Strain Measurements on Single Crystals and Macrograins with the Aid of an Automated Phi-Psi Goniometer

Abstract

A back reflection goniometer with possibilities of Φ and Ψ rotations of the specimen was developed for stress-strain analysis in single crystals and macrograins and was completely automated. A computer software in PASCAL language was developed. The system is capable of i) optimising the Φ, Ψ and 2θ positions for a reflection, ii) scanning all the specified reflections one after another, iii) determining the lattice spacings after applying suitable corrections to the intensity data and iv) correcting the lattice spacings for temperature variations. Experimental results of measurements on an aluminum single crystal in annealed and plastically deformed conditions are presented to indicate the speed, reproducibility and accuracy of measurements. Principal sources of errors and their control in the developed system are discussed.