Mechanical properties and recrystallisation behaviour of Fe base ODS alloys

Developments in higher temperature exchangers and other applications require high strength as well as oxidation resistance at very high temperature. In order to meet such requirements, Dour Metal has developed ODM new range of oxide dispersion strengthened (ODS) iron base alloys realised by powder mechanical alloying. Compositional and thermomechanical manipulations can be used to develop the structure enabling the service temperature to be increased up to about 1200°C. An optimization of the structure is required to obtain the best high temperature creep resistance. This consist in minimizing the grain densities and the misorientation between adjoining grains. The paper will discuss some results on evolution of the texture during different thermomechanical treatments on ODS Fe base tubes. Typical rupture strength will be presented for temperature ranging from 900 to 1100°C. The emphasis will be given to alloy ODM 751 which most recent work has been performed.