(華南理工大學(xué) 機(jī)械工程學(xué)院， 廣州 510641)
摘 要: 將激光熔覆與激光表面氮化技術(shù)相結(jié)合制取TiNi-TiN梯度材料。采用先進(jìn)的六孔同軸送粉噴嘴系統(tǒng)， 分別將純Ti、 Ni粉末按一定比例送入激光熔化區(qū)，在粉末熔化過程中發(fā)生Ti、 Ni間高溫合成反應(yīng)， 原位合成一定厚度的TiNi金屬間化合物熔覆層， 然后將原位合成的熔覆層在富氮氣氛中進(jìn)行激光氮化處理， 表面形成一層金黃色的TiN。 利用光學(xué)顯微鏡和掃描電鏡觀察了熔覆層組織， 并測量了熔覆層及氮化層的厚度 。 對不同工藝參數(shù)獲得的熔覆層用X射線衍射儀進(jìn)行了物相鑒定， 并對氮化試樣的熔覆層進(jìn)行了顯微硬度分布測試， 得出了較好的制取TiNi-TiN梯度材料的工藝參數(shù)為： 激光功率600 W， 掃描速度0.5 m/min， 鈦送粉量2.5 g/min; 鎳送粉量3.2 g/min。
關(guān)鍵字: 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
