摘要
借助ＳＥＭ、ＴＥＭ对激光熔覆ＴｉＣ／Ｎｉ＋Ｃｒ过程中陶瓷相ＴｉＣ的行为进行了研究。结果表明：未受基体中Ｆｅ扩散影响的熔覆层表层，ＴｉＣ仍保持为完整的六边形截面颗粒。交互扩散区的ＴｉＣ颗粒在凝固应力作用下可能产生裂纹。溶解促进裂纹的萌生和扩展。溶解后的陶瓷相与粘结相交互作用生成（Ｆｅ，Ｃｒ）２３Ｃ６。溶解后的陶瓷相在凝固过程中重新析出，析出的陶瓷相可使涂层强化。
The behaviour of ceramic phase in laser cladding TiC/Ni+Cr on steel is investigated with SEM and TEM. The results show that TiC phase in the surface layer keeps themselves completeness because they can not be dissolved in Ni+Cr alloy. In the interdiffusion zone, TiC phase is dissolved and interdiffusion will take place in the substrate diffused and the coating. The existence of Fe alloy is the prerequiste of interdiffusion. Cracks may appear in the large TiC grains in the interdiffusion zone under the effect of solidifing stress and the diffusion accelerates the crack initiation and growth. A new ceramic phase(Fe, Cr) 23C6 is produced as the result of interaction between TiC dissolved and binding alloy. The TiC dissolved is re-precipitated and binding alloy is hardened during solidifing.
