Grain boundary effects on the mechanical properties of bismuth nanostructures

作者：Burek Michael J; Jin Sumin; Leung Michael C; Jahed Zeinab; Wu Janet; Budiman Arief Suriadi; Tamura Nobumichi; Kunz Martin; Tsui Ting Y^*

来源：Acta Materialia, 2011, 59(11): 4709-4718.

DOI：10.1016/j.actamat.2011.04.017

• Nanoindentation
• Grain boundaries
• Ultrafine grained microstructure
• Plastic deformation
• Yield phenomena

Cylindrical bismuth nanopillars with diameters between 130 and 1100 nm were fabricated by electron beam lithography and electroplating. The microstructure of the electrodeposited bismuth was established to be polycrystalline with a wide distribution of grains from similar to 0.1 to 1 mu m in size. A clear transition in the mechanism governing the plastic deformation of bismuth nanopillars is observed as the nanopillar size becomes comparable with the average grain size of 280 nm. In larger nanopillar specimens, where the average grain size is much smaller than the nanopillar diameter, deformation is dominated by grain boundary-mediated mechanisms. When the bismuth nanopillar diameter approaches the average grain size the deformation behavior transitions to a mechanism dominated by dislocation dynamics. This transition is identified by post-compression scanning electron microscopy, strain rate sensitivity, and average flow stresses.

• 出版日期2011-6