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Article Citation - WoS: 2Citation - Scopus: 2Influence of Surface Finish on Flexural Strength and Microhardness of Indirect Resin Composites and the Effect of Thermal Cycling(Taylor & Francis Ltd, 2012) Bicer, Arzu Zeynep Yildirim; Dogan, Arife; Dogan, Orhan Murat; Sengonul, Merih Cemal; Artvin, ZaferThis study investigated the effect of surface finish and thermal cycling procedures on flexural strength and surface microhardness of three indirect resin composites, Artglass (R), Signum (R), and Solidex (R). The specimens were prepared in sufficient number and size according to flexural and microhardness test requirements (n=10). Scanning electron microscopy-energy dispersive x-ray (SEM-EDX) analysis was also used for studying the morphology, dispersion, and elemental compositions of fillers. The EDX results showed that Artglass contained 1.57% aluminium oxide (Al2O3), 53.29% silicon dioxide (SiO2), and 2.62% barium oxide (BaO); Signum had 55.69% silicon dioxide (SiO2) and Solidex had 44.99% silicon dioxide (SiO2) of total mass. Artglass appeared to display the best flexural strength values under all the test conditions employed (range: 116.8 +/- 32.18 to 147.8 +/- 47.97 MPa), and it was followed by Signum (range: 93.7 +/- 22.84 to 118.0 +/- 33.45 MPa). Thermal cycling did not seem to have affected the flexural strength of Artglass and Signum (p > 0.05); however, it led to a significant decrease, from (110.5 +/- 20.69 MPa) to 74.0 +/- 13.30 MPa (p < 0.001), in the strength of polished Solidex specimens. While surface microhardness of the three materials increased by polishing ( Artglass: 55.7 +/- 2.64/74.1 +/- 8.63 Vickers Hardness Numbers (VHN); Signum: 44.8 +/- 3.12/60.7 +/- 4.50 VHN; Solidex: 44.0 +/- 2.31/53.4 +/- 3.58 VHN for unpolished/polpolished specimens), thermal cycling had a deleterious effect on this property (p < 0.001).Article Citation - Scopus: 5Micro-Wedm of Ni55.8ti Shape Memory Superalloy: Experimental Investigation and Optimisation(Inderscience Publishers, 2021) Meshri,H.A.M.; Akar,S.; Seyedzavvar,M.; Kiliç,S.E.Nickel-titanium superalloy has gained significant acceptance for engineering applications as orthotropic implants, orthodontic devices, automatic actuators, etc. Considering the unique properties of these alloys, such as high hardness, toughness, strain hardening, and development of straininduced martensite, micro-wire electro-discharge machining (μ-WEDM) process has been accepted as one of the main options for cutting intricate shapes of these alloys in micro-scale. This paper presents the results of a comprehensive study to address the material removal rate (MRR) and surface integrity of Ni55.8Ti shape memory superalloy (SMA) in the μ-WEDM process. The effects of discharge current, pulse on-time, pulse off-time, and servo voltage on the performance of this process, including MRR, white layer thickness, surface roughness, and micro-hardness of the machined surface, were investigated by multi-regression analysis using response surface methodology (RSM). The optimisation of input parameters based on the gradient and the swarm optimisation algorithms were also conducted to maximise the MRR and minimise the white layer thickness, surface roughness, and micro-hardness of the machined samples. © 2021 Inderscience Enterprises Ltd.. All rights reserved.Article Comparative Analysis of Vibration Axis Effects on Ultrasonic Vibration-Assisted Machining of Inconel 718(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Namlu, R.H.; Kilic, Z.M.Inconel 718 is widely utilized in critical engineering sectors, particularly aerospace, owing to its exceptional creep resistance, corrosion resistance, and retention of mechanical strength at elevated temperatures. However, its high hardness, low thermal conductivity, and strong work-hardening tendency make it extremely difficult to machine using conventional techniques. Ultrasonic Vibration-Assisted Machining (UVAM) has emerged as an effective strategy to overcome these limitations by superimposing high-frequency, low-amplitude vibrations onto the cutting process. Depending on the vibration direction, UVAM can significantly change chip formation, tool–workpiece interaction, and surface integrity. In this study, the influence of three UVAM modes—longitudinal (Z-UVAM), feed-directional (X-UVAM), and multi-axial (XZ-UVAM)—on the machining behavior of Inconel 718 was systematically investigated. The findings reveal that XZ-UVAM provides the most advantageous outcomes, primarily due to its intermittent cutting mechanism. Compared with Conventional Machining (CM), XZ-UVAM reduced cutting forces by up to 43% and areal surface roughness by 37%, while generating surfaces with more uniform topographies and smaller peak-to-valley variations. Furthermore, UVAM enhanced subsurface microhardness as a result of the surface hammering effect, which may improve fatigue performance. XZ-UVAM also effectively minimized burr formation, demonstrating its potential for high-quality, sustainable, and efficient machining of Inconel 718. © 2026 by the authors.
