Effects of Normal Load and Sliding Distance on the Dry Sliding Wear Characteristics of Invar-36 Superalloy

Abstract

In the present study, the wear and friction behavior of Fe-based Invar-36 superalloy was investigated against an alumina ball under various sliding distances (25, 50, 75 and 100 m) and normal loads (5, 15 and 25 N) using a ball-on-disk tribometer. The worn surfaces were characterized using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and 2D-profilometry. The experimental results show that the coefficient of friction (COF) of Invar-36 (0.37-0.51) significantly decreased with increasing normal load, with a minimum value at 25 N. On the other hand, a slight increase in friction coefficient was observed with increasing sliding distance. Moreover, the wear volume of Invar-36 (ranged from 2.63 to 157.17×10-3 mm3) was observed to increase with increasing normal load and sliding distance. The specific wear rate found a constant increase from 1.98-2.99×10-5 to 6.33-11.45×10-5 mm3/Nm at increasing normal loads. On the contrary, the wear rate was gradually reduced when the sliding distance was increased especially at higher applied loads, due to the densification process. In addition, the wear mechanism was complex, including oxidation, adhesion and abrasion and plastic deformation, became more intense as the normal load or the number of sliding cycles was increased.