Deformation twinning characteristics in hot-rolled Fe-6.5wt%Si alloy with different degree of order

Abstract

Tensile deformation behavior of the Fe-6.5 wt%Si alloy with different degree of order at intermediate temperatures (200-500 °C) was investigated. Deformation twinning was observed in this body centered cubic A2 phase together with ordered structures. It is found that the ductility of the quenched samples with low degree of order is higher than that of the furnace cooled samples with high degree of order. Deformation twinning occurred in the quenched samples after dislocation slip during deformation at 200-300 °C, while no deformation twins were observed in the furnace cooled samples. The results indicate that the low degree of order is an essential precondition for the deformation twinning, which can also enhance dislocation slip. The <001> orientation along the rolling direction and large grain size can reduce the critical twinning stress. High strain rate and low deformation temperature can further promote the formation of the twinning by dislocations pile-up and high work hardening rate. Our work provides new insights into the deformation mechanism in the Fe-6.5 wt%Si alloy.