| dc.description.abstract | The experiment uses ultrasonic detection method (Ultrasonic testing) after tensile test measurement ductile iron, its microstructure and ultrasonic attenuation rate, the relationship between the speeds of sound. With optical microscopy (OM) was observed for structural change and try to assess ductile iron ultrasonic attenuation rate changes in internal energy inside the material to infer structural changes, combined with martix to speculate micro-structural changes within the material. 5MHz frequency of use of the probe, the attenuation rate of the scattering factors, the main effect of the coarse particulate material in many low attenuation less fine particles, less coarse particles, fine particles much decay rate; when graphite ratio high, will increase in the scattering factors.
Non-destructive testing method (Ultrasonic attenuation and scattering factors change) detect changes in the case of ductile iron particle thickness, grain size (100 to 200) can be found in the following 20μm when the number of particles, the more attenuation rate increases will follow. | en_US |