Department of Applied Physics and Materials Science - Applied Physics

News & Events


Material's Spacing is Key to Brittle-to-ductile Transition


Julia R. Greer, her postdoctoral scholar Dr.Dongchan Jang, and colleagues have used experiments and atomistic simulations of nano-twinned metals (which have the unique combined effect of being strong and ductile) to decipher the specific role of the twin boundaries. They have found that it is the spacing between the twin boundaries that determines whether a material is brittle or ductile as opposed to the sample size, as would be expected. Greer states "this is probably the first study that truly isolated the twin boundaries by making samples which contained only twin boundaries, periodically spaced throughout the sample, and then tested them in tension. This understanding will help in the design of better structural materials and provide a certain amount of predictability in doing so, which has not been possible to date." [Nature Nanotechnology Article and Movies]

Tags: APhMS research highlights Julia Greer Dongchan Jang

Nanoscale Structures with Superior Mechanical Properties


Julia Greer, Assistant Professor of Materials Science and Mechanical Engineering, and Dongchan Jang, Postdoctoral Scholar, have developed a way to make some notoriously brittle materials ductile—yet stronger than ever—simply by reducing their size. Professor Greer describes, "We are entering a new era in materials science, where structural materials can be created not only by utilizing monolith structures, like ceramics and metals, but also by introducing 'architectural' features into them." [Caltech Press Release]

Tags: APhMS research highlights MCE Julia Greer Dongchan Jang