Texture and microstructure in very fine grain Al-Al3Ti alloys obtained by extrusion of mechanically alloyed powders

Texture has been investigated in warm extruded Al - Al3Ti bars obtained fro m mechanically alloyed powders. The effects of various high volume fraction s of Al3Ti phase (9, 18, and 27 vol-%,) and the very fine grain sizes that can be obtained via the mechanical alloying processing route are described. Increasing the volume fraction of Al3Ti phase tends to decrease the anisot ropy of the extruded product. The 'conventional' aluminium texture characte rised by a predominant < 111 > (Al) fibre usually present in extruded bars is replaced at high volume fraction of Al3Ti particles (27%) and small size of aluminium grains (300 nm) by a weak and broad < 441 > (Al) fibre. This is suggested to be associated with a modification of the predominant deform ation mechanism, changing from dislocation slip towards grain boundary slid ing at small grain size.