Browsing by Author "Wang, X."

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    Electrohydrodynamic jet printing of PZT thick film micro-scale structures
    (Elsevier, 2015-06-08) Wang, D.; Zhu, X.; Liang, J-S; Ren, T.; Zha, W.; Dong, W.; Rocks, Sophie A.; Dorey, Robert A.; Xu, Z.; Wang, X.
    This paper reports the use of a printing technique, called electrohydrodynamic jet printing, for producing PZT thick film micro-scale structures without additional material removing processes. The PZT powder was ball-milled and the effect of milling time on the particle size was examined. This ball-milling process can significantly reduce the PZT particle size and help to prepare stable composite slurry suitable for the E-Jet printing. The PZT micro-scale structures with different features were produced. The PZT lines with different widths and separations were fabricated through the control of the E-Jet printing parameters. The widths of the PZT lines were varied from 80 μm to 200 μm and the separations were changed from 5 μm to 200 μm. In addition, PZT walled structures were obtained by multi-layer E-Jet printing. The E-Jet printed PZT thick films exhibited a relative permittivity (ɛr) of ∼233 and a piezoelectric constant (d33, f) of ∼66 pC N−1.
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    Fracture toughness and fatigue crack growth rate properties in wire + arc additive manufactured Ti-6Al-4V
    (Wiley, 2016-11-29) Zhang, Xiang; Martina, Filomeno; Ding, Jialuo; Wang, X.; Williams, Stewart W.
    This paper presents an experimental investigation of the fracture and fatigue crack growth properties of Ti-6Al-4V produced by the Wire + Arc Additive Manufacture (WAAM) process. First, fracture toughness was measured for two different orientations with respect to the build direction; the effect of wire oxygen content and build strategy were also evaluated in the light of microstructure examination. Second, fatigue crack growth rates were measured for fully additive manufactured samples, as well as for samples containing an interface between WAAM and wrought materials. The latter category covers five different scenarios of crack location and orientation with respect to the interface. Fatigue crack growth rates are compared with that of the wrought or WAAM alone conditions. Crack growth trajectory of these tests is discussed in relation to the microstructure characteristics