Evaluation of Inconel 718 Creep Behavior

Superalloys are used primarily in aerospace applications. These applications require a material with high mechanical strength, good resistance to fatigue and creep, good corrosion resistance and ability to operate continuously at elevated temperatures. These alloys were developed for elevated temperature service, where relatively severe mechanical stressing is encountered, and where high surface stability is frequently required. Inconel 718 has being investigated because it is one of the most widely used superalloys. Constant load creep tests were conducted on a standard creep machine at 600 and 700°C and stress levels of 300 MPa. Sets of curves and experimental parameters for the primary, secondary and tertiary regions, as a function of stress and temperature applied were obtained. The ductility, the creep rate and lifetime was evaluated.

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Creep Behavior of the Inconel 718 Superalloy

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.326-328.509 ◽

2012 ◽

Vol 326-328 ◽

pp. 509-514 ◽

Cited By ~ 9

Author(s):

Tarcila Sugahara ◽

Karina Martinolli ◽

Danieli A.P. Reis ◽

Carlos de Moura Neto ◽

Antônio Augusto Couto ◽

...

Keyword(s):

Elevated Temperature ◽

Creep Behavior ◽

Inconel 718 ◽

Base Alloy ◽

High Surface ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Secondary Creep ◽

Creep Tests ◽

Surface Stability

A superalloy is an alloy developed for elevated temperature service, where relatively severe mechanical stressing is encountered, and where high surface stability is frequently required. High temperature deformation of Ni-base superalloys is very important since the blades and discs of aero engine turbine, because need to work at elevated temperature for an expected long period. The nickel-base alloy Inconel 718 has being investigated because it is one of the most widely used superalloys. The objective of this work was to evaluate the creep behavior of the Inconel 718 focusing on the determination of the experimental parameters related to the primary and secondary creep states. Constant load creep tests were conducted with at 650, 675 and 700°C and the range of stress was from 625 to 814 MPa to according to ASTM E139 standard. The relation between primary creep time and steady-state creep rate, obeyed the equation for both atmospherics conditions at 650, 675 and 700°C. The microstructural characterization employing the technique of scanning electron microscopy has been a valuable tool for understanding the mechanisms of creep.

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Mechanical Behavior of Inconel 625 at Elevated Temperatures

10.20944/preprints201812.0359.v1 ◽

2018 ◽

Author(s):

Mauro M. de Oliveira ◽

Antônio A. Couto ◽

Gisele F. C. Almeida ◽

Danieli A. P. Reis ◽

Nelson B. de Lima ◽

...

Keyword(s):

Elevated Temperatures ◽

Aging Effect ◽

Tensile Tests ◽

Constant Load ◽

Anomalous Behavior ◽

Inconel 625 ◽

Dynamic Strain ◽

Intergranular Cracking ◽

Creep Tests ◽

Temperature Range

Abstract: The Inconel 625 is a nickel-based alloy has been widely used in the high-temperature application. The Inconel 625 exhibits unstable plastic flow at elevated temperature characterized by serrated yielding, known as Portevin-Le Chatelier effect. The aim of this work is to evaluate the mechanical properties at high temperatures of the Inconel 625. The tensile tests were performed in the temperature range of room temperature until 1000 °C and strain rate of 2x10^-4 to 2x10^-3 s^-1. The creep tests were performed in the temperature range of 600-700 °C, in the stress range of 500-600 MPa in a constant load mode. The surface fracture was observed by optical and scanning electron microscopy. Serrated stress-strain behavior was observed in the curves obtained at 200 to 700 °C, which was associated with the dynamic strain aging effect. The yield strength and the elongation values show an anomalous behavior as a function of the test temperature. An intergranular cracking was observed 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.

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Effect of silicon on creep properties of titanium 6Al-2Sn-4Zr-2Mo alloy

MATEC Web of Conferences ◽

10.1051/matecconf/202032104021 ◽

2020 ◽

Vol 321 ◽

pp. 04021

Author(s):

M-L Anti ◽

V Collado Ciprés ◽

J Mouzon ◽

P. Åkerfeldt ◽

R Pederson

Keyword(s):

Creep Resistance ◽

Elevated Temperatures ◽

Beta Phase ◽

Optical Microscope ◽

Creep Tests ◽

Creep Properties ◽

Aerospace Applications ◽

Different Temperatures ◽

Light Optical Microscope ◽

Scanning Electron

The alloy Ti-6Al-2Sn-4Zr-2Mo is a titanium alloy for elevated temperatures often used in aerospace applications. Minor additions of silicon have proven to improve the creep resistance of this alloy. In this work, three different amounts of silicon (0.015, 0.07 and 0.162 wt% Si) were added to cast Ti-6242 and creep tests were performed at different temperatures and loads. Creep resistance increased significantly with silicon addition by means of silicide precipitation hindering dislocations movement. Silicon rich nanoparticles in the microstructure were detected and their effect on creep resistance was investigated. The instruments used in this study were light optical microscope (LOM) and scanning electron microscopy (SEM). Precipitates larger than 150 nm were found to be located heterogeneously in the microstructure, whereas smaller precipitates, ranging from 20-100 nm were homogeneously spread in the material. All silicides were predominantly situated next to the beta-phase in the alloy, either at the prior-beta grain boundaries or the beta-phase in between the alpha-colonies.

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Creep Properties of a High Niobium Containing γ-TiAl Alloy Sheet Material

MRS Proceedings ◽

10.1557/proc-753-bb3.3 ◽

2002 ◽

Vol 753 ◽

Cited By ~ 3

Author(s):

A. Bartels ◽

S. Bystrzanowski ◽

R. Gerling ◽

F.-P. Schimansky ◽

H. Kestler ◽

...

Keyword(s):

Activation Energy ◽

Stress Exponent ◽

Elevated Temperatures ◽

Sheet Material ◽

Rolling Direction ◽

Constant Load ◽

Alloy Sheet ◽

Tensile Creep ◽

Creep Tests ◽

Fine Grained

ABSTRACTIn this study Ti-46Al-9Nb (at%) sheet material processed by a powder metallurgical route was examined. Subsequent to hot rolling the sheets were subjected to a stress-relief treatment at 1273K for 3 hours. During this heat treatment a fine-grained near gamma microstructure has been formed. 100 hours tensile creep tests under constant load were carried out at 700°C in rolling direction, transverse direction as well as 45° direction. Using the method of load changes a stress exponent of 4.1 was determined. Furthermore, the apparent activation energy was determined in the temperature range of 715 – 775°C. Both stress exponent and activation energy suggest that diffusion assisted dislocation climb is the dominant creep mode. A comparison of these results with those of so-called conventional or so-called “2nd generation” γ-TiAl based alloys, e.g. Ti-46.5Al-4(Cr,Nb,Ta,B) (at%) and Ti-47Al-4(Cr,Mn,Nb,Si,B) (at%), indicates a significantly better creep resistance and a higher activation energy of the high Nb containing alloy. Additionally, internal friction experiments were conducted in order to analyze the deformation behavior under very small strains at elevated temperatures.

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Mechanical Behavior of Inconel 625 at Elevated Temperatures

Metals ◽

10.3390/met9030301 ◽

2019 ◽

Vol 9 (3) ◽

pp. 301 ◽

Cited By ~ 11

Author(s):

Mauro de Oliveira ◽

Antônio Couto ◽

Gisele Almeida ◽

Danieli Reis ◽

Nelson de Lima ◽

...

Keyword(s):

Elevated Temperatures ◽

Aging Effect ◽

Tensile Tests ◽

Constant Load ◽

Anomalous Behavior ◽

Inconel 625 ◽

Dynamic Strain ◽

Intergranular Cracking ◽

Creep Tests ◽

Electron Microscopes

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.

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Creep Behavior of the Titanium Alloy with Zirconia Plasma Sprayed Coating

Materials Science Forum ◽

10.4028/www.scientific.net/msf.660-661.221 ◽

2010 ◽

Vol 660-661 ◽

pp. 221-224

Author(s):

Danieli A.P. Reis ◽

Carlos de Moura Neto ◽

M.J.R. Barboza ◽

H.R. Silva ◽

Cosme Roberto Moreira Silva ◽

...

Keyword(s):

Constant Load ◽

Coated Sample ◽

Stabilized Zirconia ◽

Creep Tests ◽

Uncoated Sample ◽

Second Stage ◽

Experimental Parameters ◽

Sprayed Coating ◽

Plasma Sprayed

The proposal of this research has been the study of the plasma spayed coating on creep of the Ti-6Al-4V, focusing on the determination of the experimental parameters related to the first and second creep stages. Yttria (8 wt %) stabilized zirconia (YSZ) (Metco 204B-NS) with CoNiCrAlY ( AMDRY 995C) has been plasma sprayed coated on Ti-6Al-4V substrate. Creep tests with constant load had been done on Ti-6Al-4V coated samples, the stress level was from 250 to 319 MPa at 600 °C. Highest values of tp and the decrease of the second stage rate had shown a better creep resistance on coated sample. Results indicate that the coated sample was greater than uncoated sample, thus the plasma sprayed coating prevent the sample oxidation efficiently.

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Impression creep of lead

Journal of Materials Research ◽

10.1557/jmr.1994.0903 ◽

1994 ◽

Vol 9 (4) ◽

pp. 903-908 ◽

Cited By ~ 34

Author(s):

Donyau Chiang ◽

J. C. M. Li

Keyword(s):

Creep Test ◽

Elevated Temperatures ◽

Constant Load ◽

Constant Stress ◽

Tensile Creep ◽

Indentation Creep ◽

Impression Creep ◽

Creep Tests ◽

Creep Measurements ◽

Cylindrical Punch

The impression creep behavior of lead was investigated using a 100 μm diameter punch at ambient and elevated temperatures (433 K-563 K) under punching stresses of 6–70 MPa. The results were compared with the data obtained from conventional creep tests reported in the literature. Unlike the indentation creep test, the impression creep test showed a steady-state velocity after a short transient period when the flat-end cylindrical punch was pushed against the lead surface by a constant load. Both the temperature and stress dependences were comparable to those of the constant stress tensile creep tests under similar conditions. A master curve for lead was established by collecting data from the impression creep tests and the constant stress tensile creep tests. The indentation creep measurements for lead were included also. However, the indentation data depend on the load applied.

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Influence of Abrasive Water Jet parameters on the surface integrity of Inconel 718

10.21203/rs.3.rs-197952/v1 ◽

2021 ◽

Author(s):

Lorena Cano Salinas ◽

Kamel Moussaoui ◽

Akshay Hejjaji ◽

Mehdi Salem ◽

Anis Hor ◽

...

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Residual Stresses ◽

Inconel 718 ◽

Surface Characterization ◽

Elevated Temperatures ◽

High Surface ◽

Water Jet ◽

Depth Of Cut ◽

Abrasive Water Jet

Abstract Inconel 718 (IN718) is a precipitation hardened nickel-base super-alloy exhibiting high strength and good corrosion resistance at elevated temperatures and on the downside it is characterized by poor machinability. Abrasive Water Jet (AWJ) process, offers a potential method to machining difficult-to-cut materials such as IN718. The present work investigates the influence of Abrasive Water Jet parameters on surface roughness, topography, depth of cut and residual stress when milling IN718. Surface characterization was conducted through 3D optical microscopy and SEM techniques. Residual stresses were measured in longitudinal and transverse directions with respect to the machining path using X-ray diffraction (XRD) technique. The obtained results showed that milled surfaces have a homogeneous texture with embedded abrasive particles and high surface roughness. AWJ process introduced high compressive residual stresses with similar order of level in both directions (X and Y). In addition, it was observed that jet pressure is the most influencing parameter on roughness and depth of cut, whilst traverse speed and step-over distance had a significant effect on the residual stress. Based on the experimental analysis, an empirical model to predict the depth of cut was proposed. The validation of the proposed model, has shown around 5% error in the predicted and actual pocket depth.

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SANICRO 71

Alloy Digest ◽

10.31399/asm.ad.ni0108 ◽

1965 ◽

Vol 14 (12) ◽

Keyword(s):

Nuclear Power ◽

Elevated Temperatures ◽

Power Reactor ◽

Base Alloy ◽

Heat Treating ◽

Good Resistance ◽

Nuclear Power Reactor ◽

Temperature Performance ◽

Resistance To Stress ◽

Nickel Base

Abstract Sanicro 71 is a nickel-base alloy having good resistance to stress-corrosion, oxidation and creep at elevated temperatures. It is recommended for nuclear power reactor heat exchanger tubes, aircraft turbojet engines and for equipment in the textile, plastic, and chemical industries. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-108. Producer or source: Sandvik.

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BRUSH ALLOY 3

Alloy Digest ◽

10.31399/asm.ad.cu0454 ◽

1983 ◽

Vol 32 (3) ◽

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Corrosion Resistance ◽

Physical Properties ◽

Copper Alloy ◽

Elevated Temperatures ◽

Physical And Mechanical Properties ◽

Heat Treating ◽

Good Resistance ◽

Good Corrosion Resistance

Abstract BRUSH Alloy 3 offers the highest electrical and thermal conductivity of any beryllium-copper alloy. It possesses an excellent combination of moderate strength, good corrosion resistance and good resistance to moderately elevated temperatures. Because of its unique physical and mechanical properties, Brush Alloy 3 finds widespread use in welding applications (RWMA Class 3), current-carrying springs, switch and instrument parts and similar components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-454. Producer or source: Brush Wellman Inc..

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