Umwandlungsplastizität und Form-Gedächtnis-Effekt in einer Eisenlegierung mit 16% Mangan

During the quenching of wire shaped specimens of steel X8Mn16 fec austenite changes under reduction of length in hcp ϵ-martensite. If the transformation takes place under the influence of an external tensile stress an elongation results. This transformation plasticity consists of a reversible and an irreversible part. The reversibel part rises by the formation of stress-induced ϵ-martensite in preferred orientation and is built back under reduction of length during the following heating over the Af-temperature. By this it is verified that the strain-memory-effect can occur in iron alloys too. A plastic deformation of the austenite below the recristallisation temperature prevents the γ → ϵ-transformation.     

Reaktivität von mechanisch aktiviertem Quarz

By grinding of quartz arises a strong disorder. In this amorphous range the centres of defectelectrons or the E'centres are concentrated. The amorphous range shows a changed reactivity.     

Kristallographische Polarität von AIIIBV - Mischkristallen

From the measurement of X-ray intensity differences of opposite {111}-surfaces in Ga₁ – _xAl_xAs- und Ga₁ – _xAl_xSb-mixed crystals with high Al concentration it was concluded which of the two surfaces is terminated by a layer of the group V atoms. The results are correlated with etching studies.     

Die Bestimmung der Kristallinität von Schlacken

The use of glassy materials, for example blast furnace slags, required the knowledge of their chemical constitution and crystallinity. With a light-optical method of integration the anisotropic effects of crystalline components in slags were measured by a new apparatus.     

Einfluß der Substruktur auf die optische Homogenität von Rubin-Laserstäben

The relation between mosaic structure and optical homogenity was measured of 90° ruby laser rod. The optical homogenity was measured by the interferometric method and the mosaic misorientation by Berg-Barrett method and the oscillation spectrometer respectively. The proportionality between the number of the interference stripes and the rotation of the mosaic blocks about an axis perpendicular to the growth axis and crystallographic c-axis was found.     

Einfluß der Temperung auf die optische Homogenität von Korund-Einkristallen

The influence of annealing corundum rods was investigated in controlling the number of interference stripes. Annealing at least of 1100-1200°C improves optical homogeneity of the perfect crystals. Annealing at 1900-1980°C only slightly improves optical homogeneity of rubies.     

Über den Zusammenhang zwischen Kompressibilität und Härte von Mineralen und nichtmetallischen kristallinen Substanzen

An attempt is made to find out an experimental correlation between diamond pyramid microhardness number HV (according to Vickers) and compressibility χ of nonmetallic intrusion substances. By means of thermoelastic considerations, especially with respect to diamond and related to the bonding theory of crystals, a logarithmic plot of χ (log HV) yields a group of straight χ-lines. Further, as a technical consequence, a computation formula is given for conversing Mohs' hardness test numbers to HV-numbers and vice versa.     

Erosivität und Mechanolumineszenz

One of the complicated properties of solids is also their erosivity. An exact and simple definition makes the erosivity as an easy measurable property of solids. The erosion which is the reason of erosivity has two aspects: 1. technological as an working procedure, 2. methodical as a method for the measuring of erosivity. Because with the erosion there are two objects in interaction, the abrasive particles and the material to be machined — with their collision deformations occurs. It is possible in some cases to observe mechanoluminescence. The mechanoluminescence can be used as to the interpretation of the erosionsmechanism as to the regulation of the experimental collisions.     

Orientierte Einlagerungen von Nonylphenolpolyglykoläthern in Zwischenschichträumen von Montmorillonitkristallen

Polyoxathylated nonylphenols were adsorbed by hydrogen bonding to oxygen-rich montmorillonite surfaces. These compounds were also held in the interlayer spaces of montmorillonite and tended to form mono- and double-layers. The kind of complexes and the orientation of molecules in the interlayer spaces are discussed.     

Präparation und Charakterisierung von Granateinkristalloberflächen

The preparation of single crystal substrates of gadolinium gallium garnet as a typical example of a brittle material is described. The mechanical polishing with iron oxide and diamond as well as a mechano-chemical polishing procedure basing on SiO₂/H₃PO₄ are investigated. Working damage is investigated by X-ray topography, double crystal spectrometry and selective etching. Results are discussed in the frame of a brittle fracture model of the abrasion process.     

Herstellung von Rubin-Saphir-Übergängen

A method for the preparation of ruby-saphire crystals is described. Some information on the optical behaviour of the transition are given.     

Ein Beitrag zur Ätzung von Fluorit-Spaltflächen

The etching method for the study of dislocation networks in fluorite was proved critically. Cleaved surfaces of natural and synthetic fluorite crystals were examined; the etchants used were phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, aqueous solutions of boric acid and of FeCl₃ at various concentrations and temperatures. The density of etch pits, the relation of the points of attack when different acids were used, the eccentricity of the pits, the arrangement of the etch pits on matching cleavage faces, the formation of the etch pits around microhardness indents and along small-angle grain boundaries confirm the conclusion that the etch pits on the cleaved surfaces of fluorite form at the points of emergence of dislocation lines.     

Oberflächenbeurteilung von bearbeiteten Siliziumscheiben

For the judgement of various polished surfaces of silicon single disks was used the method of reflexion high energy electron diffraction (RHEED) in the electron microscope and on the other hand the X-ray-method of double crystal spectrometry. Because of the obtained diffraction pictures and the obtained rocking curves and because of the completing figures of surfaces with the replica method on the electron microscope, it is possible to estimate the silicon single disks relating to the mistakes in the surface range.     

Struktur von AIIBVI-Epitaxieschichten in Abhängigkeit von den Aufdampfbedingungen

The structure of epitaxial films of A^IIB^VI-compounds is discussed. Especially the results of investigations concerning the epitaxy of CdSe on cleavage planes of NaCl and CaF₂ using high-vacuum evaporation are treated. Epitaxial films of A^IIB^VI-compounds usually show defect structures due to the co-existence of the zincblende and wurtzite structures, oriented overgrowth of these two phases, twinning and stacking faults. The resulting complex diffraction patterns (for electron diffraction in transmission) are discussed. The nature of the substrate, substrate temperature, and deposition rate besides experimental factors decisively influence the orientation, structure, and phase composition of the films. An influence of deviations from the stoichiometric composition has to be taken into account.     

Zur elastischen Wechselwirkung von Punktdefekten und Einschlüssen in der Nähe von Festkörperoberflächen

Calculating the interaction energy of point defects and inclusions in solids the influence of solid surfaces usually is neglected. But in the immediate vicinity of the boundary surfaces the deformations around the defects are, connected with a certain extra contribution to the total energy which was calculated applying continuum mechanics methods. The medium is assumed to be isotropic and homogeneous. An analytic expression for the interaction energy of two spherical inclusions near a half-room boundary surface is derived. The results show the interesting phenomenon that both attraction and repulsion between the defects occur, only depending upon the geometrical parameters.     

Einkristallzüchtung von Hämatit aus Boraxschmelze

Experiments are reported concerning the growth of hematite single crystals the magnetic properties of which were studied. Crystals were grown by a flux method on the basis of borax in the temperature range from 1300 °C to the temperature of solidification, the cooling rate being 10 grd · h⁻¹. Several physical qualities that are connected with the perfection of hematite single crystals are summarized briefly.     

Über die Rekristallisationstextur von Aluminiumdrähten

The recrystallisation texture of aluminium wires was investigated by measuring 8 pole figures. From these the inverse pole figures were calculated. The texture may be interpreted as a threefold fibre texture with the ideal orientations [100], [111], [11 √2 ]. The latter component represents the largest volume fraction of the crystals but it was found only in the outer parts of the wire. The recrystallisation texture is similar to but not identical with its original drawing texture.