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 characterise them in the as-deposited state and after several heat-treatment cycles with different holding times. The idea is to promote phase transformations of the films towards the intermetallic bulk materials. The structure and mechanical properties of binary films and films alloyed with silver were studied as a function of several heat treatment holding times at 600°C. The room temperature stresses were also evaluated and show that during annealing 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 resulting from a fine precipitation. After 162 h heat treatment the grain size increases, but the intrinsic stresses compromise the ductility results obtained.