The Microstructure Degradation of the IN 713C Nickel-Based Superalloy After the Stress Rupture Tests

The aim of the work was to examine the degradation phenomena taking place in the microstructure of the as-cast IN 713C superalloy after stress rupture tests, performed at T = 980 °C under a tensile stress of 150 MPa. A directional growth of γ′ phase (rafting) and decomposition of the NbC primary carbides accompanied by the precipitation of M23C6 secondary carbides rich in chromium and of γ′ phase were observed. It was also indicated that the decomposition of the NbC primary carbides may be accompanied by the precipitation of M3B2 borides rich in Mo.