CONSTITUTION OF NICRALFE ALLOYS

Ferritic ODS-Fe-base alloys exhibit excellent hot gas corrosion resist ance. Compared with ODS-Ni-base alloys, their high temperature strengt hs are low. On the other hand, the resistance of Ni-base alloys agains t hot temperature corrosion is small compared with ODS-Fe-base alloys. Development of NiCrFe-base alloys yields a material, which combines t he high temperature corrosion resistance of ferritic ODS-Fe-base alloy s and the excellent high temperature strength of ODS-Ni-base alloys. T he NiCrFe alloy must exhibit a f.c.c. matrix, to guarantee sufficient high temperature strength. Because Al, which is added to improve hot g as attack resistance, acts as a ferrite resp. aluminide former in NiCr Fe-alloys the constitution of NiCrAlFe-alloys was investigated. Influe nces of Co, Mo and W on the constitution will be discussed. The NiCrAl Fe-alloys were moreover characterized by measurements of tensile prope rties, the resistance of selected ODS-NiCr-FeAl alloys to hot gas atta ck was tested by annealing treatments at 1100-degrees-C at air.