Date 2018-11-06 

MSE Regular Seminar

■ Title :  Design, Fabrication, and Mechanical Characterization of 3D Hollow Ceramic Nano-Architectures


■ Speaker :  Prof. Dongchan Jang (KAIST NQE)  


■ Date and Time :  11/6 (Tue) 16:00


■ Venue :  Applied Engineering Building (W1) 1st Floor, Multimedia Lecture Room


 Host :  Prof. Pyuck-Pa Choi


 Abstract :  Density-strength tradeoff appears to be an inherent limitation for most materials and therefore design of cell topology that mitigates strength decrease with density reduction has been a long-lasting engineering pursue for porous materials. Continuum-mechanics-based analyses on mechanical responses of the conventional porous materials with bending-dominated structures often give the density-strength scaling law following the power-law relationship with exponent of 1.5 or higher, which consequentially determines the upper bound of the specific strength for a material to reach. In this work, we present a new design criterion capable of significantly abating strength degradation in lightweight materials, by successfully combining size-induced strengthening effect in nanomaterials with architectural design of cellular porous materials. Hollow-tube-based 3D ceramic nano-architectures satisfying such criterion were fabricated in large area using Proximity field nano-Patterning (PnP) and atomic layer deposition (ALD). Experimental data from micro-pillar compression confirmed that the strengths of these nano-architectural materials scale with relative densities with power-law exponent of 0.93,hardly observable value in the conventional bending-dominated porous materials. Our discovery of new density-strength scaling law in the nano-architectured materials will contribute to creating new lightweight structural materials attaining unprecedented specific strengths overcoming the conventional limit.