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采用SEM、TEM和XRD研究了珠光体钢丝冷拉拔过程中的组织演变,重点在于渗碳体的变形和溶解。结果表明,渗碳体表现出了很高的变形能力,随着累积应变量的增大,片条组织逐渐转向拉拔方向;在大应变钢丝组织中渗碳体片条厚度小,部分区域只有0.5nm甚至更薄,且已很难见到渗碳体的滑移或剪切变形。在初始钢丝中铁素体含有过饱和的碳,在拉拔应变量为1.51之后,可能转变为四方结构的马氏体,且只有很少量的渗碳体溶解。在高应变量钢丝样品中,用原子探针场离子显微镜探测碳原子浓度以判定渗碳体是否溶解时,应考虑渗碳体的形变及其形貌。
The microstructure evolution of pearlite steel during cold drawing was studied by SEM, TEM and XRD. The emphasis was on the deformation and dissolution of cementite. The results show that the cementite shows a high deformation capacity. With the increase of the cumulative strain, the strip gradually turns to the drawing direction. In the large strain wire structure, the thickness of the cementite strip is small, 0.5nm or even thinner, and have been difficult to see the cementite sliding or shear deformation. Ferrite contains supersaturated carbon in the initial wire, which may transform into tetragonal martensite at a drawing strain of 1.51 and only a small amount of cementite dissolves. In high strain steel samples, the presence of cementite should be taken into account when determining the concentration of carbon atoms by atomic probe field ion microscopy to determine if cementite is dissolved.