双相不锈钢冷轧退火组织转变的EBSD原位研究

In situ observation on microstructure evolution by EBSD during annealing in the cold-rolled duplex stainless steel

本文采用扫描电子显微镜(SEM)及电子背散射衍射(EBSD)技术对经30%压下量冷轧的双相不锈钢UNS S32304在1 050℃下退火的显微组织转变进行了原位追踪。结果表明,轧制变形后,两相的变形抗力具有明显差异,奥氏体塑性变形量较比铁素体大;经1 050℃真空退火2 min后,两相晶内取向差的变化表明铁素体较比奥氏体发生了更大程度的回复;再经1 050℃真空退火5 min后,样品中两相晶粒取向与其初始取向具有较大差异,表明发生了以再结晶为主并伴有少量相变反应的组织变化。

The microstructure evolution in 30%（ the thickness reduction） cold-rolled duplex stainless steel UNS S32304 during annealing at 1 050℃ was investigated by means of off-line in-situ electron back scatter diffraction（ EBSD） and scanning electron microscope（ SEM） techniques. The results showed that austenite and ferrite exhibit different deformation resistance during cold rolling. Larger plastic deformation occurs in austenite than that in ferrite. The average misorientation between the grain pairs,which sharing the same location but under different states of cold rolling and annealing for each phase,suggests that ferritic grains are more liable to recovery than austenitic ones during annealing at 1 050℃ for 2 min. And also,further 5 min annealing brings about significant orientation changes for both two phases,indicating that primary recrystallization occurred with a limited phase transformation.