The effect of nonstoichiometry on the positive temperature dependence of strength of Ni3AI and Ni3Ga

Noguchi, Osami; Oya, Yoshihiro; Suzuki, Tomoo

doi:10.1007/bf02643570

Cited by 160 publications

(34 citation statements)

References 39 publications

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“…Optical microscopy and X-ray analysis were made for the constitution of the phase Fig.1. The Ni-Ga-Zn phase diagram reported by Bhan and Schubertt (7) is helpful in constructing the diagram, because in many respects the behavior in Ni3Al is analogous to that in Ni3Ga (8). The site preference of Zn being for Al-site in Ni3Al can be confirmed by the direction of solubility lobe in the ternary region.…”

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confidence: 86%

The Effect of Zinc Addition on the Mechanical Properties of Ni3Al

et al. 1985

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The Effect of Zinc Addition on the Mechanical Properties of Ni3Al

et al. 1985

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“…One of the present author and his co-workers have pointed out that the change in activation energy for the thermally activated process to provide the mechanical anomaly in the compound is discontinuous just at stoichiometry (9) and that all these alloying elements substitute Al sites in the compound (10). Therefore, the ternary additions are made to keep nickel content constant in its offstoichiometry being deviated slightly to the Ni rich side as 75.1-75.2 at%Ni.…”

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confidence: 93%

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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“…Most experiments done by different researchers have involved prior heat treatment at 850 °C or higher for long periods of the order of 1 or 2 days [3]. Some discrepancies, however, have been noticed in the lattice constants of alloys in the Ni3AI homogeneity region which have not been satisfactorily explained or accounted for [4]. Widely different values of the order parameter have also been © Springer-Verlag 1990 reported for these alloys.…”

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confidence: 99%