MSE Regular Seminar
■ Title: Nanomechanics for innovative structural materials
■ Speaker: Prof. Ju-Young Kim (UNIST MSE)
■ Date and Time: 5/8 (Tue) 16:00
■ Venue: Applied Engineering Department (W1-1) Multimedia Lecture Hall (1st Floor)
■ Host : Prof. Byeongha Shin
■ Abstract : Nanomechanics is a branch of nanoscience studying fundamental mechanical properties of materials at the nanometer scale. The essence of nanomechanics is that mechanical properties have been changed dramatically at the nano-scale, unlike general mechanical properties of materials at bulk-scale. Key mechanical properties for structures and devices with micron- and nanometer-sized features are essential to be measured at the appropriate scale, thereby taking into account the so-called size effect. One research topic on application of nanomechanics that we have been performing is ‘nanoporous gold (np-Au)’. The np-Au made by dealloying is composed of a bicontinuous network of ligaments and pores. This material has been extensively studied for catalyst, sensor, actuator and other applications due to its high surface-to-volume ratio. However, np-Au shows brittle behavior even though individual ligaments are composed of ductile metal, hence the mechanical properties of np-Au need further investigation for improved reliability. Many researches have been performed in various ways to resolve this issue. Firstly, the identification of whether or not np-Au structures itself are self-similar during ligament coarsening was carried out through 3D reconstruction by FIB tomography. In addition, methods to synthesize np-Au with various microstructures in terms of initial dislocation density, grain size, twin structures have been developed. We correlated microstructures and mechanical behavior of np-Au, which gives insight into development of innovative structural materials that are light, strong, and tough.