Inconel Alloy X-750 Research Articles

Fabrication and tribological properties of WC-reinforced Inconel X-750 alloy at elevated temperature

The nickel-based superalloy Inconel X-750, valued for its exceptional mechanical properties, is used in gas-lubricated foil bearings. However, prolonged exposure to high temperatures can lead to wear failure, affecting their service life. Here, we propose a novel method named ultrasonic strengthening grinding (USG) that applies a WC coating on Inconel X-750. Friction tests reveal that at 600 °C, the friction coefficient and wear rate of the USG-treated samples were reduced by 30.2 % and 79.7 %, respectively. Detailed experiments and analysis demonstrate that the surface grain refinement and the WC-rich coating cooperate to improve the high-temperature tribological properties. These findings offer new insights into the design of wear-resistant coatings for enhancing the high-temperature tribological performance of Inconel X-750 Alloy.

On the Development of a Heat Treatment for Inconel Alloy X-750 Produced Using Laser Powder Bed Fusion

On the Development of a Heat Treatment for Inconel Alloy X-750 Produced Using Laser Powder Bed Fusion

Effect of cutting parameters on various output responses for cryo-treated INCONEL X750 alloy

Effect of cutting parameters on various output responses for cryo-treated INCONEL X750 alloy

Triple heat treatment effects of Inconel X-750 superalloy on its microstructure, hardness, and high-temperature fretting wear characteristics

Inconel X-750 alloy specimens were undergone the triple heat treatment process: solution annealing (1149 °C/2h), equalization treatment (843 °C/24h), and precipitation treatment (704 °C/20h). Then microstructure characterization and hardness tests were performed prior to the self-mated pin-on-disk fretting wear tests in the range of 25 °C-650 °C temperature conditions. This type of alloys is widely used in bump-type gas foil bearing applications where complex fretting phenomenon occurs between foils under harsh operating conditions. Conducted investigations revealed that the heat-treated sample developed more precipitated phases in the matrix and along the grain boundaries with higher bulk hardness. Fretting wear surface morphologies indicate that the formation of glaze layer composed of NiO, Cr2O3, and mixed Ni(Fe,Cr)2O4 oxides prevail on the wear scar during the elevated temperatures, harnessing significantly lower friction coefficient and wear loss. Severe material transfers and galling were the dominant wear mechanism in the non-heat-treated alloy interface which caused the stick-slip frictional behavior. On the contrary, the heat-treated alloy surfaces demonstrated the stable coefficient of friction and 3–10 times lower wear rates at high temperatures due to the additional Cr-rich carbides. It is believed that these hard and lubricious Cr2O3 internal oxide precipitates form healing glaze barrier in the interface by protecting against severe material transfer/build-up.

High-Temperature Superlubricity Performance of h-BN Coating on the Textured Inconel X750 Alloy

The high-temperature superlubricity performances of h-BN coatings on the nontextured and textured surface of an Inconel X750 alloy is reported in the present paper. The hardness and bond strength of the h-BN coating and alloy were investigated. The tribological properties of the X750 alloy and coatings on the X750 alloy substrate were investigated at different temperatures. The surface texture was manufactured on the surface of the X750 alloy, and then coatings were deposited on the textured surface to reduce the cracking of the coating and enhance the stability of the antifriction behaviors of the h-BN coatings. The tribotest results showed that the texture is helpful to enhance the interface thermal compatibility of the coating and substrate and store the wear debris generated during sliding. Therefore, a stable superlubricity was achieved at high temperatures, and a super low friction mechanism is also discussed.

Revealing hot deformation behavior of inconel X-750 superalloy: A novel hot processing map coupled with grain boundary engineering

In this work, a series of isothermal hot compression tests were performed at the temperature of 900–1150 °C with the strain rate ranging from 0.01 to 10s−1 in Inconel X-750 alloy (referred as Alloy X-750). Based on the flow stress data, the back-propagation artificial neural network model was utilized to accurately predict the flow stress at elevated temperatures. Subsequently, by constructing a modified hot processing map coupled with the variation of Σ3n (n = 1, 2, and 3) twin boundaries fraction, the optimal processing parameters were determined to be in the range of 1100–1150 °C and 1-10s−1 for Alloy X-750. Moreover, the possibility of grain boundary engineering via hot deformation were also evaluated by using some critical quantification descriptors of twin related domains (TRDs), such as the number of grains in the TRDs, the lengths of the longest chain, and the average TRDs size. All the results can further verify the validity of modified hot processing map. Finally, the high-temperature flow behavior combined with the relevant microstructure characterization showed that discontinuous dynamic recrystallization is considered as the predominant softening mechanism, while the continuous dynamic recrystallization and particle-stimulated nucleation also additionally contribute to the recrystallization nucleation during the hot deformation of Alloy X-750.

APPLICATION OF INTEGRATED TAGUCHI METHOD AND PRESENT-WORTH METHOD TO OPTIMIZE THE TURNING PARAMETERS OF INCONEL X750 ALLOY WITH AL2O3 NANOFLUID IN COCONUT OIL

A previous study has shown the successful application of the Taguchi method in both the direct and indirect perspectives to compute the optimal parameters during the turning of Inconel x-750 alloy. The study deployed signal-to-noise ratios to minimize the output of surface roughness, tool wear and cutting force but the machining economic parameters were not mentioned. Yet, the techno-economic dimension of machining aids profitable adjustments of the turning operations. To correct this deficiency, the present article introduces a techno-economic dimension to the turning process using literature data. This paper is about combining three variants of the Taguchi methods in five distinct formulations. The Taguchi, Taguchi-Pareto and Taguchi-ABC methods are combined with the present worth method by introducing the interest rate and inflationary rate at different points in the S/N ratio (SNR) calculations. Aspect ratios and direct parameter combinations replace the traditional direct parameter analysis in the factor-level framework. The present worth, optimal parametric setting and performance flow analysis are needed for all five formulations to ascertain the direction of performance analysis for the turning process. Concerning the direct and aspect ratios, the cutting velocity (PWV, 949.1444) and the feed rate-cutting velocity ratio (PWF/V, 0.026) are the first and last positions, respectively. Regarding the Taguchi experimental run, the present worth of the feed rate-cutting velocity ratio (PWF/V, -155.403) was the first position while the present worth of the cutting velocity (PWV, -185.009) is the last position. Results for other formulations show promising attributes for the methods. The work could be useful for planning purposes in turning operations.

Microstructure criterion for the preferential locations of helium bubble precipitation in a polycrystal

Helium bubble distribution at grain boundaries and inside grains affects materials' susceptibility to helium embrittlement. In this paper, we propose a microstructure criterion to quantitatively analyze the helium bubble preference for precipitation locations. The results show that the grain-boundary energy and the helium-to-vacancy ratio are the key factors in determining bubble formation mainly at the grain boundaries or in the grain interiors. Experimental observation based on the electron backscatter diffraction technique confirmed that helium bubbles are more likely to precipitate in the grain interiors of Inconel X750 alloy than pure nickel due to grain-boundary segregation-induced decrease in grain-boundary energy. The precipitation of intergranular bubbles can be reduced by lowering grain-boundary energy and reducing the helium-to-vacancy ratio at grain boundaries. This work provides a general framework for explaining the intrinsic relation between the formation of inter- and intra-granular helium bubbles and promising strategies for designing highly helium-enduring materials.

Study of Tribological Properties of EN8 Steel against Inconel X-750 Alloy under Dry and Lubricated Conditions

Study of Tribological Properties of EN8 Steel against Inconel X-750 Alloy under Dry and Lubricated Conditions

Analyzing The Effect of Aspect Ratios on Optimal Parametric Settings Using Taguchi, Taguchi-Pareto, and Taguchi-ABC method: A Case Study in Turning Operations for The Inconel X750 Alloy

The aspect-based Taguchi optimization approaches have been newly accepted as important routes to optimizing the turning experimental parameters. Unfortunately, due to its embryonic development, scholars have left unexplained the effects of introducing the aspect ratios on the optimal parametric setting. To correct this deficiency, this article proposes an approach to evaluating the effects of introducing aspect ratios in turning experiments, combined with direct factors, on the optimal parametric settings. To correct this deficiency, the purpose of this article is to highlight that a standard universal evaluation method is absent in optimization analysis using the Taguchi method; it proposes an approach to evaluating the effects of introducing aspect ratios in turning experiments, in combination with direct factors, on the optimal parametric settings. Using A novel method of establishing the influence of introducing aspect ratios on the optimal parametric settings is suggested using literature review, and the examination method may be a solid basis for optimal parametric setting evaluations in future undertakings of turning operational evaluations. The Inconel X750 alloy is considered in turning operations, and experimental data from the literature are used to illustrate the method. This article finds that quantifiable differences in the mean values of optimal parametric settings exist for the turning operation of Inconel X750 alloy. The study's originality is its attention to the aspect ratio analysis regarding the optimal parametric setting in a wide range of values. This article aims to initiate discussions for a universal agreement on how the influence of introducing the aspect ratios in the factor-level combination framework of the Taguchi method may be constituted. The utility of this research effort is to enhance resource distribution planning fog turning zero material.

Optimizing Turning Parameters for The Turning Operations of Inconel X750 Alloy with Nanofluids Using Direct and Aspect Ratio-based Taguchi Methods

For the turning process, the computation of optimal parametric settings for parameters has been traditionally achieved using standard parametric values, but comparative values between the standard parameters have been ignored. But these aspect ratios reveal some evaluation dimensions that account for robust measurement schemes that promote enhanced effectiveness of the process. To address the issue, an aspect-ratio-based mechanism has been introduced to optimize the turning parameters in three Taguchi methodical variants of classical Taguchi, Taguchi-Pareto, and Taguchi-ABC methods. A total of twelve alternatives were developed, with each alternative containing three standard parameters and two aspect ratios since only three standard parameters are involved in the evaluation. The evaluation of parameters in non-prioritized and prioritized forms was considered for each alternative. The Taguchi method accounts for the non-prioritized method, while Taguchi-Pareto and Taguchi-ABC methods are the prioritized parametric structures. The delta values and ranks across the prioritized and non-prioritized parameters were evaluated by their mean values. The optimal parametric settings were evaluated for all alternatives in the prioritized and non-prioritized forms of evaluation. The results, using literature data, confirmed the feasibility of using the approach. The outcome of the methods is in enhancing the planning scheme for the turning operation. The benefit of the study is an enhanced analysis of turning operation’s improvements and estimation of related economic advantages through turning resources conservation.

Study on the effect of machining characteristics of B4C powder mixed EDM of Inconel X-750 alloy

ABSTRACT EDM is identified as one of the favoured machining processes for frontiers material and their alloys. The present investigation is the influence of the B4C into a dielectric fluid of EDM process machining with Inconel X-750 alloy using W-Cu electrode. The process input parameters are selected as discharge current, pulse on time, pulse off time, and B4C powder concentration to examine their performance responses on material removal rate, surface roughness, and white layer thickness. In this process, a newly designed and fabricated dielectric tank is used for doing experiments. Taguchi L27 orthogonal array is adopted for planning and designing of experiments. ANOVA is considered to find the effect of B4C powder concentration on performance responses, and their input parameters interactions with percentage contributions. The result is notified that the addition of B4C powder into dielectric fluid improves material removal rate, surface roughness, and white layer thickness. Further, the optimum condition of the machined samples, surface topography is studied by using a scanning electron microscope. It reviled that uniform craters, small and pocket marks are formed on the machined surface.

Multi-Objective Optimization of Process Parameters for Powder Mixed Electrical Discharge Machining of Inconel X-750 Alloy Using Taguchi-Topsis Approach

Abstract The paper investigates the influence of boron carbide powder (B4C) mixed in dielectric fluid on EDM of Inconel X-750 alloy. The process parameters selected as discharge current (Ip), pulse on time(Ton), pulse off time(Toff), boron carbide(B4C) powder concentration to examine their performance responses on Material Removal Rate (MRR), Surface Roughness(Ra) and Recast Layer Thickness (RLT).In this study, o examine the process parameters which influence the EDM process during machining of Inconel X-750 alloy using combined techniques of Taguchi and similarity to ideal solutions (TOPSIS).Analysis of variance (ANOVA) was conducted on multi-optimization technique of Taguchi-TOPSIS. ANOVA results identified the best process parameters and their percentages. It developed the mathematical equation on Taguchi-TOPSIS performance characteristics results. The multi optimization results indicated that Ip and Toff are more significant parameters; V, and Ton parameters are less significant. Finally, surface structures were studied at optimized EDM conditions by using scanning electron microscope (SEM).

Investigation on the deformation mechanisms and size-dependent hardening effect of He bubbles in 84 dpa neutron irradiated Inconel X-750

Microstructural characterization and calculation of how several intrinsic features contribute to the mechanical properties of highly strained Inconel X-750 alloy specimens irradiated to 84 dpa at two distinct temperature ranges (300 °C–330 °C and 120 °C–280 °C) were performed. The individual contributions of different microstructural features to the critical resolved shear stress (CRSS) of the material, including the γ matrix, γ′ precipitates, irradiation induced defects, and helium bubbles, were calculated. The obstacle strength of He bubbles was found to be size-dependent and a critical size was determined. For bubbles < 2.4 nm, the obstacle strength is only approximately 0.03 while it can be as high as 0.55 for bubbles > 6.6 nm. In the high temperature range (300–330 °C) irradiated specimen, localised dislocation slip was found responsible for the failure of the specimen during micro-tensile testing, associated with significant helium bubble elongation. Elongation of helium bubbles on both the primary and adjacent secondary {1 1 1} planes was likely induced by the cross slip of screw dislocations. Nanotwins were also found adjacent to the shear failure surface in the high temperature specimen, but no elongated bubbles were found within the nano-twinned region. In the low temperature range (120–280 °C) irradiated highly strained specimen, a dislocation network structure was revealed.

Performance of cryogenically treated carbide inserts under sustainable cryo-lubrication assisted milling of Inconel X750 alloy

Owing to their superior features even under elevated temperatures, the nickel-based superalloy Inconel X750 is among the materials demanded in many critical areas. However, such alloys are hard to cut because of their characteristic properties i.e., strain hardening, poor thermal conductivity, high mechanical resistance at elevated temperature, the presence of abrasive carbide fragments and chemical proximity. Therefore, it is important to develop the machinability characteristics of these materials with sustainable machining methods that offer high performance. For this, in this work, a number of attempts were made during the milling of the Inconel X750 alloy. During the experiments, the performance of each cutting tool was investigated by considering three different tools which are uncoated carbide tool, cryogenically treated cutting tool and TiAlN coated tool. Since the machinability of superalloys is difficult in the dry environment, three different sustainable cooling/lubrication conditions such cryogenic LN2, MQL and hybrid cooling/lubrication (MQL + LN2) have been used in conjunction with these tools. In evaluating the effectiveness of the employed methods, flank wear, tool damage types, surface roughness/topography, cutting force and maximum temperatures were analyzed. As a result, even if the cryogenically treated tool performed slightly better than those of untreated, it still did not reach the performance level of the TiAlN coated tools. The hybrid cooling/lubrication system with coated tool offered the best solution in terms of all criteria. On the other hand, MQL outperforms LN2 cooling for tool wear, surface roughness/topography and cutting force, LN2 cooling is better than MQL in temperature reducing.

Enhancing Tribological Properties of Inconel X-750 Superalloy through Surface Topography Modification by Shot Blasting

Abstract The profound usage of Inconel X-750 in structural and high-pressure conditions mandates improved tribological properties. One of the methods to achieve this is through surface topography modifications. In this work, the viability of the shot blasting technique is explored to enhance the wear resistance of Inconel X-750. For this purpose, aluminum oxide particles with 80 mesh size were shot blasted on the superalloy surface at a constant pressure of 0.6 MPa. The 3D surface topography of Inconel X-750 alloy confirms substantial surface deformation and increased surface roughness after shot blasting. Furthermore, the surface characteristics of shot-blasted superalloy were meticulously examined using a string of techniques: optical profilometer, scanning electron microscope, and electron probe microanalysis. The tribological properties of Inconel X-750 before and after shot blasting were examined using a reciprocating tribometer with a ball-on-flat configuration. Results showed that shot blasting the superalloy has tremendously enhanced the wear resistance by ∼78%, which could be attributed to the reduced sliding contact area, enhanced surface hardness, and the hindrance in the transition of wear mechanism from abrasion tribo-oxidation to adhesion.

Comparative study of parametric effects on the performance of simple and powder mixed EDM using aluminium and graphite powder on Inconel X750 alloy

In the present scenario, Electrical Discharge Machining (EDM) is one of the most entrenched non-conventional machining processes which are widely used in different manufacturing sectors worldwide. Generally, the conductive materials, which having geometrically complex shape and extremely difficult to machine by conventional machining processes are machined by EDM. The further improvement of the machining efficiency of this EDM process may be enhanced by using powder suspended dielectric fluid which is called Powder Mixed EDM (PMEDM) process. In this research work, an attempt has been made to analyze the comparative study of parametric effects on the performance characteristics like material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) in terms of average value of roughness parameter (Ra) of simple (without powder) and powder mixed EDM using Aluminium (Al) and Graphite powder on Inconel X750 alloy by experimental investigation. Here, in our study, Peak current (Ip) pulse on time (Ton) and pulse off time (Toff) have been taken as the variable process parameters and concentration of powder (Cp) is taken as 6 g/l in all cases throughout the experimentation. From the experimental results, it has been observed that PMEDM gives lower MRR but better surface finish in comparison with conventional EDM technique (without powder). Also, it has been noticed that graphite powder mixed EDM is more effective for getting better surface finish of Inconel X750 alloy compared to Al mixed PMEDM process.

Effect of High Undercooling on Dendritic Morphology and Mechanical Properties of Rapidly Solidified Inconel X750 Alloy

The rapid dendrite growth kinetics of Inconel X750 alloy was explored under electromagnetic levitation and free fall conditions. The dendrite growth velocity of the primary γ phase varies as a double exponential function with undercooling (ΔT). The critical undercooling for the transformation of the primary γ phase from dendrites to equiaxed grains in electromagnetic levitation (EML) and drop tube (DT) experiments is similar. With comparable undercoolings, the grain size of γ phase solidified in the DT is much smaller than that in the EML owing to the effect of large cooling rate. As the undercooling continuously increases to 230 K, the phase constitution changes from γ and precipitated phases to single γ phase. Based on EDS and TEM results, the precipitated phase is confirmed as (Ti, Nb)C phase, and the γ/(Ti, Nb)C interface is semicoherent. The compressive and nanomechanical properties of Inconel X750 alloy solidified in EML experiments were also investigated. The results show that the elastic modulus of γ phase is smaller than that of (Ti, Nb)C phase. According to the compression tests, the elastic modulus of Inconel X750 alloy is improved by high undercooling. Interestingly, the elastic modulus decreases when the undercooling is larger than 230 K, which is attributed to the increasing solubility of Ti and Nb in γ phase and the disappearance of (Ti, Nb)C phase.

Effect of Machining Parameters on Turning of Inconel X750 Using PVD Coated Carbide Inserts

It is one of the few studies conducted on the machining of Ni-based Inconel X750 alloy, which has a wide range of applications in the main industries (gas turbines etc.) and aerospace (rotor blades etc.) industries. In this study, cutting tool wear, cutting forces and surface roughness were investigated in dry turning of Inconel X750 super alloy with coated carbide cutting tool. For the determining of the wear types and mechanisms electronic microscope and SEM were used. 4 different cutting speeds (40, 60, 80 and 100 m/min) and 3 different feed rate (0.1, 0.15 and 0.2 mm/rev) values were used in the experiments. The cutting depth was kept constant at 1 mm. According to the results; with increasing feed rate, the value of Fc, Ff and Fp cutting force components increased. The feed rate was significantly influential on Ra. The cutting geometry and the cutting edge sharpness induced by the formation of stable BUE caused Ra to increase. The most suitable parameters for turning the Inconel X750 alloy in terms of all evaluation criteria were the cutting speed of 60 m/min and 0.1 mm/rev.

Microstructural characterization of Inconel X750 alloy used in reactors components

Microstructural characterization of Inconel X750 alloy used in reactors components