Mechanical alloying of the Fe-Pb system immiscible in the equilibrium state

Abstract

X-ray diffraction and Mossbauer spectroscopy were used to study the mechanical alloying of the Fe-Pb system, which is immiscible under equilibrium conditions, in a planetary ball mill by the example of an Fe(95)Pb(5) composition. The formation of a supersaturated bcc solid solution of Pb in α-Fe with a limiting concentration of 1.7 at. % Pb has been established. The most fraction of Pb in the mechanically alloyed samples was present as segregates at the boundaries of the nanocrystalline bcc phase. No dissolution of iron in lead has been observed. The mechanism of formation of the supersaturated solid solution includes sequential stages of the formation of a nanostructure in α-Fe, penetration of Pb along α-Fe grain boundaries and its segregation at the boundaries, and the saturation of α-Fe with lead.