| Popis: |
The structural phase transition of gamma -Fe precipitates in a Cu matrix is studied using the X-ray diffraction technique. At low temperature, the FCC lattice uniformly contracts along the c axis by 0.17%. In the c plane the mean value of the lattice spacing expands by 0.19%, but the atomic positions are modulated by a sinusoidal wave propagating along the (110) direction with the (110) polarisation vector. Various properties of the periodic lattice wave (PLW) are studied. The wavelength and amplitude of the PLW depend on the size of the precipitates. The origins of the PLW and the size effects are discussed. |
