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本文叙述了球墨铸铁(基体组织为不同含量的珠光体和铁素体)在拉伸、冲击应力下的型性变形和断裂过程。在通常情况下,球墨铸铁是以滑移方式进行变形的。当塑性变形受阻时,则在变形严重不协调的局部区域中的球墨、铁素体和珠光体内,都可形成裂纹。在扫描电镜中可以看到球墨的年轮状结构,而裂纹往往沿着脆弱的年轮状界面形成。铁素体基体球铁的断裂是一种高能量吸收过程的断裂;其裂纹为一弧线,尾端较钝。珠光体基体球铁的断裂是一种低能量吸收过程的断裂;其裂纹为一折线,尾端尖细。
This paper describes the ductile deformation and fracture process of ductile iron (matrix with different contents of pearlite and ferrite) under tension and impact stress. Normally ductile iron is deformed in a slip-on manner. When the plastic deformation is hindered, cracks can form in the nodular, ferrite and pearlite in the localized areas where the deformation is not coordinated well. In scanning electron microscopy, the annual ring structure of nodules can be seen, and the cracks often form along the weak annual ring interface. Ferrite matrix ductile fracture is a high-energy absorption process of fracture; the crack is an arc, the blunt end. The fracture of pearlite matrix ductile iron is a kind of fracture of low energy absorption process; the crack is a broken line and the tip is sharp.