Pole Figure Data Research Articles

Cathode ray tube display of automatically recorded pole figure data

A storage oscilloscope has been attached to the IBM 1800 computer that is used for pole-figure data acquisition. It allows fast plotting of pole figures by modulation of the cathode ray beam according to the pole density as it scans the stereographic projection along a spiral path. The time needed to plot the pole figure is reduced by a factor of eight as compared with a mechanical plotter.

An X-ray diffractometry technique for preferred orientation studies in rocks

An X-ray diffractometry technique is described for determining the pole-figure data of certain crystal planes belonging to a particular mineral in a rock. Various factors affecting recorded intensities are discussed. The method was used for determining the orientation pattern of the (001) planes of 10Å micaceous minerals in shale and mudstone. The results obtained indicated a preferred orientation of these planes in both the shale and the mudstone. A summarized review of previous work on preferred orientation studies using X-ray counting techniques is also given.

Effect of texture, grain size, and cold work on the precipitation of oriented hydrides in Zircaloy tubing and plate

The effects of texture, grain size and cold work on the precipitation of oriented hydrides in Zircaloy tubing and plate have been investigated. Hydride orientations were measured in samples cooled under no applied stress and also under a tensile stress of 20 000 psi. In the former samples, the orientations were found to correlate with crystallographic texture as characterized by inverse pole figure data. In the stressed samples, the stress produced a change in hydride orientation which was related more to grain size and degree of residual cold work.

Technique for Preparing Laminated Pole Figure Samples

A new method is described for making composite samples for the x-ray diffraction, back reflection pole figure technique. Considerable savings, in material and machining costs, are realized by cutting strips, for lamination, at 45° to the rolling direction. The required reference surface is obtained, during lamination, by maintaining an angle of 54.7° between the strips and the surface developed by the cut edges. The advantages of the composite technique (better averaging, minimization of errors, and evaluation of random intensity from the pole figure data) are retained by this modification.

Orientation in cold‐rolled polypropylene

AbstractSheets of isotactic polypropylene were prepared to have initially random orientation and were subsequently rolled at temperatures below the crystalline melting point. Their crystal orientation was investigated. The orientation of the c axis (fiber axis) was determined from pole figure data obtained by x‐ray diffraction. It was found that rolling produced orientation of the c axis in two preferred directions in the plane defined by the rolling direction and the normal to the sheet. These two directions made equal angles of inclination with the rolling direction. With increased severity of rolling the component of the orientation vector in the rolling direction increased and the angles between the preferred c axis orientation and the rolling direction decreased. Increasing the temperature reduced the angle of inclination of the preferred c axis orientation. This double c axis orientation was not observed in extruded film. An explanation of the c axis orientation in cold‐rolled polypropylene is offered on the basis of local necking down within the sample during the deformation.

Recent Developments in the Measurement of Orientation in Polymers by X-Ray Diffraction

AbstractFrom pole figure data, the orientation of a crystallographic direction R in any reference direction Q in a sample can be quantitatively expressed by the average <cos2σ>, where σ is the angle between Q and R in a crystal. In general, <cos2σ> can be evaluated in terms of the experimental averages <cos2ϕhkl> whereϕhkl is the angle between Q and the normal to the (hkl) planes. The number of independent <cos2ϕhkl> measurements needed varies from one to five depending on the crystal system, hkl indices, and other factors discussed. Experimental techniques found useful for measuring <cos2φ> are described.

Spurious Areas in Pole Figures

Spurious maxima are frequently observed in pole figures determined by x-ray diffraction techniques employing the Geiger-counter spectrogoniometer. Their origin must be fully understood in order to avoid misleading interpretations of the pole-figure data. By making film patterns and by the balanced filter technique—in each case with the specimen oriented for the appearance of one of the spurious peaks—these spurious maxima can be identified as diffraction of a component from the white radiation by a strongly diffracting (hkl) plane, and at a 2θ angle corresponding to Ka diffraction from the (hkl) plane under investigation. Spurious (110) and (112) peaks of this type may be observed in the (200) pole figure of iron and its alloys; spurious (111) and (220) peaks may appear in the (200) pole figure of face-centered-cubic metals such as nickel. These cannot be completely suppressed by filtering the Mo radiation used or by modifying the operating conditions such as tube voltage, spectrometer resolution, or counter type. Spurious (101̄1) peaks may appear in the (0002) pole figure of titanium and zirconium as the result of CuKa diffraction, and they can be avoided by increasing the resolution of the slit system.

Automatic Pole Figure Recorder

A device has been developed for the direct recording in stereographic projections of pole figure data as they are supplied from a Geiger counter x-ray diffraction apparatus. The specimen is rotated systematically in a suitable goniometer about two axes in synchronism with movements of the chart and printer on the recorder. When the diffracted intensity attains any one of seven preset levels, the printer impresses a point of corresponding color on the chart. The point is printed at the location that has the stereographic co-ordinates of the pole of the diffracting volume. After all possible orientations of the specimen have been explored, an array of colored points will have been obtained on the chart. When contour lines are sketched through points of like color, the usual pole figure with iso-intensity lines is obtained.

Recrystallization of a Cold-Rolled Copper Single Crystal

Based on pole figure data and microstructural observations, the recrystallization orientation found in a copper strip previously cold-rolled 99.5 pet from a single crystal with an initial (110) [112] orientation may be described as: a 30° rotation, clockwise and counterclockwise, about octahedral poles of the cold-rolled texture such that ail four poles function at a low annealing temperature (400°C) and only three of them function at high temperatures (500° to 1050°C). The relative inrensity of deformation stresses on various slip planes can be correlated with the choice of poles affecting the rotations found in the recrystallized orientations.