Surface modification technique of titanium alloy to improve the tribological properties using sub-ns laser irradiation in PAO oil

Abstract

Titanium alloy is widely used in different industrial applications. For the surface modification to improve the tribological properties, laser irradiation is a promising technology, which offers high efficiency, and high automation potential and geometrical flexibility. In this study, a novel method of surface modification for titanium alloys by carbonization using low fluence of laser irradiation in the atmosphere of PAO oil is proposed. Results show that the carbon content on the surfaces significantly increases with the laser shot number, with the laser irradiated spot showing little change of Ra. XPS analysis confirms that the carbon from the oil has bonded to the Titanium inside the alloy. By comparison with that irradiated without oil, the hardness of that irradiated in oil is much higher, demonstrating the feasibility of the surface modification of titanium carbide layer generation. To investigate the tribological properties, laser scanning irradiation in oil with different laser pulses were carried out to create laser modified areas and reciprocating ball-on-disk friction tests under oil lubrication were conducted. The laser modified areas show friction of 0.13, much lower than that of the unirradiated which is approximate 0.55, and the sliding lifetime of low friction is also increased with the laser pulse number. Moreover, by introducing patterning laser irradiation onto the uniformly irradiated area, the wear resistance can be further greatly improved, and the sliding lifetime can extend to 13 times of the optimal result of uniform irradiation.

Carbonization of a Molybdenum Substrate Surface and Nanoparticles by a One-Step Method of Femtosecond Laser Ablation in a Hexane Solution

“…With detailed process design and accurate adjustment of the precursor ratio and temperature, these mature technologies are exact synthesis methods for carbide nanomaterials. Pulsed laser ablation in liquids is also a flexible method to fabricate various NPs using bulk metal targets and solutions. − Moreover, femtosecond laser irradiation is a precision method of surface chemical modification, , which is becoming more and more efficient in precision surface processing, benefiting from the development of high-output lasers. , Franzel et al reported the synthesis of multiphasic inhomogeneous Mo/MoC NPs by picosecond laser ablation of Mo foil in ethanol . In this work, we irradiated a Mo substrate with a focused femtosecond laser beam in an oxygen-free organic hexane solution.…”

“…Pulsed laser ablation in liquids is also a flexible method to fabricate various NPs using bulk metal targets and solutions. 34 − 36 Moreover, femtosecond laser irradiation is a precision method of surface chemical modification, 37 , 38 which is becoming more and more efficient in precision surface processing, benefiting from the development of high-output lasers. 39 , 40 Franzel et al reported the synthesis of multiphasic inhomogeneous Mo/MoC NPs by picosecond laser ablation of Mo foil in ethanol.…”