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Full-Text Articles in Mechanical Engineering
Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings, Hai Ni, Xiaodong Li
Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings, Hai Ni, Xiaodong Li
Faculty Publications
Nano-/micronecklaces with SiO2 beads in boron strings were synthesized by simply sublimating the desired powders in a sealed quartz tube at high temperature. The boron strings have a rectangular cross section with width varying from 80to1000nm while the SiO2 beads bear either spindle or spherical shape with a size ranging from 100nmto5μm. The spacing between the SiO2 beads is uniform in each boron string. Both the boron strings and the SiO2 beads are amorphous and free of defects. The supersaturated vapors of silicon and oxygen induced the SiO2 bead formation.
Elastic Modulus Of Amorphous Sio2 Nanowires, Hai Ni, Xiaodong Li, Hongsheng Gao
Elastic Modulus Of Amorphous Sio2 Nanowires, Hai Ni, Xiaodong Li, Hongsheng Gao
Faculty Publications
Amorphous SiO2 nanowires with diameter ranging from 50 to 100 nm were synthesized using chemical vapor deposition(CVD) under an argon atmosphere at atmospheric pressure. Nanoscale three-point bending tests were performed directly on individual amorphous SiO2 nanowires using an atomic force microscope (AFM).Elastic modulus of the amorphous SiO2 nanowires was measured to be 76.6±7.2GPa, which is close to the reported value of the bulk SiO2 and thermally grown SiO2 thin films, but lower than that of plasma-enhanced CVD SiO2 thin films. The amorphous SiO2 nanowires exhibit brittle fracture failure in bending.
High-Pressure Torsion-Induced Grain Growth In Electrodeposited Nanocrystalline Ni, X. Z. Liao, A. R. Kilmametov, R. Z. Valiev, Hongsheng Gao, Xiaodong Li, A. K. Mukherjee, J. F. Blingert, Y. T. Zhu
High-Pressure Torsion-Induced Grain Growth In Electrodeposited Nanocrystalline Ni, X. Z. Liao, A. R. Kilmametov, R. Z. Valiev, Hongsheng Gao, Xiaodong Li, A. K. Mukherjee, J. F. Blingert, Y. T. Zhu
Faculty Publications
Deformation-induced grain growth has been reported in nanocrystalline (nc) materials under indentation and severe cyclic loading, but not under any other deformation mode. This raises an issue on critical conditions for grain growth in nc materials. This study investigates deformation-induced grain growth in electrodeposited nc Ni during high-pressure torsion (HPT). Our results indicate that high stress and severe plastic deformation are required for inducing grain growth, and the upper limit of grain size is determined by the deformation mode and parameters. Also, texture evolution suggests that grain-boundary-mediated mechanisms played a significant role in accommodating HPT strain.