Solid Solution Hardening of Ni&lt;SUB&gt;3&lt;/SUB&gt;Al with Ternary Additions

Mishima, Yoshinao; Ochiai, Shouichi; Hamao, Noboru; Yodogawa, Masayoshi; Suzuki, Tomoo

doi:10.2320/matertrans1960.27.648

Cited by 81 publications

(27 citation statements)

References 33 publications

(11 reference statements)

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“…In view of these previous works, the present results should be treated more carefully taking the effect of modulus change by ternary additions. An investigtion is now under way to provide comprehensive understanding on the degree of solid solution hardening not only by Bsubgroup elements but also by transition metal elements by the present authors (30).…”

Section: Solid Solution Hardeningmentioning

confidence: 94%

Mechanical Properties of Ni3Al with Ternary Addition of B-subgroup Elements

et al. 1986

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A systematic evaluation has been made on the magnitude of the positive temperature dependence of strength in Ni3Al as affected by ternary additions of B-subgroup elements. The rate of change in activation energy to provide the mechanical anomaly per one atomic per cent of the solute, dU/dc, is determined for a variety of the ternary additions. It is shown that the larger the valence difference between the parameter change in the compound per one atomic percent of the solute, da/dc, the larger the dU/dC. These are well interpreted in terms of the phase stability concept to determine the relative magnitude of the mechanical anomaly in the Ll2 compounds, in which e/a ratio of the compound and the atomic radius ratio of the components, Re/RA, are the key factors to alter the stability of the phase against other geometrically close packed phases and thereby control the occurrence and the magnitude of the mechanical anomaly. The effect of ternary additions of B-subgroup elements on the rate of solid solution An intermetallic compound Ni3Al is one of the L12 compounds which show an anomalous positive temperature dependence of strength. The compound based on Ni3Al is a major microstructural constituent in commercial nickel base superalloys as precipitates to provide dispersion strengthening, and its volume fraction often reaches 60% or more. In alloy designing the superalloys for an improved high temperature performance, the best utilization of this compound is anticipated, which mechanical properties are known to be strongly affected by ternary alloy substitutions for one of or both of the components.In considering the effect of ternary additions on the mechanical properties of the compound Ni3Al, two factors are important, and they are the solid solution hardening and the magnitude of the positive temperature dependence of strength. Historically a work by Guard and Westbrook(1) was the first attempt on this regard in which the temperature dependence of hardness in Ni3Al as affected by various ternary additions was investigated. Recently the temperature dependence of 0.2% flow stress in Ni3Al with additions of several ternary alloying elements has been investigated by Thornton et a1.(2), Rawlings and StatonBevan(3) and Aoki and Izumi(4). There have been several reports(5)-(8) on the crystallographic orientation dependence of flow stress in single crystalline Ni3Al with small additions of Ti, Nb or W, but in those cases the alloy additions were made in order to suppress the peritectic reaction in the Ni-Al binary

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Section: Solid Solution Hardeningmentioning

confidence: 94%

Mechanical Properties of Ni3Al with Ternary Addition of B-subgroup Elements

et al. 1986

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“…The description of the solid solution strengthening contribution was based on the model proposed by Gypen and Deruyttere, [34] which assumes a superposition of strengthening of individual solutes based on their concentration in the matrix and precipitate phase, both of which were calculated using thermodynamic models in ThermoCalc. The empirical solid solution strengthening coefficients were derived from the work of Mishima et al [35] at 77 K and were further calibrated versus temperature using the trough model proposed by Roth et al [36] An average grain size of 15 lm was utilized in the calculations along with a grain size coefficient of 450 MPa lm À1/2 , as proposed by Parthasarathy et al [33] As the experimental yield strength data available was obtained on material aged using P-SHT1, the average secondary c¢ size obtained through image analysis for this condition (Figures 1(a) and (b)) was used as an input for the models, i.e., the secondary c¢ size was set to 152 nm for both alloys. However, as the elemental partitioning coefficients used in the calculations could not be experimentally obtained, ThermoCalc was used to estimate them and as a result, the volume fraction as predicted by ThermoCalc was also used in the calculations so as not change the underlying alloy composition.…”

Section: Discussionmentioning

confidence: 99%

On the Effect of Nb on the Microstructure and Properties of Next Generation Polycrystalline Powder Metallurgy Ni-Based Superalloys

Christofidou

Hardy

et al. 2018

Metall Mater Trans A

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The effect of Nb on the properties and microstructure of two novel powder metallurgy (P/M) Ni-based superalloys was evaluated, and the results critically compared with the Rolls-Royce alloy RR1000. The Nb-containing alloy was found to exhibit improved tensile and creep properties as well as superior oxidation resistance compared with both RR1000 and the Nb-free variant tested. The beneficial effect of Nb on the tensile and creep properties was due to the microstructures obtained following the post-solution heat treatments, which led to a higher γ′ volume fraction and a finer tertiary γ′ distribution. In addition, an increase in the anti-phase-boundary energy of the γ′ phase is also expected with the addition of Nb, further contributing to the strength of the material. However, these modifications in the γ′ distribution detrimentally affect the dwell fatigue crack-growth behavior of the material, although this behavior can be improved through modified heat treatments. The oxidation resistance of the Nb-containing alloy was also enhanced as Nb is believed to accelerate the formation of a defect-free Cr2O3 scale. Overall, both developmental alloys, with and without the addition of Nb, were found to exhibit superior properties than RR1000.

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“…In Ni 3 Al, solid solution hardening by several transition elements has been studied, and it has been found that the potency of the solid solution strengthening due to Nb atoms is much higher than that due to Ti atoms. 20) However, solid solution hardening behavior by transition metals in Ni 3 V has not been reported so far although Ni 3 V can be strengthened by refinement of variant structures in D0 22 phase. 21) These hardness levels may also be affected by the microstructure in another constituent, i.e., the channel region.…”

Section: The Effect Of Nb and Ti Addition On Hardnessmentioning

confidence: 99%

Effect of Nb and Ti Addition on Microstructure and Hardness of Dual Two-Phase Intermetallic Alloys Based on Ni3Al-Ni3V Pseudo-Binary Alloy System

et al. 2010

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The microstructures and hardness property of dual two-phase intermetallic alloys that are composed of various kind of volume fractions of geometrically closed packed (GCP) Ni 3 Al(L1 2 ) and Ni 3 V(D0 22 ) phases was studied. Higher volume fraction of primary Ni 3 Al precipitates was observed in the Ti and Nb added alloys when keeping Al content the same. Also, the microstructures in the eutectoid (channel) region consisting of Ni 3 Al+Ni 3 V were sensitive to alloying addition. The hardness of dual two-phase intermetallic alloys was basically explained by mixture rule in hardness between primary Ni 3 Al precipitates and eutectoid region. Nb and Ti addition raised hardness of dual two-phase intermetallic alloys by solid solution hardening in the constituent phases. This hardening was more significant in Nb addition than in Ti addition. In addition to hardness owing to the mixture rule, additional hardening arising from interfacial area between primary Ni 3 Al precipitates and eutectoid region was found. With increasing Ni 3 Al/channel (eutectoid) interfacial area, the additional hardening increased. As temperature increases, the additional hardening monotonously decreased for the base and Nb added alloys but little decreased for the Ti added alloys.

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Solid Solution Hardening of Ni<SUB>3</SUB>Al with Ternary Additions

Cited by 81 publications

References 33 publications

Mechanical Properties of Ni<SUB>3</SUB>Al with Ternary Addition of B-subgroup Elements

Mechanical Properties of Ni<SUB>3</SUB>Al with Ternary Addition of B-subgroup Elements

On the Effect of Nb on the Microstructure and Properties of Next Generation Polycrystalline Powder Metallurgy Ni-Based Superalloys

Effect of Nb and Ti Addition on Microstructure and Hardness of Dual Two-Phase Intermetallic Alloys Based on Ni<SUB>3</SUB>Al-Ni<SUB>3</SUB>V Pseudo-Binary Alloy System

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