A fiber laser was used to nitride Ti–6Al–4V titanium alloy the effect of the process parameters on the surface morphology was studied. The surface chemical composition of the nitride layer and the phase of black powder on the surface were analyzed, the two-dimensional and three-dimensional surface topography of the nitride layer surface were measured, and the cross-section microstructure of the nitride layer was photographed. The effects of laser power, laser scanning speed, nozzle distance, and nitrogen flow rate on the surface morphology were studied. The experiments show that the laser power mainly affects the surface oxidation, the laser scanning speed mainly affects the surface roughness, and the nozzle distance has a great influence on the surface morphology. The gas flow rate, however, had a slight effect on the surface morphology. A large heat input and a high nitrogen flow rate caused an increase in TiN and TiO₂ black powders. Surface oxidation did not affect the formation of a continuous TiN layer nor surface roughness. Finally, the critical energy density leading to increased surface roughness was calculated.

中文翻译：

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Ti-6Al-4V光纤激光氮化层的表面形貌

光纤激光器用于氮化Ti-6Al-4V钛合金，研究了工艺参数对表面形貌的影响。分析了氮化物层的表面化学成分和表面上的黑色粉末相，测量了氮化物层表面的二维和三维表面形貌，并拍摄了氮化物层的横截面微观结构。研究了激光功率，激光扫描速度，喷嘴距离和氮气流量对表面形貌的影响。实验表明，激光功率主要影响表面氧化，激光扫描速度主要影响表面粗糙度，喷嘴距离对表面形态影响很大。然而，气体流速对表面形态有轻微的影响。₂黑粉。表面氧化既不影响连续TiN层的形成，也不影响表面粗糙度。最后，计算了导致表面粗糙度增加的临界能量密度。