High-temperature flow behavior and processing map of Inconel 625 alloy under electric heating

Isothermal tensile tests of Inconel 625 were conducted over a wide temperature range (1173-1373 K) and strain rate domain (0.001-0.1 s -1 ) using a self-built electric heating tensile testing platform. The flow stress behavior and microstructural evolution under varying deformation conditions were systematically investigated, along with optimization of processing parameters. A strain-compensated Arrhenius constitutive model was established, demonstrating high predictive accuracy validated by a correlation coefficient (R = 0.9901) and an average absolute relative error (AARE=5.75%). Based on the dynamic materials model (DMM) theory, hot processing maps were constructed, revealing that flow instability primarily occurs in regions of low temperature and high strain rates. At a true strain of 0.2, the optimal processing windows were identified within two domains: 1223–1323 K / 0.001–0.01 s -1 and 1323–1373 K / 0.001–0.1 s -1 . Microstructural analysis confirmed that dynamic recrystallization (DRX) dominates the softening mechanism. Elevated temperatures and low strain rates promote significant grain growth, with pronounced coarsening observed at 1323 K. Damage nucleation sites preferentially distribute at precipitates and grain boundaries.