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Full-Text Articles in Engineering
Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig
Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig
Materials Science and Engineering Faculty Research & Creative Works
The rigorous solution of the grain-boundary diffusion problem has been approximated by a series expansion method. The calculations show that higher-order terms may be neglected in the bulk adjacent to the grain boundary. Thus, in this region Whipple's and Suzuoka's solutions represent a close approximation to the problem. Inside the grain boundary, however, higher-order approximations have to be taken into account. These approximations gain importance in the case of wide grain boundaries. The solutions obtained for an instantaneous source have been fitted to available grain-boundary diffusion data of Ni2+ in MgO at 1200°C. Numerical calculations give for the bulk diffusion …
Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis
Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Phase Equilibria And Thermodynamic Studies In The System Cao-Feo-Fe2o3-Sio2, M. Timucin, Arthur E. Morris
Phase Equilibria And Thermodynamic Studies In The System Cao-Feo-Fe2o3-Sio2, M. Timucin, Arthur E. Morris
Materials Science and Engineering Faculty Research & Creative Works
Phase equilibria and thermodynamic properties of the system CaO-FeO-Fe2O3-SiO2 were studied at 1450° and 1550°C, over a range of pO2 from 1 to about 10-11 atm. Isothermal phase diagrams and activity-composition diagrams were constructed for 0, 5, 10, 20, and 30 wt pct SiO2 sections. The data are applicable to further understanding the behavior of simple BOF steelmaking slags. © 1970 The Minerals, Metals & Materials Society - ASM International - The Materials Information Society.
The Fe-Ho Binary System, G. J. Roe, Thomas J. O'Keefe
The Fe-Ho Binary System, G. J. Roe, Thomas J. O'Keefe
Materials Science and Engineering Faculty Research & Creative Works
The Fe-Ho phase diagram was determined on the basis of data obtained by X-ray diffraction, metallographic and differential thermal analysis techniques. Since emphasis was centered in the region where intermetallic compounds predominate, neither the iron nor holmium terminal regions were included in this study. Eutectic reactions were found to occur at 16.5 wt pct Fe and 875° C, 61 wt pct Fe and 1284° C, and 79 wt pct Fe and 1338° C. The congruent melting points of the compounds Ho6Fe23 and Ho2Fe17 were found to be 1332° and 1343° C, respectively. Two other intermetallic compounds were found, HoFe2 and …
Electron Emitter Tips And Method, P. D. Ownby
Electron Emitter Tips And Method, P. D. Ownby
Materials Science and Engineering Faculty Research & Creative Works
Boron is deposited on the (110) plane facet at the center of a tungsten electron emitter tip by chemical vapor deposition of boron triiodide. The emission current density is greatest in the center of the emitting area (FIG. 2).
Thermal Expansion Of Orthorhombic Pbo, Charles A. Sorrell
Thermal Expansion Of Orthorhombic Pbo, Charles A. Sorrell
Materials Science and Engineering Faculty Research & Creative Works
Thermal expansion of orthorhombic PbO was investigated by high‐temperature X‐ray diffraction. The coefficients in the a0, and c0 directions are equal and Pb–O chains extended in the a0 direction and bonded into layers in the b0 direction; appreciable Pb–Pb bonding is indicated. Coordination and bond distances observed in PbSiO3 and lead silicate glasses, which are similar to those of massicot, and PbnOn polymeric units reported in PbO vapor are interpreted as additional evidence of the importance of PbO chains as structural entities. Copyright © 1970, Wiley Blackwell. All rights reserved
Thermal Expansion Of Tetragonal Pbo, Charles A. Sorrell
Thermal Expansion Of Tetragonal Pbo, Charles A. Sorrell
Materials Science and Engineering Faculty Research & Creative Works
Thermal expansion of tetragonal PbO, investigated by high‐temperature X‐ray diffraction in vacuum, is nearly isotropic, with the coefficient in the c0 direction only slightly greater than that in the a0 direction. Volume thermal expansion is only slightly greater than in massicot. Retardation of the litharge‐massicot transformation is tentatively interpreted as the result of very low oxygen partial pressures caused by catastrophic oxidation of the stainless‐steel sample holder and resulting oxygen scavenging by lead vapor. Copyright © 1970, Wiley Blackwell. All rights reserved
Carburization Of Type 316l Stainless Steel In Static Sodium, F. B. Litton, Arthur E. Morris
Carburization Of Type 316l Stainless Steel In Static Sodium, F. B. Litton, Arthur E. Morris
Materials Science and Engineering Faculty Research & Creative Works
The transport of carbon from an iron-87 wt.% carbon alloy through static sodium to Type 316L stainless steel was investigated at temperatures of interest to the liquid-metal fast-breeder reactor (LMFBR) program. The rate-controlling step for the experimental geometry employed was the diffusion of carbon in the source. © 1970.
Exact Solution For A Model Of Dislocation Pipe Diffusion, J. Mimkes, Manfred Wuttig
Exact Solution For A Model Of Dislocation Pipe Diffusion, J. Mimkes, Manfred Wuttig
Materials Science and Engineering Faculty Research & Creative Works
The dislocations are treated as an ideal array of parallel pipes of radius and diffusivity Dp embedded in the bulk material of the diffusivity Db. The exact solution of this problem of diffusion along semi-infinite edge dislocations is presented for cubic, tetragonal, and hexagonal crystals. The solution makes it possible to evaluate the dislocation pipe radius a and the ratio of diffusivities from one experiment. It is applied to experimental data for self-diffusion in tellurium available in the literature. The results of the calculations are a dislocation pipe radius a=(1.5 0.5)x10-4 cm and an activation energy for the pipe diffusion …