Zhang Baoguang, Yang Kun, Zhang Xiaoming, Liu Haitao, Zhang Weina, Wang Jian
State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China.
State Key Laboratory of Porous Metal Materials, Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China.
Materials (Basel). 2023 Aug 2;16(15):5417. doi: 10.3390/ma16155417.
In this study, the Fe-16Mn-9Al-0.8C-3Ni (wt.%) lightweight steel was fabricated by novel twin-roll strip casting technology. The microstructure, tensile properties and strain-hardening behavior of the present steel have been investigated and compared to those of conventionally processed steels with similar chemical compositions. After annealing, a unique gradient microstructure of intermetallic compound (B2)-austenite was obtained along the thickness direction, consisting of granular B2 (average: 430 nm) and fine austenite (average: 1.82 μm) at the surface layer, blocky B2 (average: 1.03 μm) and medium austenite (average: 3.98 μm) at the quarter layer and polygonal B2 (average: 1.94 μm) and coarse austenite (average: 6.13 μm) at the center layer. The cooperative action of B2 pinning dislocation, plane slip and back stress led to stronger strain hardening, among which the strong back stress effect originated from the multistage discontinuous austenite deformation and the mechanical incompatibility between austenite and B2 is believed to be the most important reason, thereby achieving an excellent balance of strength (ultimate tensile strength: 1147 MPa) and ductility (total elongation: 43.2%). This work not only developed a new processing way to fabricate Ni-containing Fe-Mn-Al-C lightweight steel with outstanding mechanical properties, but also provided a potential solution for manufacturing some other metallic materials accompanied by brittle B2 intermetallic.
在本研究中，采用新型双辊薄带连铸技术制备了Fe-16Mn-9Al-0.8C-3Ni（重量百分比）轻质钢。研究了该钢的微观结构、拉伸性能和应变硬化行为，并与具有相似化学成分的传统加工钢进行了比较。退火后，沿厚度方向获得了一种独特的金属间化合物（B2）-奥氏体梯度微观结构，表层由粒状B2（平均：430纳米）和细小奥氏体（平均：1.82微米）组成，四分之一层由块状B2（平均：1.03微米）和中等奥氏体（平均：3.98微米）组成，中心层由多边形B2（平均：1.94微米）和粗大奥氏体（平均：6.13微米）组成。B2钉扎位错、平面滑移和背应力的协同作用导致了更强的应变硬化，其中强烈的背应力效应源于多阶段非连续奥氏体变形，奥氏体与B2之间的力学不相容性被认为是最重要的原因，从而实现了强度（极限抗拉强度：1147兆帕）和延展性（总伸长率：43.2%）的优异平衡。这项工作不仅开发了一种新的加工方法来制备具有优异力学性能的含镍Fe-Mn-Al-C轻质钢，还为制造一些伴有脆性B2金属间化合物的其他金属材料提供了潜在的解决方案。
