Abstract:Blended elemental powders with the nominal compositions (mole fraction, %) of Ti₅₄Al₄₆, Ti₅₂Al₄₈ and Ti₅₀Al₅₀ were mechanically alloyed in a planetary ball milling system for up to 100h.The structure evolution in these powders was characterized by scanning electron microscope, X-ray diffraction and differential thermal analysis techniques. It was found that elemental powders were progressively trans formed into nanocrystalline Ti(Al) supersaturated solid solution, then into amorphous phase. With increasing Al content, the formation of a fully Ti(Al) supersaturated solid solution and amorphous phase were accelerated, which are attributed to the fine grain size. And the grain size condition for formation of amorphous phase in this system is ≤16nm.

Key words: Ti-Al alloy; mechanical alloying; amorphisation