Evaluating the reinforcement content and elastic properties of Mg-based composites using dual-mode ultrasonic velocities.

Based on the wave-mode-converted principle, an immersion-focused transducer is employed to determine the longitudinal wave and shear wave velocities. The experimental condition is then investigated to obtain the converted shear wave, which is used to analyze the relationship between the reinforcement content and the dual-mode ultrasonic velocities. In addition, the elastic modulus is calculated. Magnesium-based composite samples with different reinforcement contents are manufactured to conduct an ultrasonic experiment, wherein the dual-mode velocities vary with the change in the reinforcement content; the correlation coefficient is 99.17%. An ultrasonic dual-mode velocity model is developed to analyze the distribution of the reinforcement content. By employing the measured values obtained from the destructive method, the largest errors in the reinforcement content and elastic modulus evaluated using the proposed method are found to be -5.76% and 5.85%, respectively. The shear wave velocity determined using a normal-incidence shear-wave transducer reveals the accuracy with which the errors are measured. This method provides an effective tool to nondestructively evaluate the microstructure and elastic properties of Mg-based composites.