Abstract
Experiments have been carried out to determine under what condition it is possible to produce or eliminate “Sub-grain structure” in Al-Cu alloy.
The sub-grain structure has been observed in cast alloy which is tempered at low temperature after quenching from solution treatment. The sub-grain, however, does not appear when the cast alloy is deformed and annealed to complete recrystallisation.
The sub-grain structure is well developed in the specimen which is tempered at low temperature after one of the following treatments. (1) When recrystallized specimen is hot-worked and cooled rapidly. (2) When recrystallized specimen is cold or hot worked and then annealed below recrystallisation point. It has been shown that the slip bands of cold worked specimen change the form into sub-grain structure in the process of recovery.
