Publication Date

2015

Document Type

Thesis

Committee Members

Sheng Li (Advisor), Nikolai Priezjev (Committee Member), Zifeng Yang (Committee Member)

Degree Name

Master of Science in Mechanical Engineering (MSME)

Abstract

Scuffing failure is a catastrophic thermal failure mode induced by the extreme surface temperature of the contacting components. As two mechanical elements roll against each other with high sliding motion, the frictional heat flux elevates the surface temperature to exceed the critical limit, resulting in the welding of the surfaces. The relative motion then tears the welded surfaces apart, causing the damage. Scuffing failure has been an important failure mode for rolling machine elements such as bearings and gears in aerospace applications, owing to the very high operating speeds. Recently, this failure mode has extended to the automotive field, where the power density of the transmission system has been continuously increasing. Employing a two-disk contact set-up, this experimental study investigates the scuffing load carrying capacity of two new alloys, which are paired with the lubricant of the Mil-PRF-23699 turbine fluid, in comparison to the baseline material of AISI 5120, under different speed conditions. The variations of the friction coefficient with the sliding are also quantified for all the three alloy-lubricant pairs under various load and speed conditions. It is observed that the new materials failed to improve the scuffing performance with the lubricant and the operating conditions considered. It is suggested to use a different additive package in the lubricant, which may be more effective for the formation of the protective tribo-film along the new material surfaces. It is also suggested to extend the operating speed range for higher speed applications.

Page Count

88

Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded

2015

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