Ultrafast formation of single phase B2 AlCoCrFeNi high entropy alloy films by reactive Ni/Al multilayers as heat source

High entropy alloy films of AlCoCrFeNi B2-ordered structure are formed during an ultrafast heating process by reactive Ni/Al multilayers. The self-propagating high-temperature reaction occurring in multilayers after ignition represents heat source which is used for the transformation a thin Al/CoFe/CrNi multilayer into single-phase high film. materials design combined thus determines phase formation. Conventional rapid thermal annealing transforms film with multiple equilibrium phases. Ultrafast combustion synthesis produces ultrafine-grained compound alloy. rates order one million K/s, much higher than those annealing, about 7 K/s. results compared differential scanning calorimetry experiments ranging from 100 K/s up to 25000 It shown that rate clearly formation kinetics prevents long-range diffusion and promotes run-away transformation. Thus, using as new pathway fabrication single high-entropy films.