Investigation of the microstructural and corrosion behavior of 3xxx alloys cast by twin roll casting method after alternative thermo-mechanical process

In this study, it is aimed to obtain the strength conditions demanded by the building and construction industry and not to change the temper transition suddenly by applying different thermo-mechanical processes to the 3004, 3005 and 3105 aluminum alloys cast by the twin roll casting method. For this purpose, alloys with alternative thermo-mechanical processes were subjected to tensile and bendability tests, and their corrosion behavior, texture and microstructure were investigated. 3004, 3005 and 3105 alloys were first cold rolled to 2,5 mm thickness and then annealed at two different temperatures, 450 and 500°C, for 4 hours. After cold rolling from 2,5 mm to 0,8 mm, it was final annealed at three different temperatures, 280, 300 and 320°C, for 4 hours. Microstructures of as-cast, intermediate and final annealed samples were examined by optical microscope, grain sizes were measured, segregation distribution with SEM-EDS and texture structure were determined by EBSD analysis. For the determination of mechanical properties, tensile and bendability tests occurred and evaluation was made in terms of strength and formability. The increase in the final annealing temperature with the intermediate annealing applied to the alloys decreased the intermetallic density causing segregation. The additional homogeneous annealing applied to the 3004 alloy sample had a positive effect on the dissolution of intermetallic precipitates in the matrix. The distribution of intermetallic phases and the texture structure affected the bendability, the best bendability was found in the 3005 alloy samples, and the lowest bending performance was found in the 3004 alloy samples. Regarding the texture analysis, it was determined that the recrystallization texture increased when the intermetallic density in the structure decreased. The relatively stronger rolling texture was detected in 3004 samples compared to other alloys, and this was predicted to cause higher planar anisotropy. The corrosion properties of the final annealed samples were characterized by the salt fog test and Tafel extrapolation method. The correlation was determined between the relevant test methods and corrosion resistance increased as the annealing temperature increased. The increase in the intermediate annealing temperature in the process flow improved the corrosion resistance after the final annealing. The best corrosion resistance was found in the 3005 sample, which was intermediate annealed at 500°C and final annealed at 320°C.