High-temperature Nickel-based Alloy Research Articles

Fabrication characterization and compression failure analysis of Ni-based alloy ABD-900AM TMPS structures via laser powder bed fusion

The novel high-strength and high-temperature nickel-based alloy developed for additive manufacturing, i.e., ABD-900AM, shows great potential in next-generation aircraft engines. However, there are limited investigations about the printing capability of ABD-900AM with complex structure as well as compression behaviors of this new alloy system. To meet the lightweight requirement, ABD-900AM with triply periodic minimal surface (TPMS) is fabricated by selective laser melting (SLM) in the present work, and the printing quality and compression performance of different TPMS structures are analyzed utilizing both experimental and computational methods. First, six types of TPMS structures are designed, and the external contours fabricated by SLMed ABD-900AM are detected through 3D optical scanning. In general, high fabrication quality is achieved with the proper process parameters, while the positive deviations are observed at the lateral surfaces and edges, and the negative deviations are observed at the upper regions of the cellular structures. Further, compression tests of SLMed ABD-900AM TPMS structures are conducted, and the failure mechanisms are evaluated. The equivalent elastic modulus is ranked as Diamond > Split-P > Primitive > Gyroid > I-WP > Lidinoid. The SLMed ABD-900AM TPMS structures shows advantages compared to these TPMS structures fabricated using typical metal alloys. Finally, the computational models of SLMed ABD-900AM TPMS structures are built up in the commercial software ABAQUS. The stress-strain behaviors and the failure process of different SLMed ABD-900AM TPMS structures are successfully reproduced.

Effect of remelting on cracking of Inconel 939 fabricated via laser powder bed fusion

Laser remelting of each layer during laser powder bed fusion (L-PBF) is an important strategy used for enhancing the quality of components. However, the impact of remelting on internal cracking has not been completely understood. This study investigates the feasibility of employing remelting to mitigate internal cracking using Inconel 939 (IN939) as an example, a high-temperature nickel-based alloy with high susceptibility to cracking during L-PBF. The effects of remelting parameters, strategies, and the number of remelting cycles on microstructure features and defects were studied. The residual stresses in remelted samples and initial melt samples were measured for different laser scanning strategies. Reduction in residual stresses is identified as a key factor in minimizing cracking, with the lowest residual stresses observed in remelted samples using the chess strategy. Additionally, crack density in remelted samples was decreased with reducing cellular dendrite size in the fabricated sample. In comparison to initial melt samples, remelted samples exhibited an 85% reduction in crack density and a 60% reduction in porosity. These findings present a potential approach for defect inhibition during L-PBF processing of IN939 and other high-temperature alloys.

Enhancement of spectral model transferability in LIBS systems through LIBS-LIPAS fusion technique

BackgroundLaser-induced breakdown spectroscopy (LIBS) is extensively utilized a range of scientific and industrial detection applications owing to its capability for rapid, in-situ detection. However, conventional LIBS models are often tailored to specific LIBS systems, hindering their transferability between LIBS subsystems. Transfer algorithms can adapt spectral models to subsystems, but require access to the datasets of each subsystem beforehand, followed by making individual adjustments for the dataset of each subsystem. It is clear that a method to enhance the inherent transferability of spectral original models is urgently needed. ResultsWe proposed an innovative fusion methodology, named laser-induced breakdown spectroscopy fusion laser-induced plasma acoustic spectroscopy (LIBS-LIPAS), to enhance the transferability of support vector machine (SVM) original models across LIBS systems with varying laser beams. The methodology was demonstrated using nickel-based high-temperature alloy samples. Here, the area-full width at half maximum (AFCEI) Composite Evaluation Index was proposed for extracting critical features from LIBS. Further enhancing the transferability of the model, the laser-induced plasma acoustic signal was transformed from the time domain to the frequency domain. Subsequently, the feature-level fusion method was employed to improve the classification accuracy of the transferred LIBS system to 97.8 %. A decision-level fusion approach (amalgamating LIBS, LIPAS, and feature-level fusion models) achieved an exemplary accuracy of 99 %. Finally, the adaptability of the method was demonstrated using titanium alloy samples. Significance and noveltyIn this work, based on plasma radiation models, we simultaneously captured LIBS and LIPAS, and proposed the fusion of these two distinct yet origin-consistent signals, significantly enhancing the transferability of the LIBS original model. The methodology proposed holds significant potential to advance LIBS technology and broaden its applicability in analytical chemistry research and industrial applications.

Study of nano-broaching properties on nickel-based high-temperature alloys based on molecular dynamics simulation

Broaching technology, as the preferred high-volume machining process for nickel-based high-temperature alloy turbine disk tongue and groove machining, directly determines the reliability and stability of the turbine disk during its service. Although a host of scholars have carried out extensive experimental studies on the broaching process, there are few reports on the exploration of the atomic scale response in the broaching process. In this paper, the plastic deformation, defect evolution and distribution, surface formation, and stress changes during nano broaching of nickel-based single-crystal alloys are analyzed based on the molecular dynamics simulation (MD) method to reveal their broaching properties. The results show that the thermal softening effect induced by the accumulation of cutting temperature is the main reason for the violent plastic deformation within the matrix. The phase transition of the matrix structure, the depth of the subsurface damage layer, and the dislocation density increase with the increase of the cutting distance at the initial stage of the broaching process, and then slow down the upward trend at the stable broaching stage, and fluctuate in a certain range gradually. Meanwhile, the sources of atoms in chips produced by different broaching teeth in the broaching process alternates with the cutting distance. In addition, the diffusion depth of hydrostatic pressure and von Mises stress increases significantly with the increase of broaching distance. The simulation results can provide atomic-scale details for the broaching process of single-crystal Ni Fe Cr alloys and help to optimize the nano-broaching process of nickel-based high-temperature alloys.

Laser melting deposition of Inconel625 to Ti6Al4V bimetallic structure via vanadium interlayer

Inconel 625 (IN625) nickel-based high-temperature alloy and Ti6Al4V (TC4) titanium alloy are widely used in the aerospace industry due to their respective excellent properties. Developing the IN625/TC4 bimetallic structure (BS) has more apparent benefits and broader application prospects. Still, it has been challenging for industry research to connect these two materials successfully. In this study, IN625/TC4 BS without metallurgical defects such as cracks was successfully fabricated by adding the V interlayer using laser melting deposition (LMD) technique, and its microstructure and mechanical properties were investigated. The results indicate that IN625/TC4 BS can be divided into five regions from the IN625 side to the TC4 side, namely IN625 region, IN625/V transition region, rich V region, V/TC4 transition region, and TC4 region. The phase evolution of the five regions is as follows: γ-Ni + laves → γ-Ni + (Ni2Cr)V + TiNi3 + (V, Cr, Ni) solid solution → (V, Cr, Mo) solid solution + TiNi → β-Ti + TiNi + Ti2Ni → α-Ti + β-Ti. The Vickers hardness in the transition region is not uniformly distributed, with the highest value reaching 955 HV. The tensile strength of IN625/TC4 BS via V interlayer is approximately 267.6 MPa. The fracture location is located at the interface between rich V region and V/TC4 transition region, and its fracture morphology displays features of a quasi-cleavage fracture.

Hot corrosion behavior of hot isostatic pressing treated TiC/GTD222 composite fabricated by selective laser melting

Purpose This paper aims to design a novel TiC/GTD222 nickel-based high-temperature alloy with excellent hot corrosion resistance by incorporating appropriate amounts of C, Al and Ti elements into GTD222 alloy. Design/methodology/approach The composite material was prepared using the selective laser melting (SLM) technology, followed by a hot isostatic pressing (HIP) treatment. Subsequently, the composite underwent a hot corrosion test in a 75% Na2SO4 + 25% NaCl mixed salt environment at 900 °C. Findings The HIP-SLMed TiC/GTD222 composite exhibits a relatively low weight loss rate. First, the addition of alloying elements facilitates the formation of multiple protective oxide films rich in Al, Ti and Cr. These oxide films play a crucial role in enhancing the material’s resistance to hot corrosion. Second, the HIP treatment results in a reduction of grain size in the composite and an increased number of grain boundaries, which further promote the formation of protective films. Originality/value The hot corrosion behavior of the TiC/GTD222 nickel-based composite material prepared through SLM and HIP processing has not been previously studied. This research provides a new approach for designing nickel-based superalloys with excellent hot corrosion resistance.

Thermal-mechanical fatigue life prediction considering fatigue-creep interaction effects

This study proposed a multiaxial variable temperature and amplitude damage assessment model to predict the variable temperature and amplitude fatigue life of high-temperature alloys, which are often subjected to varying multiaxial mechanical and temperature loads. To validate the proposed model, seven variable temperature and amplitude fatigue tests were conducted on GH4169 nickel-based high-temperature alloy. The proposed model shows good accuracy and reliability in predicting the lifetime of high-temperature alloy components under multiaxial mechanical and temperature loads.

Studies on the growth mechanism of aluminide coating on K444 alloy surface by chemical vapor deposition

The studies of the growth mechanism of aluminide coatings by chemical vapor deposition (CVD) is an important prerequisite for optimizing the thermal protection properties of aluminide coatings and improving the CVD process parameters; however, the current research on the growth mechanism of CVD aluminide coatings on nickel-based alloys is relatively limited, and there is a lack of systematic studies in this area. In this work, aluminide coatings were prepared on the surface of nickel-based superalloys by the CVD method, and elemental diffusion and microstructure effects between coating and substrate at different deposition temperatures and times, as well as the growth kinetics and formation mechanism of CVD aluminide coatings were investigated. The results showed that the coating prepared on the surface of K444 nickel-based high-temperature alloy by CVD was an externally diffused aluminide coating with a bilayer structure: the outer layer of the coating was the β-NiAl phase. The interdiffusion layer was mainly composed of nickel-aluminum compounds, carbides, and topologically close-packed phase. The growth of the CVD aluminide coating was mainly controlled by the grain boundary diffusion mechanism.

First-principles study of influence of Si on <i>γ</i> phase in Inconel 718 alloy

Inconel 718 (IN 718) is the most widely used nickel-based high-temperature alloy today. It is widely adopted in important fields such as aerospace, energy and chemicals, and is also one of the few high-temperature alloys, of which some can be fabricated by using additive manufacturing. There is a lack of research on the effect of Si on the structure and properties of IN 718 alloy on a microscopic scale. In this paper, the effect of Si doping on the γ phase in IN 718 alloy is investigated by first-principles calculations through using the CASTEP package. The lattice constants, total energy, defect formation energy, formation enthalpy, cohesive energy, density of states, and electron density difference of the γ phase are calculated before and after Si doping, and population analysis is performed. The calculation of the lattice constant reveals that the doping of Si atoms expands the cell volume of the γ phase supercell, which contributes to a certain solution strengthening effect, and is conducive to the improvement of the hardness of the alloy. The energy and electronic structure calculations show that the Si atoms prefer to occupy the Ni atomic positions in the γ phase. The number of valence electrons between the atoms, the distribution of the charge density, and the strength of the bonds between the atoms also change with Si doping, thus modifying the interaction of the atoms within the γ phase, reducing the stability of the γ phase, and favouring the precipitation of the second phase. Besides, uniform and dense IN 718 coatings with low-coat Si doping are successfully fabricated by using plasma cladding. The experimental results demonstrate that Si doping has no significant effect on the type of matrix structure of IN 718 coatings, but causes a slight expansion of the lattice of the alloy, which is consistent with the calculation result. The addition of Si can result in a transformation of the alloy coating from columnar crystal to equiaxed crystal, refining the grain size of the alloy, while reducing the volume fraction of the γ phase and increasing the volume fraction of the second phase. Moreover, the addition of Si exacerbates the segregation of Nb and Cr elements in the IN 718 coatings.

The effect of solid solution temperature on the precipitation phase and properties of plasma arc welded joints of Inconel625 high temperature alloy

The effect of solid solution temperature on microstructure and mechanical properties of plasma welded nickel-based high temperature alloy Incone l625 was investigated by solid solution treatment (The solid solution temperature range is 950 °C to 1150 °C and the intergroup interval is 50 °C). The results show that after solid solution treatment at 950 °C, chain carbides are precipitated at the austenite grain boundary of the base material. With solid solution temperature increasing, carbon chains dissolve gradually at the grain boundary. When solution temperature is higher than 1050 °C, carbides at the grain boundary completely melt back into the matrix. At the weld, dendritic crystal and Laves phase dissolve with the increase of solid solution temperature. When the solid solution temperature is 1100 °C, the dendritic crystal and Laves phase at the weld completely melt into the matrix and transform into cellular crystals. When the solid solution temperature is increased to 1150 °C, the cellular crystal grows further at the weld. When the solid solution temperature is 1100 °C, the comprehensive mechanical properties of the joint are the best.

Development of High-Temperature Wire-Grid Thin Film Strain Gauges.

Aero-engine turbine stator blades are often used in harsh environments with high temperatures and high pressure and are prone to fatigue fractures. Real-time and accurate monitoring of blade surface stress and strain is critical to ensure safe operation. In this study, thin-film strain gauges (TFSGs) that can be used in high-temperature environments above 1000 °C were designed and fabricated using a PtRh6 thin film as the sensitive material. The hysteresis effect of the stress transfer upon establishing a thermo-mechanical coupling finite element model of the Inconel718 high-temperature nickel-based alloy equal-strength beam PtRh6 TFSGs was analyzed and the optimal combination of thin-film thickness and longitudinal grid length of wire-grid TFSGs was determined. In order to solve the problem of high-temperature insulation, the insulating properties of a single-layer Al2O3 insulating film, a single-layer ZrO2 insulating film, a double-layer Al2O3/ZrO2 composite insulating film, and a four-layer Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film at high temperature were compared and studied using scanning electron microscopy to analyze the microscopic morphology and composition of the four insulating film structures. The results showed that the four-layer Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film had the best insulating properties at high temperatures. On this basis, an Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film, PtRh6 sensitive layer, and Al2O3 protective film were sequentially deposited on a high-temperature nickel-based alloy equal-strength beam using DC pulsed magnetron sputtering technology to obtain an Inconel718 high-temperature nickel-based alloy equal-strength beam PtRh6 TFSG. Its gauge factor (GF) and temperature coefficient of resistance (TCR) were calibrated, and the results showed that the sensor could be used in harsh environments of 1000 °C. The above results provide new ideas for measuring stress and strain in aerospace under high-temperature and high-pressure environments.

Microstructure and mechanical properties of K438 alloy processed by selective laser melting and subsequent heat treatment

In this work, K438 nickel-based high-temperature alloy was successfully prepared and heat-treated by selected laser melting (SLM). A comparative study of the microstructure and mechanical properties of different samples was carried out to reveal the influence of SLM process parameters and heat treatment. The layer-by-layer fabrication in SLM created a special sunflower-shaped dendrites and the extremely fast cooling rate resulted in a large number of low angle grain boundaries (LAGBs) and inhomogeneous γ’ phases being found in the samples. After heat treatment, the orbital structure within the tissue disappeared and the coarse square γ’ phase (0.4 to 0.8 μm) melted and precipitated fine rounded secondary γ’ phases (0.05 μm). During recrystallisation, the LAGBs to high angle grain boundaries (HAGBs) transition occurs and many fine grain clusters appear at the grain boundaries, resulting in subcrystalline nucleation based on subcrystals and an increase in UTS. • The selective laser melting was applied to prepare the K438 nickel-based high-temperature alloy. • Crack morphology and crack evolution patterns by VED were investigated. • The evolution of the microstructure, phase and carbides after heat treatment were investigated. • Probing the optimum VED and heat treatment regime for K438 alloy

Tribological investigation of advanced coatings subjected to Venusian environment of 2.4 MPa CO2 pressure and 462 °C

Mechanical components in future missions to Venus will encounter high pressure (HP) and high temperature (HT) CO2 harsh conditions. Herein, the surface of Inconel 718 (INC 718), a HT nickel-based alloy was modified by applying advanced coatings by different deposition techniques. Three commercial coatings, namely Nedox PF-F™ (nickel-phosphorous alloy, referred as Nedox), Cera Tough™ (titanium-doped molybdenum disulfide alloy, referred as TiMoS2), and Balinit® DLC (amorphous hydrogenated diamond-like carbon, DLC) were coupled with PS400, a NASA-developed HT alloy, and slid against each other under HPHT Venusian-simulated environment. It was found that modifying one of the contacting surfaces (metal-on-coating) via PS400-deposition reduced the friction by 25%, whereas the wear increased significantly, compared to metal-on-metal contact. Sliding of the three coatings against PS400 coating (coating-on-coating) enhanced the frictional and wear performance significantly, in particular for PS400 vs. TiMoS2, attributed to the high wear resistance of the coating and the formation of beneficial oxide particles. The coefficient of friction (COF) was reduced by 38 and 43%, for PS400 vs. TiMoS2, and PS400 vs. DLC tribo-pairs, respectively compared to INC 718 vs. INC 718. In addition, the total wear rate decreased up to ten times, compared to metal-on-metal sliding.

Numerical Simulation and Multi-Objective Parameter Optimization of Inconel718 Coating Laser Cladding

Aiming at the difficulty of temperature control in the laser cladding process of high-temperature nickel-based alloys, the influence of cladding parameters on the temperature of the molten pool, and the quality of the cladding layer were explored. Firstly, through the analysis of the finite element method, the Inconel718 single-pass cladding model was established on the surface of 45 steel by using parametric language and life–death element technology, the influence of different laser power and scanning speed on the temperature of the molten pool center was explored, and reasonable process parameters scope were selected. Secondly, taking the cladding parameters as independent variables, and taking the dilution rate and forming coefficient of the cladding layer as the response variables, using BBD (Box–Behnken Design) to design experiments the response surface analysis method was used to establish the regression prediction model of the cladding process parameters and response indicators, and the genetic algorithm was used to carry out multi-objective optimization to obtain the best results. The optimal parameter combination is a laser power of 1756 W, a scanning speed of 19.43 mm/s, and a powder feeding rate of 19.878 g/min. Finally, a multi-pass lap joint experiment was carried out with the optimal parameters, and it was found that the cladding layer has a dense and fine structure and a good metallurgical bond with the matrix, which can effectively guide the actual production.

Correction: Seleznev et al. Ceramic Cutting Materials and Tools Suitable for Machining High-Temperature Nickel-Based Alloys: A Review. Metals 2021, 11, 1385

In the original article [...]

Multi-physics FE-analysis and measurements for thermo-mechanical fatigue crack growth rate testing applications

The presented methodology in this study is addressed to in-phase (IP) and out-of-phase (OOP) loading cycles in stationary and transient thermo-mechanical fields. The subject of the numerical and experimental study is a single edge notch tension (SENT) specimen produced from a high-temperature nickel-based alloy ХН73М. In order to determination a local thermo-mechanical stress-strain rate and displacement fields a new algorithm for the multi-physics numerical calculations developed and implemented incorporates Maxwell 3D, Fluent and Transient Structural modules of ANSYS 2021R1. The employment of proposed algorithm to represent the cyclic history associated with the TMF conditions in the experiments, multi-physics finite element (FE) modelling of the stress, strain and displacement fields in the SENT specimen was performed. Additionally, time dependent non-uniform temperature fields were determined with the same cyclic variations and magnitudes as in the experimental OOP and IP cycling. As a complement to the FEM computations, the infra-red thermography temperature distribution measurements was implemented for the TMF state in the experiments in the SENT specimen. The comparison multi-physics FE-analysis and direct measurements shown in the present study is intended to contribute to a better understanding of the different mechanisms driving TMF crack growth and the address the outstanding questions associated with basic methodology.

Tool wear mechanism of turning Inconel 718 and EEMD-based feature analysis

In the cutting process of high temperature alloys, the performance of the tool is closely related to the surface quality of the workpiece. In this paper, a turning test was conducted on nickel-based high-temperature alloy Inconel 718 using PVD-coated carbide tools, and the microscopic morphology of tool wear was observed by scanning electron microscopy (SEM), and the chemical elemental composition of the tool wear surface was analyzed by energy spectrum analyzer (EDS), and the wear mechanism of PVD-coated carbide tools in three stages of tool wear was analyzed in detail. On this basis, the characteristic quantities closely related to tool wear were extracted in the time and frequency domains by the collected cutting force signals, which provide effective characteristic inputs for the subsequent study of online tool wear monitoring.

Optimization and Simulation of Electrochemical Machining of Cooling Holes on High Temperature Nickel-Based Alloy

Optimization and Simulation of Electrochemical Machining of Cooling Holes on High Temperature Nickel-Based Alloy

Ceramic Cutting Materials and Tools Suitable for Machining High-Temperature Nickel-Based Alloys: A Review

Nickel-based superalloys are attractive to many industrial sectors (automotive, military, energy, aerospace, etc.). However, their physical properties make them difficult to machining using traditional tools. Therefore, new materials for the machining of Ni-based alloys are required. Ceramic-based composites could act as a tool to replace the current materials. The incentives for this paper are to provide an overview of existing ceramic composites and draw some conclusions that will help in solving the problem of choosing materials for the processing of Ni-based superalloys. Despite the diversity of ceramic composites in this work, the possibility of using the SiAlON ceramic for Ni-based alloy machining is highlighted.

Researching the Properties of Samples Fabricated Using Selective Laser Melting from A High-Temperature Nickel-Based Alloy

A possible application of a metal powder composition made of a high-temperature nickel-based alloy with high heat strength (the material is analogous to Inconel 718) in selective laser melting (SLM, an additive manufacturing technology) was considered. Peculiarities of material formation in the course of selective laser melting of the metal have been researched, and the mechanical properties of the material were determined. The effect of the thermal treatment mode on the mechanical characteristics was investigated. It was shown that the tensile strength of samples made of a high-temperature nickel alloy when the samples have not been subjected to thermal treatment is ~950 MPa; samples subjected to thermal treatment is ~1070 MPa.