Tribological performance of open and closed textured Ti-3Al-2.5V under effect of MoS2 as solid lubricant for aerospace applications

Abstract

Titanium alloys in the present study are studied for friction and wear behaviour using zirconia counter face. Nanosecond laser was used to fabricate circular and S-shape surface morphologies on Ti-3Al-2.5V substrates. The textured profiles are studied using 3D profilometer and field emission scanning electron microscope for texture ablation and universal tribometer is used to study the friction coefficient and wear behaviour of textured patterns. Friction and wear performance of textured surfaces are studied at applied load of 30, 45, 60 and 75 N. Circular textures of 100 µm while “S” textures of 360 µm length and 200 µm width are fabricated on Ti3Al-2.5-V substrates. Laser parameters used to create textures are laser power, scanning speed and laser frequency of 10-Watt, 350 mm/s and 10 KHz respectively. Friction and wear tests are performed on ablated titanium alloy surfaces for a siding distance of 100 m under the effect of virgin PAO4 lubricant with addition of 1 % by weight MoS2 particles. The results showed an ablation depth of 15.02 µm and 20.48 µm for circular and “S” textures respectively. Both the textured a reduced friction coefficient when lubricated with virgin PAO4 + 1 %MoS₂. At an increasing load from 30 to 75N, friction coefficient decreased from 0.0441 to 0.0382 for circular textures while it almost remained constant from 0.0699 to 0.0641 for “S” textures. “S” textures outperformed circular profiles by reducing friction coefficient by 50 % when MoS₂ particles are added in virgin PAO4 lubricating oil. In terms of wear resistance, open texture profiles were the most promising in contact situations likely to occur in lubrication when 1 % by weight MoS₂ particles were added into lubricant.