Tuning Nano-Scale Grain Size Distribution in Multilayered Al-Mn Alloys

Al—Mnx/Al—Mny multilayers with a wide range of structures ranging from microcrystalline to nanocrystalline and amorphous were electrodeposited using a single bath method under galvanostatic control from room temperature ionic liquid. By varying the Mn composition by −1-3 at. % between layers, the grain sizes in one material can be systematically modulated between two values. For example, one specimen alternates between grain sizes of about 21 and 52 nm, in an alloy of average composition of 10.3 at. % Mn. Nanoindentation testing revealed multilayers with finer grains and higher Mn content exhibited better resistance to plastic deformation. Other alloy systems also are expected to be electrodeposited under similar circumstances.