节约型双相不锈钢2101高温变形过程中微观组织演化

来源期刊：金属学报2010年第6期

论文作者：方轶琉 刘振宇 张维娜 王国栋 宋红梅 江来珠

文章页码：641 - 646

关键词：节约型双相不锈钢2101； 高温变形； 连续动态再结晶； 孪晶

Key words：lean duplex stainless steel 2101； hot deformation； continuous dynamic recrystallization(CDRX)； twin

摘    要：采用电子背散射衍射技术(EBSD)和TEM研究了节约型双相不锈钢2101在温度为1000℃和应变速率为5 s^-1的高温变形过程中的微观组织演化.结果表明,铁素体和奥氏体都发生以小角度晶界不断向大角度晶界转变为特征的连续动态再结晶(CDRX).固溶退火后双相不锈钢奥氏体内出现大量退火孪晶.随变形量增加,奥氏体中具有∑3位向关系的晶界逐渐消失.高温变形过程中双相微观组织演化机制的耦合作用共同决定了流变曲线特征.

Abstract: Duplex stainless steels (DSSs) were processed to have a balanced microstructure containing approximately equal amounts of ferrite and austenite,which exhibit exceptional mechanical properties and corrosion resistance.Lean duplex stainless steel (LDX) 2101 with lower contents of Ni and Mo had been developed in order to further reduce the cost.The coexistence of ferrite and austenite during hot deformation led to a complicated deformation behavior.However,little research had been dedicated to studying the microstructure evolution in LDX 2101 compared with traditional DSSs.In addition,the reported results of microstructure evolution both in ferrite and austenite phases of traditional DSSs exhibited obvious controversy.In the present paper,the microstructure evolution of the LDX 2101 during hot compression at a strain rate of 5 s^-1 and 1000℃ was studied by electron backscatter diffraction (EBSD) together with TEM.The results showed that continuous dynamic recrystallization (CDRX) occurred both in ferrite and austenite phases by gradual transformation of low angle grain boundary into high angle grain boundary.In addition,a large number of Σ3 twins appeared after solution annealing treatment.The hot deformation resulted in a progressive disappearance of the Σ3 twin boundaries in austenite phase.Flow curve characteristics of the LDX 2101 during hot deformation were interpreted by the coupling behaviors of the microstructure evolution of its both phases.