Interface reactions and growth of intermetallic in a CoCrFeMnNi/Al intermetallic laminate composite

Metal-intermetallic laminate (MIL) can incorporating the high strength and stiffness of the intermetallic compound with the ductile metal. In present study, the CoCrFeMnNi/Al high-entropy allay intermetallic laminate (HIL) composites was fabricated by solid-solid diffusion at 600 °C, 620 °C and 640 °C. Microstructure evolution and growth kinetics across the intermetallic/metal interfaces was investigated using the SEM, EDS, FIB and TEM techniques. Microstructural characterization shows the interfacial phases consisted of a four-layer structure between CoCrFeMnNi and Al sheets. The intermetallic layers arranged form CoCrFeMnNi side to the Al side, identified to be Al(MnCo)Ni 2 + Cr(CoFeMn) + Al 10 (CoCrFeMnNi) 3 layer (L1), Al 10 (CoCrFeMnNi) 3 layer (L2), Al 9 (CoCrFeMnNi) 2 layer (L3) and Al 9 (CoFeNi) 2 + Al 11 (CrMn) 4 layer (L4), respectively. It is observed that the growth kinetics model of L2-L4 layer changed to a mixed kinetic growth mechanism with the temperature increasing, while L1 layer remains nearly constant. The types of intermetallic compounds formed at the CoCrFeMnNi/Al interface are determined by both the variance in atomic diffusion rates and the interatomic mixing enthalpy.