Warm deformation behavior and work-softening mechanism of Fe–6.5wt.%Si alloy

Abstract

Warm deformation behavior of the Fe–6.5wt.%Si alloy was studied by isothermal compression in the temperature range of 300–700 °C. The results show that the influence of the ordered phases on the flow stress gradually weakens with increasing deformation temperature. The flow stress of the furnace-cooled sample with the high degree of order at 300 °C is higher than that of the quenched sample with the low degree of order, and the flow stresses of both samples are nearly the same at 500–700 °C. The hardness difference between two samples deformed at 500 °C gradually decreases with increasing strain, accompanying with a reduction in hardness of the furnace-cooled sample, which indicates a work-softening behavior. The analyses of dislocation configurations and ordered structure suggest that the dynamic recovery and deformation-induced disorder result in the work-softening behavior. An appropriate deformation temperature window for improving the formability of the Fe–6.5wt.%Si alloy is about 500–600 °C.