Showing papers on "Inconel published in 2010"
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TL;DR: In this article, the results of an experimental investigation on the wear mechanisms of uncoated tungsten carbide (WC) and coated tools (single layer (TiAlN) PVD, and triple-layer (TiCN/Al 2 O 3 /TiN) CVD) were presented.
231 citations
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TL;DR: Inconel 718 (IN718) is used in aerospace applications due to its superior mechanical properties and the high-speed machinability of this material under laser-assisted machining (LAM) and dry conditions as mentioned in this paper.
142 citations
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TL;DR: In this article, a series of experiments was carried out using electrical discharge machining process in order to explore the influence of electrode type and material, i.e., single and multi-channel tubular electrodes made of brass and copper materials.
Abstract: This paper presents a comparative experimental investigation of electrical discharge machining fast hole drilling of aerospace alloys, namely Inconel 718 and Ti–6Al–4V. A series of experiments was carried out using electrical discharge machining process in order to explore the influence of electrode type and material, i.e., single and multi-channel tubular electrodes made of brass and copper materials. The comparisons were made from the results of material removal rate, electrode wear, microhardness, and scanning electron microscope images taken from the machined/drilled hole surfaces. The experimental results reveal that the single-channel electrode has comparatively better material removal rates and lower electrode wear ratio. However, scanning electron microscope images show that multi-channel electrodes produce better surfaces than single-channel electrodes for both aerospace alloys. Microstructural changes while drilling operations for both types of electrodes result in an annealing effect on Inconel 718 and a tempering effect on Ti–6Al–4V alloy. In addition, multi-channel electrodes produce comparatively lower hardness values.
107 citations
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TL;DR: In this paper, the susceptibility of pre-weld heat treated laser beam welded IN 738 superalloy to heat affected zone (HAZ) cracking was studied, and the authors found that a pre-Weld heat treatment that produced the minimal grain boundary liquation resulted in a higher level of cracking compared to those with more intergranular liquation.
101 citations
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TL;DR: In this paper, the wear performance of Inconel 617 and Stellite 6 alloys was investigated and compared with that of the X32CrMoV33 hot work tool steel.
89 citations
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TL;DR: In this article, the effect of initial microstructure on alloy 617 creep behavior at 850 °C and 950 °C was investigated at both temperatures with a strain rate drop at the beginning of the tests followed by a creep rate increase to a plateau before the onset of the tertiary creep.
85 citations
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TL;DR: In this paper, a laser-heating of Inconel 718 alloy is considered and the resulting temperature and stress fields are predicted using the finite element method (FEM) using an experiment carried out to treat the alloy surface by a laser beam at high pressure nitrogen environment.
80 citations
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TL;DR: The effect of heat input from laser beam welding (LBW) on the microstructural evolution of superalloy Inconel 718 was investigated in this article, where LBW was carried out on 1.6-mm-thick sheets with an average grain size of 13 μm (ASTM # 9.5).
Abstract: The effect of heat input from laser beam welding (LBW) on the microstructural evolution of superalloy Inconel 718 was investigated. LBW was carried out on 1.6-mm-thick sheets with an average grain size of 13 μm (ASTM # 9.5), and four different heat inputs in the range of 74.5 mm−1 to 126.6 J mm−1 were used. Full penetration was achieved in all weld experiments. Microstructures of the welds were evaluated using an optical microscope and a field emission scanning electron microscope. Increasing the heat input changed the resulting weld shape from a wine glass shape to a stemless glass shape with wider surface bead widths, and the measured average dendrite arm spacing was increased from 1.06 μm to 2.30 μm, indicating the corresponding solidification rate in the range of 1.75 × 105 K s−1 (°C s−1) to 3.5 × 106 K s−1 (°C s−1). The welds also were free from microfissuring even at the lowest heat input trials. The Nb concentration of Laves phase for the current LBW samples was ≈20.0 wt pct. The coefficients of partition and distribution for Nb were determined to be approximately 3.40 and 0.50, respectively.
76 citations
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TL;DR: In this article, microstructural features were examined by optical and scanning electron microscopy and X-ray diffraction for the Ni-based superalloy Inconel 625.
Abstract: It is commonly observed that there is a performance gap between the corrosion resistance of thermally sprayed coatings and the equivalent bulk material. This is attributed to the significantly modified microstructure of the sprayed coatings. However, currently there is no detailed understanding of which aspects of microstructural modification are primarily responsible for this performance gap. In this work several deliberately microstructurally modified versions of the Ni-based superalloy Inconel 625 were produced. These were subjected to potentiodynamic electrochemical testing in 0.5M H2SO4 to investigate the links between specific microstructural features and electrochemical behaviour. Samples were prepared by high velocity oxy-fuel (HVOF) thermal spraying, laser surface remelting using a high power diode laser and conventional powder sintering. Microstructural features were examined by optical and scanning electron microscopy and X-ray diffraction. Potentiodynamic testing was carried out on the following forms of Inconel 625: wrought sheet; HVOF sprayed coatings; sintered powder compacts; laser melted wrought sheet and HVOF sprayed coatings. Using the corrosion behaviour, i.e. passive current density, of the wrought sheet as a baseline, the performance of different forms of Inconel 625 were compared. It is found that a fine dendritic structure (with associated microsegregation) produced by laser remelting wrought sheet has no significant effect on corrosion performance. Up to 12% porosity in sintered powder samples increases the passive current density by a factor of only around 2. As observed previously, the passive current density of HVOF sprayed coatings is 20 - 40 times greater. However, HVOF coatings subjected to laser surface remelting are found to have a passive current density close to that of wrought material. It is concluded that, whilst porosity in coatings produces some decrease in corrosion resistance, the main contributing factor is the galvanic corrosion of localised Cr-depleted regions which are associated with oxide inclusions within HVOF sprayed samples.
73 citations
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TL;DR: In this paper, the mean stress effect on high-cycle fatigue life was evaluated for three nominally identical batches of cast Ni-base superalloy Inconel 713LC under load symmetrical cycling and cycling with tensile mean load.
72 citations
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25 Mar 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a thermal fatigue test of the X32CrMoV33 hot work tool steel was terminated after 1500 cycles due to severe surface degradation and temper softening, both leading to a relatively poor thermal fatigue resistance, in spite of favorable thermo-physical properties.
Abstract: The principle failure mechanism in thixoforming dies is thermal fatigue as the mechanical loading on the tooling is modest owing to a mushy feedstock. Samples of X32CrMoV33 steel, Inconel 617 and Stellite 6 alloys were submitted to thermal cycling under conditions which approximate thixoforming of steels. The thermal fatigue test of the X32CrMoV33 hot work tool steel was terminated after 1500 cycles due to severe surface degradation and temper softening, both leading to a relatively poor thermal fatigue resistance, in spite of favorable thermo-physical properties. The response to thermal cycling of the Ni- and Co-based superalloys, Inconel 617 and Stellite 6, under steel thixoforming conditions, on the other hand, was encouraging. The Inconel 617 and Stellite 6 samples are much more resistant to oxidation and temper softening than the hot work tool steel, providing a superior resistance to thermal fatigue cracking with few and relatively shallow cracks after as many as 5000 thermal cycles.
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TL;DR: In this article, the authors evaluated the performance of two nickel-based alloys, namely, Inconel 600 and Conconel 625, against cavitation erosion and jet impingement erosion through vibratory cavitation equipment and a jet apparatus for erosion-corrosion.
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TL;DR: In this article, the microstructural and mechanical properties of friction-stir-welded and post-heat-treated Inconel 718 alloy were investigated, and it was shown that applying heat treatment after FSW led to improvements in the mechanical properties.
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TL;DR: In this paper, the influence of various conditions of Inconel 738 superalloy welding or deposition welding has been studied in order to shed light on the coupling between thermal, metallurgical and mechanical states in the heat affected zone (HAZ) in which cracking may occur particularly during welding and post-weld heat treatment.
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TL;DR: In this article, the effect of traverse speed on abrasive waterjet machining (AWJM) of Inconel 718 nickel-based superalloy was experimentally investigated, and it was observed that the surface roughness and kerf taper ratio tended to increase with traverse speed, while kerf wideness decreased.
Abstract: In this study, the effect of traverse speed on abrasive waterjet machining (AWJM) of Inconel 718 nickel-based superalloy was experimentally investigated. In the experiments, six different traverse speeds of 80, 130, 180, 230, 280, and 330 mm/min were employed. Following the tests, the surface roughness of the machined job, the kerf taper ratio, and kerf wideness were measured. The characteristics of machined surface were also investigated using scanning electron microscope (SEM) and atomic force microscope (AFM). As a consequence, it is observed that the surface roughness and kerf taper ratio tended to increase with traverse speed, while kerf wideness decreased.
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TL;DR: In this article, nano-multilayered TiAlCrSiYN/TiAlCrN coatings have been developed with various ratios of Ti/Al/Cr within Si+Y containing nano-layers for machining direct aged Inconel (DA) 718 and powder metallurgical ME 16 Ni-based superalloys.
Abstract: New nano-multilayered TiAlCrSiYN/TiAlCrN coatings have been developed with various ratios of Ti/Al/Cr within Si + Y containing nano-layers. The layered nanostructure of the coatings has been studied by STEM-HAADF mode and the nano-metric composition obtained by in-situ EDS. Micro-mechanical characteristics were investigated using a Micro Materials NanoTest System. Thermogravimetric-Differential Thermal Analysis (TG-DTA) was used within a temperature range of 25–1200 ° C for oxidation resistance evaluation. The wear performance of nano-multilayered TiAlCrSiYN/TiAlCrN coatings during machining of direct aged Inconel (DA) 718 and powder metallurgical ME 16 Ni-based superalloys has been investigated. The kinetic coefficient of friction under metal cutting conditions of Inconel was measured. The temperature range was 25–1000 ° C. It was shown that the composition of the nano-multilayered coatings and their characteristics have to be tuned for specific applications. A nano-multilayered coating with increased amount of Al (60 at.%) in Si + Y containing nano-layers that has strong oxidation resistance and a higher range of micro-mechanical properties related to crack propagation under scratch conditions behaves better during machining of Inconel DA 718 alloy. For machining of the more high temperature strong and thermally resistant ME 16 superalloy, a nano-multilayered coating with less Al (55 at.%) in Si + Y containing nano-layers that combines improved oxidation resistance with higher hardness and other beneficial micro-mechanical properties associated with resistance to plastic deformation performs best.
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TL;DR: The fatigue and fracture behavior of nickel-based superalloy Inconel 718 was investigated up to the very high cycle regime under rotary bending tests at room temperature.
Abstract: The fatigue and fracture behavior of nickel-based superalloy Inconel 718 was investigated up to the very high cycle regime under rotary bending tests at room temperature. It was found that this superalloy can still fracture after exceeding 107 cycles. Fractographic analysis revealed that there was a transition from fatigue crack initiation at multi-sites to single initiation with decreasing stress levels. The fracture surface can be divided into four areas according to the appearance, associated with fracture mechanics analysis of the corresponding stress intensity factors. The fracture mechanism dominant in each area was disclosed by scanning electron microscope examination and analyzed in comparison with those obtained from the crack growth tests. Subsequently, life prediction modeling was proposed by estimating the crack initiation and propagation stage respectively. It was found that Chan (2003)’s model for initiation life and the Paris law for growth life can provide comparable predictions against the experimental life.
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TL;DR: In this article, Zirconium diboride-SiC (ZS) composite and SCS-9a silicon carbide fibers were joined to titanium and Inconel 625 using Pd-base brazes, Palco and Palni.
Abstract: Zirconium diboride–SiC (ZS) particulate ceramic-matrix composites containing either carbon powder (termed ZSC composite) or SCS-9a silicon carbide fibers (termed ZSS composite) were joined to titanium and Inconel 625 using Pd-base brazes, Palco and Palni (T
L ~ 1492–1513 K). The joints exhibited intimate contact and evidence of interdiffusion of Zr, Si, Pd, and Co, with the Palni joints exhibiting most extensive chemical interaction, greater propensity toward cracking, and partial melting of the Inconel substrate. The joint region comprised of braze-plus-interaction zone exhibited comparable Knoop hardness in Palni and Palco joints. The fully dense ZS had the highest (2000–2600 HK200) and ZSC the lowest (300–750 HK200) Knoop hardness. The ZSS composites displayed a large dispersion in hardness because of incomplete densification (~30% porosity) and transversal cracking from the CTE mismatch between SCS-9a fibers and the ZS matrix. Steady-state thermal calculations reveal that for joined assemblies (~0.51 cm total thickness in the study), joining Ti or Inconel to ZS shall decrease the thermal resistance by nearly 33–43% relative to the metal substrate, thus enhancing the heat dissipation capability in advanced components made using such joints.
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TL;DR: In this article, the effects of laser-assisted micro-milling on the machined surface finish, edge burrs, tool wear and workpiece microstructure were evaluated experimentally.
Abstract: This paper is focused on numerical modeling and experimental evaluation of laser-assisted micro-milling (LAMM). An experimental setup consisting of a 25 W CO2 laser, three-axis CNC linear stages and a high-speed spindle was used to implement the LAMM process. Micro-endmills between 100 and 300 µm in diameter were used to perform side-cutting operations with and without laser preheat on four materials: AISI 316, AISI 422, Ti-6Al-4V and Inconel 718. A three-dimensional transient finite-volume-based thermal model was used to analytically predict appropriate process parameters on the basis of material-removal temperatures. The effects of LAMM on the machined surface finish, edge burrs, tool wear and workpiece microstructure were evaluated experimentally.
01 Jan 2010
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TL;DR: In this paper, the effect of high temperature hold times on the fatigue crack growth behavior of Inconel 718 has been observed in three different temperatures, namely 450 °C, 550 °C and 650 °C.
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TL;DR: In this paper, the authors showed that the changes in corrosion behavior and microstructure of the oxide film were most likely due to the hydrogen enhanced preferential dissolution of Cr cations in the water.
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TL;DR: In this paper, the effects of cutting parameters on thermal characteristics, including practical cutting regions, the formation of the kerfwidth and the heat transfer phenomenon, in the cutting of Inconel 718 super-alloy sheets using a CW Nd:YAG laser were investigated.
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TL;DR: In this article, the effects of circular magnetic arc deflection (arc stirring) on grain structure of gas tungsten arc weld overlays made on Inconel 690 substrates with 52M filler wire were investigated.
Abstract: The formation of a columnar grain structure in high chromium nickel based alloy welds can be associated with cracking and poor resolution for ultrasonic non-destructive examination. The objective of this research was to characterise the effects of circular magnetic arc deflection (arc stirring) on grain structure of gas tungsten arc weld overlays made on Inconel 690 substrates with 52M filler wire. Welds and weld overlays were made at various arc stirring frequencies, and microstructures were analysed using optical and electron backscattered diffraction microscopy. Significant refinement of grain size occurred at a stirring frequency of 7 Hz. Ultrasonic non-destructive examination confirmed 100% improvement in signal/noise ratio in weld overlays made with magnetic stirring.
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TL;DR: In this paper, the effects of circular magnetic arc deflection (arc stirring) on grain structure refinement of gas tungsten arc weld beads made in Inconel 690 substrates were investigated.
Abstract: The objectives of this work were to characterise and understand the effects of circular magnetic arc deflection (arc stirring) on grain structure refinement of gas tungsten arc weld beads made in Inconel 690 substrates. Welds were made at various arc stirring frequencies (1·5–50 Hz), and microstructures were analysed using optical and electron backscattered diffraction microscopy. Optimum refinement of grain size occurred at a stirring frequency of ∼7 Hz. Analysis of computational fluid flow, heat transfer and solidification model results suggested that grain detachment was the primary mechanism for grain refinement.
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TL;DR: In this article, nano-crystalline TiAlCrSiYN plasma vapor deposited (PVD) coatings were developed for oxidation and wear protection at elevated temperatures, and compositional tuning of the coatings was performed to enhance oxidation protection.
Abstract: Nano-crystalline TiAlCrSiYN plasma vapor deposited (PVD) coatings were developed for oxidation and wear protection at elevated temperatures. Compositional tuning of the coatings was performed to enhance oxidation protection at elevated temperatures. The oxidation kinetics of the coatings has been studied over 180 h at 900 °C in air. Post-oxidation microstructural examinations of specimens were performed using transmission electron microscopy (TEM), secondary electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and glow discharge optical emission spectroscopy (GDOES). Micro mechanical characteristics of the coating were studied using a micro materials nanotest system. Wear resistance of the coatings were studied during turning of Inconel 718. Experimental results clearly indicate that the aluminum-rich PVD TiAlCrSiYN coatings with 60 at.% of Al can improve oxidation resistance of titanium aluminide alloy at the temperature 900 °C as well as wear resistance during machining of Inconel 718. It was shown that during oxidation, continuous protective alumina-based oxide films form on the surface. These oxides are predominantly (Al,Cr)2O3-based films. Self-healing behavior of the TiAlCrSiYN coatings was observed in its ultra-fine nano-crystalline structure.
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TL;DR: In this paper, an investigation has been performed to characterize dissimilar metal welds between type 310 austenitic stainless steel (SS) and Inconel 657 superalloy.
Abstract: This investigation has been performed to characterize dissimilar metal welds between type 310 austenitic stainless steel (SS) and Inconel 657 superalloy. The welds were produced using four types of filler materials: Inconel 82, Inconel A, Inconel 617, and type 310 SS. The weldments were characterized in detail using optical metallography and scanning electron microscopy. It can be concluded that Inconel A weld metal does not promote severe hot cracking. Continuous NbC precipitates in the Inconel 82 weld metal can sensitize the weld metal to solidification cracking. The presence of high amounts of Mo in Inconel 617 weld metal led to the formation of brittle phases. In addition, continuous precipitates were observed in the 310 SS weld metal, which can lead to poor resistance of the weld metal to hot cracking. In the aged condition, Inconel 82 and Inconel A exhibited good thermal stability, whereas Inconel 617 and type 310 SS exhibited poor thermal stability. Also, after subjecting the heat-affected zone and interface between Inconel weld metal and base metals to aging treatment, unmixed zone of Inconel 657 base metal side has disappeared. Elimination of this region can be attributed to high-temperature interdiffusion of alloying elements. Finally, it is found that Inconel A and Inconel 82 weld metals are the best choices for the dissimilar welds performed here, respectively.
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TL;DR: In this paper, a predictive tool has been implemented to determine the suitable conditions for deposition welding of inconel 738LC which is particularly susceptible to hot cracking and showed the importance of the heating temperature prior to welding.
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TL;DR: In this paper, a thermal stressing of Jet-A was conducted in a flow reactor on iron and nickel-based metal surfaces at a fuel flow rate of 1 mL/min for 5 h at a wall temperature of 350 °C and 3.5 MPa (500 psig) so that both liquid-phase autoxidation and thermal decomposition of autooxidation products contribute to the formation of carbonaceous deposits.
Abstract: Thermal stressing of Jet-A was conducted in a flow reactor on iron- and nickel-based metal surfaces at a fuel flow rate of 1 mL/min for 5 h at a wall temperature of 350 °C and 3.5 MPa (500 psig) so that both liquid-phase autoxidation and thermal decomposition of autoxidation products contribute to the formation of carbonaceous deposits. The deposits produced were characterized by field emission scanning electron microscopy (FESEM) and temperature programmed oxidation (TPO). The effect of metal surface on deposit formation increases in the following order: AISI316 < AISI 321 ≈ AISI 304 < Inconel 600 < AISI 347 < Inconel 718 < FecrAlloy < Inconel-750X. The variation in the activity of the metal substrates is attributed to their reaction with reactive sulfur compounds in the fuel and interaction of oxygenated intermediates formed by autoxidation during thermal stressing.
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TL;DR: In this article, the morphology of the weld zone (WZ) was studied in a joint formed from dissimilar materials, composed of austenitic AISI 304 stainless steel and Inconel 600 nickel alloy, welded with an Nd:YAG-pulsed laser.
Abstract: In this work, the morphology of solidification of the weld zone (WZ) was studied in a joint formed from dissimilar materials, composed of austenitic AISI 304 stainless steel and Inconel 600 nickel alloy, welded with an Nd:YAG-pulsed laser. The laser beam and optical system parameters were selected with a view to obtain a weld with total penetration and good surface finish. The microstructural characterization was carried out using an optical microscope, in which a WZ was seen with total penetration, keyhole-type, presence of small pores and absence of cracks. The welded joints were also characterized by means of an electron scan microscope. Measurements taken by X-ray spectrometry for dispersion of the energy in the WZ indicated a slightly heterogeneous distribution of nickel and iron. It was seen that the start of solidification in the WZ occurred by means of epitaxial growth. The morphology of WZ solidification was basically denditric and cellular, being influenced by the temperature gradient, solidific...