SUBJECT: Ph.D. Proposal Presentation
BY: Matthew Siopis
TIME: Friday, January 31, 2014, 11:00 a.m.
PLACE: Love Building, 109
TITLE: Wear at High Sliding Speeds and High Contact Pressures
COMMITTEE: Dr. Richard Neu, Co-Chair (ME)
Dr. Richard Cowan, Co-Chair (GTMI)
Dr. Naresh Thadhani (MSE)
Dr. Jeffrey Streator (ME)
Dr. Scott Bair (ME)


Metal on metal wear at high sliding speeds and high contact pressures results in the melting of one or both of the sliding solid bodies due to heat generated at the contact interface and can be characterized as melt lubrication. Typical engineering applications subjected to these extreme conditions include ultrahigh speed machining, rocket sleds, large caliber cannon, and electromagnetic launchers. Sliding speeds on the order of 1,000 m/s and contact pressures in excess of 100 MPa are common and difficult to replicate in a laboratory environment making the existing published experimental data rather limited. Several one of a kind test apparatuses have been designed to reproduce these conditions. A unique wedge experiment using a minor caliber electromagnetic launcher has been developed and implemented at Georgia Tech to investigate different tribomaterial pairs at sliding speeds up to 1,450 m/s and contact pressures up to 150 MPa. Three different combinations, 6061-T6 aluminum on C110-H2 copper, 6061-T6 aluminum on 1018 steel, and 6061-T6 aluminum on molybdenum are to be investigated. Microscopy of the slider will provide insight into the wear mechanism responsible for material removal, while wear data from experimentation will provide information regarding the contact interface physics with respect to the dissipation and partitioning of heat at the interface. These results are to be used to validate, extend or develop a melt lubrication model. Expansion of the current knowledge via experimentation and modeling will provide insight into designing more efficient and effective tribological systems subjected to similar operating conditions.