微量硼对微量硫引起的纯铁高温脆性断裂的影响

硫引起的高温脆性断裂是制约钢铁材料生产和使用的核心问题之一,针对此问题,利用高温拉伸试验和SEM断口观察研究了微量硼对含微量硫(质量分数为0.006%)的纯铁高温塑性及断裂方式的影响,在利用扫描俄歇电子谱仪对界面偏析定量分析的基础上,讨论了微量硼影响的原因.结果表明,微量硼的添加能明显提高含微量硫的纯铁的高温塑性,抑制硫界面偏析造成的高温脆性断裂.微量硼的这种影响是由于硼沿界面偏析,显著降低硫的界面偏析倾向,抑制硫界面偏析引起的高温沿晶孔洞形成.

Effect of Trace Boron on High Temperature Brittle Fracture of Iron Caused by Trace Sulfur

The high temperature brittle fracture caused by sulfur is one of key problems to restrict the production and the use of steel.Aiming at this problem,the effect of trace boron on the ductility and fracture mode of iron containing trace sulfur(mass fraction 0.006%) at high temperatures was investigated by tensile tests at high temperatures and SEM observations of fractured surfaces.The role of trace boron was discussed based on analysis of the segregation at interfaces by scanning Auger electron spectroscopy.The experimental results showed that the addition of trace boron increases markedly the high temperature ductility of iron containing trace sulfur and restrains the brittle fracture caused by the interface segregation of sulfur.Such effect of trace boron results from that trace boron can segregate to interfaces of iron,remarkably decreasing the segregation of sulfur and therefore restraining the formation of cavities at grain boundaries caused by intergranular segregation of sulfur.