An X-ray study of the structure distortion of nickel stretched at normal and elevated temperatures

Small-angle scattering is applied to N-1 nickel after extension at room temperature and 600 °C; large-angle scattering is also used. Block sizes and lattice distortions are deduced by harmonic analysis of the shape of the (420) line. The small-angle scattering is interpreted in terms of double Bragg reflections, whose intensity is very sensitive to block disorientation. Room-temperature deformation increases the disorientation angle, but the increase at 600 °C is only slight and occurs only in the initial stage of creep. Microdistortion and block fragmentation occur most extensively in the initial stage. Block fragmentation occurs at high creep rates at 600 ° C, but some block growth occurs at lower rates. The microdistortion is only slightly increased by creep.