This Brief highlights the search for strain gradients and geometrically necessary dislocations as a possible source of strength for two cases of deformation of materials at small scales: nanoindented single crystal copper and uniaxially compressed single crystal submicron gold pillars.
When crystalline materials are mechanically deformed in small volumes, higher stresses are needed for plastic flow. This has been called the "Smaller is Stronger" phenomenon and has been widely observed. studies suggest that plasticity in one case is indeed controlled by the GNDs (strain gradient hardening), whereas in the other, plasticity is not controlled by strain gradients or sub-structure hardening, but rather by dislocation source starvation, wherein smaller volumes are stronger because fewer sources of dislocations are available (dislocation starvation hardening).
Dr. Arief Suriadi Budiman received his Ph.D. in Materials Science and Engineering from Stanford University, CA. Before deciding to pursue his doctoral career, he first embarked on his technical career with Hewlett-Packard, Co in Singapore researching and developing microfabrication processes for HP's latest generation of inkjet print head MEMS chip. During his doctoral candidacy at Stanford's Department of Materials Science & Engineering under the supervision of Professor William D. Nix (MRS Von Hippel Award 2007), Dr. Budiman received several research awards (MRS Graduate Silver Award 2006, MRS Best Paper 2006) and contributed to several journal publications. Most recently Dr. Budiman has been awarded the prestigious Los Alamos National Laboratory (LANL) Director's Research Fellowship to conduct top strategic research for the energy and national security missions of the Los Alamos National Laboratory's. At the Center for Integrated Nanotechnologies (CINT) at Los Alamos, Dr. Budiman's research program involves nanoscale multilayered composite materials for extreme environments with potential applications in advanced energy systems including for next generation nuclear power reactors.