Microstructure and High Temperature Mechanical Properties of Inconel 617

摘要

Inconel 617 is a candidate tube material for high temperature gas-cooled reactors (HTGR). The microstructure and mechanical properties of Inconel 617 were studied after exposure at high temperature of 1050℃. The dominant oxide layer was Cr-oxide. The internal oxide and Cr-depleted region were observed below the Cr-oxide layer. The major second phases are M_(23)C_6 and M_6C types of carbides. The composition of M_(23)C_6 and M_6C were determined to be Cr_(21)Mo_2C_6 and Mo_3Cr_2(Ni,Co)_1C, respectively, by EDS. These carbides are coarsened during exposure. M_6C carbide is more stable than M_(23)C_6 at high temperature. There was not much change in mechanical properties after exposure at 1050℃ for 1000 h.