先进高强度冷轧TWIP钢的组织和力学性能

Microstructure and mechanical properties of advanced high strength cold-rolled TWIP steel

采用真空熔炼法制备Fe-20Mn-3.0Cu-1.38C高强度高塑性合金钢,通过单向拉伸、X射线衍射(XRD)、光学显微镜(OM)和透射电子显微镜(TEM)方法研究了不同冷轧变形量(12.8%~73.37%)对该合金钢微观组织、力学性能的影响,分析了冷轧变形量为32.28%该合金钢的拉伸变形微观机制。结果表明,该合金冷轧变形前后均为单相奥氏体组织,无马氏体相变发生。随着冷轧变形量的增加,合金钢的屈服强度、抗拉强度均显著提高,伸长率则减小。当冷轧变形量为32.28%,该合金钢的规定非比例延伸强度高达1383.99 MPa,抗拉强度为1619.83 MPa,达到超强钢的水平,并仍然保留41.12%的伸长率,综合性能优异。该冷轧变量下的合金拉伸变形过程中,产生TWIP效应,位错的塞积、形变孪晶的产生以及位错与孪晶间的交互作用共同提高材料的塑性和强度。

Fe-20Mn-3. 0Cu-1. 38C alloy steel with high strength and high ductility was prepared by vacuum melting method. Influence of different cold-rolled deformation ( 12. 8%-73. 37%) on microstructure and tensile properties of Fe-20Mn-3. 0Cu-1. 38C steel were investigated by unidirectional tensile, X-ray diffraction, OM and TEM, and the deformation mechanism of 32. 28% cold rolled alloy steel was studied. The results show that the Fe-20Mn-3. 0Cu-1. 38C steel before and after deformation is fully composed of austenite without martensite. The yield and tensile strength increase apparently with cold rolled deformation increasing, while the elongation is opposite. When the cold rolling deformation is 32. 28%, the alloy steel exhibits superior tensile properties, the yield strength and tensile strength are 1383. 99 MPa, 1619. 83 MPa, respectively. And it still retains 41. 12% elongation. During its tensile deformation with 32. 28% cold rolling deformation, TWIP effect is happened, and the increase of strength and plasticity is attributable to large quantity of dislocation pile-up, the generation of deformation twins and the interaction of each other.