Internal nitridation during creep of IN617 superalloy
Yue Wang, Qu Liu, Kejian Li, Zhipeng Cai, Li Shi, Haitao Wang, Haitao Wang
Abstract
Internal nitridation of IN617 was investigated during creep rupture at 1000 °C. The results indicated that internal nitridation seriously deteriorated creep properties. Various nitrides including π phase, AlN , Cr 2 N and TiN were found. Stable AlN and TiN precipitated inside grains and distributed widely. Less stable π phase and Cr 2 N only precipitated at the high-energy boundaries with sufficient N and Cr concentrations. Nitridation occurred all over the cross-section (8.9 mm thick) near the fracture surface of the creep specimen ruptured under 16 MPa. It suggested that creep aggravated internal nitridation because of providing continuous crack paths for nitrogen penetration.