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Materials Science and Engineering
Materials Science and Engineering Faculty Research & Creative Works
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Articles 1 - 16 of 16
Full-Text Articles in Engineering
Evolution Of Non-Metallic Inclusions In Foundry Steel Casting Processes, Marc Harris, Von Richards, Ronald J. O'Malley, Semen Naumovich Lekakh
Evolution Of Non-Metallic Inclusions In Foundry Steel Casting Processes, Marc Harris, Von Richards, Ronald J. O'Malley, Semen Naumovich Lekakh
Materials Science and Engineering Faculty Research & Creative Works
The evolution of nonmetallic inclusions was examined for 4320 steel at an industrial steel foundry. The steel was followed from electric arc furnace melting through ladle refining to final casting. Timed sampling was performed at all stages of the process. Samples were analyzed using an automated SEM/EDS system. The overall evolution of oxide inclusions in terms of nucleation, growth, and flotation during liquid processing was studied using area fraction and average diameter. Chemical composition evolution was observed using a joint ternary plotting tool developed under this program. It was found that the use of zirconium as an addition for nitrogen/oxygen …
Evolution Of The Statistical Distribution In A Topological Defect Network, Fei Xue, Xueyun Wang, Ion Socolenco, Yijia Gu, Longqing Chen, Sang-Wook Cheong
Evolution Of The Statistical Distribution In A Topological Defect Network, Fei Xue, Xueyun Wang, Ion Socolenco, Yijia Gu, Longqing Chen, Sang-Wook Cheong
Materials Science and Engineering Faculty Research & Creative Works
The complex networks of numerous topological defects in hexagonal manganites are highly relevant to vastly different phenomena from the birth of our cosmos to superfluidity transition. The topological defects in hexagonal manganites form two types of domain networks: type-I without and type-II with electric self-poling. A combined phase-field simulations and experimental study shows that the frequencies of domains with N-sides, i.e. of N-gons, in a type-I network are fitted by a lognormal distribution, whereas those in type-II display a scale-free power-law distribution with exponent ~ 2. A preferential attachment process that N-gons with a larger N have higher probability of …
A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer
A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer
Materials Science and Engineering Faculty Research & Creative Works
Crack free functionally graded material (FGM) Ti6Al4V-TiC has been fabricated by laser metal deposition (LMD) using TiC and Ti6Al4V powder which were premixed for different ratios. This study focuses on the influence of laser processing parameters and TiC compositional distribution on microstructure, Vickers hardness and phase. The microstructure is analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and hardness tests. Primary carbide, eutectic carbide and unmelted carbide are found in the deposit area. When laser power increased, the primary and secondary dendrite arm spacing increased. The laser power and scanning speed did not influence the Vickers hardness distribution significantly.
Impact Of Stoichiometry On Structural And Optical Properties Of Sputter Deposited Multicomponent Tellurite Glass Films, Okechukwu Ogbuu, Qingyang Du, Hongtao Lin, Lan Li, Yi Zou, Erick Koontz, Charmayne Smith (Lonergan), Sylvain Danto, Kathleen Richardson, Juejun Hu
Impact Of Stoichiometry On Structural And Optical Properties Of Sputter Deposited Multicomponent Tellurite Glass Films, Okechukwu Ogbuu, Qingyang Du, Hongtao Lin, Lan Li, Yi Zou, Erick Koontz, Charmayne Smith (Lonergan), Sylvain Danto, Kathleen Richardson, Juejun Hu
Materials Science and Engineering Faculty Research & Creative Works
Multicomponent TeO2-Bi2O3-ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. We observed that thin films sputtered in an oxygen-rich environment are optically transparent while those sputtered in an oxygen-deficient environment exhibit broadband absorption. The structural origin of the optical property variation was studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy which revealed that the presence of under-coordinated Te leads to the observed optical …
Electrolytic Recovery Of Bismuth And Copper As A Powder From Acidic Sulfate Effluents Using An Emew® Cell, Wei Jin, Paul I. Laforest, Alex Luyima, Weldon Read, Luis M. Navarro, Michael S. Moats
Electrolytic Recovery Of Bismuth And Copper As A Powder From Acidic Sulfate Effluents Using An Emew® Cell, Wei Jin, Paul I. Laforest, Alex Luyima, Weldon Read, Luis M. Navarro, Michael S. Moats
Materials Science and Engineering Faculty Research & Creative Works
Effective removal of bismuth is a primary concern during copper electrorefining. A novel electrowinning process using an emew® cell was developed to recover bismuth and copper from a copper electrorefining waste stream. Significant removal and co-deposition of copper and bismuth were achieved from a highly acidic sulfate industrial effluent using a current density of 350 A m-2, but the current efficiency was low (27%). Operating at a lower current density (75 A m-2) facilitated the preferred removal of Cu, while increasing current efficiency to 67.4% due to the decrease of aside-reaction. Consequently, a two-stage process was …
Enhancing Grain Refinement Of Austenitic Steel With Ti Additions By Melt Treatment Sequence Optimization, Gun Ge, Semen Naumovich Lekakh, Ronald J. O'Malley
Enhancing Grain Refinement Of Austenitic Steel With Ti Additions By Melt Treatment Sequence Optimization, Gun Ge, Semen Naumovich Lekakh, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Erratum: "Impact Of Symmetry On The Ferroelectric Properties Of Catio₃ Thin Films" (Applied Physics Letters 106:162904 (2015)), Michael D. Biegalski, Liang Qiao, Yijia Gu, Apurva Mehta, Qian He, For Full List Of Authors, See Publisher's Website.
Erratum: "Impact Of Symmetry On The Ferroelectric Properties Of Catio₃ Thin Films" (Applied Physics Letters 106:162904 (2015)), Michael D. Biegalski, Liang Qiao, Yijia Gu, Apurva Mehta, Qian He, For Full List Of Authors, See Publisher's Website.
Materials Science and Engineering Faculty Research & Creative Works
There is a typo of the space group. All the Pnmb should be Pbnm (or Pnma). So the Glazer notation should be changed to (a-a-c+) for Pbnm space group on page 4 of the article. We have also noticed that the thermodynamic analysis of CaTiO3 thin film is not correct. The films are (001)PC-oriented or (101)-oriented. Therefore, there is no need to rotate the coordinate system (on page 4 of the article). By applying the thin film boundary condition, i.e., ε11 = ε22 = εs, ε …
Origin Of Interfacial Polar Order In Incipient Ferroelectrics, Yijia Gu, Nan Wang, Fei Xue, Long-Qing Chen
Origin Of Interfacial Polar Order In Incipient Ferroelectrics, Yijia Gu, Nan Wang, Fei Xue, Long-Qing Chen
Materials Science and Engineering Faculty Research & Creative Works
There are ample experimental evidences indicating that the ferroelastic domain walls of incipient ferroelectrics, such as SrTiO3 and CaTiO3, are polar. The emergence of such interfacial polar order at a domain wall is exciting and believed to arise from the coupling between a primary order parameter, such as a strain or an antiferrodistortive (AFD) order parameter, and polarization. There have been several mechanisms proposed to explain the emergence of interfacial polar order, including biquadratic coupling, AFD-antiferroelectric coupling, and flexoelectric coupling. Using CaTiO3 as an example, we demonstrate, using both asymptotic analytics and numerical calculation, that the …
Focus On Properties And Applications Of Perovskites, Fatih Dogan, Hong Lin, Maryline Guilloux-Viry, Octavio J. Pena
Focus On Properties And Applications Of Perovskites, Fatih Dogan, Hong Lin, Maryline Guilloux-Viry, Octavio J. Pena
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Impact Of Symmetry On The Ferroelectric Properties Of Catio₃ Thin Films, Michael D. Biegalski, Liang Qiao, Yijia Gu, Apurva Mehta, Qian He, For Full List Of Authors, See Publisher's Website.
Impact Of Symmetry On The Ferroelectric Properties Of Catio₃ Thin Films, Michael D. Biegalski, Liang Qiao, Yijia Gu, Apurva Mehta, Qian He, For Full List Of Authors, See Publisher's Website.
Materials Science and Engineering Faculty Research & Creative Works
Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO3, through the careful control of the biaxial strain state and TiO6 octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO3 films grown on La0.18Sr0.82Al0.59Ta0.41O3 (LSAT) and NdGaO3 (NGO) substrates experienced a 1.1% biaxial strain state …
Producing High Strength Aluminum Alloy By Combination Of Equal Channel Angular Pressing And Bake Hardening, Hamid Alihosseini, Mohsen Asle Zaeem, Kamran Dehghani, Ghader Faraji
Producing High Strength Aluminum Alloy By Combination Of Equal Channel Angular Pressing And Bake Hardening, Hamid Alihosseini, Mohsen Asle Zaeem, Kamran Dehghani, Ghader Faraji
Materials Science and Engineering Faculty Research & Creative Works
A combination of severe plastic deformation by equal channel angular pressing (ECAP) and bake hardening (BH) was used to produce high strength ultrafine-grained AA6061 aluminum alloy. 2, 4 and 8 passes of ECAP were performed, and the bake hardenability of samples was tested by 6% pre-straining followed by baking at 200 °C for 20 min. The microstructures obtained for various passes of ECAP were characterized by XRD, EBSD, and TEM techniques. The microstructures were refined from an average grain size of 20 µm to 212 nm after 8 passes of ECAP. Maximum bake hardenability of 110 MPa, and final yield …
Method And System For Purifying Charged Radioisotopes, Cathy Sue Cutler, Gary John Ehrhardt, Hendrik Petrus Engelbrecht, D. E. Day
Method And System For Purifying Charged Radioisotopes, Cathy Sue Cutler, Gary John Ehrhardt, Hendrik Petrus Engelbrecht, D. E. Day
Materials Science and Engineering Faculty Research & Creative Works
The present invention provides a simple and inexpensive method for removing metal and other impurities in a radioisotope solution. The invention further includes the development of a new parent/daughter generator system for collecting the daughter isotope in a concentrated solution.
Nanoscale Mechanical Switching Of Ferroelectric Polarization Via Flexoelectricity, Yijia Gu, Zijian Hong, Jason Britson, Long-Qing Chen
Nanoscale Mechanical Switching Of Ferroelectric Polarization Via Flexoelectricity, Yijia Gu, Zijian Hong, Jason Britson, Long-Qing Chen
Materials Science and Engineering Faculty Research & Creative Works
Flexoelectric coefficient is a fourth-rank tensor arising from the coupling between strain gradient and electric polarization and thus exists in all crystals. It is generally ignored for macroscopic crystals due to its small magnitude. However, at the nanoscale, flexoelectric contributions may become significant and can potentially be utilized for device applications. Using the phase-field method, we study the mechanical switching of electric polarization in ferroelectric thin films by a strain gradient created via an atomic force microscope tip. Our simulation results show good agreement with existing experimental observations. We examine the competition between the piezoelectric and flexoelectric effects and provide …
Quantitative Modeling Of The Equilibration Of Two-Phase Solid-Liquid Fe By Atomistic Simulations On Diffusive Time Scales, Ebrahim Asadi, Mohsen Asle Zaeem, Sasan Nouranian, Michael I. Baskes
Quantitative Modeling Of The Equilibration Of Two-Phase Solid-Liquid Fe By Atomistic Simulations On Diffusive Time Scales, Ebrahim Asadi, Mohsen Asle Zaeem, Sasan Nouranian, Michael I. Baskes
Materials Science and Engineering Faculty Research & Creative Works
In this paper, molecular dynamics (MD) simulations based on the modified-embedded atom method (MEAM) and a phase-field crystal (PFC) model are utilized to quantitatively investigate the solid-liquid properties of Fe. A set of second nearest-neighbor MEAM parameters for higherature applications are developed for Fe, and the solid-liquid coexisting approach is utilized in MD simulations to accurately calculate the melting point, expansion in melting, latent heat, and solid-liquid interface free energy, and surface anisotropy. The required input properties to determine the PFC model parameters, such as liquid structure factor and fluctuations of atoms in the solid, are also calculated from MD …
Dynamic Phases, Pinning, And Pattern Formation For Driven Dislocation Assemblies, Caizhi Zhou, Charles Reichhardt, Cynthia Olson Reichhardt, Irene J. Beyerlein
Dynamic Phases, Pinning, And Pattern Formation For Driven Dislocation Assemblies, Caizhi Zhou, Charles Reichhardt, Cynthia Olson Reichhardt, Irene J. Beyerlein
Materials Science and Engineering Faculty Research & Creative Works
We examine driven dislocation assemblies and show that they can exhibit a set of dynamical phases remarkably similar to those of driven systems with quenched disorder such as vortices in superconductors, magnetic domain walls, and charge density wave materials. These phases include pinned-jammed, fluctuating, and dynamically ordered states, and each produces distinct dislocation patterns as well as specific features in the noise fluctuations and transport properties. Our work suggests that many of the results established for systems with quenched disorder undergoing plastic depinning transitions can be applied to dislocation systems, providing a new approach for understanding pattern formation and dynamics …
Composition- And Pressure-Induced Ferroelectric To Antiferroelectric Phase Transitions In Sm-Doped Bifeo₃ System, Fei Xue, Linyun Liang, Yijia Gu, Ichiro Takeuchi, Sergei V. Kalinin, Long-Qing Chen
Composition- And Pressure-Induced Ferroelectric To Antiferroelectric Phase Transitions In Sm-Doped Bifeo₃ System, Fei Xue, Linyun Liang, Yijia Gu, Ichiro Takeuchi, Sergei V. Kalinin, Long-Qing Chen
Materials Science and Engineering Faculty Research & Creative Works
A three-dimensional phenomenological model is proposed to describe both ferroelectricity and antiferroelectricity based on the Ginzburg-Landau-Devonshire theory. Its application to the multiferroic Sm-doped BiFeO3 system describes the temperature-, pressure-, and composition-induced ferroelectric to antiferroelectric phase transitions. The constructed temperature-composition and temperature-pressure phase diagrams show that compressive hydrostatic pressure and Sm doping have similar effects on the ferroelectric and antiferroelectric phase transitions. It is also indicated from the temperature-pressure phase diagram that the experimentally observed phase of BiFeO3 under the hydrostatic pressure from 3 GPa to 10 GPa is a PbZrO3-like antiferroelectric phase.