Effect Of Grain Refinement On High Temperature Oxidation Behavior And Mechanical Property Of Inconel 617

Abstract

Ni-base superalloys are used for the high temperature applications such as turbine blades, structural materials for nuclear reactors. Inconel 617 is a candidate material for high temperature gas-cooled reactors (HTGR). In this research, the grain refined Inconel 617 specimen with 50% of cold rolled was obtained to evaluate the high-temperature oxidation behavior. The microstructure and mechanical properties of Inconel 617 were studied after exposure at high temperature of 950oC in air and helium environments. Component and distribution of elements formed by high temperature thermal oxidation test was analyzed by electron probe microscopy analyzer (EPMA). The Cr depleted zone formed in matrix by the internal oxide layer (Al2O3) and external oxide layer (Cr2O3) was observed through secondary electron microscopy (SEM). Also, Vicker`s hardness of the specimen after high-temperature thermal oxidation test was measured to evaluate the mechanical properties. The depth of internal oxide layer of the specimen recrystallized at 1050oC and subsequently thermally oxidized at 950oC for 480hrs in helium atmosphere was decreased and the mechanical property was improved.