in-situ cryogenic nano-mechanical tests LN 2 or LHe in 77 K4 K Temperature controller (PID) : heater control Cold finger Indenter tip sample electron gun SEM chamber (UHV) Mechanical data acquisition Cu wire out Bi-polar heater Tip cooling assembly Si diode temperature sensors Ceramic block Current in-situ cryogenic mechanical testing set-up at Caltech (designed by L. Meza) The world’s first time cryogenic nanomechanical measurement Seok-Woo Lee (Postdoc)

in-situ cryogenic nano-mechanical tests 2 Current in-situ cryogenic mechanical testing set-up at Caltech (designed by L. Meza) Fundamental understanding of mechanical behavior of materials at low temperatures for space applications COLD!!

D in-situ cryogenic nano-mechanical tests SIZE EFFECTS at different temperatures Nanopillar Size effects size-dependent strength S.-W. Lee et al. Phil. Mag. (2012) Theoretical estimation for W What are you going to do with me? 1. Fabrication of nanostructures Different sizes Different materials 2. Nano-mechanical testing at different temperatures 3. Data analysis (stress-strain) and fundamental understanding (atomistic, dislocation dynamics) Welcome any enthusiastic SURF students !!! Seok-Woo Lee,