Magnetotransport in a spatially modulated magnetic field

Duport Adrien Jean. Lecture de deux premiers articles du titre 1 de l'institution des officiers de police, lors de la séance du 28 décembre 1790. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XXI - Du 26 novembre 1790 au 2 janvier 1791. Paris : Librairie Administrative P. Dupont, 1885. p. 692

Microwave heating, isothermal sintering, and mechanical properties of powder metallurgy titanium and titanium alloys

This article presents a detailed assessment of microwave (MW) heating, isothermal sintering, and the resulting tensile properties of commercially pure Ti (CP-Ti), Ti-6Al-4V, and Ti-10V-2Fe-3Al (wt pct), by comparison with those fabricated by conventional vacuum sintering. The potential of MW sintering for titanium fabrication is evaluated accordingly. Pure MW radiation is capable of heating titanium powder to ≥1573 K (1300 C), but the heating response is erratic and difficult to reproduce. In contrast, the use of SiC MW susceptors ensures rapid, consistent, and controllable MW heating of titanium powder. MW sintering can consolidate CP-Ti and Ti alloys compacted from -100 mesh hydride-dehydride (HDH) Ti powder to ~95.0 pct theoretical density (TD) at 1573 K (1300 C), but no accelerated isothermal sintering has been observed over conventional practice. Significant interstitial contamination occurred from the Al2O3-SiC insulation-susceptor package, despite the high vacuum used (≤4.0 × 10-3 Pa). This leads to erratic mechanical properties including poor tensile ductility. The use of Ti sponge as impurity (O, N, C, and Si) absorbers can effectively eliminate this problem and ensure good-to-excellent tensile properties for MW-sintered CP-Ti, Ti-10V-2Fe-3Al, and Ti-6Al-4V. The mechanisms behind various observations are discussed. The prime benefit of MW sintering of Ti powder is rapid heating. MW sintering of Ti powder is suitable for the fabrication of small titanium parts or titanium preforms for subsequent thermomechanical processing

Phase equilibria in the ZrO2–HfO2–Nd2O3 system at 1500 °C and 1700 °C

The phase equilibria in the ZrO2–HfO2–Nd2O3 ternary system at 1500 °C and 1700 °C were studied over the whole concentration range by X-ray diffraction and microstructural analyses. Corresponding isothermal sections were constructed from the data obtained. It was found that solid solutions in this system are derived from a tetragonal (T) modification of ZrO2, a monoclinic (M) modification of HfO2, a hexagonal (A) modification of Nd2O3, a cubic phase with a fluorite (F) structure of ZrO2 (HfO2), and an ordered phase with a pyrochlore (Py) structure of Nd2Zr2O7 (Nd2Hf2O7). The phase boundaries and unit cell lattice parameters were determined. The solubility of Nd2O3 in M − HfO2 is pretty low and about less than 1 mol%, as confirmed by XRD and microstructural analyses. The ordered pyrochlore-type (Py) phase of Nd2Zr2O7 (Nd2Hf2O7) forms continuous series of solid solutions at 1500 °C and 1700 °C. The homogeneous region of these continuous series of solid solutions changes insignificantly with increasing temperature. The changes in the construction of the isothermal section of the ZrO2-HfO2-Nd2O3 phase diagram at 1500 °C compared to 1700 °C are associated with the thermal stability of cubic fluorite-type (F) solid solutions. Other phases in the ZrO2-HfO2-Nd2O3 ternary system are not detected at the studied temperatures