Mechanical alloying process of Al_95–xFe_xCr₅ mixed powders by a high energy planetary ball mill

Abstract

Al_95–xFe_xCr₅ (X=10, 25, 35, 50) ternary powder mixtures and Al–(10, 25, 35, 50) at%Fe binary powder mixtures were mechanically alloyed by high-energy ball milling using a ball-to-powder weight ratio of 238: 10. The structural evolution during milling was investigated by X-ray diffraction techniques and transmission electron microscopy. The solid solutions of α–Al(Fe, Cr) and α–Fe(Cr) were formed in the early stage of milling for Al–Fe–Cr powder mixtures. In the case of Al–10 at%–5 at%Cr powder mixtures, the Al₈₀Cr_13.5Fe_6.5 compound was formed and disappeared during milling, and Al₅(Fe, Cr)₂ and Al(Fe, Cr) were detected after longer time milling. In Al–25 at%–5 at%Cr powder mixtures, Al₅(Fe, Cr)₂, Al(Fe, Cr) and amorphous phases were consecutively formed during milling. In milling process of Al–35 at%–5 at%Cr and Al–50 at%–5 at%Cr powder mixtures, only the Al(Fe, Cr) compound was found and it finally became an amorphous phase. Retardation of amorphization was recognized in the Al–Fe–5 at%Cr ternary system, and the composition range of amorphous formation was almost in agreement with the results of enthalpy calculation for the solid solution and amorphous phase in the systems.