Determination of dynamic recrystallization parameter domains of Ni80A superalloy by enhanced processing maps

The determination of intrinsic deformation parameters inducing grain refinement mechanism of dynamic recrystallization (DRX) contributes to the relative forming process design. For Ni80A superalloy, the processing maps were constructed by the derivation of the stress-strain data coming from a series of isothermal compression tests at temperatures of 1273-1473 K and strain rates of 0.01-10 s(-1). According to the processing maps and microstructural validation, the deformation parameter windows with DRX mechanism were separated in an innovative deformation mechanism map. In addition, the deformation activation energy representing deformation energy barrier was introduced to further optimize such windows. Finally, the enhanced processing maps were constructed and the parameter domains corresponding to DRX mechanism and lower deformation barrier were determined as follows: at epsilon=0.3, domains: 1296-1350 K, 0.056-0.32 s(-1) and 1350-1375 K, 0.035-0.11 s(-1); at epsilon=0.5, domains: 1290-1348 K, 0.2-0.5 s(-1) and 1305-1370 K, 0.035-0.2 s(-1); at epsilon=0.7, domains: 1290-1355 K, 0.042-0.26 s(-1); at epsilon=0.9, domains: 1298-1348 K, 0.037-0.224 s(-1).