CONTROL OF LAMELLAR ORIENTATION IN TIAL BASE ALLOY USING A COMBINATION OF HEAVY EXTRUSION AND REACTIVE SINTERING

Polycrystalline TiAl alloy has been produced using heavy extrusion fol lowed by reactive sintering. Many grains that have a lamellar orientat ion parallel to the extrusion direction were observed in as-reactive s intered materials. Texture measurements were conducted on the as-extru ded and as-reactive sintered materials. A [10 (1) over bar 0] fibre te xture was found for Ti in the as-extruded material and for the alpha(2 ) phase in the as-reactive sintered material. The deformation texture of Ti remained after reactive sintering. Thus, the control of crystal orientation of the elemental Ti powder is an effective method of contr olling the lamellar direction of reactive sintered TiAl alloy.