Tribological Performance of Molybdenum Stellite Alloys under Dry-Sliding Wear

Abstract

Elements tungsten and molybdenum are the key constituents of Stellite alloys as solutes to strengthen the solid solution matrix. Meanwhile, they also promote formation of W-rich and Mo-rich carbides when present in large quantities in high-carbon Stellite alloys. Extensive studies on tungsten Stellite alloys, in particular, Stellite® 6, have been reported in the literature; however, molybdenum Stellite alloys, especially, the influence of Mo content on the performance of the alloys, have been rarely investigated. In this research, the tribological performance of three molybdenum Stellite alloys with varying C and Mo contents is studied using pin-on-disk dry-sliding wear test at ambient temperature, focusing on the effect of test duration and interrupted test on the wear behavior of the alloys. The worn surfaces are examined using SEM/EDS, and the analyses of the surface morphologies help explore the wear mechanisms of these alloys in dry-sliding condition. A wear model is developed for molybdenum Stellite alloys, based on the Archard equation in check with the wear test data, using hardness as a controlling factor.