EXPERIMENTAL STUDY OF TRIBOLOGICAL PERFORMANCE OF LASER TREATED STEEL SURFACE WITH SMART COATING UNDER THE VIBRATIONAL LOADING

Abstract

High-performance materials such as stainless steels and nickel based super alloys are widely used in demanding applications where high mechanical and thermal properties are required. The applications of super alloys are mainly found in jet engines, power plants and gas turbines demanding high fatigue strength, corrosion and oxidation resistance as well as wear resistant properties. In order to use them, they go through various machining processes such as milling, turning, cutting, polishing etc. until the final product is achieved. Modern manufacturing industries employs various machining tools and technologies to improve the machining process of heat resistant super alloys. However, there are still challenges which needs to be addressed. Among them, adhesive wear of the machining tools is one of the main wear mechanism during the tribological interaction of tool and workpiece, preventing them to achieve the desired quality and surface finish of the end product. Moreover, it damages the tool reducing its lifecycle and in return, increasing the production cost. Among the cutting tools tungsten carbide (WC/Co) tools coated with TiAlN coating due to their good high temperature performance are extensively used. Nonetheless, these coatings still face issue like adhesive wear, abrasion, oxidation at higher temperature damaging the tools and subsequent machining. Therefore, it is imperative to understand the initiation mechanism of adhesive wear during the tribological interaction of super alloys and coated cutting tool material. In this research work, the tribological response of two coatings deposited by physical vapour deposition (PVD), having the composition Ti60Al40N and Ti40Al60N have been studied against two super alloys material, i.e. Inconel 718 and stainless steel 316L. A high temperature SRV (Schwingung (Oscillating), Reibung (Friction), Verschleiß (Wear)) reciprocation friction and wear test set up was employed to investigate the friction behaviour, wear rate and dominant wear mechanisms. For Ti60Al40N coating, the experimental results revealed that generally, friction increases in case of sliding against Inconel 718 up to 400 °C and drops at 760 °C. A high wear volume at room temperature and a decrease to a minimum at 760 °C has been observed for Inconel 718. On the other side, Stainless steel 316L (SS 316L) faces a continuous rise in friction coefficient with highest value at 760 °C during sliding against Ti60Al40N coating. Wear is highest at 400 °C for SS 316L pin. The worn surfaces shows that both workpiece materials experience increase in material transfer due to adhesive wear with rise in temperature. At 400 °C, adhesion is the primary wear mechanism for both workpiece materials. A further rise in temperature to 760 °C promotes the adhesive wear through oxides formation on both material surfaces. Similarly, Ti40Al60N coating shows the same friction behaviour with change in average steady state friction values for both material of Inconel 718 and SS 316L. Both workpiece materials responds in a similar way to wear volume loss, i.e. lowest at room temperature and highest at 760 °C. For Inconel 718, transfer of coating constituents on to the Inconel 718 pin surface was detected and associated with coating rupture and peeling, exacerbating with rise in temperature. Adhesion, abrasion, and oxidation are primary wear mechanisms at 400 °C and 760 °C. For SS 316L, coating vi transfer only happen at 400 °C. No damage of coating at 40 °C, a complete damage at 400 °C, and formation of dense porous oxides layers at 760 °C have been noticed. At 400 °C, adhesion, abrasion, and chipping while at 760 °C, adhesion, three body abrasion, ploughing and oxidation are the main wear mechanisms. Additive manufacturing has revolutionized component fabrication by enabling the production of complex geometries and tailored surface textures unachievable by traditional methods. However, AM surfaces often exhibit intrinsic roughness, porosity, and microstructural heterogeneity, which can detrimentally affect frictional characteristics and accelerate wear under operational stresses. To mitigate these drawbacks, laser surface treatment is employed as an effective post-processing technique to modify surface hardness, induce compressive residual stresses, and homogenize surface microstructure, thereby improving wear resistance and mechanical integrity. The incorporation of advanced smart coatings—such as magnetorheological fluids and shape- memory polymers—further enhances the tribological system by providing adaptive vibration damping and frictional modulation capabilities, which are particularly advantageous in high- frequency vibrational environments. The research methodology involves detailed finite element analysis (FEA) using ANSYS Workbench, simulating a representative pin-on-disk tribological configuration under dry sliding conditions coupled with various vibrational load profiles. Comparative simulations across three primary surface conditions—untreated AM, laser-treated, and smart-coated laser-treated surfaces—are conducted to quantify and analyze key tribological metrics including coefficientof friction, wear depth, contact pressure distribution, and vibrational response characteristics. The simulation results reveal a marked improvement in tribological performance for laser-treated and smart-coated surfaces, exhibiting reduced frictional forces, diminished wear rates, and superior vibration attenuation compared to conventional AM surfaces. These findings elucidate the synergistic effects of combining advanced manufacturing, surface engineering, and smart material technologies to realize robust, adaptive, and long-lasting tribological systems.