Heterogeneous deformation of a two phase nickel – tungsten alloy

The pattern of co-deformation of micrometre sized W particles in a spherodised Ni - W alloy has been studied in a series of plane strain deformed specimens. The microstructural changes were characterised by optical microscopy, SEM and TEM. A pronounced heterogeneity was found in the strains sustained by the particles, with some particles remaining equiaxed at high imposed strains while others sustained strains equal to the imposed strain. Two factors were shown to be important in this behaviour: the spacing of the slip bands in the matrix relative to the spacing and the size of the particles, and the heterogeneous distribution of W particles in the starting microstructure. The results of plane strain deformation have been compared with those reported for wire drawing of two phase structures.