this process and continues growing in the form of spheres.

The diffused graphite in the eutectic grain branches off in the shape of a more or less dendritic structure. Figure 1 illustrates eutectic grains in flake graphite cast iron that are made visible by means of etching.

Additional references:

Eutectic grain count

  • Figure 1: Macro structure of flake graphite cast iron in sand casting. The eutectic grains have been made visible by means of etching, 10:1. Source: Maria Paz Arrula, Fagor Ederlan Tafalla.