Microcrack Healing Mechanism within Metals under Ultrasonic Cavitation Revealed by Molecular Dynamics Simulations

This study employs molecular dynamics to simulate the atomic-level effects of ultrasonic cavitation on microcrack-containing aluminum blocks, aiming to deepen our understanding of its mechanism on metallic materials. The results indicate that the microcrack size tends to decrease or close after impact. Following cavitation impact, many dislocations form around the microcrack tip, facilitating partial and complete closure through dislocation shielding and atomic diffusion. The crack healing process is intricately linked to the external forces generated by the impact and the changes in surface energy within the crack. Following crack healing, stresses in the matrix tend to concentrate around the healed microcrack area, stacking faults, and grain boundaries. Additionally, cracks, grain size, grain boundaries, and grain orientation influence stress distribution. This study investigates the atomic-scale microstructural evolution and mechanical behavior changes of aluminum blocks containing microcracks under cavitation impact. The findings offer valuable insights into the effects of cavitation on metals with microcracks, providing theoretical support for future applications of ultrasonic cavitation technology in the processing of metallic materials with cracks.