| Title |
Microstructure and Mechanical Properties of AA1050/AA6061 Layered Sheet Fabricated by Differential Strain Cold Roll-Bonding |
| Authors |
조상현(Sang-hyeon Jo) ; 허현준(Hyeon-Jun Heo) ; 유효상(Hyo-Sang Yoo) ; 이성희(Seong-Hee Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2025.63.9.687 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Cold roll-bonding; Heterogeneous microstructure; Aluminum alloys; Mechanical properties; Annealing |
| Abstract |
A cold roll-bonding process using AA1050 and AA6061 sheets with different initial strain levels
was applied to fabricate an AA1050/AA6061 layered sheet, which was subsequently annealed at various
temperatures ranging from 200 to 400oC. The as-roll-bonded sheet exhibited a typical deformation structure
in which the grains were elongated along the rolling direction. The evolution of the microstructure in the
layered sheets varied significantly depending on the location, resulting in an inhomogeneous distribution of
hardness along the thickness direction. After annealing at 200oC, the AA1050 region still exhibited a deformed
structure; however, the AA6061 region, which had experienced a higher initial strain, showed partial
recrystallization. While complete recrystallization occurred at temperatures above 350oC, microstructural
heterogeneity across the thickness remained. This heterogeneity greatly affected the mechanical properties
of the layered sheet. The specimen annealed at 350oC exhibited the best mechanical properties in terms of
the balance between tensile strength and elongation. In conventionally annealed specimens, strength typically
decreases while ductility increases as the annealing temperature rises. However, in this study, the specimen
annealed at 350oC demonstrated superior strength and ductility compared to the one annealed at 300oC. The
underlying reasons for this behavior are discussed in detail. |