Abstract

Adding micro textures by laser texturing technology to one or both sliding surfaces of relative motion has been recently studied as an environmentally friendly and efficient way to improve tribological behaviors of metals, including the reduction of friction and wear. Meanwhile, protic ionic liquids are gradually gaining increasing attention as neat lubricants and lubricant additives because of their simple synthetic procedures where the halogen elements can be easily avoided from their molecular components. The eco-friendly protic ionic liquids can be strongly adsorbed on the substrate surfaces to form ordered lubricant films which prevent the rubbing pair from direct contact. Also, protic ionic liquids may have tribo-chemical reactions with the contact materials to generate the tribo-layer on the top of the surface which may be responsible for good tribological performance. This study focuses on the influence of laser micro textures on the tribological performance of titanium alloy—Ti6Al4V lubricated by polyalphaolefin (PAO) 40 and its mixture of 2-hydroxyethylammonium 2-ethylhexanoate (Eet). Multiple texture types are created by varying the energy density of pulse and the distance between dimples. The parameter adaptations modify the outer layers of the Titanium alloy with specific topographies and properties, and the microstructural modifications and oxidation processes lead the textured surfaces with different surface roughness and wettability. A custom-designed reciprocating ball-on-flat tribometer was used to assess the tribological performance of the textured surfaces at room temperature. The wettability of these tribological systems is characterized by dropping lubricants on textured and untextured surfaces to measure the contact angle. The friction coefficient and wear volume of textured surfaces are decreased compared to the untextured surface under different lubricant conditions. Compared to the traditional lubricant – PAO40, when employing protic ionic liquid mixture, the more significant reduction of friction and wear volume can be observed, especially for the textured surface with variations of energy densities. It is believed that both laser surface texturing and the use of PILs have a positive effect to improve the tribological properties of titanium alloys under a variety of extreme conditions. Meanwhile, the combination of laser texturing technology and protic ionic liquid has been proved as a more efficient way to reduce the frictional behavior of titanium alloys, which exhibits the great potential of using protic ionic liquid for the titanium applications to extend their tribology applications in aerospace and other fields.

Library of Congress Subject Headings

Titanium alloys--Surfaces; Surfaces (Technology)--Mechanical properties; Tribology; Lubrication and lubricants; Ionic solutions

Publication Date

7-2021

Document Type

Thesis

Student Type

Graduate

Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)

Advisor

Patricia Iglesias Victoria

Advisor/Committee Member

Michael Schertzer

Advisor/Committee Member

Rui Li

Campus

RIT – Main Campus

Plan Codes

MECE-MS

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