[3B5] Ultrasonic evaluation of grain size based on specimen expansion
X Gong¹, X Chen¹,², Y Yao¹,², G Wu¹ and H Chen¹
¹Nanchang Hangkong University, China
²University of the West of England, UK
An ultrasonic evaluation model based on specimen expansion is developed for the quantitative evaluation of grain size. GH4169 (Inconel 718) with different solution treatments was subjected to ultrasonic longitudinal wave testing and metallographic observation experiments. Average grain size and ultrasonic characteristics, such as velocity, attenuation coefficient, etc, were calculated and represent the real sample set. A two-dimensional grain structure diagram of the polycrystals is constructed by a Voronoi diagram. According to this 2D grain structure diagram, an acoustic simulation model of two-dimensional grains is set up to calculate the ultrasonic characteristics. A simulated sample set of grain size ultrasonic eigenvalues based on the acoustic simulation was then generated. Based on the real sample set data, a virtual sample set was generated using the multi-distribution overall trend diffusion technique. The effect of the number of virtual and simulation samples used on the accuracy of the model was analysed. All samples were used to construct an ultrasonic grain size evaluation model. Compared to models using a single set of real samples, a set of real and simulated samples and a set of real and virtual samples, the new model using three sets is the most accurate.
