Residual Stress Analysis of TiH₂ Film Based on Two-dimensional X-ray Diffraction

It is very hard to obtain a desired X-ray diffraction (XRD) peak of TiH₂ film on Mo substrate through tranditional θ-2θ scanning method, since most of XRD peaks of TiH₂ are very close to those of Mo. In this paper, the residual stress was investigated in a TiH₂ film on Mo substrate, and the grazing incidence two-dimensional XRD method was adopted to eliminate disturbance from diffraction peaks of substrate material in order to achieve sufficiently high diffraction intensity. With the elastic modulus of TiH₂ film measured by a nanoindenter and the diffraction crystal plane (311) of TiH₂ film chosen for XRD analysis, the residual stresses of different depths of TiH₂ film were worked out using grazing incidence two-dimensional XRD method and side inclination method. The results indicate that there exists biaxial normal residual stress with an ellipse distribution in the TiH₂ film and the residual stress would change from tensile stress to compressive stress with gradual increase of measurement depth.