A lecture given by Carlos Capdevila Montes, at the Adventures in the Physical Metallurgy of Steels (APMS) conference held in Cambridge University. About oxide dispersion strengthened, mechanically alloyed steel. In order to meet future energy demands, new materials will be required to withstand extreme environments. Ferritic FeCr(Al) oxide dispersion strengthened (ODS) steels are an example of engineered steel composite that have excellent potential for use in next-generation high-temperature applications where superior creep strength and oxidation resistance is paramount. Originally designed as heat resistant steels for conventional fossil-fuel power plants, the high-Cr ODS steels are a successful example of development to overcome the issues to meet material requirements for next generation nuclear systems. In order to maintain mechanical properties under harsh conditions, i.e., combination of cyclic thermal loads, exposure to highly corrosive environments, and a hard and intense mixed proton/neutron fields, to the end of life of a component in a nuclear reactor, a highly stable microstructure is essential. Nanostructured ferritic FeCr(Al) ODS steels are ideal candidates for those applications, because these alloys usually contain a high density of Y/Al-rich and Ti/Al- rich nanoparticles, high dislocation densities and fine grains. As it is reported here, the presence of nanoscale, uniformly dispersed oxide particles act as pinning points to inhibit dislocation movement, retard recovery and recrystallization processes.