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为了研究微观断口形貌与珠光体组织的关系,从而揭示断裂机理,做了下面的工作。试样选用含碳量为0.70%的钢轨钢,沿轨长方向取圆棒拉伸试样和冲击断口试样,并观察它们的微观断口,在这两种试样断口的纤维区都发现片层状断口形貌,为了搞清这种断口形貌形成的原因,用断口金相技术进行了研究。一、断口的宏观和微观观察宏观断口形貌如图1所示。断口分为三个区域,暗灰色的纤维区,亮灰色有金属光泽的放射区和最外边的唇边为瞬时断裂区。在扫描电镜下观察各个区域的微观形态。图2(a)为纤维区的形貌有韧窝,撕裂岭和片层状形貌。图2(b)为放射区的形貌,主要
In order to study the relationship between microscopic fracture morphology and pearlite structure, thereby revealing the fracture mechanism, the following work has been done. The specimens were made of steel with a carbon content of 0.70%. The round bar tensile specimens and the impact fracture specimens were taken along the length of the orbit and their microscopic fracture surfaces were observed. In the fiber regions of the fracture surfaces of both specimens, Layered fracture morphology, in order to find out the reasons for the formation of such fracture morphology, fracture metallography was studied. First, the macroscopic and microscopic observation of fracture Macroscopic fracture morphology shown in Figure 1. Fracture is divided into three areas, dark gray fiber area, the bright gray metallic radiation zone and the outermost edge of the instantaneous fracture zone. The microscopic morphology of each area was observed under a scanning electron microscope. Fig. 2 (a) shows that the morphology of the fiber zone is dimpled, torn ridge and lamellar. Figure 2 (b) for the radiation zone morphology, the main