Browsing by Author "Guo, Xingye"

Now showing 1 - 10 of 21
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    3D Printed ABS and Carbon Fiber Reinforced Polymer Specimens for Engineering Education
    (Springer, 2016) Golub, Michael; Guo, Xingye; Jung, Mingyo; Zhang, Jing; Department of Mechanical Engineering, School of Engineering and Technology
    Three 3D printed plastic materials, ABS, ABS plus, and CFRP, have been studied for their potential applications in engineering education. Using tensile test, the stress strain curves of the materials have been measured. The Young’s modulus, ultimate strength, and fracture toughness of the materials are calculated from the stress strain curve. The results show that CFRP has the highest stiffness or Young’s modulus. ABS plus has strongest mechanical properties, with highest ultimate strength and fracture toughness. With the measured properties, the 3D printed samples are a viable solution for engineering students to learn mechanical properties of materials.
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    Abrasive Resistant Coatings—A Review
    (MDPI, 2014-05-21) Wu, Linmin; Guo, Xingye; Zhang, Jing; Mechanical Engineering, School of Engineering and Technology
    Abrasive resistant coatings have been widely used to reduce or eliminate wear, extending the lifetime of products. Abrasive resistant coatings can also be used in certain environments unsuitable for lubrications. Moreover, abrasive resistant coatings have been employed to strengthen mechanical properties, such as hardness and toughness. Given recently rapid development in abrasive resistant coatings, this paper provides a review of major types of abrasive coatings, their wearing mechanisms, preparation methods, and properties.
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    Additive Manufacturing of Metallic Materials: A Review
    (Springer, 2017) Zhang, Yi; Wu, Linmin; Guo, Xingye; Kane, Stephen; Deng, Yifan; Jung, Yeon-Gil; Lee, Je-Hyun; Zhang, Jing; Mechanical Engineering, School of Engineering and Technology
    In this review article, the latest developments of the four most common additive manufacturing methods for metallic materials are reviewed, including powder bed fusion, direct energy deposition, binder jetting, and sheet lamination. In addition to the process principles, the microstructures and mechanical properties of AM-fabricated parts are comprehensively compared and evaluated. Finally, several future research directions are suggested.
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    Atomistic Modeling of Anisotropic Mechanical Properties of Lanthanum Zirconate Nanocystal
    (Elsevier, 2021-02) Guo, Xingye; Zhang, Jian; Park, Hye-Yeong; Jung, Yeon-Gil; Zhang, Jing; Mechanical and Energy Engineering, School of Engineering and Technology
    Lanthanum zirconate (La2Zr2O7, or LZ) has been widely recognized as a promising candidate material for thermal barrier coating (TBC) applications since it has low thermal conductivity, high-temperature phase stability, and low sintering activity. However, the mechanical properties of LZ crystal have not been fully understood, which hinders it from future applications. In this work, atomistic simulations were performed to study the anisotropic mechanical properties of LZ crystal. Using both the first principles and molecular dynamics (MD) calculations, uniaxial tensile tests of LZ crystal in [001], [011], and [111] directions were simulated. The stress-strain curves of the tensile tests were calculated, and the ultimate tensile strength and toughness were derived. The Young's moduli in [001], [011], and [111] directions were calculated using both the stress-strain curves and an analytical method for small deformation. Additionally, shear stress-strain curves in {111}<110> and {111}<112> directions were investigated using both the first principles calculations and the MD method. Results show that Young's modulus of LZ crystal is highly anisotropic. The crystal has the highest Young's modulus in [111] direction, and {111}<112> direction is the favorable slip system during shear deformations.
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    Characterization of Microstructure and Mechanical Properties of Direct Metal Laser Sintered 15–5 PH1 Stainless Steel Powders and Components
    (Springer, 2016) Zhang, Jing; Zhang, Yi; Guo, Xingye; Lee, Weng Hoh; Hu, Bin; Lu, Zhe; Jung, Yeon-Gil; Lee, Je-Hyun; Department of Mechanical Engineering, School of Engineering and Technology
    15–5 PH1 stainless steel powder is one of the common materials used for the DMLS process. In this study, both the powder and parts fabricated via DMLS have been characterized. The microstructure and elemental composition have been examined. The microhardness and surface roughness have also been measured. The results show that most powder particle are in spherical with a particle size of 5 ~ 60 μm. Chemical compositions of the powder compare well with the literature data. The thickness of rough surface is about 1 μm. The measured Rockwell hardness is HRC 42.9±0.3, which is also in good agreement with literature.
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    Density Functional Theory Study of Gas Adsorption on Lanthanum Zirconate Nanostructured Coating Surface
    (Office of the Vice Chancellor for Research, 2015-04-17) Guo, Xingye; Zhang, Jing; Jung, Yeon-Gil; Li, Li; Knapp, James
    Lanthanum zirconate (La2Zr2O7) is a typical pyrochlore ceramic material, which can be used as thermal barrier coating (TBC). However, it may deteriorate by oxidizing and corrosive gases, such as CO2, O2, SO2 and CH4 during its operation process at elevated temperatures. This work investigates CO2, O2, SO2 and CH4 gas adsorption mechanism on La2Zr2O7 nanostructured coating surfaces using the density functional theory (DFT) calculations. La2Zr2O7 surface energies on (001), (011) and (111) planes were calculated. Results show the most thermodynamically stable surfaces of La2Zr2O7 are (011) and (111) planes, due to their low surface energies. Adsorption energies of CO2, O2, SO2 and CH4 on (001), (011) and (111) planes in different sites were studied as well. The results show the most favorable gas adsorption sites for CO2, O2, SO2 and CH4 occur at 3-fold and 4-fold sites. The most favorable gas adsorption plane for CO2, O2, SO2 and CH4 is (111) plane.
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    First principles study of thermodynamic properties of lanthanum zirconate
    (2014) Guo, Xingye; Zhang, Jing
    Lanthanum zirconia (La2Zr2O7) has become an advanced thermal barrier coating material due to its low thermal conductivity and high temperature stability. In this work, the first principles calculations were used to study the thermodynamic properties of the material. Lattice parameters, bulk and shear modulus, and specific heat of La2Zr2O7 were calculated by means of density functional theory (DFT). Hydrostatic pressure-dependent elasticity constants and bulk modulus were also studied. The thermal conductivity was calculated based on the Fourier's law. The calculated properties are in excellent agreement with the experimental and calculation results in literature.
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    Ideal tensile strength and shear strength of ZrO2(111)/Ni(111) ceramic-metal Interface: A first principle study
    (Elsevier, 2016-12) Guo, Xingye; Zhang, Yi; Jung, Yeon-Gil; Li, Li; Knapp, James; Zhang, Jing; Department of Mechanical Engineering, School of Engineering and Technology
    The ideal mechanical strengths of ZrO2(111)/Ni(111) ceramic-metal (C-M) interface are calculated through simulated tensile and shear deformations using the first principles calculations. The structures of ZrO2(111)/Ni(111) interfaces with 1- and 3-layer Ni thicknesses are optimized and the mechanical properties are investigated. For tensile deformation in [111] direction, the Young's moduli of the 1-layer Ni and 3-layer Ni M-C models are 139.9 GPa and 60.2 GPa, respectively; and ultimate tensile strengths are 11.6 GPa and 7.9 GPa, respectively. For shear deformation in {111} 〈110〉 system, the shear moduli of the 1-layer Ni and 3-layer Ni M-C models are 43.9 GPa and 30.4 GPa, respectively; and ultimate shear strengths are 7.0 GPa and 3.0 GPa, respectively. For shear deformation in {111} 〈11View the MathML source〉 system, the shear moduli of the 1-layer Ni and 3-layer Ni M-C models are 30.9 GPa and 17.3 GPa, respectively; and ultimate shear strengths are 6.0 GPa and 1.8 GPa, respectively. Overall, 1-layer Ni C-M interface models have better mechanical properties than those of 3-layer models. The observed strengths are explained by using charge distribution, electron localization function, and Bader charge transfer analyses. The results are important for designing robust thermal barrier coating through optimizing bond coat thickness.
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    Implementation of Conformal Cooling & Topology Optimization in 3D Printed Stainless Steel Porous Structure Injection Molds
    (2016) Jahan, Suchana A.; Wu, Tong; Zhang, Yi; El-Mounayri, Hazim; Tovar, Andres; Zhang, Jing; Acheson, Douglas; Nalim, M. Razi; Guo, Xingye; Lee, Weng Hoh
    This work presents implementation of numerical analysis and topology optimization techniques for redesigning traditional injection molding tools. Traditional injection molding tools have straight cooling channels, drilled into a solid body of the core and cavity. The cooling time constitutes a large portion of the total production cycle that needs to be reduced as much as possible in order to bring in a significant improvement in the overall business of injection molding industry. Incorporating conformal cooling channels in the traditional dies is a highly competent solution to lower the cooling time as well as improve the plastic part quality. In this paper, the thermal and mechanical behavior of cavity and core with conformal cooling channels are analyzed to find an optimum design for molding tools. The proposed design with conformal cooling channels provides a better alternative than traditional die designs with straight channels. This design is further optimized using thermo-mechanical topology optimization based on a multiscale approach for generating sound porous structures. The implemented topology optimization results in a light-weight yet highly effective die cavity and core. The reduction in weight achieved through the design of dies with porous structures is meant to facilitate the adoption of additive manufacturing for die making by the tooling industry.
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    Lanthanum Zirconate Based Thermal Barrier Coatings: A Review
    (Elsevier, 2017-08) Zhang, Jing; Guo, Xingye; Jung, Yeon-Gil; Li, Li; Knapp, James; Department of Mechanical Engineering, School of Engineering and Technology
    This review article summarizes the latest information about the manufacturing techniques of lanthanum zirconate (La2Zr2O7, LZ) powder and La2Zr2O7 based thermal barrier coatings (TBCs). Lanthanum zirconate is a promising candidate material for TBC applications, due to its lower thermal conductivity and higher thermal stability compared to other traditional TBC systems. In this work, the physical, thermal, and mechanical properties of the powder and coatings are evaluated. The durability experiments of the TBCs in various thermal, mechanical, and corrosive conditions are also reviewed. In addition, theoretical studies on the powder and coatings properties are presented. Finally, future research directions of lanthanum zirconate as TBC applications are proposed.