A cantilever beam method for evaluating Young’s modulus and Poisson’s ratio of thermal spray coatings

• Published in: Journal of thermal spray technology 1995-12, Vol.4 (4), p.377-383
• Main Authors: Rybicki, E. F., Shadley, J. R., Xiong, Y., Greving, DJ
• Format: Article
• Language: English
• ISSN: 1059-9630; 1544-1016
• DOI: 10.1007/BF02648639

The cantilever beam method to evaluate the Young's modulus and Poisson's ratio of thermal spray coatings is presented. The method uses strain gages located on the coating and substrate surfaces. A series of increasing loads is applied to the end of the cantilever beam. The moment at the gaged section is calculated. Using a laminated plate bending theory, the Young's modulus and Poisson's ratio are inferred based on a least squares fit of the equilibrium equations. The method is verified by comparing predicted values of Young's modulus and Poisson's ratio with reference values from a three-dimensional finite element analysis of the thermal spray coated cantilever beam. The sensitivity of the method is examined with respect to the accuracy of measured quantities such as strain gage readings, specimen dimensions, applied bending moment, and substrate mechanical properties. The method is applied to evaluate the Young's modulus and Poisson's ratio of four thermal spray coatings of industrial importance. Coatings were: Bondarc 75B nickel 5 aluminum applied to 6061, Walcoloy austenitic stainless steel applied to 1018, WC-Co applied to 1018 and yttria stabilized zirconia applied to 6061.