title: Detecting grain rotation at the nanoscale.
abstract: It is well-believed that below a certain particle size, grain boundary-mediated plastic deformation (e.g., grain rotation, grain boundary sliding and diffusion) substitutes for conventional dislocation nucleation and motion as the dominant deformation mechanism. However, in situ probing of grain boundary processes of ultrafine nanocrystals during plastic deformation has not been feasible, precluding the direct exploration of the nanomechanics. Here we present the in situ texturing observation of bulk-sized platinum in a nickel pressure medium of various particle sizes from 500 nm down to 3 nm. Surprisingly, the texture strength of the same-sized platinum drops rapidly with decreasing grain size of the nickel medium, indicating that more active grain rotation occurs in the smaller nickel nanocrystals. Insight into these processes provides a better understanding of the plastic deformation of nanomaterials in a few-nanometer length scale.
authors.affiliation: Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Katie
authors.initials: K
authors.lastname: Lutker
authors.forename: Jialin
authors.initials: J
authors.lastname: Lei
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Yan
authors.forename: Shizhong
authors.initials: S
authors.lastname: Yang
authors.forename: Ho-kwang
authors.initials: HK
authors.lastname: Mao
mesh_terms: D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000648:ultrastructure*; D009532:Nickel / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D011312:Pressure; D012399:Rotation; D014961:X-Ray Diffraction
chemical_list: D010984:Platinum; D009532:Nickel