An approach using thin films as a predictive way to produce new bulk materials

The aim of the present work is to produce (TiAl)-based films and characteri se them in the as-deposited state and after several heat-treatment cycles w ith different holding times. The idea is to promote phase transformations o f the films towards the intermetallic bulk materials. The structure and mec hanical properties of binary films and films alloyed with silver were studi ed as a function of several heat treatment holding times at 600 degreesC. T he room temperature stresses were also evaluated and show that during annea ling the stresses move from a compressive to a tensile state. The 18 h heat treatment leads to a sharp hardening of the binary film thought as resulti ng from a fine precipitation. After 162 h heat treatment the grain size inc reases, but the intrinsic stresses compromise the ductility results obtaine d. (C) 2000 Elsevier Science B.V. All rights reserved.