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Effect of friction surfacing parameters on the microstructural, mechanical properties, and wear characteristic of Al‑Cu‑Mg alloy coating reinforced by nickel aluminide

Farajollahi Ramezanali, Aval Hamed Jamshidi, Jamaati Roohollah

Archives of Civil and Mechanical Engineering

2022

Vol. 22, no. 2

art. no. e75, 1--18

This research has studied the microstructure, mechanical properties, and tribological properties of AA2024-Al3NiCu composite coating fabricated by friction surfacing. The Al3NiCu intermetallic was created in the aluminum matrix by adding nickel during the stir casting process and then performing the homogenization treatment. The results showed that with increasing the axial feeding rate from 87.5 to 125 mm/min and the rotational speed from 600 to 800 rpm, the coating efficiency grew up to 79%. Moreover, no significant microstructural differences (grain size, precipitate size, and morphology) were observed in different parts of the coating. Applying the coating at a rotational speed of 800 rpm, a traverse speed of 125 mm/min, and an axial feeding rate of 125 mm/min raised the hardness and shear strength of the AA2024 aluminum alloy substrate by 17% and 21%, respectively, while lowering its wear rate by 37%.

Thermal analysis of the industrial shoe brakes to reduce the risk of failure during braking

Ungureanu Miorita, Ungureanu Nicolae Stelian, Cosma Marius

Archives of Mining Sciences

2020

Vol. 65, no. 1

35--46

The aim of the study was to develop an assessment methodology for the temperature of the surfach of the friction pair during the braking for mine hoists. During the braking process, the work of friction is transformed into heat at the level of friction surfaces, and in case high temperatures are reached, the friction coefficient is influenced negatively, thus the risk of braking failure exists. In the first part of the study we measured the temperature of the friction surfaces for a particular case of hoist in real braking conditions. In the second part of the study is presented a theoretical model for the calculation of the temperatures resulted in the braking process for the hoist equipped with shoe brakes. The theoretical model for calculation was simulated numerically for a particular case in real braking conditions. Based on the conclusions resulted after the study, a series of hypotheses and recommendations for adjusting the control of the process parameters have been given out, in order to avoid the excessive heating of the brakes of the hoists and, respectively, their improved safety, maintenance and availability.

Effect of the friction films’tribosynthesis mechanism on the antifriction properties of composite materials based on nickel

Roik T., Gavrish A., Vitsuk J.

Selected Engineering Problems

2015

nr 6

81--90

In a paper the results of effect the friction films’ tribosynthesis mechanism on the antifriction properties of new composite materials based on nickel with solid lubricant CaF2 for high speed printing equipment have been presented. Paper generalizes the formation of antiscoring films, so called secondary structures, on the contact surfaces of the examined materials during friction process. Research of the friction surfaces was carried out using the method of Auger spectrum analysis. It was shown the mechanism of the antifriction films’ tribosynthesis depends on operation conditions, material and counterface chemical composition. It has been demonstrated that it is possible to predict and control the anti-friction properties of materials by technological means. To do this, it is necessary to choose a chemical composition of the friction pair, which could ensure the high functional properties, and could open a possibility purposefully to choose the operating conditions of the material in a printing equipment’s friction unit.