我们观察了中碳镍铬钼钢沿晶韧性断口的形貌,见图1(图版78)。钢样在锻造过程中发生了过热,形成沿原始奥氏体晶界断裂的石状断口。断口表面上的夹杂物经X射线能谱分析和萃取复型的选区电子衍射分析鉴定为立方结构的MnS。观察断口形态,似乎每个韧窝(也称塑坑)中都有一个夹杂物。我们进一步利用扫描电子显微镜观察了上述试样匹配断口的形态,进行了拍照,如图2(图版78)所示。为了方便观察和分析,将图2局部放大,得图3(图版78)。由此清晰可见,夹杂物并不是都在断门的一面上,而是按几率分布在断口的两面上,保持 We observed the morphology of the intergranular fracture of the MCC steel, see Figure 1 (Plate 78). The steel sample overheated during the forging process to form a stone fracture along the original austenite grain boundaries. The inclusions on the fracture surface were identified as cubic structure MnS by X-ray energy spectrum analysis and selected area electron diffraction analysis. Observe fracture morphology, it seems that each dimple (also known as Plastic Pit) has an inclusion. We further observed by scanning electron microscopy of the specimen matching fracture morphology, took a picture, as shown in Figure 2 (Figure 78). In order to facilitate observation and analysis, Figure 2 is partially enlarged, Figure 3 (Figure 78). It is clear from this that inclusions are not on the side of the broken door, but according to the probability distribution on both sides of the fracture, to maintain