大功率CO2激光原位直接反应合成TiN/Ti 复合材料的研究

使用大功率CO₂激光原位直接反应合成TiN /Ti 复合材料, 分析了材料的微观结构、物相组成、成分及显微硬度分布。结果发现: 氮化层是富钛结构的, 由TiN 相和α-Ti 构成, TiN 以枝晶形式在氮化层均匀分布。材料横截面显微硬度连续变化。氮化层的氮化程度随激光作用时间的增加而增加, 辐照的激光能量密度越高, 氮化层的厚度越大。激光功率密度, 激光扫描速度, 氮气喷射压强分别为3. 35×105W·cm-2, 300mm·min-1, 0.35M Pa 时, 材料表面硬度值达到Hv1600, 氮化层的厚度有350Lm。

STUDY OF TiN/Ti COMPOSITE MATERIAL BY REACTIVE CO2 LASER DIRECT SYNTHESIS IN SITU

TiN/Ti composite material was prepared with high power CO2 laser focused on the surface of titanium alloy in nitrogen ambient. The microstructure, composition and micro hardness of the material were analyzed with SEM, XRD, EP (electron probe) and Micro hardometer. The results show that nitride layers consist of TiN and α-Ti phase. TiN dendrites distribute in nitride layer homogeneously. The nitride level and maximum micro hardness increase with reaction time increasing. The cross section micro hardness of the material changes continuously. The higher laser energy density, the deeper nitride layers. The depth of nitride layer and the surface micro hardness are 350μm and Hv1600 as the laser power density is of 3.35×105 W·cm-2 , scanning velocity of 300mm·min -1 , and nitrogen pressure of 0.35MPa respectively.