Hot working behavior of Fe–29Ni–17Co analyzed by mechanical testing and processing map

Abstract

The hot workability of Fe–29Ni–17Co was analyzed using hot compression tests over temperature range of 900–1200°C and at strain rates of 0.001s−1 to 10s−1. In order to analyze the hot ductility behavior of the material, hot tensile tests were performed at the same temperature range and strain rate of 0.1s−1. The flow curves at temperatures higher than 1000°C were typical of dynamic recrystallization, while at lower temperatures work hardening was more dominant. The strain rate sensitivity parameter increased considerably with increasing temperature and the corresponding influence of strain rate was found negligible. The power dissipation and the instability maps of the studied material were developed based on the dynamic material model. From the developed processing map of the material, better workability at temperatures beyond 1000°C was elicited. Hot tensile tests reported a hot ductility trough over the range of 1100–1150°C. It contributed to a slight decrease in the reduction in area and strain to fracture. Despite the influence of hot ductility trough, mechanical testing and microstructural observations emphasized the better workability of the studied material at temperature range of 1000–1200°C and the studied strain rates.