Shen Shunquan, Chen Xiaoxiao, Chen Jianbo, Zhang Wenwu
Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315021, China.
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
Materials (Basel). 2024 Aug 29;17(17):4271. doi: 10.3390/ma17174271.
The TC4 titanium alloy is widely used in medical, aerospace, automotive, shipbuilding, and other fields due to its excellent comprehensive properties. As an advanced processing technology, laser processing can be used to improve the surface quality of TC4 titanium alloy. In the present research, a new type of rotational laser processing method was adopted, by using a beam shaper to modulate the Gaussian spot into a line spot, with uniform energy distribution. The effects of the laser power and rotational speed on the laser ablation surface of the TC4 titanium alloy were analyzed. The results reveal that the melting mechanism of the material surface gradually changes from surface over melt to surface shallow melt with the increase in the measurement radius and the surface roughness increases first, then decreases and, finally, tends to be stable. By changing the laser power, the surface roughness changes significantly with the variation in the measurement radius. Because low laser power cannot provide sufficient laser energy, the measurement radius corresponding to the surface roughness peak of the microcrack area is reduced. Under a laser power of 11 W, the surface roughness reaches its peak when the measurement radius is 600 μm, which is 200 μm lower than that of a laser power of 12 W, 13 W, and 14 W. By changing the rotational speed, the centrifugal force generated by the rotation of the specimen affects the distribution and re-condensation of the molten pool of the surface. As the rotational speed increases, the shallow pit around the pit is made shallower by the filling of the pit with molten material and the height of the bulge decreases, until it disappears. The surface oxygen content of the material increases first and then decreases with the increase in the measurement radius and gradually approaches the initial surface state. Compared with a traditional laser processing spot, the rotational line spot covers a larger processing area of 22.05 mm. This work can be used as the research basis for rotational modulation laser polishing and has significance for guiding the innovative development of high-quality and high-efficiency laser processing technology.
TC4钛合金因其优异的综合性能而广泛应用于医疗、航空航天、汽车、造船等领域。作为一种先进的加工技术，激光加工可用于提高TC4钛合金的表面质量。在本研究中，采用了一种新型的旋转激光加工方法，通过光束整形器将高斯光斑调制为线光斑，能量分布均匀。分析了激光功率和转速对TC4钛合金激光烧蚀表面的影响。结果表明，随着测量半径的增加，材料表面的熔化机制逐渐从表面过熔变为表面浅熔，表面粗糙度先增大，后减小，最终趋于稳定。通过改变激光功率，表面粗糙度随测量半径的变化而显著变化。由于低激光功率不能提供足够的激光能量，微裂纹区域表面粗糙度峰值对应的测量半径减小。在11W激光功率下，测量半径为600μm时表面粗糙度达到峰值，比12W、13W和14W激光功率下的测量半径低200μm。通过改变转速，试样旋转产生的离心力影响表面熔池的分布和再凝固。随着转速的增加，熔坑周围的浅坑因熔料填充而变浅，凸起高度降低直至消失。材料表面氧含量随测量半径的增加先增加后减小，并逐渐接近初始表面状态。与传统激光加工光斑相比，旋转线光斑覆盖的加工面积更大，为22.05mm。这项工作可为旋转调制激光抛光的研究提供基础，对指导高质量、高效率激光加工技术的创新发展具有重要意义。
