Milling characteristics of extruded eutectoid Zn-Al alloy

Mechanical milling-induced phase transformations, microstructural changes and preferred crystal orientation of the extruded eutectoid Zn-Al-based alloy are reported. Decomposition of a metastable η′_E phase and a four-phase transformation: α+ε→T′+η, were greatly accelerated by mechanical milling. The mechanism of the milling-induced microstructural change from a lamellar structure to a fine grain structure was found to be different from that which occurred under tensile and creep deformations in the extruded eutectoid Zn-Al-based alloy. A preferred crystal orientation was observed as well, in the alloy during milling, which was supported by a rolling-induced preferred orientation in the same alloy.