Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Ataturk University, Fen Bilimleri Enstitüsü, Makine Mühendisliği Anabilim Dalı, Turkey
Approval Date: 2019
Thesis Language: Turkish
Student: HALİL ÇELİK
Supervisor: Halim Kovacı
Abstract:
The majority of damages such as wear, fatigue, corrosion and fracture are caused by the surfaces of the materials. Many surface treatments are used to eliminate these damages. Plasma nitriding, a thermochemical surface treatment, is a surface treatment used to improve the tribological properties of surfaces exposed to wear. In recent years, in order to increase the efficiency of plasma nitriding process, a duplex surface treatment has been proposed with the effect of both processes on the surface by applying the shot peening process which is a pre-treatment. In addition to all these processes, another issue is related to how the magnetic field affects surfaces. Because, as it is known with the advancement of today's technology, many materials are exposed to magnetic field. Although many studies have been conducted on the effect of magnetic field on wear, studies such as the wear of duplex surface treated materials under magnetic field have remained quite shallow. The main purpose of this study characterize the effects of this duplex process on the friction and wear behaviour of metallic materials under magnetic influences. For this aim, AISI 4140 steel specimens were shot peened at 16, 20 and 24 Almen intensities and were nitrided with 500°C plasma using a 50N2% -50% H2 gas mixture for 1 and 4 hours. Wear tests were performed under non-magnetic and magnetic field to specify tribological properties of the specimens and structural and mechanical properties of specimens were analyzed by XRD, SEM, 3D profilometer and microhardness tester. As a result of the studies, the duplex surface treatments were carried out to determine the mechanical properties and wear performance of the material; surface hardness, by creating residual stresses on the surface, by reducing the grain size of the surface and by forming hard phases on the surface of the material. In addition, the magnetic field raised the surface energy of the metallic materials to form an oxide film on the surface.It was concluded that this film layer prevented the wear of the surface more than normal during wear and as a result the tribological properties of the surface were positively affected.