Modeling Grain Size and Strain Rate in Linear Friction Welded Waspaloy

The high-temperature deformation behavior of the Ni-base superalloy, Waspaloy, using uniaxial isothermal compression testing was investigated at temperatures above the gamma' solvus, 1333 K, 1373 K, and 1413 K (1060 A degrees C, 1100 A degrees C, and 1140 A degrees C) for constant true strain rates of 0.001, 0.01, 0.1, and 1 s(-1) and up to a true strain of 0.83. Flow softening and microstructural investigation indicated that dynamic recrystallization took place during deformation. For the investigated conditions, the strain rate sensitivity factor and the activation energy of hot deformation were 0.199 and 462 kJ/mol, respectively. Constitutive equations relating the dynamic recrystallized grain size to the deformation temperature and strain rate were developed and used to predict the grain size and strain rate in linear friction-welded (LFWed) Waspaloy. The predictions were validated against experimental findings and data reported in the literature. It was found that the equations can reliably predict the grain size of LFWed Waspaloy. Furthermore, the estimated strain rate was in agreement with finite element modeling data reported in the literature. (C) The Minerals, Metals & Materials Society and ASM International 2013