Yilbas B S, Ali H, Al-Sharafi A, Al-Qahtani H
Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.
Heliyon. 2019 Feb 5;5(2):e01211. doi: 10.1016/j.heliyon.2019.e01211. eCollection 2019 Feb.
Laser processing of Ti6Al4V alloy surface, via repetitive pulses, is realized incorporating the nitrogen assisting gas. The texture characteristics of the surface and wetting state are analyzed. The free energy of the laser treated surface is estimated. The influence of the dust particles on the treated and untreated surfaces is examined. The solution formed due to water condensate on the dust particles is evaluated. The adhesion of the mud dried solution on the treated and untreated surfaces is assessed through determining the tangential force required for the removal of the solution from the surface. The findings demonstrate that the high power laser repetitive pulse heating results in formation of the hieratically distributed micro/nano pillars on the workpiece surface. The wetting state of the processed surface remains hydrophilic because of the large gap size between the micro/nano pillars. The free energy of the laser textured surface is similar to that obtained for the TiN coated surfaces, which is because of the nitride compounds developed during the processing. The dried liquid solution strongly adheres at the surface and the force needed for removing the dried liquid solution is almost four times of the friction force at the surface. The liquid solution gives rise to locally scattered shallow pit sites on as received surface. This phenomenon does not occur for the laser treated surface, which is related to the passive layer developed on the surface.
通过重复脉冲对Ti6Al4V合金表面进行激光加工，并引入氮气辅助气体来实现。分析了表面的织构特征和润湿状态。估算了激光处理表面的自由能。研究了灰尘颗粒对处理过和未处理过的表面的影响。评估了灰尘颗粒上因水凝结而形成的溶液。通过确定从表面去除溶液所需的切向力，评估了干燥泥浆溶液在处理过和未处理过的表面上的附着力。研究结果表明，高功率激光重复脉冲加热导致在工件表面形成分层分布的微/纳柱。由于微/纳柱之间的间隙较大，加工表面的润湿状态保持亲水性。激光织构表面的自由能与TiN涂层表面的自由能相似，这是由于加工过程中形成了氮化物化合物。干燥的液体溶液强烈附着在表面，去除干燥液体溶液所需的力几乎是表面摩擦力的四倍。液体溶液在原始表面上产生局部分散的浅坑部位。激光处理过的表面不会出现这种现象，这与表面形成的钝化层有关。
