Hot Rolling of Flame Retardant Magnesium and Aluminum Alloys to Produce a Cladding Plate

In order to facilitate the adoption of bimetallic clad sheets, which are composed of flame retardant Mg and Al alloys, as structural materials in transportation vehicles, the rolling speed, asymmetric roll speed ratio, and thickness of flame retardant Mg sheets have been examined with a roll bonding process at an elevated temperature. As the rolling speed increases, the required reduction ratio to make a full adhesion increases at a rate of the 2nd order to compensate for the insufficient holding time. The asymmetric ratio in the speed of the upper and lower rolls does not substantially influence the cladding integrity between the flame retardant Mg and Al6005 strips. The DRXed grain structure in flame retardant Mg cannot impose substantial contact pressure at the interface during the roll bonding process, which necessitates a high reduction ratio to induce sufficient contact pressure for bonding. The larger DRXed grain structure induced by large plastic deformation in the initial Mg strip is subject to producing a thicker intermetallic layer when the minimum reduction ratio is achieved between the flame retardant Mg and Al6005 alloys. These conclusions are based on EDS line and point analyses at the Mg/Al interface and the results of SEM investigations.