Accession Number : AD0787838

Title :   Wear Particle Formation Mechanisms.

Descriptive Note : Annual rept. Sep 73-May 74,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE MATERIALS PROCESSING LAB

Personal Author(s) : Koba,Harry ; Cook,Nathan H.

Report Date : MAY 1974

Pagination or Media Count : 98

Abstract : A lightly loaded, room temperature, lubricated bronze on steel sliding system was studied to determine the mechanisms of wear debris formation. Examination of the sliding surfaces was carried out with both optical and scanning electron microscopes. The lubricating oil was processed through a Ferrograph Analyzer to remove the wear particles so that they could be examined. It was found that both the bronze and steel surfaces were capable of a high degree of strain during sliding contact. The high surface strain caused by repeated surface contact during sliding allowed for the nucleation and progressive propagation of surface and sub-surface cracks, to produce wear particles. Cross-sections showed cracks nucleating at voids which had become elongated due to a sub-surface strain gradient. Material transferred from one surface to another appeared to aid in the surface smoothening process. Large pieces (20 micrometers and over) were found to be made up of many smaller wear particles which became compacted due to sliding contact. (Modified author abstract)

Descriptors :   *Wear, *Bronze, *Steel, Particles, Fracture(Mechanics), Crack propagation, Sliding, Friction, Deformation, Strain(Mechanics), Lubricating oils, Deformation, Surface properties, Microscopy, Electron microscopy

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE