Collaborative Research: Understanding Acoustoplasticity through Multiscale Computational and In-Situ, Time-Resolved Experimental Approach

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Materials, especially metals, can be deformed more easily when exposed to high frequency elastic waves. Such phenomenon is called acoustoplasticity and has been used in several applications, such as metal forming, extrusion, welding, flip-chip bonding, and ultrasonic additive manufacturing. Despite its widespread use, these processes are still at a “trial and error” stage due to the lack of a clear understanding of the underlying mechanisms. This award supports fundamental research to unravel the deformation processes that drive acoustoplasticity through a combined computational and experimental approach, from the atomistic up to the microstructural scale. The knowledge gained from this award can improve vibration/ultrasonic assisted manufacturing methods, especially ultrasonic additive manufacturing, which has the potential for on-demand, in-space manufacturing. This award will support cross-cutting research between mechanics, high performance computing, data science, material characterization, and testing. Student recruitment, including for summer undergraduate research opportunities, will focus on underrepresented minorities. Additionally, hands-on computational and experimental workshops will target K-12 school children and teachers.The mechanisms behind acoustoplasticity in metals are not fully understood because: (1) acoustic excitation occurs in the macroscale, but its effects can be spread over orders of magnitude in the spatio-temporal scale; (2) single-scale models smear out the mechanisms spread over multiple scales and cannot address the full complexity; and (3) probing the acoustic-affected dislocation plasticity is challenging due to the fast time scale of the events. This research will fill these knowledge gaps by combining multiscale simulations, time resolved nonlinear waves, and microscopy. The complex dynamics of plastic deformation under ultrasonic vibrations will be characterized through concurrent atomistic-continuum simulations. The in-situ, time-resolved experiments will be used to capture the microstructural evolution under ultrasonic vibrations, e.g., with the use of scanning electron microscopy and electron back scatter diffraction. Finally, a mechanism-based parameter will be calibrated to bridge the simulations and experiments across multiple spatio-temporal scales for a multiscale understanding of acoustoplasticity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.