As can be seen there are numerous defects and strains present within the substrate, as indicated by the extreme variations in the diffracted intensity of the x-ray beam. A typical topograph of one of the smaller diameter silicon carbide substrates is shown in Figure 5 (b). The samples were then analyzed in the ACT system. Third substrate was 4 cm in diameter and had a crystallographic orientation of approximately 16 ° off the. Transmission Laue diffraction analysis is limited to thin specimens (in general, mt. The x-ray source is collimated (usually with a pin-hole collimator) and then incident upon the sample when the transmission configuration is used, or through a hole in a film followed by the sample when the back-reflection configuration is used. In the Laue method, a continuous (white radiation) x-ray source is utilized. In some instances, the nature and degree of crystalline perfection is of little significance to the performance of the material, however, in many industrial applications the crystalline perfection is critical.Ĭonventional methods for examination of single crystal specimens rely on the Laue technique of x-ray diffraction whereby patterns of individual spots (reflections) are obtained from individual planes. That is, is the material single crystalline or polycrystalline, deformed or "strain free", populated with imperfections or low in defects. While radiography provides valuable information as to density variations within a given material, it does not provide information as to the crystalline nature of the material. In the nondestructive testing field when the word x-ray is mentioned, the concept of radiography immediately comes to mind. Key Words: Single crystal Topography X-ray diffraction Turbine blade Quartz Silicon carbide INTRODUCTION One technique which has proven to be useful in a variety of single crystal inspection applications is x-ray diffraction topography.This paper describes the details of an x-ray diffraction topographic system which was used and shows topographic images illustrating the utility of the system as applied to nickel based alloy, turbine blades, quartz resonators, and silicon carbides substrates. Because the quality assurance requirements for one industry are not necessarily those of another, a characterization technique which can be tailored to the needs of a particular industry is desirable. From the microelectronics industry which uses silicon and gallium arsenide single crystal substrates in integrated circuit production, to the aerospace and power generation industries which are producing single crystal, nickel based alloy, turbine blades, there is a need to fully characterize these materials. Single crystal materials are finding more use in industrial applications everyday. Methods and Instrumentation Practical Application of X-Ray Diffraction Imaging. ![]() Practical Application of X-Ray Diffraction Imaging
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