Articles
Publication Date: 2024
Journal of Materials Engineering and Performance (10599495)33(6)pp. 2616-2622
CMSX-4 nickel base superalloy is the second-generation alloy of this single crystal, which has improved its mechanical properties due to the lack of grain boundaries. According to the working conditions in using this superalloy, achieving less surface defects and lower surface roughness after the manufacturing process is very important. Therefore, the comparison of the surface of this superalloy after grinding, wire electro discharge machining (WEDM) and electrochemical machining (ECM) has been investigated by scanning electron microscope (SEM) and surface roughness. Surface roughness after WEDM, ECM and grinding are 3.337, 0.549, and 0.458 micro-meter, respectively. ECM and grinding processes are suitable from the point of view of surface roughness. On the other hand, in the SEM images after ECM, the defects caused by this process were not observed (compared to the other two processes). Besides, hardness after WEDM, ECM and grinding are 38.9, 39.7 and 40.1 HRC respectively. To conclude, the ECM process has desirable results and is a suitable alternative process for manufacturing parts with smooth surface and less surface defects. © ASM International 2023.
Publication Date: 2024
Scientia Iranica (23453605)31(20)pp. 1880-1888
Modeling and determining the optimal conditions for the Jet Electrochemical Machining (Jet-ECM) process is critical. In this study, a hybrid approach combining numerical and Design of Experiments (DOE) methods have been applied to model and determine the optimal conditions for Jet-ECM. The voltage (V), inner tool diameter (I), initial machining gap (G), and electrolyte conductivity (C) are considered input variables. Additionally, dimensional accuracy (E) and machining depth (D) are response variables. Twenty-seven numerical simulations have been performed using the Box–Behnken design to implement the Response Surface Methodology (RSM). Consequently, two mathematical models have been obtained for these response variables. The effects of the input variables on the response variables are investigated using statistical techniques such as variance analysis. Furthermore, the desirability function approach has been applied to determine the optimal conditions for dimensional accuracy and depth of machining. The results show that the optimal values for achieving maximum depth of machining while maintaining a dimensional accuracy of 0.05 mm are as follows: electrolyte conductivity of 8 S/m, voltage of 36.9 V, initial machining gap of 200 μm, and inner tool diameter of 0.4 mm. © 2024 Sharif University of Technology.
Publication Date: 2023
Computational Particle Mechanics (21964386)10(1)pp. 143-153
Nowadays, various methods are being formed on new composites and nanocomposite compounds. Investigating the properties of nanocomposites and finding their optimal properties pave the way for a better use of them. In this study, first, mechanical molecular dynamics method is used to investigate mechanical properties of aluminum/carbon nanotubes (Al-CNT) nanocomposite, then, the effect of temperature change, strain rate, and chirality of nanotubes on the elastic modulus and ultimate stress of nanocomposite have been investigated. However, in order to simultaneously investigate these three parameters on the properties of nanocomposite and to find an optimal point for the elastic modulus and ultimate stress, the experimental design method for optimization was used. Derringer method was used to determine optimal parameters for simultaneous optimization of two response variables, namely elastic modulus and ultimate stress. It can be concluded that the optimal conditions occur simultaneously at 50 K, strain rate 0.01, and chirality (5,5), in which the value of the elastic modulus is 156 GPa and the ultimate strain value is 13.7 GPa and simultaneous minimum value of elastic modulus and ultimate stress occur at 650 K, strain rate 0.0205, chirality (3,3), in which the value of elastic module is 94 GPa and the ultimate strain value is 6.44 GPa. © 2022, The Author(s) under exclusive licence to OWZ.
