灰口铸铁激光表面合金化的凝固组织与性能

本文探讨了灰口铸铁激光表面合金化Si的快速凝固组织的形成过程与机理。合金化组织的成分为≤2.0%C及1.62%～9.21%Si，硬度值在830～1120HV范围内。在激光快速加热及随后的快速自传导冷却过程中，随合金熔体的凝固速率及陡降的温度梯度变化，凝固组织的形态及尺寸发生变化。借助于扫描电镜、能谱仪和透射电镜，对其组织及相分布进行了观察与分析，揭示了合金化组织的硬化机理。磨损试验结果表明，这种高硬度的凝固组织具有很好的耐磨性。

THE SOLIDIFIED STRUCTURES AND PROPERTIES BY LASER SURFACE ALLOYING OF F. G. CAST IRON

The experiments were carried out on laser surface alloying of F. G. cast iron with pure Si Powder. The composition of the solidified structures located in the range of ≤2.0%C and 1.62%～9.21%Si. The processing and mechanism of rapid solidification were discussed. During the quick heating by laser beam and subsequent rapidly self-quenching the solidification rate and temperature gradient were chanted, which determined the morphology and seale of the solidified structure. By means of SEM with EPMA system and TEM, the details of structure and phase were observed. The hardening mechanisms of the alloyed structures were reveled. The structure had not only high hardness value of 830～1120HV, but also high wear resistance which was shown in wear testing.