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Churning toward stronger, more uniform aluminum casts

  • Magazine Article
  • 17TOFHP02_10
Published February 01, 2017 by SAE International in United States
  • English

Macrosegregation is the uneven distribution of alloying elements within a solidified aluminum part, creating, for example, copper-poor regions. This is most likely to occur in the center of a casting, where it remains hidden until the casting is reprocessed for another use such as rolling a thick slab into a flat sheet. These unbalanced structures can form on a scale from several fractions of an inch to several yards and they can lead to cracking, shearing, or other mechanical failure of the material.

This issue is thought to be particularly significant as industry moves toward faster production schedules and larger sheet metal runs-for example, parts for trucks and airplane wings. Greater emphasis on aluminum recycling also poses issues where the composition of secondary elements may be unpredictable.