A New Method of X-Ray Stress Measurement of Single Crystals
Yuji SAITO, Masanori KURITA and Hitoshi ISHII
Abstract:An x-ray stress measuring method for a single crystal is proposed. This method can be applied to a orthorhombic single crystal having x, y and z crystal symmetry planes, the x-y plane being the specimen surface. In the plane stress state, residual stresses ƒÐ0x and ƒÐ0y can be determined using slopes M and M' of sin2ƒÕ diagrams for the x and y measurement directions. Various stresses ƒÐa were applied to a silicon single crystal wafer specimen in longitudinal (x) direction using a four points bending loading device, and the peak positions of different diffraction planes were measured in the x and y directions by x-ray diffraction method. The measured peak positions of diffraction planes were plotted in the sin2ƒÕ diagram for various applied stresses ƒÐa. Although the peak positions of different planes in the sin2ƒÕ diagram deviated from the straight lines determined by the least squares method, the straight lines crossed at a point, and the slopes and intercepts of the straight lines varied linearly with the applied stress ƒÐa. The peak positions for a fixed ƒÕ angle varied proportionally to the applied stress ƒÐa, and the measured proportionality constants ki and k'i in the x and y directions, respectively, almost agreed with the theoretical values. Key Words:Residual stress, Experimental stress analysis, Elasticity, Nondestructive inspection, Stress analysis, Single crystals, X-ray stress measurement, X-ray diffraction