Characterization of Cr-Bearing Intermetallics Causing Pinhole Formation in Twin Roll Cast 8079 Aluminum Alloy Thin Foils

8079 alloy, produced by the twin roll casting method, is widely used in the production of thin foils due to its hardness and elongation properties. However, some quality problems must be overcome in cold rolled foils that are thinned to a thickness of around 7 microns. At the beginning of the problems that need to be solved, pinhole formations whose number is above the acceptance criteria come. In this study, pinholes caused by intermetallic or intermetallic-like structures containing Cr were investigated. However, in order to solve the problem, it should be known which metallurgical or mechanical reasons cause pinhole formation. A number of characterization methods were applied to foil samples. It is aimed to make inferences about which production step or which operation in the casting system is the source of the problem.