Precipitation strengthening of nano-scale TiC in a duplex low-density steel under near-rapid solidification  

作　　者：Jian-lei Zhang Cong-hui Hu Yu-xiang Liu Yang Yang Gang Ji Chang-jiang Song Qi-jie Zhai 

机构地区：[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-UnitéMatériaux et Transformations,University of Lille,French National Centre for Scientific Research(CNRS),French National Institute for Agricultural(INRAE),Centrale Lille Institute,59000,Lille,France

出　　处：《Journal of Iron and Steel Research International》2021年第9期1141-1148,共8页

基　　金：the National Natural Science Foundation of China(No.51974184);National MCF Energy R&D Program of China(No.2018YFE0306102);Independent Research Project of State Key Laboratory of Advanced Special Steel and Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University.

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 γ-austenite and δ-ferrite, respectively. Ti addition also decreased the volume fraction of γ-austenite significantly. Correspondingly, the yield strength was increased, but the elongation was significantly decreased due to the significant decrease of γ-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 κ-carbide.

关 键 词：Precipitation strengthening Nano-scale TiC precipitate Low-density steel Yield strength Strain hardening 

分 类 号：TF762.4[冶金工程—钢铁冶金]