A SIMPLE METHOD FOR DETERMINING ORIENTATION AND MISORIENTATION OF THE CUBIC-CRYSTAL SPECIMEN

With the aid of a double-tilt holder, a simple method for determining orientation and misorientation of a cubic crystal specimen in a transmission electron microscope is developed. To use this method, a recognizable zone axis from one grain needs to be aligned along the beam direction, the corresponding tilt positions (alpha(0), beta(0)) of the two rotation axes must be obtained from the meter reading of the holder and the rotation position of the Kikuchi pattern around the beam direction must be measured on the fluorescent screen with the aid of apparatus for the direct measurement of a diffraction-pattern position on screen. After the input of (alpha(0), beta(0)) and the rotation positions, the orientation of the grain can be calculated using a computer program. The misorientation matrix R, rotation angle Theta(m), axis l(m) and sense can then be calculated for any selected set of two grains. The accuracy of determination of the orientation of any particular grain is about 1 degrees and, in the case of the determination of misorientation angles between two grains within a sample, the precision is within 0.1 degrees. This method is considered to be much simpler and more rapid than previous methods because no photographs of Kikuchi patterns need to be taken and only one zone-axis orientation needs to be adjusted along the beam direction.