Tribological Tests Effect on Changes in the Surface Layers of Iron-Containing Antifrictional Aluminum Alloys

Abstract

Antifrictional properties and surface parameters of Al-Si-Cu-Sn-Pb alloys have been investigated. The effect of iron addition (∼1%) on the structure and tribological properties of aluminum alloy samples has been studied. Tribological properties were explored using the "shoe-roller" scheme with step-by-step pressure changes. The investigations were carried out both in and without a lubricant. The SEM-(with elemental analysis) and SPM-microscopy methods were applied to study sample surface and under-surface layers of the samples at the transversal sections. After tribological tests have been carried out, the topography of both surface and under-surface layers at the transversal sections has been studied. During the tests without lubrication solid particles, presumably, oxides were formed. The particles increase the surface destruction, thus, doing their part of an abrasive and contributing to (scuffing) score. After testing in the lubricant particles containing silicon and copper and having a rounded shape were also formed. These particles remain on the surface and are rolled in the lubricant. They creating a kind of a "protective cover" contributing to the contact pair stable operation. The under-surface layer 50-100 µm thick formation was found at the sections after tribological tests without lubrication. The samples sections were prepared after testing with lubrication. The study of the samples sections demonstrated the formation of the under-surface layer with thickness 30-40 µm. The elements redistribution in these layers was shown. After the tribological tests were carried out, the counterbodies (rollers) were also explored. The SPM method has been shown the film formed on the surface is uneven in thickness after tests without lubrication. This leads to the macrorelief development during friction and can lead to (scuffing) score. On the contrary, after tests in lubricant the secondary structures film formed is distributed on the surface as a thin uniform layer. This film has the protective properties. It was shown that alloys containing iron (up to 1%) have good tribological characteristics when tested both in and without the lubricant. Thus, they can be used as antifrictional materials.

Defects and their interaction with lubrication in cupping process of recycled aluminum alloy sheet

“…The results showed that the samples with high iron content had greater wear resistance and hardness, but the friction coefficient would be improved, demonstrating that the iron phase enhanced the wear resistance of recycled aluminum. 16,17 These studies have contributed to the application of plastic forming of recycled aluminum alloys in production. There has been a great deal of research on the production processes and intermetallic compounds, but little research has been conducted on the effects of recycled aluminum alloy defects on plastic forming.…”

Evolution of the Mechanical Properties of the Surface Layers of Aluminum Alloys under the Conditions of Sliding Friction

“…One of the modern trends in materials design is the development of new antifriction aluminum alloys that can replace bronze in the manufacture of monometallic plain bearings [1,2,3,4,5]. The alloy material should have a wear resistance that is comparable with bronze resistance in friction contact with steel; and also steel counter body should wear weakly [6,7]. Replacing bronze with an aluminum alloy gives a noticeable economic effect, since aluminum is 2.5 times cheaper than copper in terms of unit weight and 3.3 times lighter than copper.…”