Dynamic recrystallization during hot deformation of GH690 alloy: A study using processing maps

The hot deformation behavior of GH690 alloy is investigated in the temperature range of 950-1200 °C and a strain rate of 10−3s−1 to 2 s−1. It is found that the flow stress increases with strain, and then decreases as it reaches a peak flow stress. On the basis of the experiment data, processing maps are developed using the dynamic materials model (DMM). The processing maps exhibit two domains. One is the stable region occurring in the temperature range of 1120-1180 °C and the strain rate of 0.0325-0.447 s−1, the other is the instability zone occurring in the temperature range of 950-1180 °C and the strain rate of 0.18-2 s−1. Under the guidance of the processing maps, a rolling experiment is carried out, and it is found that the yield strength, ultimate tensile strength and elongation of the plate are 565 MPa, 685 MPa and 51.13% respectively.