Alloy 602 CA is a M23C6 carbides strengthened Nickel-based superalloy. In this alloy, M23C6 is different from that found in other superalloys because of its high volume fraction, wide size distribution and distinct precipitation locations. To investigate M23C6 evolution behaviors during hot deformation in Alloy 602 CA, a series of tests are carried out in this study. The test temperature ranges from 900 to 1100 °C and strain rate ranges from 0.001 to 0.1 s−1, with a true strain of 0.7. It is found that hot deformation of the material decreases the distance between carbides which leads merging happening to change the morphology of primary M23C6. Secondary carbides mainly come from the dissolution of large primary carbides and precipitate along grain boundaries and twin boundaries which impede dynamic recrystallization (DRX) from happening. Volume fractions of M23C6 decrease from 900 to 1100 °C. At 900 °C and 1100 °C, the precipitation equilibrium is reached in the preheating period before hot deformation and deformation only change the size distribution of carbides. 1000 °C is a transition temperature where the volume fraction decreases as strain rate increases. The temperature rise initiated by adiabatic heating has a great influence on this precipitation behavior.
Graphical Abstract