• Title/Summary/Keyword: NIMONIC 80A

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Mechanical Properties of Forged Nimonic 80A Superalloy Fabricated by Vacuum Spray Casting (진공분무주조법에 의해 제조한 Nimonic 80A 초내열합금 단조재의 기계적 특성)

  • Lee, Yun-Soo;Hyun, Soong-Keun;Jung, Dae-Hyun;Byun, Joong-Sig
    • Korean Journal of Metals and Materials
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    • v.50 no.4
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    • pp.263-270
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    • 2012
  • This study investigates the effect of heat treatment on the mechanical properties of a forged Ni-based superalloy called Nimonic 80A. Nimonic 80A ingot samples were fabricated by vacuum spray casting to achieve a fine and homogenized microstructure. The ingot samples were subsequently hot-forged with the diameter of 220 mm at 1373 K. From the center to the surface of the forged Nimonic 80A, its average grain size decreased and its micro-Vickers hardness increased slightly. Solution treatment was carried out at 1353 K with 8 hours of air cooling followed by aging treatment, which was carried out in the range of 873-1073 K with various times from 0.5 to 256 hours. To set the optimum aging conditions, micro-Vickers hardness tests were performed. The maximum hardness value of 388.0 Hv was obtained by aging at 973 K for 32 hours. Also, tensile tests were performed for optimum aging conditions at room temperature and 873 K. The results can be used effectively to perform reasonable heat treatment of Nimonic 80A superalloy.

The Effects of the Incident Nitrogen Ion Dose on the Plasma Immersion Ion Implantation of Nimonic 80A (Nimonic 80A의 PIII에 미치는 질소이온주입량의 영향)

  • You, Y.Z.;Chun, H.G.;Kim, D.I.;Cha, B.C.;Koo, K.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.18 no.6
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    • pp.369-374
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    • 2005
  • Nitrogen ion implantation in Nimonic 80A using plasma immersion ion implantation (PIII) was investigated at a pulse voltage of -60 kV and ion dose of $3{\times}10^{17}{\sharp}/cm^2$, $6{\times}10^{17}{\sharp}/cm^2$, $12{\times}10^{17}{\sharp}/cm^2$. PIII is an effective technology to improve the surface hardness and wear resistance of materials. And also this technology is not limited by the shape and size of materials. PIII would be a promising technique in the future. Surface hardness and wear resistance of the $N^+$ ion implanted Nimonic 80A were increased with the increase in the incident ion dose. The surface hardness of the untreated Nimonic 80A is 420 Hv, the hardness of implanted Nimonic 80A is 1050 Hv at $N^+$ ion dose of $12{\times}10^{17}{\sharp}/cm^2$. The wear loss of the untreated is 82.5 mg, the wear loss of the implanted is 0.004g at $N^+$ ion dose of $12{\times}10^{17}{\sharp}/cm^2$. The $Cr_2N$ is detected on the surface of the implanted Nimonic 80A by XRD analysis.

High Temperature Deformation Behavior of a NIMONIC 80A Ni-based Superalloy (Ni계 초내열합금 NIMONIC 80A의 고온변형거동)

  • Ha, M.C.;Hwang, S.W.;Kim, C.S.;Kim, C.Y.;Park, K.T.
    • Transactions of Materials Processing
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    • v.22 no.5
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    • pp.258-263
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    • 2013
  • The deformation behavior of NIMONIC 80A was studied in the high temperature range of $900{\sim}1200^{\circ}C$ and for strain rates varying between 0.02 and $20s^{-1}$ via the hot compression test. Processing maps for hot working were constructed on the basis of the power dissipation efficiency using a dynamic material model. The results showed that the strength during hot compression increased with increasing strain rate and decreasing temperature. At low strains, the processing map of NIMONIC 80A did not reveal any instability domain regardless of the strain rate and temperature. However, at high strains, the processing map exhibited an instability domain at a low strain rate of $0.2s^{-1}$ and within a temperature range of $900{\sim}960^{\circ}C$. In the instability domain, the deformed microstructure exhibited shear bands and carbide precipitation while, in the safe domain, full recrystallization occurred.

Wear Behavior of Plasma Transferred Arc Deposited Layers for Ni - and Co - base Alloy (Ni계 및 Co계 합금 PTA 오버레이용접층의 마모거동에 관한 연구)

  • 윤병현;이창희;김형준
    • Journal of Welding and Joining
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    • v.19 no.5
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    • pp.540-547
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    • 2001
  • This study has evaluated the wear behavior of PTA (Plasma Transferred Arc) Inconel 625 and Stellite 6 overlays on Nimonic 80A substrate. Nimonic 80A alloy was also included for comparison. In order to evaluate the wear performance, three-body abrasive wear test and pin-on-disk dry sliding wear test were performed. Microstructural development during the solidification of deposits is also discussed. Wear test results show that the wear rate of Stellite 6 deposit is lower than that of Inconel 625 deposit and Nimonic 80A. The sliding wear resistance of overlay deposits follows a similar trend to the abrasive wear resistance, but for Nimonic 80A. The main wear mechanisms were abrasive wear for Inconel 625 deposit, adhesive wear and delamination for Stellite 6 deposit in pin-on-disk dry sliding wear test and ploughing in three-body abrasive wear test. Cross sectional examinations of the worn surface of pin specimens after pin-on-disk dry sliding wear test implies that the plastic deformation near worn surface has occurred during the wear testing.

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Microstructure Evolution of Superalloy Nimonic 80A (초내열합금 Nimonic 80A의 미세조직 변화에 관한 연구)

  • Jeong H. S.;Cho J. R.;Park H. C.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.174-177
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    • 2004
  • The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand the microstructure variation evolution. The microstructure change evolution occurs by recovery, recrystallization and grain growth phenomena. The dynamic recrystallization evolution has been studied in the temperature range $950-1250^{\circ}C$ and strain rate range $0.05-5s^{-1}$ using hot compression tests. The metadynamic recrystallization and grain growth evolution has been studied in the temperature range $950-1250^{\circ}C$ and strain rate range 0.05, $5s^{-1}$, holding time range 5, 10, 100, 600 sec using hot compression tests. Modeling equations are developed to represent the flow curve, recrystallized grain size, recrystallized fraction and grain growth phenomena by various tests. Parameters of modeling equation are expressed as a function of the Zener-Hollomon parameter. The modeling equation for grain growth is expressed as a function of initial grain size and holding time.

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Properties of Nimonic 80A Alloy with Change in the Chemical Compositions and Heat Treatment Paths (화학조성 및 열처리경로 변화에 따른 Nimonic 80A 합금의 특성)

  • Choi Byong-Kang;Jeong Hae-Yong;Bae Cha-Hurn
    • Korean Journal of Materials Research
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    • v.15 no.12
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    • pp.773-779
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    • 2005
  • Properties of Ni-base superalloys of Nimonic 80A alloy system were investigated by the observation of microstructures, precipitates ana hardness as a function of the chemical compositions ana the paths of heat treatment. The higher hardness values showed, the higher Ti/Al ratio among high compositions of Cr and Co element. The lower (Ti+Al) and Fe contents decreased in the same Ti/Al ratio, the higher hardness values showed. This results are considered that coherent deformation was increased with increasing Ti/Al ratio. Hardness showed higher value when Cr contents was $18 wt\%$ less than $21wt\%Cr$. In $3.15 wt\%$Co alloy, $\gamma'$ phase was very fine as around 50nm and, its volume fraction and hardness showed the highest value by 2step-aging treatment.

Correcting Stress-Strain Curves of Nimonic 80A Alloy based on Direct Measurement of Barreling and Heat Generation (압축시험에서의 배럴링 및 소성발열 직접 측정에 의한 Nimonic 80A 합금의 응력-변형률 선도 보정)

  • S.H. Kang;H.W. Jung;H. Lee;S.J. Kim;Y.S. Oh;J. Jung;S. Oh;H. Kim
    • Transactions of Materials Processing
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    • v.32 no.4
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    • pp.215-220
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    • 2023
  • In this study, the correction process of stress-strain curves obtained from hot compression test is introduced since the barreling induced by friction and adiabatic heat generation induced by plastic work occur under high strain rate. A shear friction factor was quantitatively estimated by measuring the dimension of barreling and temperature rise due to adiabatic heat generation was directly measured during compression test. Thereafter, the stress-strain curves were re-evaluated by introducing several equations to correct the effects of the friction and temperature rise. It was found that adiabatic factor at strain rate of 10/s is in the range of about 0.5 to 0.75 for Nimonic 80A and decreases as the assigned temperature increases.

The Corrosion Behavior Study by AC Impedance Method for the Aging Heat Treated Nimonic 80A Superalloy (교류임피던스법에 의한 Nimonic 80A 초내열합금 시효열처리재의 부식거동 고찰)

  • 백신영
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.6
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    • pp.761-769
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    • 1999
  • In this paper the effect of aging heat treatment to the Corrosion behavior for the Nimonic 80A superalloy was studied by AC Impedance methods. Tested solution was 3.5% with tempera-ture $25^{\circ}C$ Electro-chemical corrosion test were carried out for the Nimonic 80A super-alloy which solution heat treated at $1080^{\circ}C$ for 8 hours followed by aging heat treated at $650^{\circ}C,\;700^{\circ}C,\;750^{\circ}C\;800^{\circ}C$ and $850^{\circ}C$ with 16hours under vacuum environment. The obtained results were as follows; 1. Base metal and solution-treated materials were exhibited similar corrosion tendency as Ran-dle equivalent cell. The value of passive film resistance was 579 ohms for the base metal and 124,770 ohms for the solutionized metal such a difference was arose by the ${{\gamma}_^'}$ precipitate on the metal surface during heat treatment. 2. The measure value of $R_p$ for heat-treated at $650^{\circ}C,\;700^{\circ}C,\;800^{\circ}C$and $850^{\circ}C$ were 97,943, 93, 111, 26,961, 15,798 and 11,780ohm respectively. Which indicated that the passive film resistance Rp was reduced as aging temperature increased due to the growth of grain size and sensitization at the grain boundary. 3. The similar tendency was exhibited for corrosion behavior of the electro-chemical corrosion polarization method and AC impedance method and confirmed that AC impedance method was useful tool for corrosion research.

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Corrosion Behavior of Ni-Base Superalloys in a Hot Molten Salt (고온 용융염계에서 Ni-Base 초합금의 부식거동)

  • Cho, Soo-Haeng;Kang, Dae-Seong;Hong, Sun-Seok;Hur, Jin-Mok;Lee, Han-Soo
    • Korean Journal of Metals and Materials
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    • v.46 no.9
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    • pp.577-584
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    • 2008
  • The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Inconel 713LC, Inconel MA 754, Nimonic 80A and Nimonic 90 in the molten salt $LiCl-Li_2O$ under an oxidizing atmosphere was investigated at $650^{\circ}C$ for 72~216 hrs. Inconel 713LC alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Inconel 713LC were $Cr_2O_3$, $NiCr_2O_4$ and NiO, and those of Inconel MA 754 were $Cr_2O_3$ and $Li_2Ni_8O_{10}$ while $Cr_2O_3$, $LiFeO_2$, $(Cr,Ti)_2O_3$ and $Li_2Ni_8O_{10}$ were produced from Nimonic 80A. Also, corrosion products of Nimonic 90 were found to be $Cr_2O_3$, $(Cr,Ti)_2O_3$, $LiAlO_2$ and $CoCr_2O_4$. Inconel 713LC showed local corrosion behavior and Inconel MA 754, Nimonic 80A, Nimonic 90 showed uniform corrosion behavior.