Effect of Ultrasonic Vibration on Compression Behavior and Microstructural Characteristics of Commercially Pure Aluminum

The principle objective of this research is to investigate the modeling of compression behavior and microstructural evolution of pure aluminum in the ultrasonic-assisted compression test. A dislocation density-based constitutive model was developed based on the existing frameworks and calibrated using experimental data to predict the stress-strain response of pure aluminum during UAC tests. An experimental set-up was designed to work at resonance condition with frequency of around 20 kHz and variant longitudinal vibration amplitudes at the range of 0~20 μm. The verified model and experimental samples were used for parameter studies and the study of grain formation of aluminum after conventional and ultrasonic upsetting. Results showed that the developed constitutive model was able to predict compression behavior of aluminum suitably. An increase in the flow stress drop, residual flow stress, and dislocation density occurred when the applied vibration intensity was raised. In addition, it was observed that the more homogenous microstructure with nearly equiaxed grains and also the higher microhardness values can be achieved when ultrasonic vibration is imposed on samples during compression test.