低密度钢中有序析出相的研究进展

Research Progress of Ordered Precipitates in Low-density Steels

随着“减重、节能、降低碳排放”的绿色制造理念越来越深入人心,对传统钢铁材料升级换代的需求显得尤为迫切,第三代汽车用钢已成为各国研发机构和企业关注的焦点。高强度、高韧性、轻量化的先进钢铁材料成为第三代汽车用钢的一个新的研发方向。主要通过在Fe中添加较多的轻质元素如Al、Mn、Si等进行合金成分设计来显著降低钢材密度;同时通过调控基体组织和析出相构成、形态来平衡钢材的强度和塑韧性,从而使钢具有高的强塑积和低的密度。本文针对Fe-Al、Fe-Mn-Al、Fe-Mn-Al-C系低密度钢的成分及组织特征,介绍了低密度钢中Kappa碳化物,(Fe,Mn)Al、NiAl型B2相,(Fe,Mn)3Al型DO 3相和β-Mn相的晶格参数及相关性能特征。结合国内外对低密度钢的最新研究,着重对低密度钢相图的热/动力学计算、各有序析出相的元素配分和析出行为(特征、形态、大小)、析出相对钢组织演变与强韧性机制的影响等进行了总结,并基于现有的研究,展望了高强度、高韧性、低密度钢进一步的研究方向。

With the growing popularity of the green manufacturing concept of“weight reduction,energy saving and carbon emission reduction”,the requirement for upgrading traditional steel materials is particularly urgent.The third generation of automobile steel has become a focus of increasing attention of research and development institutions and enterprises in various countries.As a new research and development direction of the third generation automotive steel,high strength and toughness low-density advanced steel is mainly designed by adding more light elements such as Al,Mn and Si elements into steel,which can significantly reduce the density of steel.The strength and plasticity of steel can be balanced by adjusting matrix structure and precipitated phase composition and morphology,so that it has high strength and plasticity and low density.In the presentation,the lattice parameters and related properties of Kappa carbides,(Fe,Mn)Al,NiAl-type B2 phase,(Fe,Mn)3Al-type DO3 phase andβ-Mn phase in low-density steels are introduced according to the composition and structure characteristics of Fe-Al,Fe-Mn-Al and Fe-Mn-Al-C low-density steels.Based on the latest research on low-density steels in China and overseas,the thermal and dynamic calculation of phase diagrams of low-density steels,the elemental partition and precipitation behavior(characteristics,morphology,size),the effect of precipitation on the microstructure evolution and strength-toughness mechanism of steels are summarized.Based on current research,the future research directions of high strength,high toughness and low density steels are prospected.