Preparation and characterization of Al₁₁Cr₄ phase by diffusion of Al/Cr composite film

Highlights: • Al₁₁Cr₄ was prepared by diffusion of electrodeposited Al/Cr composite film. • The compositional range of Al₁₁Cr₄ was from Al75.0Cr25.0 to Al76.0Cr24.0. • The decomposition temperature of Al₁₁Cr₄ was 829 °C. - Abstract: Al–Cr alloys were prepared by making Al/Cr composite films go through a low temperature heat treatment. Al/Cr composite films were electrodeposited from aqueous solution and ionic liquid successively. The effects of the composition of Al/Cr composite film on the phase constitutions of Al–Cr alloy were then investigated. The samples were characterized by metallographic microscope (OM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and spherical aberration corrected transmission electron microscope (Cs-TEM). The decomposition temperature of Al–Cr alloy was studied using differential thermal analysis. The results showed that single Al₁₁Cr₄ phase can be obtained from the Al/Cr composite film at the composition range of 75.0–76.0 at.% Al. The Al₁₁Cr₄ would decompose into Al₄Cr and Al₈Cr₅ at 829 °C