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采用显微硬度测试、扫描电镜(SEM)、透射电镜(TEM)和三维原子探针(3DAP)等测试手段分析了珠光体钢丝在冷拔过程中显微硬度、组织变化及大应变变形后碳原子的分布和浓度变化。结果表明:随着应变量的增加,组织逐渐转向拉拔方向,片层间距减小,最后在纵截面上形成平行于拉拔方向的层片状组织,横截面上呈现为卷曲状的层片组织;3DAP测试显示,渗碳体在变形过程中发生了部分溶解,溶解的碳原子从渗碳体相移动到铁素体相,碳原子在铁素体中形成过饱和;在拉拔过程中铁素体内部位错密度增加、片层间距减小和渗碳体发生分解释放出碳原子对位错运动产生较大阻力,使珠光体钢丝的硬度随着拉拔应变量的增加而增加。
The microhardness, microstructure and carbon deformation of pearlite during cold drawing were analyzed by means of microhardness test, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP) Atomic distribution and concentration changes. The results show that with the increase of strain, the tissue turns to the drawing direction gradually and the distance between the layers decreases. Finally, a lamellar structure parallel to the drawing direction is formed on the longitudinal section, and the curled layer appears on the cross section The 3DAP test showed that the cementite partially dissolved in the deformation process, the dissolved carbon atoms migrated from the cementite phase to the ferrite phase, and the carbon atoms were supersaturated in the ferrite. During the drawing process, the iron The increase of dislocation density, the decrease of the interlamellar spacing and the decomposition of cementite release the carbon atoms to generate more resistance to the dislocation movement, which makes the hardness of pearlite steel wire increase with the increase of drawing strain.