Abstract

In the paper, the deformation features of the propagation of cleavage cracks in low-alloy low-carbon steel with a ferritic-pearlite microstructure by example of steel 09G2S after hot rolling are investigated. The studied cleavage cracks were obtained in impact bending tests at temperatures in the ductile to brittle transition interval. The study was carried out by transmission electron microscopy, transmission Kikuchi diffraction, and electron backscattered diffraction. It is shown that the deformation accompanying the growth of the cleavage crack in the ferritic-pearlite microstructure is formed when the joints between the cracks propagating in parallel planes break. The crack growth within a single plane occurs without any recorded deformation. The joints are broken by a ductile mechanism according to the scheme of mixed loading by opening and shear. Overlapping of the cleavage cracks determines the relationship between the shear mode and the opening mode during joint deformation, which controls the shape and depth of the plastic deformation zones.

中文翻译：

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铁素体-珠光体显微组织中解理裂纹在韧脆转变区间扩展的变形特征

摘要

以09G2S钢为例，研究了铁素体-珠光体组织的低合金低碳钢热轧后解理裂纹扩展的变形特征。所研究的解理裂纹是在韧性到脆性转变区间的温度下在冲击弯曲试验中获得的。该研究是通过透射电子显微镜、透射菊池衍射和电子背散射衍射进行的。结果表明，铁素体-珠光体显微组织中伴随解理裂纹扩展的变形是在平行面扩展的裂纹之间的接头断裂时形成的。单个平面内的裂纹扩展在没有任何记录变形的情况下发生。根据开剪混合加载方案，通过延性机构破坏节点。解理裂纹的重叠决定了接头变形过程中剪切模式和张开模式之间的关系，从而控制了塑性变形区的形状和深度。