High Temperature Hardness Research Articles

Effects of L12 precipitates containing Zr, Er, and Y on the precipitation of Al–Zn–Mg alloys at elevated temperatures

Microalloying significantly enhances the high-temperature properties of nano-precipitates through solute partitioning at elevated temperatures. In this study, we investigated the effects of L12 crystal structural precipitates containing Zr, Er, and Y influence the precipitation of Al–Zn–Mg alloys using transmission electron microscopy and atom-probe tomography. The results demonstrate that the multi-addition of Zr, Er, and Y improves both ambient and high-temperature hardness of Al–Zn–Mg alloys by increasing the number density of precipitates and preventing coarsening of L12/η-MgZn2 type nano-precipitates during over-aging period at elevated temperatures. Particularly, Y forms a thermally stable L12 precipitate through multiple additions with Zr and Er, a finding supported by atom-probe tomography, which reveals a synergistic interaction between Er and Y. The Er and Y multi-addition increases the number density of fine L12-Al3(Zr, Er, Y) precipitates, providing heterogeneous nucleation sites for η-type nano-precipitates at the interfaces between L12/η precipitate, thereby increasing the formation of fine η-type nano-precipitates during the over-aging period.

Synthesis and thermophysical properties of rare-earth tantalate ZrO2-Dy3TaO7 ceramics

Abstract Thermal Barrier Coatings (TBCs) are of major concern to researchers because of their outstanding properties, such as high-temperature resistance, compressive resistance, hardness, and toughness. Its applications are wide-ranging and critical. Examples include hypersonic vehicles, aero-engines, and service in high-temperature and high-impact extreme environments. This work focuses on the preparation, thermal properties (coefficient of thermal expansion, thermal conductivity), and performance evaluation (thermal shock resistance, thermal shock resistance, and bonding) of ZrO2-Dy3TaO7 rare earth tantalate ceramic coating materials. The results show that ZrO2-Dy3TaO7 possesses a low thermal conductivity (1.25-1.50 W K−1 m−1, 900°C), a high thermal expansion coefficient (10.80-11.14×10-6 K−1, 1200°C), which is about half of the value of the thermal conductivity of 7YSZ (2.8-2.2 W K−1m−1). It is better than that of the 7YSZ (10.04×10−6 K−1, 1200°C), which meets the performance requirements of the new thermal barrier coating. In addition, ZrO2-Dy3TaO7 can achieve more than 6, 000 thermal fatigue cycles at 1200°C, and the ideal number of thermal shock cycles is 4, 040 cycles at the same temperature. These outstanding test results demonstrate that the ceramic coating can effectively protect the substrate material and provide long-term service in high-temperature copper liquid. This research lays the theoretical foundation for the development of next-generation coating materials, particularly for thermal barrier/environmental barrier integrated coating materials.

Achieving optimal comprehensive properties in heat resistant Cu-based alloys by regulating complex elemental interaction

Coherent γ′-phase precipitation strengthened heat-resistant Cu-based alloys exhibit promising application in the field of high-temperature. In the work, to further improve the comprehensive performance of the alloys, the elements Cr, Zr, Zn and Ti are introduced into the model alloy (Cu83.33Ni12.50Al4.17 at.%). The existence state of the adding elements and their influence on comprehensive properties, including the in-situ high-temperature hardness, tensile properties and stability, etc., was unveiled. Furthermore, the Cu83.33Ni11.11Al2.78Cr1.04Ti1.04Zr0.35Zn0.35 alloy with excellent comprehensive properties was designed and prepared, exhibiting a high-temperature tensile strength of 370 MPa and an elongation of 3.7 % and high temperature stability of up to 400 h at 873 K. The reasons for the improvement of comprehensive properties can be attributed to the following aspects: (1) The adding elements not only inhibit discontinuous precipitation but also refined the size of the γ' phase and improved its thermal stability; (2) Cr and Zr inhibit the precipitation of deleterious D024-Ni3Ti phase caused by Ti; (3) The BCC-Cr (precipitation strengthening phase) and Ni5Zr phases (grain boundary strengthening phase) are introduced. This study successfully demonstrates the advantages of addition of multiple-elements through regulating their interaction, thereby establishing a robust foundation for designing heat-resistant Cu-based alloys in future investigations.

Research on the Application of Superhard Coating Technology for Cutting Tools in Mechanical Processing

The superhard coating technology for cutting tools has important applications in the field of mechanical processing. This article introduces the development of superhard coating materials for cutting tools, including low-pressure gas-phase synthesis of diamond, cubic boron nitride, and physical vapor deposition (PVD) coating technology. The superhard coating of cutting tools is widely used in turning, milling, tapping, key component machining, high-speed steel drill bits and taps. Research has shown that coatings can reduce cutting forces and improve tool life, but attention should be paid to residual compressive stress. The future development direction includes researching new superhard material cutting tools and developing coating methods that are more wear-resistant and have high temperature hardness.

High-temperature hardness and scratch behaviour of differently strengthened iron aluminide laser claddings

Fe3Al-based iron aluminides provide notable high-temperature properties at a comparatively low overall ecological impact. To improve their wear resistance, different strengthening strategies are studied for which Fe3Al-based laser claddings (30 at.% Al) are alloyed either with Si, C, or Ti and B. Detailed microstructural investigations after laser metal deposition (LMD) including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) were performed. Results show that Si-alloyed claddings are single-phase with equiaxed grains of average sizes from ∼350 μm (1 at.% Si) decreasing with increasing Si content to ∼50 μm at 3 and 5 at.% Si. Contrary, the C-alloyed claddings microstructures are dendritic and ledeburite-like with perovskite-type carbides Fe3AlC0.6. The Ti- and B-alloyed cladding exhibits finely dispersed TiB2-type precipitations; at low contents in the sub-micron range and mainly present at the grain boundaries, at higher additions are quite large (3–5 μm) and present within individual grains. The individual hardphases, as quantified via nanoindentation, of Fe3AlC0.6-type carbides or TiB2-type borides exhibit average hardness values of ∼7.5 GPa and ∼ 45.5 GPa, respectively. Therefore, the hardness of C- and Ti & B-alloyed claddings increases from ∼260 HV10 (Fe3Al) to 405 HV10 (Fe3Al plus 5 at.% C) and to 340 HV10 (Fe3Al plus 3 at.% and 6 at.% B). The higher hardness of the C-alloyed cladding stems from the s higher hardphase content; the matrix hardness ranges between 4 and 5 GPa for all precipitation-strengthened claddings. Contrary, the Si-alloyed cladding exhibits a pronounced increase to 5.7 ± 0.8 GPa upon adding up to 5 at.% Si. Thus, an overall hardness of ∼350 HV10 is quantified on the expense of ductility (relaxation cracking after LMD). High-temperature hardness and scratch tests as well as wear investigations prove that the C- as well as Ti and B-alloyed claddings are superior to the plain Fe3Al and Si-alloyed ones, making them promising alternatives to other wear protection materials based on Co, Ni or Cr.

Solidification and microstructure investigation on as-cast and annealed hypoeutectic Ti–Fe alloys

This work explored the solidification behavior, microstructure development, and resulting mechanical properties of hypoeutectic Ti–Fe alloys under both as-cast and annealed conditions. Ti-(27, 28, 29)Fe (wt%) alloys were synthesized through arc-melting, followed by annealing at 950 °C for 24 h and slow furnace cooling. The investigation procedures included thermodynamic calculations, differential scanning calorimetry, scanning electron microscopy, high-temperature laser-scanning confocal microscopy, X-ray diffraction, hardness measurements, and compression tests. The study demonstrated the efficacy of annealing treatments in reducing excess eutectic in the as-cast structure formed during solidification. Results from both thermodynamic calculation and experiment for the solidification process demonstrated reasonable agreement. The high β-stabilizing effect of Fe ensured the presence of the β phase at room temperature under both studied conditions. The solid-solution hardening of the β phase, coupled with the TiFe intermetallic, substantially contributed to the increased hardness and mechanical strength, although the increase in brittleness was noticeable in the as-cast state. Subsequent annealing enhanced plasticity but resulted in a reduction in strength, albeit maintaining yield strength at a considerable level, approximately 1450 MPa.

Component regulation and high-entropy engineering for enhanced antioxidant and high-temperature mechanical properties of protective films

Transition metal nitrides (TMNs) have gained widespread application in protecting structural components due to their high strength and hardness. However, TMNs still have the challenge of structural instability and mechanical deterioration caused by oxidation under harsh high temperature conditions. Herein, we present a strategy combining component regulation with high-entropy engineering to develop an advanced high-temperature Al-containing high-entropy nitrides (HENs) material. To prevent the phase decomposition of AlN within the (NbMoTaWAl)N, theoretical simulations were employed to determine a critical atomic percent of 25.0% Al for maintaining the stability of the high-entropy structure. Ensuing experimental synthesis creates three NbMoTaWAlN films with varying Al content: a high-entropy film with 0.0% Al (HEN), a high-entropy film with 21.2% Al (HEN-Al), and an amorphous transition metal nitride film with 30.2% Al (a-TMN-Al), validating key high-entropy engineering benchmarks. It is found that the unique HEN-Al film exhibits excellent oxidation resistance and high-temperature hardness, attributed to the uniform distribution of Al atoms in the robust high-entropy structure, which creates conditions for forming a dense and continuous Al2O3 barrier layer, effectively hindering the diffusion of oxygen into the film interior. This study provides new insights to develop a new generation of high-temperature protective materials.

Foreign object damage characteristics of a thin nickel-based superalloy plate at room and high temperatures

Turbine blades with thin-walled structures usually works in harsh environments, and foreign object damage (FOD) is one of the conditions of special concern. In this paper, the FOD characteristics of thin nickel-based superalloy plates are studied by a combination of experimental, numerical and analytical methods, considering room and high temperatures, different impact conditions and plate thicknesses. An easy-to-use test system is developed to realize high speed impact of the thin nickel-based superalloy plate under elevated temperature. Crater morphologies, internal microstructure, and residual stress are analyzed after impact with different conditions. Numerical simulation of the impact process is performed by using Johnson-Cook (J-C) constitutive model. Based on Hertz theory, an analytical method for calculating the crater length and depth is proposed considering the deformation of the impact steel sphere. Results shows that the FOD characteristics at high temperature is significantly different from that at room temperature. The crater has lager dimensions under high speed and elevated temperature. Moreover, significant grain refinement is obvious and the dislocation layer is also thicker at higher speed and higher temperature. Due to the effect of high temperature softening, hardness and residual stress after impact with elevated temperature is lower than that at room temperature. Besides, non-normal impact mainly influences Goss texture and distribution of residual stress after high temperature impact. In addition, it is found that thickness have a significant effect on the FOD characteristics especially when the plate is thinner. The validity of the numerical model and analytical method is proved by comparing with the experimental results. The present study can provide data foundation and numerical analysis support for the damage assessment and maintenance of turbine blades.

High temperature hardness and thermal analysis of CoNiCrAlY alloys used as bond coats for thermal barrier coatings

CoNiCrAlY alloys, commonly used as the bond coat of thermal barrier coatings (TBCs), are often exposed to high temperatures of about 1000 °C, the evolution of mechanical and thermal properties is critical to the reliability and durability of TBCs. In this paper, the hardness and thermal properties (weight change and heat flow) of CoNiCrAlY alloys at temperatures within 1000 °C were evaluated by indentation and TGA-DSC thermal analysis. It was found that hardness and thermal properties change gradually within 600 °C but change sharply above 600 °C, exhibiting an approximately synchronized evolution. An illustrative explanation was given for the correlation in terms of the Boltzmann energy distribution theory of microscopic particles. Based on these findings, an idea of inter-calibration between the two evolutions was proposed.

Mechanical Response of Cu/Sn58Bi-xNi/Cu Micro Solder Joint with High Temperatures

Sn58Bi solder is considered a promising lead-free solder that meets the performance requirements, with the advantages of good wettability and low cost. However, the low melting point characteristic of Sn58Bi poses a serious threat to the high-temperature reliability of electronic products. In this study, Sn58Bi solder alloy based on nickel (Ni) functionalization was successfully synthesized, and the effect of a small amount of Ni on creep properties and hardness of Cu/Sn58Bi/Cu micro solder joints at different temperatures (25 °C, 50 °C, 75 °C, 100 °C) was investigated using a nanoindentation method. The results indicate that the nanoindentation depth of micro solder joints exhibits a non-monotonic trend with increasing Ni content at different temperatures, and the slope of the indentation stage curve decreases at 100 °C, showing that the micro solder joints undergo high levels of softening. According to the observation of indentation morphology, Ni doping can reduce the indentation area and accumulation around the indentation, especially at 75 °C and 100 °C. In addition, due to the severe creep phenomenon at 100 °C, the indentation hardness rapidly decreases. The indentation hardness values of micro solder joints of Cu/Sn58Bi/Cu, Cu/Sn58Bi-0.1Ni/Cu, and Cu/Sn58Bi-0.2Ni/Cu at 100 °C are 14.67 ± 2.00 MPa, 21.05 ± 2.00 MPa, and 20.13 ± 2.10 MPa, respectively. Nevertheless, under the same temperature test conditions, the addition of Ni elements can improve the high-temperature creep resistance and hardness of Cu/Sn58Bi/Cu micro solder joints.

Synthesis and characterization of onion-like carbon /TiN0.3 enhanced Si3N4 composites

Research on how to obtain Si3N4 composites with high hardness and toughness at lower temperatures is important. Si3N4 composites with onion-like carbon (OLC)-TiN0.3 were prepared using high pressure and high temperature techniques. The effects of TiN0.3 and OLC additives on the mechanical properties and microstructure of the silicon nitride ceramics were analyzed. During the sintering process, the vacancies in TiN0.3 promoted the formation of the TiC0·3N0.7 interface between the three compositions, whose particles were homogeneously dispersed in the silicon nitride matrix with strong bonding to the substrate. OLC (10 vol%)-TiN0.3 (10 vol%)-Si3N4 composites were prepared at 5 GPa, 1500 °C and held for 15 min. The Vickers hardness and fracture toughness were determined to be 18.6 GPa and 6.6 MPa m1/2, flexural strength of 531 MPa, and showed higher high-temperature hardness. This was higher than the typical values reported for Si3N4 ceramics (15–17 GPa). This work provides a new strategy for low-temperature of Si3N4 composites with both high hardness and high toughness.

Evolution of high-temperature hardness of multimodal γ′ nickel-based superalloy

Hardness reflects the comprehensive mechanical properties of materials, and its evolution during a wide temperature range reflects high-temperature performance. This study investigates the evolution of the high-temperature hardness of a nickel-based superalloy Ni16Cr13Co4Mo. Various thermal cycles featuring distinct peak heating temperatures were utilized to examine the variation of Vickers hardness with temperature. The effect of precipitated phases (specifically the γ′ phase) in the superalloy on high-temperature hardness and the deformation mechanism of the alloy was analyzed. The results show that the high-temperature hardness of the nickel-based superalloy decreases as temperature increases. However, the hardness after thermal cycles demonstrates an increase which is determined by the peak heating temperature. The increased hardness following thermal cycles is attributed to the reduction in size and the increase in the volume fraction of secondary γ′. Detailed TEM observation revealed that as the peak temperature increases, the deformation mechanism transforms from dislocation pile-ups in the γ matrix, dislocation and stacking fault shearing, microtwining in γ and γ′ phases to stacking fault shearing and piled-up dislocations in γ phase. As the result, hardness decreases as temperature increases.

Peak Response Wavelength Tunable 4H-SiC UV Detector Covering Near-Ultraviolet Region With High-Temperature Stability and Radiation Hardness

Peak Response Wavelength Tunable 4H-SiC UV Detector Covering Near-Ultraviolet Region With High-Temperature Stability and Radiation Hardness

Design and Optimization of Heat Treatment Process Parameters for High-Molybdenum-Vanadium High-Speed Steel for Rolls.

High-molybdenum-vanadium high-speed steel is a new type of high-hardenability tool steel with excellent wear resistance, castability, and high-temperature red hardness. This paper proposes a composition design of high-molybdenum-vanadium high-speed steel for rolls, and its specific chemical composition is as follows (wt.%): C2%, Mo7.0%, V7.0%, Si0.3%, Mn0.3%, Ni0.4%, Cr3.0%, and the rest of the iron. This design is characterized by the increase in molybdenum and vanadium in high-speed steel to replace traditional high-speed steel rolls with the tungsten element in order to reduce the heavy elements' tungsten-specific gravity segregation caused by centrifugal casting so that the roll performance is uniform and the stability of use is improved. JMatPro (version 7.0) simulation software is used for the composition design of high-molybdenum-vanadium high-speed steel. The phase composition diagram is analyzed under different temperatures. The content of different phases of the organization in different temperatures is also studied. The martensitic transformation temperature and different tempering temperatures with the different types of compounds and grain sizes are calculated. The process parameters of heat treatment of high-molybdenum-vanadium high-speed steel are optimized. The selection of carbon content and the temperature of M50 are calculated and optimized, and the results show that the range of pouring temperatures, quenching temperatures, annealing temperatures, and tempering temperatures are 1360~1410 °C, 1190~1200 °C, 818~838 °C, and 550~600 °C, respectively. Scanning electron microscope (SEM) analysis of the samples obtained by using the above heat treatment parameters is consistent with the simulation results, which indicates that the simulation has important reference significance for guiding the actual production.

FE modeling and simulation of the turning process considering the cutting induced hardening of workpiece materials

The accuracy of the cutting simulation model greatly depends on the constitutive models, thermophysical models, and friction models. However, accurate modeling of physical and mechanical relationships is not enough. The physical and mechanical behavior of the machined surface from the last cut should be modelled in the FE model. In this study, the cutting simulation model of S316L stainless steel was established. The above model consists of two subsequent simulated cuts. The first simulated cut was used to obtain the machined surface with the residual stress, and the second simulated cut was subsequent with the first cut to obtain the actual simulated results. The constitutive model was obtained by the split Hopkinson pressure bar (SHPB) and high-temperature hardness experiments. The specific heat capacity and thermal conductivity models were developed by laser thermal conductivity experiments with various temperatures. The friction model between the workpiece and the tool was established by orthogonal cutting experiments. The simulated cutting forces of the first and second cut were extracted and compared with the experimental results to verify the accuracy of the simulation models. The results showed that the average error of cutting forces for the first cut is 28.33 %, but that for the second cut is 8.02 %, which verifies the accuracy of the two-subsequent cutting simulation model. Additionally, the significant differences in the simulated cutting forces between the first and second cutting depict that the residual stress cannot be ignored for the accuracy verification of cutting simulation models.

Microstructure and High-Temperature Properties of Cr3C2-25NiCr Nanoceramic Coatings Prepared by HVAF

The study examines the microstructure and high-temperature properties of Cr3C2-25NiCr nanoceramic coatings on 316H high-temperature-resistant stainless steel that were prepared by high-velocity air–fuel spraying (HVAF) technology. The micromorphology, phase composition, fracture toughness, high-temperature hardness, high-temperature friction, and wear properties of the coating were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), high-temperature Vickers hardness tester, high-temperature friction and wear tester, and surface profiler. The results show that the Cr3C2-25NiCr coating prepared by HVAF presents a typical thermal spraying coating structure, with a dense structure and a porosity of only 0.34%. The coating consists of a Cr3C2 hard phase, a NiCr bonding phase, and a small amount of Cr7C3 phase; The average microhardness of the coating at room temperature is 998.8 HV0.3, which is about five times higher than that of 316H substrate. The Weibull distribution of the coating is unimodal, showing stable mechanical properties. The average microhardness values of the coating at 450 °C, 550 °C, 650 °C, and 750 °C are 840 HV0.3, 811 HV0.3, 729 HV0.3, and 696 HV0.3 respectively. The average friction coefficient of the Cr3C2-25NiCr coating initially decreases and then increases with temperature. During high-temperature friction and wear, a dark gray oxide film forms on the coating surface. The formation speed of the oxide film accelerates with increasing temperature, shortening the running-in period of the coating. The oxide film acts as a lubricant, reducing the friction coefficient of the coating. The Cr3C2-25NiCr coating exhibits exceptional high-temperature friction and wear resistance, primarily through oxidative wear. The Cr3C2-25NiCr coating exhibits outstanding high-temperature friction and wear resistance, with oxidative wear being the primary wear mechanism at elevated temperatures.

Study on the rapid synthesis of high-entropy carbonitride powder and its remarkable hardening effects on cemented carbide tool materials

As a novel high-entropy ceramic material with a multi-cation and multi-anion sublattice structure, high-entropy carbonitride ceramics (HECNs) have exhibited outstanding comprehensive properties and attracted increasing attention. In this study, a new WC-based cemented carbide material reinforced by high-entropy carbonitride (Ti0.2W0.2Mo0.2V0.2Nb0.2)(C0.7N0.3) (marked as HECN) was successfully fabricated by vacuum hot-pressed sintering. The mutual constraints between hardness and fracture toughness in extant WC-Co cemented carbide tool materials and their deficient high-temperature mechanical properties were effectively addressed. Moreover, for the low efficiency of the traditional carbothermal reduction nitridation, a novel method for rapidly preparing HECN powder was firstly proposed, namely the microwave-assisted carbothermal reduction nitridation, which could accelerate the heating rate and shorten the holding time. Single-phase HECN powder was successfully synthesized by this method, and the impacts of varying HECN content on the room and high-temperature mechanical properties of WC-based cemented carbide were investigated combined with the microstructure analysis by XRD\\SEM. The results revealed that HECN effectively inhibited the grain growth of WC in cemented carbide, and the refined WC grains provided a high-volume fraction of grain boundaries, which prevented dislocation movement and increased the hardness. With the optimized HECN content of 10 wt%, the Vickers hardness and fracture toughness of WC-HECN-Co composite reached 21.58 ± 0.36 GPa and 12.27 ± 1.17 MPa∙m1/2 respectively. Furthermore, WC-10HECN-10Co composites possessed outstanding high-temperature hardness and maintained a high hardness value of 13.16 ± 0.30 GPa at 800 °C, 37% higher than that of WC-10Co. The findings of this research hold significant practical implications for applying cemented carbide cutting tools in high-speed dry cutting.

Influence of Re addition amount on structure, mechanical, oxidation as well as corrosion behaviors of WC-15Co cemented carbide

Various contents of rhenium (Re) were successfully doped into WC-15Co hard alloys. After that, some professional analytical instruments such as SEM, XRD, hardness tester, muffle furnace, and electrochemical workstation were chosen to appraise their microstructures and properties. By comparison, rhenium doping could greatly change the high-temperature hardness and high-temperature antioxidant capacity of WC-15Co hard alloys. With the increase of rhenium doping, the high-temperature hardness and high-temperature antioxidant capacity of WC-15Co hard alloys continue to improve. In the meantime, the KIC revealed a max of 14.57 MPa·m1/2 and the flexural strength reached up to 3367 MPa at rhenium doping of 4.5 wt%. Moreover, the icorr of hard alloys in acid and alkaline environments first decreased and then increased as the increase of rhenium doping, indicating that the optimal rhenium doping was within the range of 1.5%–4.5%.Thus, an appropriate amount of rhenium doping was a good additive for optimizing the overall performance of hard alloys.

Multi-scale-phases coherent precipitation improve the comprehensive performance of heat-resistant Cu alloys

High-temperature destabilization of the strengthening phase and the generation of discontinuous precipitation at grain boundaries are mutual problem in current high-temperature alloys, especially in the novel Cu-based high-temperature alloys. In the present work, multicomponent composition design is utilized to inhibit discontinuous precipitation and improve the stability of the γ′ phase by strong enthalpic interactions between elements, while introducing coherent precipitated phases other than the γ′ phase into the alloy to simultaneously enhance the heat resistance of the alloy. The Cu85.71Ni10.72-xAl3.57Mx (M = Ti, Nb and V) alloys designed are multi-scale-phases coherent precipitation-strengthened copper alloys, as shown by systematic electron diffraction and HRTEM analysis. In-situ analysis of high temperature hardness and electrical resistivity showed that the softening rate of hardness and the rising rate of electrical resistivity decreased significantly after adding M during the heating process. The calculation results by Thermo-calc also confirmed that the addition of M delayed the re-dissolution of the γ′ phase to improve its thermal stability, and introduced additional coherent precipitated phases which remains a strengthening effect after the re-dissolution of the γ′ phase at high temperature. The enhanced stability of γ′ phase originates from the strong enthalpic interaction between elements and is also related to the promotion of precipitation of Al and reduction of vacancies and antisites in γ′ phase by adding M. In summary, multi-scale-phases coherent precipitation strengthening is an effective way to enhance the comprehensive performance of novel Cu-based high-temperature alloys, and also provides a new perspective for the development of heat-resistant alloys with excellent performance.

Artificial intelligence for experimental investigation and optimal process parameter selection in PM-EDM of nimonic alloy 901

Electrical discharge machining (EDM), a widely used non-contact machining method, employs electric discharge to remove conductive material from workpieces. This study focused on experimentally investigating and optimizing input process parameters for the PM-EDM process of a Nimonic alloy 901 (NA-901) workpiece with a silver electrode. The silicon carbide (SiC) powder particles were explored for their exceptional properties, including high temperature resistance, hardness, thermal conductivity, and resistance to corrosion and oxidation. The study evaluated the impact of input process parameters such as servo voltage (Vs), powder concentration (Cp), pulse-on-time (Ton), and peak current (Ip) on surface roughness rate (SRR),tool wear rate (TWR), and material removal rate (MRR). The Taguchi design approach with an L18 orthogonal array was used to identify the optimal parameter combination based on signal-to-noise (S/N) ratio analysis. To improve optimization, a feed-forward backpropagation neural network (FF-BPNN)was utilized to approximate solutions. The results of the experimental MRR confirmation test (E-MRR) were compared to the MRR values predicted using the FF-BPNN model (P-MRR). Similarly, the SRR (E-SRR) and the TWR (E-TWR) were compared to the predicted SRR and TWR obtained from the proposed FF-BPNN model. In summary, this study presents an experimental examination and optimization of input process parameters in the PM-EDM process of an NA-901 workpiece with a silver electrode.The use of SiC powder particles, the impact of input process parameters, and optimization were explored using Taguchi design and FF-BPNN techniques. This study's results demonstrate these approaches' effectiveness in achieving optimal PM-EDM process parameters.Finally, results revealed E-MRR as 6.894, P-MRR as 6.8913, E-SRR as 0.891, P-SRR as 0.897, E-TWR as 0.116, and P-TWR as 0.015.