S1E5
Episode 5 (August 9, 2020)
Zhen Yin
McGill University
David Veysset
MIT
Xuan Zhang
Leibniz institute for new materials
Tough and deformable transparent bio-inspired architectured materials
Abstract:
Glass is highly demanded in electronics, photovoltaic system and building structures for its transparency, hardness and chemical stability. However, its applications are limited by its inherent brittleness and low deformability. Lamination and tempering can improve impact responses of glass but do not change its brittle behaviors. Through millions of years of evolution, nature provides us with solutions to solve the problem of brittleness. Many hard biological materials, such as mollusk shells and tooth enamel, are made of brittle minerals but have toughness thousands of times higher than these minerals due to their intricate microstructures. Inspired by the structures of mollusk shells and tooth enamel, we developed tough and deformable transparent architectured glasses. The materials have highly controlled three-dimensional meso-architectures introduced by laser engraving, and interfaces made of ductile polymers. Although made of more than 90 wt% of brittle glass, the bio-inspired glasses obtain deformability and toughness comparable to many tough polymers, and impact resistance two to three times higher than laminated glass and tempered glass.
Study of far-from-equilibrium material behavior under impact loading conditions
Abstract:
Understanding high-velocity microparticle impact is essential for many fields, from space exploration to additive manufacturing and needle-less drug delivery. While impact dynamics of macroscale projectiles has been studied in real time using high-speed imaging, investigations of microscale impact have been hitherto limited to post-mortem analysis of impacted specimens. In a laser-induced particle impact test, we observe single-microparticle impact events using an ultra-high-speed camera with nanosecond time resolution. The method is used to the unit process of metal additive manufacturing by cold spray, i.e, single metallic particle impact on metallic substrates, and the transition from metallic bonding to erosion at higher impact velocities.
Mechanical Properties of Architected Carbon
Abstract:
A long-term challenge in the design and manufacture of materials and structures is to create porous materials that are simultaneously lightweight, and strong. Here we advanced the 3D microfabrication methodology in combination of two-photon lithography and high-temperature pyrolysis, to fabricate nanoarchitected pyrolytic carbon of two prototype unit-cell geometries, octet- and iso-truss, and achieved combined excellent properties with low density, high specific strength, imperfection insensitivity as well as good resilience.