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
• 来源期刊: 钢铁研究学报（英文版）
• 年，卷（期）: 2021,（9）
• 所属期刊栏目: ORIGINAL PAPERS
• 页码范围: 1141-1148
• 页数: 8页
• 语种: 英文

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 inγ-austenite andδ-ferrite, respectively. Ti addition also decreased the volume fraction ofγ-austenite significantly. Correspondingly, the yield strength was increased, but the elongation was significantly decreased due to the significant decrease ofγ-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 shearableκ-carbide.