Characterization of hot compression behavior of a new HIPed nickel-based P/M superalloy using processing maps

摘要

Isothermal forging was a critical step process to fabricate the high-performance nickel-based superalloy. The temperature and strain rate served the most critical role in determining its microstructure and mechanical properties. In this article, we employed the hot compression to simulate the isothermal forging process upon the temperature ranging from 1000 ℃ to 1100 ℃ in combination with a strain rate of 0.001-1.0 s~(-1) for a new P/M nickel-based alloy. The activation energy was determined as 903.58 kJ/mol and the processing maps at a strain range of 0.4-0.7 were developed. The instability domains were more inclined to occur at strain rates higher than 0.1 s~(-1) and manifested in the form of adiabatic shear bands. The map further demonstrated that the regions with peak efficiency of 55% were located at 1080℃/0.0015 s~(-1) and 1095℃/0.014 s~(-1) respectively. Obvious dynamic re-crystallization could be detected at the strain rate 0.01 s~(-1) leading to a significant flow stress drop and the grain growth was remarkably triggered under 1100 ℃ The findings can shed light on the forging processing optimization of the new nickel-based superalloy.