Microstructure evolution of in-situ nanoparticles and its comprehensive effect on high strength steel

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2019,（9）
• 页码范围: 1940-1950
• 页数: 11页
• 语种: 英文

摘要

A novel steel strengthened by nanoparticles was investigated in this study.A Fe-based high-strength steel was developed by the trace-element regional supply method during deoxidization to generate in situ nanoparticles with a high number density in the matrix.The results show that the endogenous nanoparticles are aluminum oxide (Al2O3) and titanium oxide (Ti3O5) formed in the liquid melt.Al2O3 functioned as a heterogeneous nucleation site for MnS during solidification;the size of the resultant complex inclusions was approximately 1-2 μm.Furthermore,13 nm Nb(C,N) precipitates grew with the Ti3Os during the tempering process.These in situ nanoparticles strongly affected refining of the grain and inclusions.The investigated steel was strengthened more than 200 MPa by precipitation strengthening and more than 265 MPa by grain refinement strengthening according to the Ashby-Orowan mechanism and the Hall-Petch relationship,respectively.