温轧TWIP钢芯三层板的组织和力学性能

Microstructure and Mechanical Properties of Warm-rolled TWIP-steel Core Three-layer Sheets

采用热轧-温轧工艺制备了孪晶诱导塑性(TWIP)钢芯的三层复合板。用电子探针(EPMA)、高分辨扫描电镜(SEM)、显微硬度计和电子万能试验机对复合板的微观组织、元素分布、显微硬度和拉伸性能进行了测试和分析。结果表明,TWIP钢与低碳钢(LC)板界面结合良好,没有孔隙、裂缝等缺陷;在结合界面附近发生了Mn元素的扩散,该扩散符合菲克第一定律;轧制工艺制备的复合板晶粒细化,材料硬度提高;TWIP钢芯三层复合板的强度和伸长率与TWIP钢芯的厚度比成正比;在拉伸过程中两侧钢板的晶粒发生协调变形,裂纹首先出现在LC一侧,随后裂纹扩展,最终在TWIP/LC界面形成贯穿的连续裂纹。

The twin-induced plastic(TWIP) steel-cored three-layer composite sheets were prepared by hot rolling-warm rolling process. The microstructure, element distribution, microhardness and tensile properties of composite sheets were tested and analyzed by electron probe micro-analyzer(EPMA), scanning electron microscope(SEM), microhardness tester and electronic universal testing machine. The results show that interface of TWIP steel and low carbon(LC) steel is well combined without any defects such as pores and cracks. The diffusion of Mn element occurs near the bonding interface, and the diffusion conforms to Fick’s first law. The grain of the composite sheet prepared by rolling process is refined and the hardness of the material is improved.The strenth and elengation of TWIP steel core three-layer composite sheets are proportional to the thickness ratio of TWIP steel core. In the process of drawing, the grains of both sides of the steel sheet are deformed harmoniously, the cracks first appear on the LC side, and then the cracks propagate, and finally the continuous cracks through the TWIP/LC interface are formed.