Effect of treatment temperature on the texture of mechanically alloyed Fe-40 at.% Al+Y2O3 intermetallic

The texture evolution of a Fe-40 at.% Al alloy reinforced with Y2O3 particl es (1 wt.%), produced by extrusion at 1373 K of mechanically alloyed powder s, was investigated after thermal treatments up to 1573 K. The orientation distribution function (ODF) of the as-extruded material shows a [110] fibre texture with a secondary [320] component. Following heating up to 1373 K, the texture does not change whereas grain re-orientation occurs at 1473 K: the [211] and [023] directions become predominant along the axis of the mai n and the secondary texture components, respectively. TEM observations afte r heating proved that dispersoid particles coarsen at temperatures higher t han 1373 K and progressively lose their capability of pinning grain boundar ies. Following the 1573 K treatment, abnormal grain growth occurs favoured by the presence of a secondary texture component. The results are discussed on the basis of the Humphreys theory. (C) 1999 Elsevier Science B.V. All r ights reserved.