BRIGE: Microwear Mechanism of Carbon Film under Extremely High Speed Surface Contact accounting for Phase Transition and Oxidation

Texas Tech University, Lubbock TX

Investigators

Abstract

ECCS-1228059 PI: Yeo, Chang-Dong Institution: Texas Tech University Title: BRIGE: Microwear Mechanism of Carbon Film under Extremely High Speed Surface Contact accounting for Phase Transition and Oxidation ABSTRACT Intellectual Merit: The main objective of this BRIGE project is to investigate the microwear mechanism of surface protective carbon films under extremely high speed contact by accounting for thermomechanical and chemical stability of materials. An integrated research will be carried out through (1) analytical modeling and computational simulations of rough surface sliding contact, and (2) systematic experiments of high speed contact to measure the wear, phase transition, and oxidation of film and substrate materials. The unique features of the proposed research are to: (a) incorporate the in-situ changes of thermomechanical and chemical film properties into the analysis of wear behaviors, and (b) quantitatively measure the physical and chemical degradation of materials after high speed contact experiments. In analytical modeling, inhomogeneous contact stress and frictional heat flux will be obtained from an improved rough surface contact model. Individual flash temperatures of surface asperities (i.e., multi-points of heat source) will be applied into a theory of heat transfer to calculate the final temperature of carbon film and substrate. The phase transition changes the strength of carbon film, while the oxidation affects the adhesion energy of carbon atoms on substrate. In computational simulations, these transient material properties will be incorporated into finite element analysis code to investigate the in-situ wear performance of carbon film. To verify and improve the proposed analytical/computational researches, systematic experiments will be performed. Broader Impacts: It is expected that the proposed research will clearly answer the question of why carbon films experience critical wear under extremely high-speed contact even with mild contact load. The outcomes of this research will thus deliver scientific solutions for carbon films to (a) improve the reliability and accuracy of a system, and thus (b) reduce energy loss from unexpected friction and wear. The exciting research outcomes will be brought into the education of college students and K-12 outreach program. The exciting research outcomes will be brought into the education of college students and the K-12 outreach program. An undergraduate course in the area of tribology and interface engineering will be created including classroom lectures and hands-on laboratory experience, and undergraduate students will readily participate in actual research activities. A simplified mock-up experiment will be developed for K-12 students, which will increase their understanding on thermomechanical contact behavior in solid materials. In particular, to broaden the participation of underrepresented groups in engineering and science, a systematically designed mock-up will be provided in summer camps and lab experience for female and Hispanic K-12 students. Currently two female students are involved in the PI?s research. The PI will keep efforts on recruitment of the underrepresented students through close interaction with the Hispanic Student Society in Texas Tech University.