Research of Surface Wear Resistance of Aluminum Alloy Modified with Minerals using Sclerometry Method

Abstract

Improving the wear resistance of the surface of metal parts used in various industries is one of the relevant areas of materials science. The aim of this work was a comparative study of the wear resistance of a sample of an aluminum alloy (EN AW-2024, an aluminum alloy of the Al-Cu-Mg system) modified with ultrafine particles of minerals using the sclerometry method, which makes it possible to measure the physicomechanical properties of the material at the microscale, as well as determining some tribological parameters (hardness and elastic modulus) of a duralumin sample with a mineral coating.Wear resistance was measured using a NanoScan-4D scanning hardness tester using the multi-cycle friction method using a sapphire sphere with control of the pressing force and the deepening of the tip into the sample. The use of such a measurement system is especially important when testing thin modified layers, when the layer thickness is comparable with the surface roughness parameters and the influence of the substrate is excluded.The measurement results showed that the wear resistance of the surface of an aluminum alloy sample modified with ultrafine mineral particles increased by more than 12 times compared to the wear resistance of an aluminum alloy surface without modification. Also, measurements of the hardness and elastic modulus of the surface of the modified sample were performed taking into account the features of measuring the mechanical parameters of thin layers.The obtained parameters of the modified surface of the aluminum alloy can be further used to build models of the processes of friction and wear of the surface modified by ultrafine particles of minerals. The lack of an acceptable explanation of the nature of the special properties of the surface modified by particles of minerals of natural origin does not exclude the use of the observed effects to significantly increase the resource of various parts and mechanisms.

Tribochemical Interaction of Multicomponent Aluminum Alloys During Sliding Friction with Steel

“…To get reasonable results the test methods should be as close as possible to the actual operating conditions. In this regard, sclerometry provides rather limited information about the real tribological properties of the material, since the conditions for the formation of secondary structures are completely different from the real ones [21,48].…”

Features of Measuring the Hardness of a Metal Surface Modified with Ultrafine Particles of Minerals

“…For example, changing only some technological regimes using the technology of mineral coatings [1], which ensure that microparticles of minerals enter the metal, it is possible to obtain modified layers of various roughness Ra (average roughness) on structural steel samples, differing by almost an order of magnitude [2]. The interest in modified layers enriched with microparticles of minerals is due to their prospects as wear-resistant and/or antifriction coatings on the surfaces of friction pairs of various metals -steels [1], titanium [3], aluminum [4] operating in an aggressive environment -abrasive, marine water, in the presence of gases, acid solutions, under thermocyclic loads [5,6]. Studies show that the thickness of the modified layer, the coefficient of friction, the hardness of the layers depend both on the composition of the mineral mixtures and on the modes of particles entering the metal and the properties of the modified metal surface.…”

“…There are common problems for all methods in determining the hardness of thin layers and coatings, such as the effect of the substrate, surface roughness, and the presence of residual stresses, which can make a significant correction in the measurement results [4]. For example, the influence of the base metal substrate in measuring hardness consists in the fact that the recorded response of the material during measurement depends on the modified layer and on the properties of the metal volume [13].…”

Coatings from minerals on stainless steel threaded compounds

“…One of the types of technologies currently developing surface hardening of a metal surface is the socalled technology of mineral coatings [6]. The essence of the technology is to create a modified surface layer with a thickness of 5-30 microns by plastic deforming it with the help of ultrasonic and mechanical effects that activate the incorporation of ultrafine mineral particles into the bulk of the metal [7,10]. The modification of the surface of a metal part is carried out at room temperature, locally, without the use of vacuumized space, baths, furnaces, which gives the technology additional marketing advantages [6][7][8].…”

“…The basic procedure for modifying the surface of a metal according to the technology of mineral coatings consists of four stages [6,7]: electrospark surface treatment; surface texturing; the introduction of ultrafine particles into the surface layer using an ultrasound unit; use of ball and roller knurling in surface treatment. As a result, a surface layer is formed that has high antifriction, wearresistant, extreme-pressure properties [8][9][10]. Another part of the technology is mixtures of ultrafine minerals, the particles of which are introduced into the surface space using some of these methods.…”