Residual Stress Analysis of Textured Coatings: CVD α Al2O3 Coatings on Metal Cutting Tools

In metal cutting tool industries, coated cemented carbides are commonly used, and we observe wide range of thicknesses, phases, textures, and residual stresses (RS) in coating films optimized for variety of applications. RS of the films is mainly a result of thermal and post-deposition mechanical processes, and its impact on the tool performance was discussed long time. A proper evaluation of RS is therefore essential for R&D and quality control of the products. Although XRD strain- sin²ψ method has been widely used to coatings in the industry, the sin²ψ dependence of strain significantly deviates from the linearity due to textures and RS gradient effects in many cases. From this point, it should be very useful to understand these effects on RS analysis and consider RS analysis of coatings.

In this presentation, we revisit the RS analysis of textured materials developed a few decades ago and then show RS analysis of CVD α - Al₂O₃ coatings available in a market considering their texture and RS gradient effect.