Investigation of physical and metallographic properties of nickel matrix composite by ultrasonic method

Ultrasonic testing (UT) is one of the most widely used non-destructive testing techniques for the characterization and evaluation of materials. In this study, the material properties of AstCrM-BN-Cr-Ti-Ni composites produced by mechanical mixing and electroless nickel plating technique were evaluated using UT. Changes in ultrasonic wave velocity, Young's modulus, density, porosity and hardness are observed in the heat-treated material at different temperatures. Samples analyzed by Scanning Electron Microscopy (SEM) and X-Ray Diffractometry (XRD) exhibited changes in grain structure at different sintering temperatures. It has been observed that the change in grain size also affects mechanical and physical properties according to ultrasonic properties. In conclusion, the experimental results showed a linear relationship between the mean grain size and the UT parameters (ultrasonic longitudinal and transverse velocity, Young's modulus), physical (sintering temperature and density) and mechanical properties (hardness and porosity) of the material. Grain growth occurs with increasing sintering temperature, porosity content decreases, hardness, Young's modulus and ultrasonic wave velocity values also increase.