中文摘要：

以Ti和h-BN为原料,在不同配比（Ti与BN物质的量比分别为16∶1,8∶1,4∶1）的情况下,采用激光熔覆的方法在Ti-3Al-2V的表面原位合成TiB/TiN复合强化涂层,利用X-射线衍射（XRD）、扫描电子显微镜（SEM）、电子探针（EPMA）和透射电子显微镜（TEM）分析涂层显微组织结构,采用硬度和摩擦实验检测涂层物理性能。检测结果表明：1）B元素的含量对涂层显微结构和分布状态有重要影响;2）当熔池中B元素满足形成TiB的浓度时发生形核与生长,TiB优先沿着TiN晶粒晶界处形核和生长;3）随着BN含量的增加,熔覆层的显微硬度与耐摩擦性能增加,最大的硬度达到基体的5倍,单位时间内熔覆层的摩擦损失量不到基体磨损量的一半。

英文摘要：

TiN-TiB/Tibased composite coating is prepared on Ti-3Al-2V by laser cladding using different molar ratios of Tiand BN, the molar ratios of Tito BN are 16：1, 8∶1 and 4∶1, respectively. The coating is evaluated and characterized by means of X- ray diffraction（XRD）, scanning electron microscope（SEM）, electron probe microanalyzer（EPMA） and transmission electron microscope（TEM）, micro-hardness tester and wear testing machine. The results reveal that： 1） B content has great effect on the microstructure and distribution of phase TiB;2） TiB nucleates and grows when solubility of B is satisfied to form TiB. Besides, TiB tends to grow on the surface of TiN or grain boundary; 3） with increased BN content, the microhardness and friction performance is improved.The maximal hardness is about 5 times of the substrate. The wear depth is less than half of that of the substrate.