Characterization of the workability of Ni-Fe-Mo alloy by complex processing maps

The hot compressive deformation behaviour of Ni-Fe-Mo alloy was investigated over a wide range of forming temperature and strain rate. The analysis was based on uniaxial compression tests performed on Gleeble 3800 thermomechanical simulation in the temperature range of 900-1150 degrees C and at strain rates ranging from 0.01 to 100 s(-1), for constant value of true strain of 0.9. Processing maps were generated basing on the Dynamic Material Model (DMM). Additionally, the complex processing map, combining both processing parameters and microstructural changes in the investigated alloy, was presented. The processing maps at different strains were also elaborated for determining the evolution of the areas of processing instability due to nonuniform strain distribution in the volume of forged parts. According to the processing map (complex map) and microstructural observation, the optimal processing parameters were chosen and it was proven to be accurate and effective through the experimental results obtained in industrial conditions. Moreover, the correctness of determined parameters of thermomechanical processing of the investigated alloy was verified by the analysis of the microstructure of the forged part obtained in industrial conditions. (C) 2019 Published by Elsevier B.V.