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.

Investigation of the wear behavior of FeNi36 alloy cut by WEDM method under different loads

“…The COF obtained from the untreated Invar-36 surface is consistent with results obtained by Kanca (2022) who found the COF between Invar-36 and the alumina ball to be 0.43 at the sliding distance of 250 m under 20 N. In both the untreated and WEDM-treated samples, the COFs decreased with the increase of the applied load, which has been reported by previous researchers such as Tressia and Sinatora (2023). This behavior is related to the reduction in the contact area due to the introduction of the wear particles at the bearing surface with the increase in the test load (Sarkar, 1980;Kanca, 2023).…”

“…With the increase in the applied load in the wear tests, the wear track width and depth values (Table 4) and thereby the wear volume increased in both untreated and WEDM-treated Invar-36 (Supplementary Figure 6a). The increase in wear volume with increasing load is owing to the formation of more intense shear stress and plastic deformation on the sample surface (Kanca, 2023). SEM images (Supplementary Figures 7–12) taken from the wear surfaces in this study confirm the formation of more intense plastic deformation with increasing load.…”