Abstract
A seriesofcandidatealumina-formingaustenitic(AFA)stainlesssteelsdesignedtoevaluatetheeffectsof
variationinAl,C,Cr,Mn,Nb,andNicontentonhigh-temperaturetensileproperties,creep,and
oxidation/corrosionresistancewerestudied.ThecompositionsassessedwerebasedonmediumNi
(20–25 wt%)andlowNi(12wt%)AFAvariationsstrengthenedprimarilybyMCand/orM23C6 carbide
precipitates,andahighNi(32wt%)AFAsuperalloyvariationstrengthenedprimarilyby γ′-Ni3Al
intermetallic precipitates.Tensileandcreeppropertiesweremeasuredat650and750/760 1C, oxidation
resistance from650to900 1C inairwithwatervaporandsteamenvironments,andsulfidation–oxidation
resistance inAr–20%H2–20%H2O–5% H2S at550and650 1C. Optimizedcompositionrangesfordifferent
use temperaturesrangesbasedontheseevaluationsarepresented.
