Jacob Gruber¹, Siddhartha Pathak², Garritt Tucker¹; ¹Colorado School of Mines, ²University of Nevada, Reno

Metal-MAX nanolaminates with layer thickness below 50nm are hierarchical, multi-layered nanocomposite materials that exhibit tunable strength and toughness, under both compressive and tensile stresses. Layering both between metal and MAX layers, as well as within the MAX phase itself give rise to unique mechanical behavior. Using atomistic simulation, the deformation of nanolaminates in a variety of configurations mirrors the behavior observed in experiment. Increased strength and toughness are observed, especially in specific orientations, and orientation also determines the failure mode, whether kinking, in-plane dislocation plasticity or interfacial sliding. Leveraging kinematic metrics at the atomic scale, we identify that these transitions arise from the competition of atomic deformation mechanisms, whose activation depends on orientation. Modulation of layer thickness allows for the competition to be tuned. This tunability has the potential for use in high-temperature structural applications, leveraging the unique mechanical properties of the composite as well as it’s thermal stability.