Stress development in FeAl8 thin films during heat treatment

The development of biaxial stress in FeAl8 thin films was investigated duri ng annealing in vacuum. The heat treatment leads to irreversible changes in the microstructure of the FeAl8 thin films, which were determined by stres s-temperature measurements, transmission electron microscopy, and X-ray dif fraction. The stress development is explained by semiquantitative considera tions of atomic rearrangement (excess-vacancy annihilation, grain-boundary relaxation, and grain growth). The stress development between 180 and 400 d egrees C is affected by grain-boundary relaxation, and between 450 and 675 degrees C by grain growth. The high thermal stability, which was measured i n previous investigations, could not be confirmed. (C) 2000 Elsevier Scienc e S.A. All rights reserved.