抄録
The early stages of decomposition of the supersaturated (α″) phase which was obtained on quenching a Ti-1.6 at%N alloy have been found to be associated with characteristic microstructural features. The tetragonally ordered α′ phase formed from α″ by continuous ordering, transforms to incoherent Ti2N precipitates, on ageing in the temperature range 323–673 K. While no perceptible growth of homogeneously transformed α′ phase was observed in the matrix, lath boundary precipitation of α′/Ti2N was found to take place during low temperature ageing (T≤373 K). On ageing at high temperature (T>373 K) both matrix and lath boundary precipitation of Ti2N occurred uniformly by the nucleation and growth process. The microstructural features observed during α′→Ti2N provide evidence for the predominance of continuous ordering at lower temperatures and the nucleation and growth process at higher temperatures.
