Effect of Solution Temperature on the Microstructure and Mechanical Properties of Nickel Based Alloy CN 617

Microstructure and strength of Ni-based alloy CN 617 after solution annealing temperature of 1125°C to 1200°C for 1 h followed by water cooling have been experimentally investigated by means of optical microscope, scanning electron microscope and transmission electron microscopy. The results show that the strength of CN 617 is inversely proportional to solution annealing temperature. The change of room temperature strength with increasing solution annealing temperature can be contributed to the total contribution of solution hardening, carbide hardening and grain boundaries strengthening. With increasing the solution annealing temperature from 1125°C to 1200°C, the average grain size increases from 31 μm to 200 μm. The dislocation density decreases from 19 ×1013/m2 to 1.4 ×1013/m2. The volume fraction and size of primary carbide also dramatically decrease.