Mc. Somani et al., MICROSTRUCTURAL VALIDATION OF PROCESSING MAPS USING THE HOT EXTRUSIONOF P M NIMONIC AP-1 SUPERALLOY/, Journal of materials processing technology, 52(2-4), 1995, pp. 225-237
The microstructural features of hot-extruded Nimonic AP-1 superalloy p
owder are presented in this paper. Experiments have been designed to v
alidate the processing maps of Nimonic AP-1 microstructurally using a
commercial extrusion process, The time average mean strain rate, epsil
on(i), has been used as the basis for selection of the extrusion param
eter viz., ram speed and extrusion ratio, Extrusion was conducted unde
r non-isothermal conditions. The microstructural evaluation of the mat
erial extruded in the dynamic recrystallization (DRX) domain of the pr
ocessing map exhibited homogeneous deformation and a recrystallized st
ructure, free from cracks and shear bands. Adiabatic shear bands and i
nter-crystalline cracks seen in the microstructures of other extruded
products have been correlated accurately with the instability and crac
king regimes of the processing map.