TiC-TiB2复合相钛基稀土激光熔覆层组织与性能

采用通快同轴送粉4002光纤激光器，在TC4表面熔覆制备了不同含量Y₂O₃的TC4+Ni45+Co-WC+Y₂O₃钛基复合耐磨涂层。采用XRD、SEM、EDS、EPMA测试研究了涂层微观组织，利用显微硬度计、摩擦磨损实验机和白光轮廓仪分析评价了涂层的显微硬度和摩擦学性能。结果表明，涂层生成相不随Y₂O₃含量变化而改变，主要包括Ti₂Ni、TiC、TiB₂以及α-Ti；未添加Y₂O₃涂层，生成相尺寸粗大，方向性明显；随着Y₂O₃的加入，涂层组织逐步细化，生成相方向性减弱；当Y₂O₃为3wt%时，涂层析出相以颗粒和短棒状相为主，合成了大量TiC-TiB₂依附生长复合相，经二维点阵错配度计算，TiB₂（0001）与TiC （111）错配度δ为0.912%，TiC与TiB₂形成了共格界面，可有效增加涂层组织分布均匀性；Y₂O₃含量为0wt%、1wt%和3wt%时，涂层显微硬度逐渐减小，磨损体积先增大后减小，摩擦系数逐渐降低；在TiC-TiB₂复合相的作用下，3wt% Y₂O₃涂层的耐磨、减摩性最优，涂层磨损机理为磨粒磨损。

Microstructure and properties of TiC-TiB2 composite phase Ti-based rare earth laser cladding layers

Wear-resistant TC4+Ni45+Co-WC+Y₂O₃ multi-channel overlapping Ti-based composite coatings with different Y₂O₃ mass fractions are cladded on TC4 by the TRUMPF 4002 coaxial powder feeding fiber laser. The microstructure of the coatings is tested and analyzed using XRD, SEM, EDS and EPMA. The microhardness and tribological properties of the coatings are analyzed by a microhardness tester, a friction and wear tester and a white light profiler. The results show that the phases in the coatings remain unchanged with different Y₂O₃ additions, mainly including Ti₂Ni, TiC, TiB₂ and α-Ti. In the coating without Y₂O₃, the phases are large in size with obvious directionality. With the addition of Y₂O₃, the microstructure of the coatings is gradually refined, and the directionality of the phases is weakened. When the Y₂O₃ addition is 3wt%, the precipitates in the coating are mainly particles and short rods, and a large number of TiC-TiB₂ dependent growth composite phases are synthesized in the coating. Based on the two-dimensional lattice misfit calculation, the misfit δ between TiB₂(0001) and TiC(111) is 0.912%, with TiC and TiB₂ forming the coherent interface, thereby effectively increasing the distribution uniformity of the coating microstructure. With the addition of Y₂O₃, the microhardness of the coating decreases gradually, the wear volume of the coating first increases and then decreases, and the friction coefficient of the coating decreases gradually. The antifriction and wear resistance of the 3wt% Y₂O₃ coating are the best under the action of the TiC-TiB₂ dependent growth composite phase, with the wear mechanism of the coating being abrasive wear.