Precipitation strengthening of nano-scale TiC in a duplex low-density steel under near-rapid solidification
Jian-lei Zhang1,2, Cong-hui Hu1, Yu-xiang Liu1, Yang Yang1, Gang Ji2, Chang-jiang Song1, Qi-jie Zhai1
1 Center for Advanced Solidification Technology (CAST), State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;
2 UMR 8207-UMET- Unite′ Mate′riaux et Transformations, University of Lille, French National Centre for Scientific Research (CNRS), French National Institute for Agricultural (INRAE), Centrale Lille Institute, 59000 Lille, France
Precipitation strengthening of nano-scale TiC in a duplex low-density steel under near-rapid solidification
Jian-lei Zhang1,2, Cong-hui Hu1, Yu-xiang Liu1, Yang Yang1, Gang Ji2, Chang-jiang Song1, Qi-jie Zhai1
1 Center for Advanced Solidification Technology (CAST), State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;
2 UMR 8207-UMET- Unite′ Mate′riaux et Transformations, University of Lille, French National Centre for Scientific Research (CNRS), French National Institute for Agricultural (INRAE), Centrale Lille Institute, 59000 Lille, France
摘要 Precipitation strengthening of nano-scale TiC is a promising method to improve mechanical properties of Fe–16Mn–9Al– 0.8C (wt.%) low-density steel. This work attempted to introduce nano-scale TiC precipitates by adding 1 wt.% Ti element. The experimental results show that these precipitates with the total fraction of about 2 vol.% were formed and no coarse precipitates were observed despite the high Ti addition. It was interesting that the polygonal and needle-shaped TiC precipitates were observed in c-austenite and d-ferrite, respectively. Ti addition also decreased the volume fraction of gamma-austenite significantly. Correspondingly, the yield strength was increased, but the elongation was significantly decreased due to the significant decrease of c-austenite. Comparing with the Ti-free steel, the formation of TiC precipitates was the main reason for the increase in yield strength of Ti-bearing steel, and TiC precipitates also led to a higher strain hardening index at the first deformation stage. TiC precipitates promoted the Orowan strengthening, resulting in a higher strain hardening capability than Ti-free steel reinforced by shearable kappa-carbide.
Abstract:Precipitation strengthening of nano-scale TiC is a promising method to improve mechanical properties of Fe–16Mn–9Al– 0.8C (wt.%) low-density steel. This work attempted to introduce nano-scale TiC precipitates by adding 1 wt.% Ti element. The experimental results show that these precipitates with the total fraction of about 2 vol.% were formed and no coarse precipitates were observed despite the high Ti addition. It was interesting that the polygonal and needle-shaped TiC precipitates were observed in c-austenite and d-ferrite, respectively. Ti addition also decreased the volume fraction of gamma-austenite significantly. Correspondingly, the yield strength was increased, but the elongation was significantly decreased due to the significant decrease of c-austenite. Comparing with the Ti-free steel, the formation of TiC precipitates was the main reason for the increase in yield strength of Ti-bearing steel, and TiC precipitates also led to a higher strain hardening index at the first deformation stage. TiC precipitates promoted the Orowan strengthening, resulting in a higher strain hardening capability than Ti-free steel reinforced by shearable kappa-carbide.
Jian-lei Zhang,Cong-hui Hu,Yu-xiang Liu, et al. Precipitation strengthening of nano-scale TiC in a duplex low-density steel under near-rapid solidification[J]. Journal of Iron and Steel Research International, 2021, 28(9): 1141-1148.