新型低密度高强高韧热轧层状钢研发

鉴于能源短缺与高安全性要求，钢铁材料的低密度化与高强韧化成为高强钢的研发热点。大量报道证明，铝等元素合金化可以显著降低钢材密度，层状复合组织大幅度提高钢铁材料的韧性。在介绍国内外传统等轴晶粒高强韧钢、层状复合钢铁材料及低密度钢研发结果的基础上，提出了Fe-Al-Mn-C低密度双相钢的低中等合金质量分数（4%～12%）的合金化设计和高温铁素体和奥氏体的几何扁平化组织调控思路，制备出具有铁素体与马氏体相间排列的层片复合双相钢组织结构的高强韧钢研发思路。初步研究结果证明，层片双相钢的组织结构设计是可行的，实现了钢铁材料的高强度化（抗拉强度为1000～1500 MPa）、低密度化（6.5～7.5 g/cm3）和高韧性化（室温V型冲击韧性为200～400 J），突破了传统等轴结构材料的强韧化机制制约，形成了新型层状复合结构强韧化的钢铁材料研发方向。强调未来需要对层片双相钢材料进行深入研究，以实现对化学成分、层片组织结构参数与材料强度、韧性和材料密度关系的定量研究，深入探讨低密度层状双相钢的层状组织调控机制及其强韧化机理，为未来高强韧金属材料研发及应用开辟出创新发展方向。

Research and development of a new hot rolled laminated structure

In view of energy shortage and high safety requirements,steels with low density,high strength and high toughness have become a hot research topic in material science. A large number of reports show that the Al and other ele-ments alloying can significantly reduce the steel density,and the laminated composite structure greatly improves the toughness of the steel. In this study,based on the introduction of high strength and high toughness steel with equiaxed grains,steel with layered composite and low-density steel at home and abroad,the idea of low density low to medium-al-loy design(4%-12%)of Fe-Al-Mn-C dual phase steel and the micro-laminated control by grain shape pancaking of both high temperature delta-ferrite phase and austenite phase during hot rolling process is proposed,which makes it possible to obtain a alternatively arranged micro-laminated composite steel with low density,high strength and high toughness. It is proved that it is feasible to obtain the dual phase steel with low density(6.5-7.5 g/cm3),micro-laminated,high strength(1 000-1 500 MPa)and high toughness(200-400 J),which breaks the limitation of toughening mechanism of conventional steel with equiaxial grain structure and opens a new research and development approach for the high strength and high toughness steel. At the end of this paper,a thorough study on the low density and micro-laminated du-al phase steel is proposed to understand the relationship between chemical composition,parameters of the micro-laminat-ed structure and the properties of strength and toughness,and to explore the strengthening and toughening mechanism of the new designed low density and micro-laminated dual phase steel,which would indeed open an innovative direction for future research and development on the low density,high strength and high toughness steels.