Showing papers on "Inconel 625 published in 2018"
TL;DR: In this article, the mechanical response of Inconel 625 lattice structures fabricated by Selective Laser Melting (SLM) has been investigated and the high ductility of the lattice enables novel insight into the structural mechanics of AM lattice and the associated deformation photography provides a reference for the validation and verification of numerical models of lattice behaviour.
247 citations
TL;DR: It is demonstrated that a subsequent homogenization heat treatment can effectively homogenize the AM alloy and remove the deleterious δ phase, and the combined experimental and modeling methodology can be extended to elucidate the phase evolution during heat treatments in a broad range of AM materials.
171 citations
27 Jun 2018-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the authors investigated the mechanical behavior and microstructure of as-built and heat-treated Inconel 625 (IN625) samples processed by laser powder bed fusion (LPBF).
Abstract: This study investigated the mechanical behaviour and microstructure of as-built and heat-treated Inconel 625 (IN625) samples processed by laser powder bed fusion (LPBF). This process offers freedom in design to build complex IN625 components in order to overcome extensive machining. However, post heat treatments must be performed to obtain specific mechanical properties to match industrial requirements. For this purpose, different heat treatments were performed on IN625 samples, and through hardness measurements, three different heat treatments were selected, as optimised conditions. A direct ageing, a solutioning and a solutioning followed by ageing treatments were chosen to study the effects of these specific heat treatments on the microstructure and tensile properties, comparing them to those of as-built condition. The tensile properties of as-built and selected heat-treated IN625 samples showed superior values to minimum requirements for wrought IN625 alloys, whereas the investigation on the microstructures and fracture surfaces of as-built and heat-treated IN625 contributed to an understanding of the tensile properties evolution. The high tensile strength of as-built samples essentially derived from very fine dendritic structures mainly below 1 µm with high dislocation density and nanometric MC carbides. The high tensile properties of ageing treatments performed at 700 °C for 24 h, whether directly aged or post-solutioning, were found to be primarily dependent on γ" phases (10–30 nm) and M23C6 carbides formation. By contrast, the tensile properties of solution-treated IN625 samples at 1150 °C for 2 h showed higher ductility coupled to lower strength than other conditions, due to the grain growth.
142 citations
TL;DR: In this paper, the thermal conductivities of five metal powders for powder bed additive manufacturing (Inconel 718, 17-4 stainless steel, Inconel 625, Ti-6Al-4V, and 316L stainless steel) were measured using the transient hot wire method.
Abstract: The thermal conductivities of five metal powders for powder bed additive manufacturing (Inconel 718, 17-4 stainless steel, Inconel 625, Ti-6Al-4V, and 316L stainless steel) were measured using the transient hot wire method. These measurements were conducted with three infiltrating gases (argon, nitrogen, and helium) within a temperature range of 295–470 K and a gas pressure range of 1.4–101 kPa. The measurements of thermal conductivity indicate that the pressure and the composition of the gas have a significant influence on the effective thermal conductivity of the powder, but that the metal powder properties and temperature do not. Our measurements improve the accuracy upon which laser parameters can be optimized in order to improve thermal control of powder beds in selective laser melting processes, especially in overhanging and cellular geometries where heat dissipation by the powder is critical.
119 citations
TL;DR: In this article, the powder characteristics, as well as the SLM process parameters influences on the quality of the Inconel 625 (IN625) feedstock materials have been accounted for this study.
Abstract: Selective Laser Melting (SLM) as an additive manufacturing process can fabricate near to net shape metallic components directly from Computer aided design models, which may be difficult to fabricate using conventional manufacturing methods. In this work, the powdered metals used as the raw material feedstock in the Selective Laser Melting (SLM) process were studied. SLM manufacturing processibility of nickel based super alloy, powders related to the particle Size Distribution (PSD), flow ability, mechanical properties and microstructures was investigated. Different powder characterisation methods were also investigated to establish which might be most useful for SLM application. Three different Inconel 625 (IN625) powder feedstock materials have been accounted for this study. Firstly, three different IN625 powders were fully characterised for chemical composition, particle size distribution and flow ability using different types of characterisation techniques. It has been found that the presence of any significant proportion of powder particles smaller than 10-μm diameter, leads to severe agglomeration and make SLM processing difficult. Secondly, coupons were manufactured using SLM from each powder with different process parameter, which were analysed for porosity and mechanical behaviour. Next, the scanning electron microscopy (SEM), electron back scattering diffraction (EBSD) are employed to investigate the microstructures. Finally, data analysis was employed on the data collected by metal powders characterization, SLM manufacturing, SEM/EBSD study and mechanical properties of the IN625. It has been observed that the powder characteristics, as well as SLM process parameters influences on the quality of the IN625 fabricated.
113 citations
TL;DR: In this paper, the effect of solution heat treatments on the microstructure and mechanical properties of Inconel 625 superalloy fabricated by laser solid forming was investigated, and the results showed that the tensile strength and microhardness and yield strength decreased with the increment of the solution temperature.
84 citations
TL;DR: In this article, three nickel base alloys (Inconel 718, Inconel 625 and Monel-400) have been studied for chip formation in the hot turning process using flame heating.
84 citations
TL;DR: In this paper, the grain boundary character distribution (GBCD) and its relationship with texture are investigated in the context of select laser melting (SLM) for metal additive manufacturing processes to fabricate complex structures.
71 citations
TL;DR: In this article, the microstructure of Ni base Inconel 625 coatings that were fabricated on the Ni base inconel 738 substrate with two processes of laser cladding and TIG cladding was investigated to obtain optimal parameters.
Abstract: The purpose of this study was to investigate the microstructure of the Ni base Inconel 625 coatings that were fabricated on the Inconel 738 substrate with two processes of laser cladding and TIG cladding For this purpose, single-pass samples were precipitated to obtain optimal parameters In the laser cladding method, laser power, laser scanning rate and powder feed rate were considered as variables, and current and its type were considered as variables for the TIG method Based on the results, using the parameters of optimum single-pass samples that were free of porosity, crack and had minor geometric dilution, coatings were applied in both methods with 50% overlap In order to microstructural, elemental and phasic characterization, field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used Based on the results, the microstructure of coatings from surface to interface of coating/substrate consists of coaxial, columnar and cellular structure dendrites, respectively, and the laser coating has a finer microstructure due to the higher cooling rate In addition, the austenite, carbide and Laves phases were observed in both coatings
65 citations
21 Feb 2018-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, temperature measurements based on careful experimentation and microstructural analysis were conducted for Ti-6Al-4V and Inconel 625 alloys deposited using the laser-based directed energy deposition process.
Abstract: Accurate temperature measurements based on careful experimentation and microstructural analysis were conducted for Ti-6Al-4V and Inconel 625 alloys deposited using the laser-based directed energy deposition process. In the case of the Ti-6Al-4V alloy, thermal measurements were made in the first layer during the first and four subsequent deposits to ascertain microstructural evolution during the heating and cooling cycles. Four energy densities were utilized during deposition of the Inconel 625 alloy to alter cooling rates and determine the impact of processing conditions on solidification morphology. The precise experimental measurements enabled a comprehensive analysis of the solid state reactions for Ti-6Al-4V, and the solidification phenomena to be elucidated for Inconel 625. The results for the Ti-6Al-4V alloy indicated that the measured thermal response could be used to anticipate initial microstructure based on cooling rates from the β-transus, and subsequent thermal cycles could be utilized to define potential transformations between α, α′, and β. Analysis of the measured thermal cycles from the liquid through solidification for the Inconel 625 alloy showed that processing parameters could be linked to factors governing the solidification process and microstructural features. Using these relationships, an accurate processing map for laser-based directed energy deposition for Inconel 625 was constructed to enable the identification of solidification morphology and microstructural scale based on critical processing parameters.
62 citations
TL;DR: In this article, laser cladding was employed to fabricate Inconel 625 composite coatings reinforced by TiC particles using a 4000W fiber laser and the morphologies of bead samples, particle distributions, mechanisms of microstructure evolution, mechanical property and corrosion performance of the individual molten pool which was produced in laser claddings composites were investigated.
TL;DR: Avoiding heat treatments that promote the formation of δ-phase in AM components that are not homogenized is highly recommended, particularly true at elevated temperatures where the microstructural stability and the consistency of mechanical properties are more likely to be affected by the presence of €phase.
Abstract: This research evaluated the kinetics of δ-phase growth in laser powder bed additively-manufactured (AM) Inconel 625 during post-build stress-relief heat treatments. The temperatures ranged between 650 °C and 1050 °C, and the times from 0.25 to 168 hours. The presence of δ-phase was verified for each temperature/time combination through multiple techniques. A conventional time-temperature-transformation diagram was constructed from the time-temperature data. Comparison to the growth in wrought IN625 with a similar nominal composition revealed that δ-phase formation occurred at least two orders of magnitude faster in the AM IN625. The results of this study also revealed that the segregated microstructure in the as-built condition has a strong influence on the kinetics of δ-phase formation in AM IN625 as compared to a homogenized material. Since control of the δ-phase growth is essential for reliable prediction of the performance of IN625 components in service, avoiding heat treatments that promote the formation of δ-phase in AM components that are not homogenized is highly recommended. This will be particularly true at elevated temperatures where the microstructural stability and the consistency of mechanical properties are more likely to be affected by the presence of δ-phase.
TL;DR: The authors suppress DSA via a unique microstructure obtained using additive manufacturing and propose a new dislocation-arrest model in nickel superalloys to elucidate the criterion for DSA to occur or to be absent as a competition between dislocation pipe diffusion and carbide–carbon reactions.
Abstract: Dynamic strain aging (DSA), observed macroscopically as serrated plastic flow, has long been seen in nickel-base superalloys when plastically deformed at elevated temperatures. Here we report the absence of DSA in Inconel 625 made by additive manufacturing (AM) at temperatures and strain rates where DSA is present in its conventionally processed counterpart. This absence is attributed to the unique AM microstructure of finely dispersed secondary phases (carbides, N-rich phases, and Laves phase) and textured grains. Based on experimental observations, we propose a dislocation-arrest model to elucidate the criterion for DSA to occur or to be absent as a competition between dislocation pipe diffusion and carbide–carbon reactions. With in situ neutron diffraction studies of lattice strain evolution, our findings provide a new perspective for mesoscale understanding of dislocation–solute interactions and their impact on work-hardening behaviors in high-temperature alloys, and have important implications for tailoring thermomechanical properties by microstructure control via AM. Detrimental serrated plastic flow via dynamic strain aging (DSA) in conventionally processed nickel superalloys usually occurs during high temperature deformation. Here, the authors suppress DSA via a unique microstructure obtained using additive manufacturing and propose a new dislocation-arrest model in nickel superalloys.
TL;DR: In this paper, the microstructure and chemical compositions of the composites were detected using scanning electron microscopy (SEM), TEM and X-ray diffraction (XRD).
TL;DR: In this article, the suitability of NMQL (carbon nanotube; CNT in vegetable oil) in machining of alloys like Inconel 625 was investigated and the objective was to minimize tool wear and surface roughness under different machining conditions.
Abstract: Superalloy Inconel 625 although having many industrial applications owing to its high strength, exhibits poor machinability because of its sticky nature and poor heat conductivity. To improve its machinability, use of cutting fluids becomes necessary to remove heat and provide lubrication in the cutting region. However, harmful effects of cutting fluids on environment and operator health restrict their application. Several efforts have been carried out to replace or minimize the quantity of conventional cutting fluids used in machining to strive for green machining and economizing machining operations. Nano-fluid minimum quantity lubrication (NMQL) technique has evolved as best alternative to flood conditions cooling /lubrication especially for machining of alloys like Inconel. This paper experimentally investigates the suitability of NMQL (carbon nanotube; CNT in vegetable oil) in machining of Inconel 625. The objective was to minimize tool wear and surface roughness under different machining conditions. Tool performance in NMQL was also compared with that under dry and flood conditions. The results revealed superiority of NMQL in terms of better tool life and improved surface finish over dry machining and nearly equivalent performance to wet (flood) machining thus provides the way forward for sustainable and environmental friendly machining.
TL;DR: In this article, the coprecipitation of the γ-phase alongside the known δ-phase was demonstrated during stress-relief annealing of AM Inconel 625 at 870°C.
TL;DR: In this article, the room temperature fatigue crack propagation behavior of Inconel 625 alloy processed by laser powder bed fusion was studied and compared to that of a wrought alloy of the same composition.
TL;DR: In this paper, the fatigue behavior of Inconel 625 (IN625) manufactured via a high-shear deposition process is quantified for the first time, and a microstructure-sensitive fatigue life model was utilized to elucidate structure-property fatigue mechanism relations of the as-deposited and feedstock IN625 materials.
Abstract: A transformative hybrid solid-state additive manufacturing process provides a new path to fabricate or repair components with wrought-like performance. In this work, the fatigue behavior of Inconel 625 (IN625) manufactured via a high-shear deposition process is quantified for the first time. In this unique process, feedstock is deposited via a hollow non-consumable rotating cylindrical tool, thereby generating heat and plastically deforming the feedstock through controlled pressure as consecutive layers are metallurgically bonded upon a substrate. To quantify the fatigue behavior of the as-deposited IN625, stress-life experiments were conducted, where improved fatigue resistance was observed compared with the feedstock. Post-mortem analysis of the as-deposited IN625 revealed a similar fatigue nucleation and growth mechanism to the feedstock for a majority of the specimens tested in this study. Last, a microstructure-sensitive fatigue life model was utilized to elucidate structure–property fatigue mechanism relations of the as-deposited and feedstock IN625 materials.
TL;DR: In this paper, an adjustable finite element-based multi-physics and multi-software platform thermal model for laser additive manufacturing in powder bed systems to predict the transient temperature and the molten pool geometry is presented.
Abstract: Nowadays, additive manufacturing via topology optimization creates new opportunities for weight reductions in aerospace industry where high fly-to-buy ratio is desired. Selective laser sintering of advanced engineering materials like nickel super alloys are also expanding to reduce the cost and time of the manufacturing in aerospace industry. Elevated temperature and temperature gradients are critical factors in selective laser sintering of metals and they significantly affect the quality and integrity factors of produced parts such as microstructures, porosity, residual stresses, and distortions. Therefore, the aerospace industry needs advanced simulation tools to predict the temperatures, temperature gradients, and molten pool geometries to better understand the physics of the selective laser melting process as well as for the process optimizations. This article introduces an adjustable finite element-based multi-physics and multi-software platform thermal model, for laser additive manufacturing in powder bed systems to predict the transient temperature and the molten pool geometry. The developed model is able to simulate 3D transient temperature and molten pool shape in the laser additive manufacturing process by including the features of melting and solidification, porous media, and temperature-dependent thermal material properties for different materials. A set of experiments of Inconel 625 is carried out in order to measure the size of the molten pool and to validate the developed thermal model. An experimental study on temperature distribution carried out with titanium and an experimental study on molten pool sizes carried out with Inconel 625 in the literature are also compared with the developed thermal model. The estimation errors of the developed model are in the range of 11–18%.
01 Dec 2018
TL;DR: In this article, the microwave energy for processing of bulk metals is effectively utilized to join Inconel-625 plates through hybrid heating technique using INCONEL-625 powder as an interface filler mat.
Abstract: Application of microwave energy for processing of bulk metals is effectively utilized to join Inconel-625 plates through hybrid heating technique using Inconel-625 powder as an interface filler mat...
31 Dec 2018
TL;DR: Inconel 625 is a nickel-based alloy that is mainly used in high-temperature applications and it exhibits an unstable plastic flow at elevated temperatures characterized by serrated yielding, well-known as the Portevin-Le Chatelier effect as mentioned in this paper.
Abstract: Inconel 625 is a nickel-based alloy that is mainly used in high-temperature applications. Inconel 625 exhibits an unstable plastic flow at elevated temperatures characterized by serrated yielding, well-known as the Portevin-Le Chatelier effect. The evaluation of the mechanical properties of Inconel 625 at high temperatures is the aim of this work. The tensile tests were executed in temperatures ranging from room temperature to 1000 °C with strain rates of 2 × 10−4 to 2 × 10−3 s−1. The creep tests were executed in the temperature range of 600–700 °C and in the stress range of 500–600 MPa in a constant load mode. The optical and scanning electron microscopes were used for surface fracture observation. In the curves obtained at 200–700 °C the serrated stress-strain behavior was observed, which was related to the dynamic strain aging effect. The yield strength and the elongation values show anomalous behavior as a function of the test temperature. An intergranular cracking was observed for a specimen tensile tested at 500 °C that can be attributed to the decohesion of the carbides along the grain boundaries. The fracture surface of the specimen tensile tested at 700 °C showed the predominance of transgranular cracking with tear dimples with a parabolic shape.
TL;DR: In this article, the Inconel 625 coatings deposited by the Cold Metal Transfer technique on a 16Mo3 boiler tube were investigated. And the clad layers were shown to have a typical cellular-dendritic structure with secondary phases in the interdendric regions (e.g. Laves phases and complex nitrides/carbides (MX)).
31 Jan 2018-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the stress relaxation behavior and mechanisms of conventionally processed and additively manufactured Inconel 625 (CP-IN625) at 600 and 700°C were investigated via compression tests up to an engineering strain of 9% with in situ neutron diffraction characterization.
Abstract: The complex thermal histories in additive manufacturing (AM) of metals result in the presence of residual stresses in the fabricated components. The amount of residual stress accumulated during AM depends on the high temperature constitutive behavior of the material. The rapid solidification and repeated thermal cycles with each laser pass result in material contraction, and subject the surrounding, constrained material to both elevated temperatures and internal stresses, providing driving forces for stress relaxation. In this study, the stress relaxation behavior and mechanisms of conventionally processed and additively manufactured Inconel 625 (CP-IN625 and AM-IN625) at 600 °C and 700 °C were investigated via compression tests up to an engineering strain of 9% with in situ neutron diffraction characterization. The stress decayed to a plateau stress equivalent to 18% of the peak stress in CP-IN625 and 16% in AM-IN625 at 600 °C, and 39% in CP-IN625 and 44% in AM-IN625 at 700 °C. At the same temperature, the stress relaxation rate in AM-IN625 was twice as high as that in CP-IN625, and the magnitude of the plateau stress in AM-IN625 was slightly lower than that in CP-IN625, as the textured AM-IN625 had much larger grains than the texture-free CP-IN625. The stress relaxation in CP- and AM-IN625 was deduced to be controlled by dislocation glide and climb, where dislocations interact with grain boundaries, solute atoms, and secondary phases. The stress relaxation constitutive behavior reported here is a necessary input for the development of accurate thermomechanical models used to predict and minimize residual stresses and distortion in AM, as well as to predict the stress relaxation behavior of Inconel 625 in high temperature structural applications.
TL;DR: In this article, the evolution of solidification microstructure and dynamic recrystallisation (DRX) during the laser solid forming of the Ni-based Inconel 625 superalloy was investigated.
Abstract: This study investigated the evolution of solidification microstructure and dynamic recrystallisation (DRX) during the laser solid forming of the Ni-based Inconel 625 superalloy. The as-deposited microstructure mainly showed epitaxially grown columnar grains with fine equiaxed grains between them. These fine equiaxed grains were formed by the discontinuous DRX (DDRX) and continuous DRX (CDRX) processes, which were induced by the cyclic thermal stress resulting from the repeated laser deposition. The bulging of pre-existing grains and sub-grain rotation were the main mechanisms of the DDRX and CDRX phenomena, respectively. Additionally, after the occurrence of DRX, the dislocations were released and there was no distortion in the recrystallised grains. Coarse equiaxed grains were present in the top zone of the deposit; these grains were formed by the columnar-to-equiaxed transition during the solidification of the molten pool after the end of the laser re-melting and deposition process.
TL;DR: In this paper, single track laser melting experiments and simulations on Inconel 625 were used to estimate the dimensions and microstructures of the resulting melt pools, which reasonably agree with their finite element calculations.
Abstract: We use single track laser melting experiments and simulations on Inconel 625 to estimate the dimensions and microstructures of the resulting melt pools. Our work is based on a design-of-experiments approach which uses multiple laser power and scan speed combinations. Single track experiments generate melt pools of certain dimensions. These dimensions reasonably agree with our finite element calculations. Phase-field simulations predict the size and segregation of the cellular microstructures that form along the melt pool boundaries for the solidification conditions that change as a function of melt pool dimensions.
TL;DR: In this article, an innovative and simplified method of electroless pure-nickel coating was plated on graphene nanoplatelets (GNPs), which were uniformly dispersed in Inconel 625 (IN625) powder with the ratio of 1:9 by ball milling.
Abstract: An innovative and simplified method of electroless pure‑nickel coating was plated on graphene nanoplatelets (GNPs). The nickel-coated graphene nanoplatelets (NiGNPs) were uniformly dispersed in Inconel 625 (IN625) powder with the ratio of 1:9 by ball milling. Then laser cladding was used to fabricate the NiGNPs reinforced IN625 composite coatings. The survivability of NiGNPs, morphology of precipitated phase, microhardness through transverse section and wear resistance at room and elevated temperatures were studied. The results indicated that the NiGNPs were successfully incorporated into IN625 coatings by laser cladding. Part of them were deduced to be damaged or dissolved into molten pool, which benefited the formation of NbC, but most of them could be observed as exposed GNPs and well-distributed welded GNPs. Compared to laser cladded IN625 coating, the composite coating showed higher hardness at bottom region of cladded coating and smaller size of HAZ due to the improvement of thermal conductivity by additional NiGNPs. Furthermore, comparative wear test demonstrated that friction coefficient (COF) and wear rate were decreased at both room and elevated temperatures. Combined with wrinkled, tiled and rolled GNPs observed on the worn surface, it was revealed that the wear properties were efficiently benefited from superior lubrication between interlayers of GNPs.
TL;DR: In this paper, the authors describe the selection of the proper welding method and welding consumables in dissimilar metal joining and compare the performance of SMAW and gas tungsten arc welding with two types of filler metals (ERNiCrMo-3 and ERSS316L) and an electrode.
Abstract: The current work was carried out to characterize welding of Inconel 625 superalloy and 316L stainless steel In the present study, shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW) with two types of filler metals (ERNiCrMo-3 and ERSS316L) and an electrode (ENiCrMo-3) were utilized This paper describes the selection of the proper welding method and welding consumables in dissimilar metal joining During solidification of ERNiCrMo-3 filler metal, Nb and Mo leave dendritic cores and are rejected to inter-dendritic regions However, ERSS316L filler metal has small amounts of elements with a high tendency for segregation So, occurrence of constitutional super-cooling for changing the solidification mode from cellular to dendritic or equiaxed is less probable Using GTAW with lower heat input results in higher cooling rate and finer microstructure and less Nb segregation The interface between weld metal and base metal and also unmixed zones was evaluated by scanning electron microscopy and energy dispersive X-ray (EDX) analysis Microhardness measurements, tensile test, and Charpy impact test were performed to see the effect of these parameters on mechanical properties of the joints
01 Jan 2018
TL;DR: In this article, the effect of cutting parameters on material removal rate and tool wear of a whisker ceramic was investigated in a nickel-based super alloys, and the results showed that tool wear is one of the major machinability aspects of super alloy.
Abstract: Rapid tool wear is one of the major machinability aspects of nickel-based super alloys. In this article, the effect of cutting parameters on material removal rate and tool wear of a whisker ceramic...
01 Oct 2018
TL;DR: In this paper, the microstructure of dissimilar metal welding of Inconel 625 and AISI 316L using continuous current gas Tungsten Arc Welding (CCGTAW) and Pulsed current gas tungsten arc welding processes with ERNiCr-3, TIG 316L and twisted (ERNiCr-1 and TIG 318L) fillers were investigated using an optical microscope and Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray (EDAX).
Abstract: This study investigated the microstructure of the dissimilar metal welding of Inconel 625 and AISI 316L using Continuous Current Gas Tungsten Arc Welding (CCGTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) processes with ERNiCr-3, TIG 316L and twisted (ERNiCr-3 and TIG 316L) fillers. Microstructure examinations were carried out using an optical microscope and Scanning Electron Microscopy (SEM)/Energy Dispersive X-Ray (EDAX). The results of the study showed the existence of a partially melted zone (PMZ) on the AISI 316L side. Weld zone (WZ) analysis showed the existence of a multi-directional grain growth on the 316L side in all specimens, although less growth was found on the Inconel 625 side. Grain growth almost disappeared using PCGTAW with twisted fillers. SEM/EDAX investigations indicated that secondary deleterious secondary phases were tiny and white in five experiments. However, a meager amount of precipitates occurred in PCGTA welding with twisted fillers. Moreover, these were particularly innocent precipitates, represented by black dots in images, whereas other tiny white secondary phases are known to be brittle. As a result, PCGTA welding with twisted fillers exhibited the best metallurgical properties.
TL;DR: Inconel 625 has been used for additive manufacturing of superalloys as mentioned in this paper, and the results show that it has a high hardness (335 HV), superior tensile strength (952 MPa), and yield strength (793 MPa).
Abstract: Additive manufacturing (AM) nickel-based superalloys have been demonstrated to equate or exceed mechanical properties of cast and wrought counterparts but their tribological potentials have not been fully realized. This study investigates fretting wear behaviors of Inconel 625 against the 42 CrMo4 stainless steel under flat-on-flat contacts. Inconel 625 is prepared by additive manufacturing (AM) using the electron beam selective melting. Results show that it has a high hardness (335 HV), superior tensile strength (952 MPa) and yield strength (793 MPa). Tribological tests indicate that the AM-Inconel 625 can suppress wear of the surface within a depth of only ~2.4 μm at a contact load of 106 N after 2 × 104 cycles. The excellent wear resistance is attributed to the improved strength and the formation of continuous tribo-layers containing a mixture of Fe2O3, Fe3O4, Cr2O3 and Mn2O3.