Joint effect of surface microtopography and near-surface structure on microcontact conditions. (Quarterly progress report, 1 February 1989-30 April 1989).

摘要

Pin-on-disk tests are now complete on all 27 ceramic Phase I specimens. The relationship between measured pin wear and both mean asperity flash temperature and mean real contact stress is examined for the subset of tests that was run at high sliding speed. Fracture indentation tests were completed at the University of Michigan on a second set of 9 ceramic specimens. The last set of nine specimens for indentation testing have been delivered to the University of Michigan. A total of 45 hardened M50 high alloy steel disks have been coated with WC, TiC and TiN and comprehensive surface roughness measurements have been made. A number of 3/8 in. diameter balls have been similarly coated. These balls will serve as the pin element in pin-on-disk tests to be performed at ORNL. Nonlinear curve fits were made to a series of correction factors that account for the presence of a coating in computing the load and area of spherical asperities. The fitted functions have been incorporated into a simulation model for analyzing the behavior of coated asperities. Example calculations are given for a steel substrate with the coating modulus spanning the range from 1/10 to 10 times the substrate modulus. 3 figs., 3 tabs.