Prof. Cha Yong Lim, Metallic Materials Division, Korea Institute of Materials Science, Korea

Title: Fabrication of Multi-layer Aluminum Alloys with Improved Mechanical Properties by Roll-Bonding Process

Abstract: Several different kinds of Aluminum alloys were processed by multi-layer accumulative roll-bonding (ARB) for ultra grain refinement and high strengthening. Several Al sheets (AA1050, AA5052, AA6061) with 1 mm thickness, 30 mm width and 300 mm length, were first degreased and wire-brushed for sound roll bonding. The different sheets were then stacked on top of each other and rolled by 50% reduction rate without lubrication at room temperature. The bonded sheet was cut into two pieces of the same dimensions and the same procedure was repeated up to 6 cycles. Microstructural evolution of bonded sheets with the number of the ARB cycles was investigated by optical microscopy (OM), transmission electron microscopy (TEM), and electron back scatter diffraction (EBSD). The grain size decreased gradually with the number of ARB cycles. The strength of the bonded sheets increased with the number of ARB cycles. The improved strength and elongation were obtained by applying annealing treatment.

Keywords: Hybrid Al Sheets, High Strength, High Elongation, Muti-layer Roll-Bonding