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Microstructure control of in situ metal matrix nanocomposites (MMNCs) poses a barrier to their large-scale production. Here, we interrogate in unprecedented detail the formation mechanisms, morphologies, and microstructures of an in situ Al/TiC MMNC processed via salt flux reaction. Through synchrotron-based X-ray nanotomography (TXM) and scanning and transmission electron microscopy, we visualize in over five orders-of-magnitude of length-scale the TiC nanoparticles, Al_3Ti intermetallics, and their co-locations. 3D reconstructions from TXM revealed a surprising variety of Al_3Ti morphologies, including an orthogonal plate structure. By combining our experimental results with phase-field simulations, we demonstrate that this growth form originates from the intermetallic nucleating epitaxially on a TiC particle which is larger than a critical size at a given undercooling. Yet TiC particles that are too small to nucleate Al_3Ti can also impact the growth of the intermetallic, by splitting the intermetallic plates during solidification. These insights on the divalent roles of the nanoparticles offer general guidelines for the synthesis and processing of MMNCs. 

As incremental forming is a relatively new sheet metal forming process, very limited analytical and finite element prediction models are available in literature to study the process mechanics and improve its performance. Thus, most studies involve many trial-and-error iterations to optimize the processing conditions in order to take advantage of high process flexibility and material formability. However, reducing efforts of trial-and-error iterations is of utmost importance to make a process financially viable. Therefore, an FE model is developed and experimentally validated to predict the forming forces involved in incremental micro-forming process. Different mass scaling factors and element-types are used to optimize and develop the model for accurate prediction in the least possible computation time.