Mechanical Enhancement of Graded Nanoporous Structure

LJ He and N Abdolrahim, JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY- TRANSACTIONS OF THE ASME, 144, 011007 (2022).

DOI: 10.1115/1.4051470

Inspired by the development of strong and ductile composite and gradient materials over the past decade, here, we report the investigation of a graded nanoporous (NP) structure utilizing molecular dynamics simulations. The structure is generated by inducing a gradient scaling parameter in a Gaussian random field model. It has a large ligament/pore size toward the core and a small ligament/pore size toward the surface. The redistribution of stress and strain under tensile loading is then scrutinized and compared between the functional graded NP structure and two conventional NP structures with identical relative density but constant ligament size. During loading, the thick ligaments in the gradient structure yield at high stress, leading to the entire structure's high mechanical strength. The thin ligaments help the structure accommodate significant plastic strain by promoting uniform deformation. Both parts of the gradient structure worked collectively and resulted in the structure exhibiting a synergy of excellent strength and good deformability.

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