Ｘ射线衍射实验证实，球铁的含硅量在 ３．０％～ ５．０％范围内逐步增加时，其衍射峰的数量、位置及强度均呈现规律性变化．值得注意的是这种变化与球铁的脆性有良好的对应关系．并推论出：球墨铸铁的含硅量为３．３％时出现的脆性与平均每一个α－Ｆｅ晶脆里深入了１／８硅原子有关 X-ray diffraction experiments confirmed that when the silicon content of ductile iron gradually increases from 3.0% to 5.0%, the number, position and intensity of diffraction peaks show regular changes. It is noteworthy that this change has a good correspondence with the ductile iron ductile. And deduced that the brittleness that occurs when the silicon content of the ductile iron is 3.3% is related to an average of 1/8 of the silicon atoms in each a-Fe crystal crisp