Abstract
On the bases of Reuss and Voigt models, a new X-ray method is proposed to measure the non-equibiaxial state of stresses in thin films which have a fiber texture with <110> axis perpendicular to the film surface. The method was successfully applied to measure the stress in TiN films coated on the steel substrate by the ion-beam mixing method. The film had a strong ‹110› fiber texture and the initial residual stress was a compression of about -5500MPa. The initial part of the changes of the in-plane stresses in the film due to external tensile loading agreed well with the prediction based on elasticity. While the substrate is under uniaxial stresses, the film was in the biaxial state of stress because of the mismatch of Poisson's ratio. When the measured stress in the film becomes tension, the stress stops increasing even though the applied strain keeps increasing. This leveling of the stress was caused by cracking of the film.
