Abstract
The precipitation of faulted γ′ has been observed at dislocations introduced by deformation before ageing in austenitic steels with high Ti:A1 ratios. The dislocation reaction was identified by electron contrast analysis. It is proposed that co-nucleation of the ordered L12 γ′ phase and the DO24 η phase occurs upon matrix stacking faults. The strong dislocation pinning thus produced may provide a mechanism for further increasing alloy strength.