Published online by Cambridge University Press: 22 February 2011
The Co3Ti phase hardens appreciably by the fine precipitation of disordered fee Co-rich phase upon aging after quenching from solution annealing temperature. Transmission electron microscope(TEM) observations revealed that the precipitates are platelet in shape, lying nearly parallel to the {100} planes of the L12-ordered matrix, and perfectly coherent with the matrix lattice at the beginning of aging. The high temperature strength increases appreciably with the fine precipitation of disordered Co-rich phase over the whole temperature range investigated. TEM observations of the underaged and deformed alloys revealed that superdislocations are pinned by precipitates indicating an attractive interaction between dislocations and precipitates. At the overaged state, thin twins are introduced in the fee Co-rich precipitates during deformation.