Deformation and Microstructure Evolution in Co-Ni-Cr-Mo Superalloy during Hot Working

Deformation and microstructure evolution in Co-33Ni-20Cr-10Mo superalloy during hot deformation are studied by carrying out compression tests between 950 A degrees C and 1200 A degrees C with an increment of 50 A degrees C at strain rates of 0.1, 1, 10, and 30 s(-1). The flow curves obtained for the aforementioned strain rates in this temperature range show that this alloy has high work-hardening characteristics; this is due to the strong dislocation-solute interactions associated with dynamic strain aging (DSA). Microstructures deformed at temperatures up to 1050 A degrees C consist of numerous deformation twins and highly dense dislocations, which are attributed to the high activation energy for deformation and the relatively low strain-rate sensitivity m in the temperature range of 950 A degrees C to 1200 A degrees C. Dynamic recrystallization (DRX), which is dependent on the strain rate, occurs at T = 1000 A degrees C, 1050 A degrees C, 1100 A degrees C, 1150 A degrees C, and 1200 A degrees C.