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■ 제 목: Design, Fabrication, and Mechanical Characterization of 3D Hollow Ceramic Nano-Architectures
■ 연 사: 장동찬 교수 (KAIST 원자력 및 양자공학과)
■ 일 시: 11월 6일(화) 16:00
■ 장 소: 응용공학동 (W1) 1층 영상강의실
■ Host : 최벽파 교수
■ 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.