Papers by Author: L. Ilucová

Abstract: The grain structure of pure aluminium processed by equal channel angular pressing (ECAP) was examined electron backscattered diffraction (EBSD) in the as pressed state and after heating preceding the creep deformation using various stereological methods. Area intensities of grain and subgrain boundaries, length intensities of triple grain and subgrain junctions, structural homogeneity and its thermal stability are strictly dependent on the number of passes.

Abstract: The effect of ECAP technology on the subgrain structure of coarse-grained pure aluminium is described by means of the orientation imaging microscopy (the selected lower bounds of misorientation (disclination) are
= 2o, 5o, 10o and 15o). Standard profile and intercept counts carried out in three suitably oriented and mutually perpendicular section planes and along 18 systematically oriented directions, resp., are used to examine the subgrain and grain structures after the number of passes N = 2, 4, 8, 12 as well the effect of subsequent annealing (several hours at 473K). The local and overall non-homogeneity and anisotropy of boundary structures have also been evaluated.

Abstract: Considerable structural inhomogeneity and anisotropy were found even after eight ECAP passes in high purity aluminium and the creep loading of ECAP material at 473K, 15MPa resulted in scattered fracture times ~ 20-60 hours. The structure revealed by orientation imaging microscopy with different disclination bounds was analysed by stereological methods. The effect of inhomogeneity and grain orientation on the creep fracture time was assessed.

Abstract: High purity (99.99%) pure aluminium processed by equal channel angular pressing (ECAP) was examined in terms of the ECAP microstructure inhomogeneity and its creep behaviour. The results indicate that an inhomogeneity of the ECAP microstructure in mesoscopic scale may influence the creep behaviour of the pressed material.