复合碳化物增强铁基激光熔覆层中碳化物的演变行为研究  

Investigation on Evolution Behavior of Carbide in Composite Carbide Reinforced Fe-based Laser Cladding Coating

作　　者：李玉安 程悦 曹鲲鹏 智仕欣 曹雅彬 LIYuan;CHENGYue;CAOKunpeng;ZHIShixin;CAOYabin(Engineering Training Center,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;School of Materials Science and Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)

机构地区：[1]石家庄铁道大学工程训练中心,河北石家庄050043 [2]石家庄铁道大学材料科学与工程学院,河北石家庄050043

出　　处：《热加工工艺》2024年第14期38-41,46,共5页Hot Working Technology

基　　金：河北省自然科学基金资助项目(E2016210107)。

摘　　要：通过碳化物“复合引入法”,利用含有TiC和Nb+C的铁基粉末制备复合碳化物增强铁基激光熔覆层,研究了熔覆层中碳化物的演变行为。结果表明,在熔覆过程中外加TiC的分解和复合碳化物的析出使得碳化物在成分构成、结构、形态、尺寸及分布等方面发生一系列的变化。在激光热作用下TiC会发生部分分解。分解释放的Ti原子和熔池中Nb原子在凝固过程中一同参与了碳化物的析出,进而和C原子一起形成复合碳化物(Nb,Ti)C。Nb原子可降低TiC的结晶速度,从而促进非晶相的形成。未完全分解的TiC可以作为异质形核点供非晶相及(Nb,Ti)C在其表面形成并长大,进而一起演变为具有核壳结构的块状相。自发形核并长大的(Nb,Ti)C尺寸较小,且呈点状分布在基体晶粒内部。在凝固终了阶段形成的(Nb,Ti)C属共晶组织,呈断续的网状分布在基体晶界处。The iron based powder containing TiC and Nb+C was used to prepare the composite carbide reinforced Fe-based laser cladding coating by means of the carbide compound introduction method,and the evolution behavior of the carbide in cladding coating was investigated.The results show that the decomposition of TiC and the precipitation of composite carbide can cause the changes in the chemical composition,structure,morphology,size and distribution of carbide during the cladding process.TiC is partially decomposed under the effect of laser.Ti atoms release by TiC and Nb atoms in molten pool can participate in the precipitation process of carbide,and then formed(Nb,Ti)C with C atoms.Nb can delay the crystallization process of TiC and promote the formation of amorphous phase.The undecomposed TiC can act as the heterogeneous nucleation core and promote the formation and growth of the amorphous phase and(Nb,Ti)C on its surface,then evolve into the core-shell phase.The(Nb,Ti)C by the spontaneous nucleation and growth always presents spot-shaped with small size and distributes in the grain of matrix.The discontinuous netlike(Nb,Ti)C is eutectic substance that formed in the terminal stages of solidification and distributes along the grain boundary of matrix.

关 键 词：激光熔覆 碳化物 分解 析出物 

分 类 号：TG174.44[金属学及工艺—金属表面处理]