原位生成Ti(C_yN_(1-y))颗粒增强金属基复合熔覆层强化机制

Strengthening Mechanism of Ti(C_yN_(1-y)) Particle on Metal Matrix Composite Layer by Laser Cladding

以横流二氧化碳激光束作为诱导热源,利用激光熔覆工艺在铸钢基材表面形成含有Ti(CyN1-y)增强粒子的铁基熔覆层,熔覆层质量良好。用光镜、X射线衍射、扫描电镜、透射电镜等微观手段对复合熔覆层的组成、形貌及强化机制进行分析,并采用光学显微硬度计对熔覆层的显微硬度进行测试。结果表明:复合熔覆层是由粘结金属基体和呈弥散分布于其中的第二相粒子Ti(CyN1-y)组成。新生成的Ti(CyN1-y)硬质点颗粒形貌多呈不规则形状,在熔覆层中的增强相是以Ti(C0.3N0.7)和Ti(C0.2N0.8)这两种形式存在的。熔覆层的显微硬度HV0.2达到800～900。复合熔覆层中存在细晶强化、硬质点的弥散强化和固溶强化等强化机制。

Fe-based composite layer with Ti（ CyN1-y） particles was prepared on the surface of cast steel by laser cladding process using transverse CO2 laser beam as inducing heat source. The microstructures and strengthening mechanism of laser clad layer were analyzed by means of optical microscopy （ OM）, X - ray diffraction （XRD） instrument, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The microhardness of the layer was measured by using microhardness meter. The resuits show that the surface quality of laser clad layer which is composed of bonding metal matrix and second phase particle Ti （ CyN1-y） homogeneously dispersed is faidy （ C0.3N0.7 ） and Ti（ C0.2N0.8 ） come into being by some new chemical （CyN1-y） particles are irregular. The microhardness of laser clad good. The newly formed particles Ti combination reactions, and most of Ti layer distributes within HV0.2 800 -900. Microanalysis of the clad layer shows that the strengthening mechanism of the layer includes fine grain strengthening, dispersing strengthening of hard particles and solid solution strengthening.