RESIDUAL STRESS ANALYSIS OF HIGHLY TEXTURED COATINGS USING MULTIPLE (hkl) REFLECTIONS

Many efforts have been made to optimize texture and residual stress of coating layers in the metal cutting tool industries. XRD sin²ψ method is widely used for residual stress analysis using a chosen (hkl) reflection, but difficulties frequently arise when applying to highly textured materials. One reason would be due to the limited available range of sin²ψ from a single (hkl) reflection. This time, I attempted to use multiple (hkl) reflections to cover a wider sin²ψ range for better analysis. Some examples of highly oriented αAl₂O₃ coatings of CVD coatings on metal cutting tools will be presented. A possibility to separate the residual stress of the highly textured grains from isotropic orientation of grains will also be discussed.