DEVELOPMENT AND CHARACTERIZATION OF FE-BASED ODS SUPERALLOY FOR HIGH TEMPERATURE APPLICATION

Abstract

Super alloys are metallic materials which exhibit high heat resistance even at temperatures of up to 90% of their absolute melting point. This is normally achieved by the combined hardening effect of carbides & rare earth oxides (mainly) in Iron (Fe) based super alloys. Oxide Dispersion Strengthened (ODS) alloys are manufactured by mechanical alloying (MA) techniques. This results in alloy powders of extremely fine grained structure, in which the dispersion fine particles are responsible for boosting the strength of materials in high temperature applications like jet turbine, aircraft turbine, furnace heating elements, etc. The alloying elements themselves are distributed very uniformly & homogeneously. The main advantage of powder forging process is the use of cost effective indigenously available raw materials, like iron instead of extrusion process where high purity powders atomized with argon gas, which is used in many leading ODS manufactures, like M/s INCO ALLOYS, USA. The aim of the present work is to develop ferritic ODS alloys through powder forging route economically & to compare its oxidation at 1100°C & corrosion behavior in 40% Na2-SO4+60% V205 at 900°C with MA 956, superfer 800H alloys. The alloy composition of the present work is Cr -22 % (In the form of Ferrochrome) Al -5.5% Y203 -0.5 % (In the form of Yttrium oxalate) Fe -72 % (Balance)