NM10.13.05 : Fabrication of Multilayered Metal Sheet by Accumulative Roll Bonding Process

5:00 PM–7:00 PM Apr 5, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Hyoung-Wook Kim1 Su-Hyeon Kim1 Cha-Yong Lim1

1, Korea Institute of Materials Science, Changwon, , Korea (the Republic of)

Accumulative roll bonding (ARB) is one of the severe plastic deformation (SPD) processes which can produce bulk ultrafine grained (UFG) metallic materials. Thus, the ARB process has been applied to fabricate various nanocrystalline metallic sheets and multi- layered composites owing to the relatively simple processing. In this study, the ARB process was used to make multi-layered metal sheets by using 1mm thick metal sheets having a different chemical composition as sandwich layers. The microstructure and mechanical properties of the fabricated sheets were investigated in detail. Multilayered Al/Cu and Cu/Cu sheets was fabricated by ARB process with combination of Al and Cu sheets. The conductivity and strength of the multilayered sheets increased with increasing the number of layers within same thickness as long as the continuity of the metal layer was maintained. Also, The fabricated 1mm thick multilayered Cu/Cu alloy sheets consist of 64 layers with the grain size of below 170nm. The sheets have very high strength and high electrical conductivity, that is, the tensile strength and electrical conductivity of the sheets are 500MPa and 85%IACS, respectively. The multilayered sheets have a good formability during ARB and subsequent rolling process, thus, layered sheet with the thickness of 0.2mm fabricated by additional cold rolling for lead frame application, the tensile strength of the final sheet increased to 610MPa with same electrical conductivity. In order to evaluate the productivity in commercial scale production, continuous ARB were designed. By optimizing the process condition, finally, 1mm thick nanocrystalline multilayered Cu strip with the width of 200 mm can be successfully fabricated by pilot clad rolling mill in industrial scale.