Laue Technique Research Articles

Study of Shapes of Diffracting Planes by X-Ray Laue Technique

Various lattice defects have been observed in the whiskers, some of which are fairly complicated compared to a single axial screw dislocation. We have developed a general method of finding out the shapes of the diffracting planes. It is based upon the laws of reflection. The method has been illustrated by analysis of four equatorial Laue spots of a Cd whisker. The corresponding planes were found to be curved.

X-ray investigations on the growth of cadmium whiskers

Whiskers of “pure” and “spectroscopically pure” cadmium grown in vacuum of the order of 10 -6 mm Hg and in an inert gas atmosphere were studied. Deliberate introduction of spec. pure tin and lead as impurities was tried in some cases. Tin did promote whisker growth but not through the VLS mechanism. Lead remained inactive. The direction of growth was mainly observed to be [ 1 ¯ 2 1 ¯ 0 ]. Three new directions of high index orientations were detected. The studies of imperfections were carried out with the Laue technique combined with a microfocus X-ray source. It was found that the imperfections vary much along the lengths and sides of the whiskers. Cases were detected where the structure of whiskers got drastically simplified towards the tip. Single twist around the growth axis of the whiskers was not found, but curvature of the planes inside the whiskers was commonly observed. They varied from several tenths to several tens of centimetres. They varied perfect whiskers showed some substructure (splitting of diffraction spots into doubletsin the nonequatorial reflections). It was found experimentally that the apparent simplicity of the equatorial layer spots is not a lattice property but is due to the geometry of the reflection itself. The structure of two kinked whiskers was also studied. In one case the kink occured as a continuation of the more perfect part of the crystal, in the other, a secondary crystal formation was the cause of the kinking.

傾角顕微鏡の金属結晶への二，三の応用例

A goniomicroscope, which permits measurements of directions of normals to facets with an area as small as 10×10 μ2, was applied to the determination of orientation of small grains of several metals and alloys and to crystallographic studies of surface planes of iron and zinc oxide whiskers and of twin bands on 3% silicon-iron. In order to determine orientations of small grains of metals, some new etchants were developed in order to produce uniformly distributed micropits, which consisted of some crystallographic facets with low indices. By measuring the normals to the facets of the micropits, the crystallographic orientation of the small region where the pits were embeded could be determined within the accuracy of 1 degree. Shapes of whiskers having prismatic flat surfaces were determined by the goniomicroscope and the orientations of the whisker crystals were also determined by an X-ray Laue technique. Side faces of square prismatic iron whiskers were found to be {100} planes and those of hexagonal prismatic zinc oxide whiskers were {1\bar100} planes. Surface serrations of twin bands on 3% silicon-iron were found to be composed of two sets of small facets; B1, B2 and C1, C2. Intersections of the specimen surface and one set of the small facets were parallel to {110} planes and intersections of twin band surface and another set of the small facets were parallel to {110} planes in the twin crystal.

SEVEN NEW HEXAGONAL POLYTYPES OF SILICON CARBIDE

A method for determining the hexagonal polytypes of silicon carbide using the Laue pattern is described. By the detailed studies on reciprocal lattice points of various hexagonal types xH of silicon carbide which are coalescent with 6H, 15R or 4H, the relations of the arrangement of their diffraction points has been derived. It is proved that there are twelve kinds of relation for the coalescence of xH with 6H, thirty for xH with 15R and eight for xH with 4H. The relations and the formulas which are given in this paper for the calculation of the numbers of hexagonal packed layers in unit cell of xH may be applied not only to the Laue technique but also to other x-ray techniques.A great number of single crystals of silicon carbide grown in laboratory by the sublimating procedure and of technical silicon carbide had been studied. Seven new hexagonal types 141H, 80H, 58H, 55H, 15H, 9H and 7H were found. The space group of all these new polytypes was determined to be C3m, and their lattice parameters c in the hexagonal cell are 355.26?, 201.57?, 146.14?, 138.58?, 37.794?, 22.676? and 17.637? respectively.

Application of a microfocus Laue technique to the study of deformation in aluminium single crystals

A microfocus Laue technique is applied to deformed single crystals; the criterion for resolution is discussed and a description is given of an indexing net and a method of measuring image distortions and magnifications. Images of kink bands and bands of secondary slip are shown and the formation of kink bands by rotation about a [211] axis is confirmed. Kink band images are shown to be caused by over-lapping images and not extinction effects at the low amounts of strain (1%) used.

Al単結晶の加工変形におけるX線的研究（その1）⟨111⟩極近傍方位を有する結晶の束状辷りに基く回転軸について

It has been found that cluster slips, uniform slips with deformation bands, or other slips would be formed by the different orientation of crystals. In the triangle of the stereographic projection, cluster slips are formed in the crystals 〈111〉 and uniform slips near the crystals 〈110〉 in the triangle. Much investigations on the rotation axis of a uniform slip in extended crystals have been reported, but few of them examined the crystals nearest to 〈111〉. In the present report, the rotation axes of cluster slips in the crystals oriented nearest to 〈111〉 were determined by the new X-ray Laue technique. There are two rotation axes in the crystals 〈111〉: the one is 〈121〉 which is normal to the slip direction on the primary slip plane, and the other is 〈111〉 which is normal to the primary slip plane. The rotation of 〈121〉 is responsible for kink bands in the cluster slip region, while the rotation of 〈111〉 seems to be responsible for the screw dislocations.