Evolution of deformation twins with strain rate in a mediummanganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V
J. Chen1, J.J. Wang1,2, H. Zhang3, W.G. Zhang1, C.M. Liu1,4
1 Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819, Liaoning, China 2 School of Materials Science and Engineering, Northeastern University, Shenyang 110819, Liaoning, China 3 Baosteel Special Steel Co., Ltd., Shanghai 200940, China 4 Northeastern Institute of Metal Materials Co., Ltd., Shenyang 110108, Liaoning, China
Evolution of deformation twins with strain rate in a mediummanganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V
J. Chen1, J.J. Wang1,2, H. Zhang3, W.G. Zhang1, C.M. Liu1,4
1 Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819, Liaoning, China 2 School of Materials Science and Engineering, Northeastern University, Shenyang 110819, Liaoning, China 3 Baosteel Special Steel Co., Ltd., Shanghai 200940, China 4 Northeastern Institute of Metal Materials Co., Ltd., Shenyang 110108, Liaoning, China
摘要 Microstructure evolutions of the medium-manganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V (in wt.%) with stacking-fault energy of 22 mJ m-2 during deformation at strain rate ranging of 10-2–1 s-1 were analyzed by means of X-ray diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The results indicate that the twinning-induced plasticity effect is the main strengthening mechanism of the studied steel, whilst the transformation-induced plasticity effect only occurs at high strain rate. With an increase in strain rate, volume fraction of the deformation twins, in particular that of the secondary twins, increases significantly along with decreasing average size. When applied strain rate is higher than 10-1 s-1, the parallel deformation twins are turned into a crossing morphology, and the original straight twin boundaries exhibit a ladder feature, which is attributed to the interactions between regular dislocations and twin dislocations at the twin boundary. The critical strain, a key indicator of the initiation of deformation twin, decreases with increasing strain rate. In addition, the ductility and strength of medium-manganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V are mainly determined by the shape and volume fraction of deformation twins.
Abstract：Microstructure evolutions of the medium-manganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V (in wt.%) with stacking-fault energy of 22 mJ m-2 during deformation at strain rate ranging of 10-2–1 s-1 were analyzed by means of X-ray diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The results indicate that the twinning-induced plasticity effect is the main strengthening mechanism of the studied steel, whilst the transformation-induced plasticity effect only occurs at high strain rate. With an increase in strain rate, volume fraction of the deformation twins, in particular that of the secondary twins, increases significantly along with decreasing average size. When applied strain rate is higher than 10-1 s-1, the parallel deformation twins are turned into a crossing morphology, and the original straight twin boundaries exhibit a ladder feature, which is attributed to the interactions between regular dislocations and twin dislocations at the twin boundary. The critical strain, a key indicator of the initiation of deformation twin, decreases with increasing strain rate. In addition, the ductility and strength of medium-manganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V are mainly determined by the shape and volume fraction of deformation twins.
J. Chen,J.J. Wang,H. Zhang, et al. Evolution of deformation twins with strain rate in a mediummanganese wear-resistant steel Fe–8Mn–1C–1.2Cr–0.2V[J]. Journal of Iron and Steel Research International, 2019, 26(9): 983-990.
2019, Vol. 26 
