Nb-Ti微合金钢热变形后组织演变及第二相粒子析出行为

利用GLEEBLE-2000对试验钢进行热模拟试验,并结合显微硬度测试,研究了一种Nb-Ti微合金钢热变形奥氏体的变形后冷却相变行为.利用JEM-2000FX电镜对碳膜萃取复型法获取的第二相析出物进行分析,从而对热变形后冷却相变中的第二相析出行为进行了研究,探讨了不同冷却速度对第二相析出的影响,结果表明,有大量弥散分布的细小粒子析出,析出相主要以Nb-Ti碳氮化物复合相形式存在,一般呈方形、椭圆形、圆形以及不规则形状,并且随着冷却速度的增加,第二相析出增多且变得细小.

Phase Transformation and Second-phase Precipitation Behavior of Nb-Ti Microalloyed Steel during Cooling after Deformation

The phase transformation behavior of Nb - Ti microalloyed steel during cooling process after deformation was studied by the Gleeble - 2000 thermomechanical experiment simulator and by means of a combined method of microscopic hardness measurement. In addition, both second - phase precipitation behavior during cooling after deformation and the effect of cooling rate on the second-phase precipitation were studied by the carbon extraction replicas technique. The results show that there a lot of fine dispersed particles which are main Nb - Ti carbonitride phase are precipitated . The shape of the secondary phase particles is general like square ,elliptical,circular shape and irregular shape. With the cooling rate increasing, the second-phase precipitation particles are seen to have become finer and the number of them are increasing.