(华南理工大学 机械工程学院， 广州 510641)
摘 要: 将激光熔覆与激光表面氮化技术相结合制取TiNi-TiN梯度材料。采用先进的六孔同轴送粉喷嘴系统， 分别将纯Ti、 Ni粉末按一定比例送入激光熔化区，在粉末熔化过程中发生Ti、 Ni间高温合成反应， 原位合成一定厚度的TiNi金属间化合物熔覆层， 然后将原位合成的熔覆层在富氮气氛中进行激光氮化处理， 表面形成一层金黄色的TiN。 利用光学显微镜和扫描电镜观察了熔覆层组织， 并测量了熔覆层及氮化层的厚度 。 对不同工艺参数获得的熔覆层用X射线衍射仪进行了物相鉴定， 并对氮化试样的熔覆层进行了显微硬度分布测试， 得出了较好的制取TiNi-TiN梯度材料的工艺参数为： 激光功率600 W， 扫描速度0.5 m/min， 钛送粉量2.5 g/min; 镍送粉量3.2 g/min。
关键字: TiN-TiNi梯度材料； 激光熔覆； 原位合成； 激光氮化
laser cladding and laser nitriding
（ Institute of Mechanical Engineering,
South China University of Technology, Guangzhou 510641, China）
Abstract: Laser cladding， together with laser nitriding was used to in-situ synthesize TiNi-TiN gradient coating on the pure nickel substrate. During the cladding process, Ti and Ni powders react with each other and in-situ synthesized a cladding layer composed of Ti, Ni intermetallic compounds. Then, laser nitrding was carried out in nitrogen-rich atmosphere. A golden yellow TiN layer forms on the cladding surface. Microscopy and scaning electron microscopy were used to investigate the microstructure of the cladding layer. The thickness of TiN layer and the clad layer were measured respectively. X-ray diffractometry was used for phase identification. Also the microhardness profile of the cladding layer was tested with Vicker hardness tester. The optimum process parameters were obtained: laser power 600 W; scanning velocity 0.5 m/min; Ti powder feeding rate 2.5 g/min; Ni powder feeding rate 3.2 g/min.
Key words: TiN-TiNi gradient material; laser cladding; in-situ synthesis; laser nitriding layer
