LOCAL LATTICE ROTATIONS AT 2ND PHASE PARTICLES IN DEFORMED METALS

An experimental investigation of local lattice rotations at non-deformable second phase particles in the size range 0.02 to 5 μm in aluminium and copper single crystals deformed to tensile strains of up to 0.5 is reported. A TEM method in which the misoriented regions are imaged in dark field as the specimen is accurately tilted has been used, and the results have been confirmed by standard X-ray and electron diffraction techniques. The region of maximum misorientation, close to the particle, is rotated about the roller axis [121] with respect to the matrix. For particles larger than ~ 2 μm, the misorientation increases linearly with shear strain, and values of up to ~ 45° have been measured. The misorientation for a given strain decreases with decreasing particle size, being very small for particles of diameter less than ~ 0.1 μm. These results, together with previous work, are used to assess the importance of the various deformation mechanisms at particles, over a wide range of strains and particle sizes. © 1979.