Superglide at an Internal Incommensurate Boundary

作者：Lancon Frederic^*; Ye Jia; Caliste Damien; Radetic Tamara; Minor Andrew M; Dahmen Ulrich

来源：Nano Letters, 2010, 10(2): 695-700.

DOI：10.1021/nl903885p

• Friction
• grain boundary
• gold
• electron microscopy
• molecular dynamics
• nanopillar

The intriguing possibility of frictionless gliding of one solid. surface on another has been predicted for certain incommensurate interfaces in crystals, based on Aubry's solution to the Frenkel-Kontorova model of a harmonic chain in a periodic potential held. Here we test this prediction for grain boundaries by comparing atomistic simulations with direct experimental observations on the structure and load-deformation behavior of gold nanopillars containing a root-two incommensurate grain boundary. The simulations show supergliding at this boundary limited by finite-size effects which cause edges to act as defects of the incommensurate structure. Structural relaxation at the edges generates stacking faults, dislocations, and asymmetric surface steps. These features as well as the related load-displacement behavior are replicated by experimental observations on the compression of nanopillars using a quantitative nanoindentation device inside a transmission electron microscope. The good agreement between the observed and predicted behavior suggests that incommensurate interfaces could play an important role in the deformation of polycrystalline materials.

• 出版日期2010-2
• 单位中国地震局