Investigation of crystallization of a mechanically alloyed Sm-Fe alloy

The crystallization of a mechanically alloyed Sm-Fe alloy was investigated. The results show that the Sm-Fe alloy prepared by mechanical alloying consists of amorphous Sm-Fe phase and crystalline α-Fe phase. The composition of the alloy is inhomogeneous, i.e., the surface of the as-milled powder is relatively poor in iron. The crystallization process involves the long-range diffusion of iron atoms and solid state reaction. After proper crystallization, the as-milled powder transforms into a Sm₂Fe₁₇ phase completely; no distinguishable crystalline α-Fe phase can be found. A metastable phase, which may be a Sm₂Fe₁₇ phase with the structure of hexagonal Th₂Ni₁₇ type, appears during the crystallization process.