Characterization of Hot Deformation Behavior of Hastelloy C-276 Using Constitutive Equation and Processing Map

Abstract

In order to clarify the microstructural evolution and workability of Hastelloy C-276 during hot forming to get excellent mechanical properties, the hot deformation behavior of this superalloy is characterized. The cylindrical specimens were isothermal compressed in the temperature range of 1000-1200°C and strain rate range of 0.001-5 s 21 on a Gleeble 1500 thermal-mechanical simulator. The flow curves and microstructural investigation indicates that dynamic recrystallization is the prime softening mechanism at the evaluated deformation conditions. The constitutive equation was presented as a function of the deformation temperature, strain rate, and strain, and the deformation activation energy was about 450 kJ/mol. The processing maps based on dynamic materials model at the strains of 0.2, 0.4, 0.6, 0.8, and 1.0 were established, and the processing map at 1.0 strain shows good correspondence to the microstructural observation. The domains in processing map in which the efficiency of power dissipation (g) is higher than 0.25 are corresponding to sufficient dynamic recyrstallization phenomenon, which are suggested to be the optimum working areas for Hastelloy C-276.

Characterization of hot deformation behavior of GH925 superalloy using constitutive equation, processing map and microstructure observation

“…At high temperature and low strain rate, i.e., 1200 C and 0.01 s À1 , the growth of recrystallized grains would decrease the h value. This phenomenon is similar with previous researches [10,31] about the superalloys. In the deformation area with high temperature and low strain rate, the h value for superalloys is general low because of the growth of recrystallized grains, weakening the fining effects of DRX [10].…”

“…This phenomenon is similar with previous researches [10,31] about the superalloys. In the deformation area with high temperature and low strain rate, the h value for superalloys is general low because of the growth of recrystallized grains, weakening the fining effects of DRX [10]. Furthermore, DRX or full recrystallization does not occur under the deformation condition of low temperature and high strain rate.…”

“…In recent years, the processing map based on dynamic materials model (DMM) is considered to be an important model for optimizing hot working processes and controlling microstructure in the forming process [10,11]. Based on processing maps, the deformation mechanisms under different deformation condition can be predicted, then deformation temperature and strain rate corresponding to local peak efficiency of power dissipation were chosen as the optimum processing parameters for hot working of materials [12,13].…”

The Kinetics of Metadynamic Recrystallization in a Ni-Cr-Mo-Based Superalloy Hastelloy C-276

“…Due to the low stacking fault energy (SFE) preserving in Hastelloy C-276, dynamic recrystallization (DRX) is likely to occur during deformation at temperature higher than 0.5T m (Ref 13,14). When deformation is interrupted at high temperature, the recrystallized grains would continue to grow.…”

Investigation on Hot Deformation Behavior and Hot Processing Map of BSTMUF601 Super-Alloy

“…The flow stress is the most basic parameter for characterizing plastic deformation properties of metals and alloys, and it determines the load and energy needed during the plastic deformation [4]. In recent years, the processing map based on the dynamic materials model (DMM) has been considered an important method for optimizing hot working processes and controlling the microstructure in the forming process [5,6]. Based on the processing map, the deformation mechanisms under different deformation conditions can be Metals 2016, 6, 70 2 of 8 predicted, and then the deformation temperature and strain rate corresponding to the local peak efficiency of power dissipation are chosen as the optimum processing parameters for the hot working of materials [7,8].…”