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采用在Ti-6Al-4V基体表面预置Ti-6Al-4V和硼、碳粉末按比例的混合粉,通过激光束扫描原位制备以钛的硼化物及碳化物为陶瓷相增强颗粒的钛基复合涂层。研究了单道及多道搭接激光工艺参数,包括脉冲频率、脉冲宽度、激光功率、激光扫描速率、预涂层厚度等对复合涂层显微组织及性能的影响。对熔覆样品横截面采用光学显微镜(OM),扫描电镜(SEM),X射线衍射仪(XRD)及显微硬度计等进行分析。优化的单道扫描工艺参数为:脉宽3.0 ms,脉冲频率15 Hz,激光线能量约11 J/mm。在此参数下进行多道激光搭接扫描,在Ti-6Al-4V基材上原位生成含有硼化钛及碳化钛硬质增强相及粘接相Ti-6Al-4V的钛基复合涂层,其复合增强相尺寸细小,在涂层中总体上分布均匀;形成的钛基复合涂层没有裂纹与气孔,与基体结合良好,多道扫描样品的显微硬度最高达800 HV,是基材硬度的2倍。优化参数下多道搭接样品的磨损量不到基体磨损量的21%。
Ti-6Al-4V substrate surface by pre-Ti-6Al-4V and boron, carbon powder proportion of the mixed powder by laser beam in situ preparation of titanium boride and carbide carbide particles as ceramic particles enhance the titanium Base composite coating. The effects of laser parameters such as pulse frequency, pulse width, laser power, laser scan rate and pre-coating thickness on the microstructure and properties of composite coatings were investigated. The cross-section of cladding samples was analyzed by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and microhardness tester. Optimized single-channel scanning process parameters: pulse width 3.0 ms, pulse frequency 15 Hz, the laser line energy of about 11 J / mm. Under this parameter, laser lap scanning was carried out to form a Ti-based composite coating containing titanium boride and titanium carbide hard reinforcing phase and Ti-6Al-4V bonding phase in situ on Ti-6Al-4V substrate , The composite reinforced phase size is small, the coating in the overall uniform distribution; the formation of titanium-based composite coating without cracks and pores, and the substrate well, multi-channel scanning sample hardness of up to 800 HV, is the substrate 2 times the hardness Multi-lap samples wear less than 21% of substrate wear under optimized parameters.