Scholarly Works, Materials Science and Engineering (MSE)

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https://hdl.handle.net/10919/24370
Research articles, presentations, and other scholarship

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Browsing Scholarly Works, Materials Science and Engineering (MSE) by Department "Institute for Critical Technology and Applied Science (ICTAS)"

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    Nanodispersed DO(3)-phase nanostructures observed in magnetostrictive Fe-19% Ga Galfenol alloys
    Bhattacharyya, Somnath; Jinschek, J. R.; Khachaturyan, Armen G.; Cao, Hu; Li, Jiefang; Viehland, Dwight D. (American Physical Society, 2008-03-10)
    Few nanometer large (<2 nm) inclusions of DO(3)-phase structure have been identified in the A2 matrix of highly magnetostrictive Fe-19% Ga alloys by high-resolution transmission electron microscopy (HRTEM). In addition, we have found that these nanostructures include a high density of {100} line defects with a Burgers vector of a(bcc)/2 < 100 >. This dispersion of DO(3)-phase nanostructures formed within the main A2 matrix and the lifting of their coherency by defects are consistent with a recent theory for the structure and properties of magnetostrictive Fe-Ga and Fe-Al alloys.
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    Role of coexisting tetragonal regions in the rhombohedral phase of Na0.5Bi0.5TiO3-xat.%BaTiO3 crystals on enhanced piezoelectric properties on approaching the morphotropic phase boundary
    Yao, Jianjun; Monsegue, Niven; Murayama, Mitsuhiro; Leng, W. N.; Reynolds, William T. Jr.; Zhang, Qinhui; Luo, Haosu; Li, Jiefang; Ge, Wenwei; Viehland, Dwight D. (AIP Publishing, 2012-01-01)
    The ferroelectric domain and local structures of Na0.5Bi0.5TiO3-xat.%BaTiO3 (NBT-x%BT) crystals for x = 0, 4.5, and 5.5 have been investigated by transmission electron microscopy. The results show that the size of polar nano-regions was refined with increasing xat. %BT. The tetragonal phase volume fraction, as identified by in-phase octahedral tilting, was found to be increased with BT. The findings indicate that the large electric field induced strains in morphotropic phase boundary compositions of NBT-x%BT originate not only from polarization rotation but also polarization extension. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3673832]
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    Thermal transport in composites of self-assembled nickel nanoparticles embedded in yttria stabilized zirconia
    Shukla, Nitin C.; Liao, Hao-Hsiang; Abiade, Jeremiah T.; Murayama, Mitsuhiro; Kumar, Dhananjay; Huxtable, Scott T. (AIP Publishing, 2009-04-01)
    We investigate the effect of nickel nanoparticle size on thermal transport in multilayer nanocomposites consisting of alternating layers of nickel nanoparticles and yttria stabilized zirconia (YSZ) spacer layers that are grown with pulsed laser deposition. Using time-domain thermoreflectance, we measure thermal conductivities of k=1.8, 2.4, 2.3, and 3.0 W m(-1) K(-1) for nanocomposites with nickel nanoparticle diameters of 7, 21, 24, and 38 nm, respectively, and k=2.5 W m(-1) K(-1) for a single 80 nm thick layer of YSZ. We use an effective medium theory to estimate the lower limits for interface thermal conductance G between the nickel nanoparticles and the YSZ matrix (G>170 MW m(-2) K(-1)), and nickel nanoparticle thermal conductivity.