Abstract Scope |
We explore the synthesis of multilayered composites where one constituent phase has a low ductility, with a final goal of enhancing the system’s strength and toughness. We synthesized multiple multilayered systems using PVD: metal-ceramic (Cu-TiN, Al-TiN, where the ceramic is the brittle phase), metal-MAX (Nb–Ti2AlC, Ti-Ti3AlC2, where the interfaces between the layers are in direct competition with the internal interfaces within the MAX layers) and a unique bcc Mg-Nb system (where the hcp-to-bcc pseudomorphic transformation leads to enhanced ductility in Mg), with a lamellar thickness reduced to the nanoscale. We utilize a combination of nanoindentation, micro-compression, micro-tensile, and fracture toughness testing of 3-point bend micro-beams, under extremes of temperature (cryo-to-1000C) and strain rate (10^-3 to 10^3/s), and post-deformation TEM analysis to evaluate their deformation mechanisms. These results are analyzed as a function of decreasing layer thicknesses using the concepts of dislocation motion within the confined nanoscale layers. |