Hot-deformation characteristics and dynamic softening of as-cast FeCrAl alloy

Abstract

A series of compression tests were conducted at various temperatures and strain rates to experimentally investigate the hot-deformation characteristics and dynamic softening of an as-cast FeCrAl alloy. There is no evident decline in stress after the peak point of a flow curve despite the occurrence of dynamic recrystallization (DRX). This phenomenon pointed out that the occurrence of DRX in the alloy could not be identified depending only on flow curves. The constitutive equation for peak stress was constructed following the determination of hot-working parameters. The predicted results correlated well with the experimental data. The dynamic softening behavior was classified depending on the analysis of microstructure evolutions at different temperatures. The softening process was dominated by dynamic recovery (DRV) at 850 and 950 °C. The higher temperature could elevate the level of dynamic softening. The softening mechanisms at 1050 °C included DRV and continuous dynamic recrystallization (CDRX) characterized by the rotation of sub-grains from low-angle boundaries to high-angle boundaries. The rotation of sub-grains during the CDRX process was unlikely to affect the strong intensity of texture after the hot-deformation process.

Keywords

• FeCrAl alloy
• Hot deformation
• Constitutive equation
• Dynamic softening