The tribological behavior evolution of TiB2/Al composites from running-in stage to steady stage

The purpose of this study was to investigate the characteristics of a friction and wear transition from the running-in stage to the steady-state stage for an Al-based composite containing TiB2 particles and fabricated by a pressure infiltration technique. The dry sliding friction and wear behavior was investigated using a 3.98 mm diameter AISI 52100 steel ball-on-disk geometry under applied loads of 1 N and 3 N. Microstructural characterization and element distribution were carried out using scanning electron microscopy (SEM) and energy dispersive X-ray spectroScopy (EDS). 3D surface topographies and roughness of the wear surfaces were measured using confocal laser scanning microscopy (CLSM). The results indicated that the formation of a transfer film and boric acid (H3BO3) was the main reason for the low friction coefficient of about 0.16 at a load of 1 N. An increase of friction coefficient was caused by the abrasion of pulled-out TiB2 particles. In the running-in stage at an applied load of 3 N, abrasive wear dominated and resulted in the formation of grooves and pulled-out TiB2 particles. In addition, at a steady-stage friction coefficient of 0.6, severe three-body abrasive wear and oxidative wear were the dominant wear mechanisms. An excellent correlation was found between friction coefficient and surface roughness, as measured by 3D topography. (C) 2016 Elsevier B.V. All rights reserved.